Research Article Received: 23 January 2014
Revised: 7 April 2014
Accepted article published: 8 December 2014
Published online in Wiley Online Library:
(wileyonlinelibrary.com) DOI 10.1002/jsfa.7040
Physicochemical properties of caper species seed oils collected from two different harvest years Erman Dumana and Mehmet Musa Özcanb* Abstract BACKGROUND: In this study the physicochemical properties, fatty acid composition and sterol and tocopheol contents of caper species seed oils were determined. RESULTS: Brightness (L* ) values of oils obtained from caper seeds ranged between 36.76 and 53.48. Viscosity values of oils of Capparis spinosa species were between 41.1 and 48.6 mPa. While oleic acid levels were high in C. spinosa species oils, linoleic acid levels were high in Capparis ovata species oils. Sterol contents of crude oils were between 3140 and 3272 mg kg−1 (mean 3220 mg kg−1 ) for C. spinosa species and between 3275 and 3312 mg kg−1 (mean 3298 mg kg−1 ) for C. ovata species. 𝜶-Tocopherol contents of C. spinosa and C. ovata oils averaged 3.87 and 2.63 mg per 100 g respectively. Radical-scavenging activities of crude oils averaged 29.78% (C. spinosa species) and 26.09% (C. ovata species). Total phenolic concentrations in crude oils averaged 0.642 mg g−1 for C. ovata species (P < 0.01). CONCLUSION: Caper seeds are a natural source of vegetable oils that are beneficial in terms of health, oil stability and resistance to oxidation. © 2014 Society of Chemical Industry Keywords: caper seed; varieties; harvest year; oil; fatty acid composition; sterol; 𝛼-tocopherol
INTRODUCTION Caper is a plant with medicinal and aromatic properties. It is a long-lasting shrubby plant belonging to the Capparaceae family, occurs in numerous types (>350) and grows naturally on all continents in many different regions of the world.1,2 It is a tropical/subtropical plant.1,3 Caper, which is called bubu, gebre, gabar, gevil, kapari, keper, kebere, tur¸suotu and ¸sebellah in different parts of Turkey, is an economically valuable plant. In various regions of the world, different organs of caper species have been used in a variety of ways since ancient times. Young shoots, flower buds and fruits are used in human nutrition. Caper has an important role in the food industry; for instance, its flower buds are stored in brine and have become an expensive product during recent years2,4 Caper is a perennial shrub of the Mediterranean Basin.5 Its oils contain high levels of tocopherols, which contribute to oil stability and oxidation resistance.6 Reactive oxygen species such as superoxide and hydroxyl radicals occur in the respiratory chain in the human body. Hydroxyl radicals are the most reactive and are responsible for free radical damage in the body. Living organisms do not have a specific molecule or enzyme to scavenge hydroxyl radicals. However, hydroxyl radicals can be scavenged by dietary antioxidants. Therefore measurement of the hydroxyl radical-scavenging activity of antioxidants is important.7 Phenolic compounds are secondary metabolities found widely in plants. Phenolic compounds prevent oxidation through their antioxidant properties, stop the reactions caused by free radicals and hinder the development of many diseases.8 Sterols are an important J Sci Food Agric (2015)
class of organic molecules. The sterols found in vegetable oils are important for nutrition and health. Sitosterols play a role in decreasing the serum cholesterol of patients with breast cancer or hypercholesterolaemia.9 – 11 Also, it is advised that foods containing sterols should be consumed to decrease the risk of cardiovascular disease.12 Research on biologically active materials is increasing for production of neutraceutics and functional foods.13 Caper seeds are good source of phytosterols in terms of nutritional, medicinal and economic aspects. The aim of this study was to compare the physicochemical properties, fatty acid composition and sterol and tocopherol contents of caper species seed oils collected from different locations in Turkey.
MATERIALS AND METHODS Materials This research was performed with six different sample groups (Capparis spinosa var. spinosa, C. spinosa var. aegyptia, C. spinosa
∗
Correspondence to: Mehmet Musa Özcan, Department of Food Engineering, Faculty of Agriculture, University of Selcuk, 42031 Konya, Turkey. E-mail: [email protected]
a Department of Food Engineering, Faculty of Engineering, University of Afyon Kocatepe University, Afyonkarahisar, Turkey b Department of Food Engineering, Faculty of Agriculture, University of Selcuk, 42031 Konya, Turkey
www.soci.org
© 2014 Society of Chemical Industry
www.soci.org var. inermis, C. spinosa var. herbaceae, Capparis ovata var. canescens ˘ and C. ovata var. palaestina) at six different locations (Mugla-Milas, Antalya-Kepez, Antalya-Serik, Mardin-Midyat, Ankara-Beypazar𝚤 and Mardin-Savur) harvested in two different years (2009 and 2010) and all analyses were conducted in triplicate. Thus each parameter was analysed according to a factorial design in the form of 6 × 6 × 2 × 3 = 216. Physicochemical methods Specific gravity, viscosity, melting point, peroxide value, free fatty acidity, iodine value, saponification value, waxy substance value and unsaponifiable matter value were analysed according to AOCS methods.14 Colour determination Colour measurement (L* , a* and b* values) of caper oil samples was performed using a D65 illuminated chromameter (CR-400, Konica Minolta, Osaka, Japan) with 8 mm clarification range in diffuse 10 mode with 2∘ observer. L* (brightness), a* (red/green) and b* (yellow/blue) colour coordinates were determined according to the CIEL* a* b* system. Measurements were made by performing three different readings for each caper oil sample.15 – 17 Total phenolics Total phenolic contents were determined according to Singleton and Rossi18 using the Folin–Ciocalteu calorimetric method. Free radical-scavenging effect To determine the antioxidant activity of caper oil samples, the method proposed by Lee et al.19 was used Fatty acid composition The fatty acid composition of seed oils was determined by the AOCS method.14 Fatty acid methyl esters were prepared by treating the oils with KOH and n-heptane and then analysed by gas chromatography (GC).20,21 An RTX-2330 column (Schımadzu, Tokyo, Japan) (60 m length × 0.25 mm diameter, 0.2 mm film thickness) was used. Column, injector and detector temperatures were 180, 200 and 200 ∘ C respectively. Carrier gas (N2 ), flammable gas and dry air flow rates were 30, 28 and 220 mL min−1 respectively. The amount of sample injected was 1 μL. 𝜶-Tocopherol analysis A high-performance liquid chromatography (HPLC) analysis method developed by Balz et al.22 was used. The mobile phase comprised 970 mL L−1 hexane and 30 mL L−1 1,4-dioxan at a flow rate of 1 mL min−1 . Maxsil 5 (250 mm × 400 mm, 5 μm), PINO OOG0053.DO Phenomenex and Chromosorb 5160 (250mm × 400mm, 5 μm) columns were used. Excitation and emission wavelengths of 293 and 326 nm respectively were employed in the fluorescence detector. Sterol analysis For sterol analysis of caper oil samples, first Zn KOH and 1000 PPM s. A. Choleston 3.𝛽.01 as internal standard was prepared. Then 0.5 g of caper oil sample was taken and 5 mL of KOH and 1 mL of internal standard were added to it. This solution was left for 1 h in a water bath at 80 ∘ C, with mixing every 15 min. Thereafter, 5 mL of water was added and the solution was cooled
wileyonlinelibrary.com/jsfa
D Erman, MM Özcan to room temperature and mixed with 5 mL of hexane. After phase separation, the upper phase was transferred into a separate vessel and N2 gas was used to blow away the hexane. Then 5 mL of water was added and the mixture was vortexed. In this process, water remained in the lower phase; the process was performed with 5 mL of hexane three times. Then hexane was blown away until the volume reached 10 mL, and the sample was transferred into a 10 mL volumetric flask. To remove any remaining water in the sample, a little sodium sulfate was added. To prepare the chelating solution, 4 units of bis(trimethylsilyl)trifluoroacetamide and 1 unit of chlorotrimethylsilane were mixed. A 500 μL aliquot was taken from the sample in the 10 mL volumetric flask and mixed with 250 mL of chelating solution and 250 mL of pyridine. This solution was left for 15 min in a drying oven at 60 ∘ C and then subjected to GC for sterol analysis.23 An Agilent Santa Clara, CA, USA SE-54 column (30 m length × 0.32 mm i.d., 0.25 μm film thickness) and a Perkin Elmer Boston, MA, USA GC autosystem were used. All gas (He, He-2 and air) flow rates were 45 mL min−1 . The column temperature was increased from 0 to 60 ∘ C (2 min) and then from 60 to 220 ∘ C (18 min) and finally held at 220 ∘ C (35 min). Statistical analysis A completely randomised experimental design was used (6 species × 6 locations × 2 years × 3 repetitions). Obtained data were statistically evaluated using SPSS 10.0 (SPSS Inc., Chicago, IL, USA), with significant differences between groups being determined by variance analysis and Duncan’s multiple comparison test.24
RESULTS AND DISCUSSION Physical properties Brightness (L* ) values of oils ranged between 36.76 (C. ovata var. palaestina from Mardin-Savur) and 53.48 (C. ovata var. canescens from Ankara-Beypazar𝚤) (Table 1). Average L* values of C. spinosa and C. ovata seed oils were 39.66 and 43.13 respectively. The brightness value of caper seed oil can vary according to species/variety, location, harvest year, soil and climatic conditions.25 The effect of ‘sample group and harvest year’ interaction with variety and location on the redness (a* ) value of crude oils was statistically significant (P < 0.01) (Table 1). The average a* value of C. ovata seed oils (15.04) was higher than that of C. spinosa seed oils (12.29). Seed oils of C. ovata var. canescens from Ankara-Beypazar𝚤 and C. spinosa var. aegyptia from Antalya-Kepez had the highest (20.55) and lowest (10.53) a* values respectively. The redness value of caper seed oil can vary according to species/variety, location and harvest year. Seed oils of C. ovata var. canescens from Ankara-Beypazar𝚤 and C. spinosa var. aegyptia from Antalya-Kepez had the highest (24.20) and lowest (0.17) yellowness (b* ) values respectively (Table 1). In addition, blueness was observed in seed oils collected from Mardin-Savur in 2009 (b* = −0.82) and 2010 (b* = −0.79). This result shows that blue colour can be present to some degree in caper seed oil as well as in other oil-bearing seed oils. The effect of ‘sample group and harvest year’ interaction with variety and location on the specific gravity of crude oils was statistically non-significant (P > 0.01) (Table 1). Specific gravitys varied between 0.929 and 0.934 g L−1 . Average specific gravitys of C. spinosa and C. ovata seed oils were 0.931 and 0.929 g L−1 respectively. Özcan and Akgül26 reported specific gravitys of 1.1045 and
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
www.soci.org
Table 1. Physical properties of caper seed oils
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
Harvest year 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010
L* colour value (brightness) 44.40i ± 0.150 38.87e ± 0.075 38.46cd ± 0.170 37.27b ± 0.181 39.12ef ± 0.017 38.53d ± 0.090 41.43g ± 0.170 39.22f ± 0.095 53.48j ± 0.009 44.09h ± 0.121 38.19c ± 0.150 36.76a ± 0.006
a* colour value (red) 14.04f ± 0.118 12.34c ± 0.032 10.53a ± 0.098 10.75a ± 0.020 13.35e ± 0.106 12.98d ± 0.159 11.60b ± 0.125 12.76d ± 0.025 18.47g ± 0.010 20.55h ± 0.104 10.64a ± 0.104 10.75a ± 0.119
b* colour value (yellow/blue) 8.28h ± 0.221 0.74c ± 0.012 0.29b ± 0.035 0.17b ± 0.070 2.33e ± 0.109 2.02d ± 0.106 2.65f ± 0.032 3.11g ± 0.105 24.20j ± 0.019 12.41i ± 0.221 −0.82a ± 0.055 −0.79a ± 0.012
Specific gravity (g L−1 ) 0.933a ± 0.023 0.932a ± 0.006 0.934a ± 0.007 0.931a ± 0.003 0.930a ± 0.005 0.930a ± 0.005 0.930a ± 0.005 0.932a ± 0.009 0.925a ± 0.002 0.929a ± 0.007 0.933a ± 0.007 0.929a ± 0.003
Refractive index (nD ) 1.465bc ± 0.02 1.466c ± 0.02 1.464abc ± 0.03 1.463a ± 0.04 1.464abc ± 0.03 1.466c ± 0.03 1.465bc ± 0.07 1.464ab ± 0.02 1.465abc ± 0.13 1.466c ± 0.20 1.463ab ± 0.06 1.464abc ± 0.05
Viscosity (mPa) 41.1d ± 0.045 41.5e ± 0.041 48.6j ± 0.037 42.1f ± 0.023 48.4j ± 0.185 43.3h ± 0.025 43.0g ± 0.062 47.1i ± 0.135 35.9b ± 0.045 43.1g ± 0.058 34.7a ± 0.090 36.3c ± 0.070
Melting point (∘ C) −17.0b ± 0.20 −16.8b ± 0.30 −15.2a ± 0.60 −15.7a ± 0.20 −15.4a ± 0.40 −15.7a ± 0.70 −15.7a ± 0.10 −15.5a ± 0.50 −17.3b ± 0.40 −17.2b ± 0.60 −17.1b ± 0.40 −17.2b ± 0.30
Values are mean ± standard deviation.
1.0840 g L−1 for C. spinosa L. var. spinosa and C. ovata Desf. var. canescens (Coss.) Heywood seed oils respectively. Our values are lower than those of Özcan and Akgül,26 probably owing to filtration of sediments and impurities. Specific gravitys of vegetable oils generally range between 0.910 and 0.932, with only castor oil showing higher values (0.950–0.970). Specific gravity is determined to get an idea about the source of oils.27 The specific gravity of caper seed oil shows parallelism with that of other vegetable oils. Average refractive indices (nD ) of crude oils obtained from C. spinosa and C. ovata seeds are given in Table 1. Values ranged between 1.463 and 1.466. Among C. spinosa species, seed oils of ˘ C.spinosa var. herbaceae from Mugla-Milas (2010) and C. spinosa var. inermis from Antalya-Serik (2010) had the highest refractive indices. Seed oil of C. ovata var. canescens from Ankara-Beypazar𝚤 (2010) had the highest refractive index (1.466) among C. ovata species. The refractive index of caper seed oil can vary according to species/variety, location, soil and climatic conditions.25 Özcan and Akgül26 reported refractive indices of 1.462 and 1.473 for C. spinosa L. var. spinosa and C. ovata Desf. var. canescens oils respectively. Our results show parallelism with those of Özcan and Akgül.26 Refractive index is examined to determine the source of oils.27 It is seen that the refractive index of caper seed oil shows parallelism with that of other edible vegetable oils. While viscosity values of C.spinosa species oils were between 41.1 and 48.6 mPa, those of C. ovata species oils ranged from 34.7 to 43.1 mPa (Table 1). Seed oils of C. spinosa var. aegyptia from Antalya-Kepez (2009) and C. ovata var. palaestina from Mardin-Savur (2009) had the highest (48.6 mPa) and lowest (34.7 mPa) viscosity values respectively. The viscosity of caper seed oil can vary according to location and harvest year. Viscosity is an important physical property that can be defined briefly as the opposition of a liquid to flow because of its internal resistance. Generally, the viscosity of oils containing low-molecular-weight fatty acids is lower than that of oils containing high-molecular-weight fatty acids that have the same unsaturation degree.17,26 Melting points of oils obtained from caper seeds varied between −15.2 and −17.3 ∘ C (Table 1). Average melting points of C. spinosa and C. ovata crude oils were −15.8 and −17.2 ∘ C respectively. Among C. spinosa species, C .spinosa var. spinosa J Sci Food Agric (2015)
˘ oil from Mugla-Milas (2009) had the lowest melting point (−17.0 ∘ C). Among C. ovata species, both C. ovata var. palaestina from Mardin-Savur (2010) and C. ovata var. canescens from Ankara-Beypazar𝚤 (2010) had a melting point of −17.2 ∘ C. Melting points of vegetable oils such as sunflower, cotton, soybean, canola and sesame oils vary between −9.4 and −31.7 ∘ C.28 The melting point of caper seed oil is lower than that of some vegetable oils (peanut, soybean and sesame oils). Chemical properties Free fatty acidity values of crude oils averaged 6.36% for C. spinosa species and 7.23% for C. ovata species (Table 2). Seed oil of C. ovata var. canescens from Ankara-Beypazar𝚤 (2009) had the highest free fatty acidity value (7.69%), while seed oils of C. spinosa var. herbaceae from Mardin-Midyat (2010) and C. spinosa var. aegyptia from Antalya-Kepez (2010) had the lowest (6.10%). The free fatty acidity of caper seed oil can vary according to location and harvest year. Özcan and Akgül26 reported free fatty acidity values of 5.48 and 6.90% for oils from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds respectively. Although somewhat higher, our free fatty acidity values generally show parallelism with those of Özcan and Akgül.26 Peroxide values of crude oils averaged 2.82 and 1.37 meq kg−1 for C. spinosa and C. ovata species respectively (Table 2). Seed oil of C.spinosa var. inermis from Antalya-Serik had the highest peroxide value (4.49 meq kg−1 ), while that of C. ovata var. palaestina from Mardin-Savur had the lowest (0.30 meq kg−1 ). The peroxide value of caper seed oil can vary according to location and harvest year. Özcan and Akgül26 reported that the peroxide value of oils obtained from both C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds was 4.4 meq kg−1 , which is somewhat higher than our values. This may be due to the high free fatty acidity or fast oxidation of crude oils in the holding period before analysis. Our results show that the peroxide value of caper seed oil is higher than that of other usable oils. Iodine values of crude oils averaged 104.51 for C. spinosa species and 121.70 for C. ovata species (Table 2). Seed oils of C.spinosa ˘ var. spinosa from Mugla-Milas (2010) and C. spinosa var. aegyptia from Antalya-Kepez (2009) had the highest (128.54) and lowest (96.16) iodine values respectively. Özcan and Akgül26 reported
© 2014 Society of Chemical Industry
wileyonlinelibrary.com/jsfa
www.soci.org
D Erman, MM Özcan
Table 2. Chemical properties of caper seed oils
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
Variety
Harvest year
Free fatty acidity (%)
Peroxide value (meq kg−1 )
Iodine value (Wijs)
Saponification value (mg KOH g−1 )
Unsaponifiable matter value (%)
2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 Harvest year
6.29ab ± 0.15 6.20ab ± 0.08 6.40abc ± 0.19 6.10a ± 0.25 6.80c ± 0.08 6.40abc ± 0.05 6.60bc ± 0.09 6.10a ± 0.08 7.69e ± 0.25 7.30d ± 0.25 7.20d ± 0.11 6.75c ± 0.12 Total saturated fatty acids (%)
4.00h ± 0.11 1.20c ± 0.05 4.19h ± 0.07 1.10bc ± 0.13 4.49i ± 0.20 2.40e ± 0.09 3.50g ± 0.05 1.70d ± 0.09 3.09f ± 0.08 1.19c ± 0.03 0.90b ± 0.10 0.30a ± 0.04 Total unsaturated fatty acids (%)
122.15h ± 0.04 128.54k ± 0.06 96.16a ± 0.04 98.04d ± 0.06 98.53e ± 0.03 98.64e ± 0.06 97.20c ± 0.05 96.85b ± 0.15 124.36j ± 0.36 123.08i ± 0.04 119.19f ± 0.12 120.18g ± 0.08 Radical-scavenging activity (%)
192.07b ± 0.070 191.99b ± 0.500 194.91c ± 0.080 193.49a ± 0.490 193.61a ± 0.390 193.26a ± 0.260 193.71a ± 0.200 193.47a ± 0.470 192.25b ± 0.200 192.27b ± 0.280 191.92b ± 0.200 192.10b ± 0.340 Waxy substance value (mg kg−1 )
2.36abcd ± 0.188 2.32abcd ± 0.030 2.29abcd ± 0.140 2.13a ± 0.026 2.21abc ± 0.297 2.19abc ± 0.061 2.11a ± 0.065 2.14ab ± 0.056 2.51cd ± 0.135 2.45abcd ± 0.045 2.48bcd ± 0.134 2.59d ± 0.119 Total phenolics (mg g−1 )
217ab ± 26877 214ab ± 47362 215ab ± 41584 213ab ± 41464 210ab ± 18384 205a ± 21855 209ab ± 45108 211ab ± 18354 235b ± 41529 229ab ± 41338 229ab ± 16.28 233ab ± 23.18
2.180k ± 0.009 1.403i ± 0.017 0.675de ± 0.009 0.728f ± 0.006 0.565c ± 0.004 0.648d ± 0.015 1.062h ± 0.031 1.557j ± 0.021 0.466a ± 0.004 0.507b ± 0.012 0.714ef ± 0.028 0.881g ± 0.014
C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010
10.455f ± 0.062 8.471a ± 0.014 16.934j ± 0.020 17.353i ± 0.057 16.791h ± 0.017 16.428g ± 0.02 1 16.916i ± 0.076 17.144k ± 0.062 9.418d ± 0.035 9.102b ± 0.030 10.098e ± 0.029 9.234c ± 0.001
89.544g ± 0.078 91.528i ± 0.015 83.065c ± 0.014 82.646a ± 0.006 83.088d ± 0.049 83.571f ± 0.035 83.517e ± 0.011 82.855b ± 0.002 90.581i ± 0.072 90.907k ± 0.026 89.901h ± 0.004 90.765j ± 0.044
58.71k ± 0.07 25.17c ± 0.02 17.45a ± 0.05 23.90d ± 0.01 24.45e ± 0.01 24.82f ± 0.06 18.00b ± 0.01 45.78j ± 0.01 31.75i ± 0.03 20.50c ± 0.02 23.90d ± 0.09 28.22h ± 0.02
Values are mean ± standard deviation.
iodine values of 154 and 102 for oils obtained from C. spinosa L.var. spinosa and C. ovata Desf. var. canescens seeds respectively. Our results do not show parallelism with those of Özcan and Akgül.26 Also, iodine values of vegetable oils such as sunflower, maize, canola, nut and cotton oils vary between 99 and 141.29 The iodine value of caper seed oil shows parallelism with that of other vegetable oils. Saponification values of crude oils averaged 193.31 mg g−1 for C. spinosa species and 192.13 mg g−1 for C. ovata species (Table 2). Seed oils of C. spinosa var. aegyptia from Antalya-Kepez (2009) and C. ovata var. palaestina from Mardin-Savur (2009) had the highest (194.91 mg g−1 ) and lowest (191.92 mg g−1 ) saponification values respectively. The saponification value of caper seed oil can vary according to species/variety and location. Özcan and Akgül26 reported much lower saponification values of 122.02 and 103.79 mg g−1 for oils obtained from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds respectively. On the other hand, saponification values of vegetable oils such as sunflower, maize, canola and cotton oils vary between 187 and 195 mg g−1 .29 The saponification value of caper seed oil shows parallelism with that of other vegetable oils. Unsaponifiable matter values of crude oils averaged 2.21% for C. spinosa species and 2.50% for C. ovata species (Table 2). Seed oils of C. ovata var. palaestina from Mardin-Savur (2010) and C. spinosa var. herbaceae from Antalya-Kepez (2009) had the highest (2.59%) and lowest (2.11%) unsaponifiable matter values
wileyonlinelibrary.com/jsfa
respectively. In a previous study, unsaponifiable matter values of oils obtained from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds were determined as 1.13 and 1.21% respectively.26 Unsaponifiable matter values of C. spinosa seed oils from Tunisia were reported as 1.7% minimum, 2.5% maximum and 2.05% on average.30 Our results show parallelism with these results. In terms of their unsaponifiable matter values, caper seed oils can be a new oil source for food and industrial applications. Radical-scavenging activities of crude oils averaged 29.78% for C. spinosa species and 26.09% for C. ovata species (Table 2). Seed oils ˘ of C. spinosa var. spinosa from Mugla-Milas (2009) and C. spinosa var. aegyptia from Antalya-Kepez (2009) had the highest (58.71%) and lowest (17.45%) radical-scavenging activities respectively. Waxy substance values of crude oils averaged 211 mg kg−1 for C. spinosa species and 231 mg kg−1 for C. ovata species (Table 2). Seed oils of C. ovata var. canescens from Ankara-Beypazar𝚤 (2009) and C. spinosa var. inermis from Antalya-Serik (2010) had the highest (235 mg kg−1 ) and lowest (205 mg kg−1 ) waxy substance values respectively. In a study carried out by Özcan and Akgül,26 waxy substance values of oils obtained from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds cultivated in Turkey were determined as 209 and 221 mg kg−1 respectively. Our values are higher than those of Özcan and Akgül.26 The difference may be due to samples being collected from different locations, thus affecting the chemical compositions of the oils.31 Morrison32
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
www.soci.org found that waxy substance values of sunflower oil samples varied between 200 and 3500 mg kg−1 . In a similar study by Carelli et al.,33 it was reported that waxy substance values of crude and refined sunflower oils were between 366 and 965 mg kg−1 . Mailer et al.34 determined wax rates ranging from 20 to 130 mg kg−1 in olive oils obtained from various locations in Australia, indicating that the wax rate of oils could vary according to climate and variety. Total phenolic contents of crude oils averaged 0.642 mg g−1 for C. ovata species (P < 0.01) (Table 2). Seed oils of C. spinosa ˘ var. spinosa from Mugla-Milas (2009) and C. ovata var. canescens from Ankara-Beypazar𝚤 (2009) had the highest (2.180 mg g−1 ) and lowest (0.466 mg g−1 ) total phenolic contents respectively (P < 0.05). The total phenolic content of crude caper oil can vary according to location and harvest year. Ak𝚤n and Akd𝚤¸sl𝚤35 reported total phenolic contents of grape seed oils between 71.192 and 87.031 mg g−1 . In a study on the biochemical characterisation of Memecik olive oils, total phenolic contents ranging from 106.89 ± 17.59 to 171.34 ± 16.80 mg kg−1 were found.36 In terms of their total phenolic contents, caper seed oils can be a new oil source for food and industrial applications. Fatty acid composition The fatty acid composition of caper seed oils from different locations is given in Table 3. Fatty acid compositions were similar in the two varieties, except for specific fatty acids. Oleic and linoleic acid contents were high in C. spinosa and C. ovata species respectively. Seed oils of C. spinosa var. aegyptia from Antalya-Kepez (2010) ˘ and C. spinosa var. spinosa from Mugla-Milas (2010) had the highest (17.353%) and lowest (8.471%) saturated fatty acid contents respectively. The amount of saturated fatty acids was higher in C. spinosa species than in C. ovata species. ˘ Seed oils of C. spinosa var. spinosa from Mugla-Milas (2010) and C. spinosa var. aegyptia from Antalya-Kepez (2010) had the highest (91.528%) and lowest (82.646%) unsaturated fatty acid contents respectively. The amount of unsaturated fatty acids was higher in C. ovata species than in C. spinosa species. Gupta and Chakraborty37 determined the major fatty acids in caper seeds as palmitic (21%), oleic (57%) and linoleic (1%) acids. Özcan and Akgül26 determined the fatty acid composition of oils obtained from C. spinosa L.var. spinosa and C. ovata Desf. var. canescens seeds cultivated in Turkey. They found palmitic (13.2 and 11.3% respectively), palmitoleic (4.6 and 1.8%), stearic (3.2 and 2.7%), oleic (49.87 and 34.66%), linoleic (25.2 and 24.5%) and linolenic (1.0 and 0.3%) acids as the main fatty acids, with unsaturated fatty acids accounting for 15% of total fatty acids. Ul’chenko et al.38 extracted (Soxhlet) the oil from seeds of C. spinosa L. fruits collected in the Jizak region of Uzbekhistan and determined the major fatty acids of the oil by GC as 16:0, 18:1 and 18:2. In a study of fatty acids found in C. spinosa fruits, Tlili et al.31 determined the fatty acid composition by GC/mass spectrometry (MS). They found that 90.09% of fatty acids in the fruit oil were unsaturated fatty acids, the dominant one being 9,12-octadecadienoic acid (49.13%). In another study, the major fatty acids of C. spinosa and C. ovata seed oils were found to be palmitic (10.23 and 8.41% respectively), stearic (2.61 and 2.07%), oleic (38.45 and 44.62%), linoleic (23.75 and 18.26%) and linolenic (1.17 and 0.56%) acids.39 In parallel with our results, those of other researchers showed that the fatty acid composition of seed oils could change according to variety/species of plant and cultivation, harvesting and postharvest conditions.40 Also, when we compared the fatty acid J Sci Food Agric (2015)
composition of commonly used sunflower oil with that of caper seed oil, it was seen that the major fatty acids of sunflower oils were palmitic (7.9–12.0%), stearic (4.5–6.7%), oleic (34.4–45.5%) and linoleic (36.9–47.9%) acids,29 while those of caper seed oils were palmitic (5–6%), stearic (2–3%), oleic (32–49%) and linoleic (28–56%) acids. This comparison shows that the fatty acid compositions of caper seed oil and sunflower oil show parallelism. In particular, unsaturated fatty acids found in C. spinosa and C. ovata seed oils have some nutritional and industrial properties. In addition, Tlili et al.31 found that C. spinosa seed oils were rich in linoleic (>20%) and linoleic (1%) acids and other essential fatty acids which are important in terms of nutritional and industrial aspects. Sterol and tocopherol contents Sterol contents of crude oils ranged between 3140 and 3272 mg kg−1 (average 3220 mg kg−1 ) for C. spinosa species and between 3275 and 3312 mg kg−1 (average 3298 mg kg−1 ) for C. ovata species (Table 4). Seed oils of C. ovata var. palaestina from Mardin-Savur (2010) and C. ovata var. canescens from AnkaraBeypazar𝚤 (2009) had the highest sterol content (3312 mg kg−1 ), while seed oil of C. spinosa var. herbaceae from Mardin-Midyat (2009) had the lowest sterol content (3140 mg kg−1 ). The sterol content of caper seed oil can vary according to variety and location. In addition, sterol contents of vegetable oils such as sunflower, maize, canola, nut and cotton oils range between 0.2 and 1%.29 Thus the sterol content of caper seed oil (0.32–0.33%) shows parallelism with that of other vegetable oils. Seed oils of C. spinosa and C. ovata contain high levels of sitosterol, stigmasterol and campesterol, which increases the nutritional and pharmacological value of caper seeds. Matthäus and Özcan41 reported sterol contents of seed oils of C. ovata and C. spinosa species of 4875.5–12189.1 and 4961.8–10009.1 mg kg−1 respectively. They also reported that the sterols consisted of 60% sitosterol, 16% campesterol and 10% stigmasterol as well as high levels of Δ5 -avenasterol (138.8–599.4 mg kg−1 ). Tlili et al.5 determined 12 different sterols in the analysis of C. spinosa seed oils by GC, with total sterol contents ranging between 2068 and 2470 mg kg−1 (average 2240.4 mg kg−1 ). On average, these sterols comprised 1289.54 mg kg−1 sitosterol (57.53%), 382.37 mg kg−1 campesterol (17.05%), 265.31 mg kg−1 stigmasterol (11.85%) and 141.63 mg kg−1 Δ5 -avenasterol (6%) as well as low amounts of cholesterol. In their analysis of sterols in C. spinosa seed oils, Matthäus and Özcan41 found an average Δ5 -avenasterol level of 336 mg kg−1 . Our results show that contents of sterols, the most important minor components in oils, are high in C. spinosa and C. ovata oils, and these substances have a role in decreasing human serum cholesterol levels.25,42 Statistical analysis results for 𝛼-tocopherol contents of oils obtained from caper seeds collected from different locations are given in Table 4. Average 𝛼-tocopherol contents were 3.87 and 2.63 mg per 100 g for C. spinosa and C. ovata species respectively. Seed oils of C. spinosa var. inermis from Antalya-Serik (2010) and C. ovata var. palaestina from Mardin-Savur (2009) had the highest (10.81 mg per 100 g) and lowest (0.84 mg per 100 g) 𝛼-tocopherol contents respectively. Matthäus and Özcan41 studied the tocopherol composition of seed oils of C. ovata and C. spinosa collected from 11 different locations in Turkey and found 𝛾-tocopherol levels of 124.3–1944.9 mg per 100 g, 𝛿-tocopherol levels of 2.7–269.5 mg per 100 g and 𝛼-tocopherol levels of 0.6–13.8 mg per 100 g. They also determined that 88% of the
© 2014 Society of Chemical Industry
wileyonlinelibrary.com/jsfa
www.soci.org
D Erman, MM Özcan
Table 3. Fatty acid composition (%) of caper seed oils
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovate var. canescens C. ovate var. palaestina
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovate var. canescens C. ovate var. palaestina
Harvest year
Lauric (C12:0)
Myristic (C14:0)
Palmitic (C16:0)
Margaric (C17:0)
Stearic (C18:0)
Arachidic Behenic Lignoceric (C20:0) (C22:0) (C24:0)
∑
SFA
Palmitoleic (C16:1)
2009
0
0.116
5.854
0
2.833
0.721
0.760
0.170
10.455
1.392
2010 2009
0 0.078
0.07 0.369
4.927 11.435
0 0.055
2.173 3.418
0.506 0.711
0.663 0.763
0.126 0.102
8.471 16.934
1.264 4.517
2010 2009
0.047 0.055
0.249 0.286
11.907 11.534
0 0
3.603 3.368
0.761 0.708
0.684 0.745
0.099 0.093
17.353 16.791
4.411 4.732
2010 2009
0 0.074
0.257 0.352
11.130 11.489
0 0
3.388 3.423
0.791 0.710
0.762 0.765
0.097 0.100
16.428 16.916
4.624 4.594
2010 2009 2010 2009 2010
0.069 0.070 0.059 0 0
0.317 0.261 0.234 0.078 0.069
11.846 5.428 5.933 5.859 5.441
0 0 0 0.060 0
3.283 2.267 1.878 2.435 2.393
0.710 0.571 0.416 0.669 0.570
0.805 0.657 0.465 0.772 0.610
0.111 0.163 0.113 0.221 0.149
17.144 9.418 9.102 10.092 9.234
4.701 1.052 1.278 1.847 1.861
∑ MUFA
∑ PUFA
Harvest Heptadecenoic Oleic Eicosenoic year (C17:1) (C18:1) (C20:1)
Erusic (C22:1)
Eicosadienoic (C20:2)
Linoleic (C18:2)
Linolenic (C18:3)
∑
UFA
2009
0.192
36.219
0.535
0.063
0
50.409
0.730
38.404
51.140
89.544
2010 2009
0.231 0
32.945 49.257
0.458 0.694
0 0.066
0 0.009
55.981 28.323
0.646 0.176
34.900 54.555
56.627 28.509
91.528 83.065
2010 2009
0.427 0
46.956 48.076
0.357 0.166
0 0.060
0 0
30.075 29.522
0.418 0.530
52.152 53.036
30.494 30.052
82.646 83.088
2010 2009
0.489 0
47.845 48.356
0.399 0.663
0 0.061
0 0.663
29.695 29.004
0.517 0.173
53.358 53.675
30.213 29.841
83.571 83.517
2010 2009 2010 2009 2010
0.467 0.177 0 0.266 0.207
48.410 35.823 38.449 41.042 41.517
0.408 0.602 0.296 0.555 0.465
0 0.097 0.049 0 0
0 0.040 0.024 0 0
28.369 52.126 50.206 45.530 46.202
0.498 0.662 0.601 0.658 0.511
53.987 37.752 40.074 43.711 44.051
28.867 52.829 50.832 46.189 46.714
82.855 90.581 90.907 89.901 90.765
SFA, saturated fatty acids; MUFA, monounsaturated fatty acids; PUFA, poly unsaturated fatty acids; UFA, unsaturated fatty acids.
total tocopherol content in C. spinosa seed oils was 𝛾-tocopherol (average 581 mg per 100 g). Abbasi et al.43 reported 𝛼-tocopherol contents of 10.9–39.7 mg per 100 g (average 29.09 mg per 100 g) and 𝛽-tocopherol contents of 10.4–24.5 mg per 100 g (average 18.28 mg per 100 g). In an HPLC study on the tocopherol composition of leaves, flowers and buds of C. spinosa from Tunisia, it was determined that leaves had an 𝛼-tocopherol content of 20.19 ± 10 mg per 100 g, while flowers and buds had 𝛼-tocopherol contents of 49.12 ± 17.48 and 28.68 ± 9.13 mg per 100 g respectively and 𝛾-tocopherol contents of 48.13 ± 15.08 and 27.8 ± 16.01 mg per 100 g respectively.31 Tlili et al.31 established the fatty acid, tocopherol and carotene contents of C. spinosa seed oils collected from seven different locations in Tunisia. According to their research, the average tocopherol content of seed oils was 6.28 mg per 100 g. Caper seed oils are rich in 𝛼-tocopherol, 𝛾-tocopherol and 𝛿-tocopherol, which are isoforms of tocopherol compounds.5,31 Our 𝛼-tocopherol results were similar to those of Matthäus and Özcan.41 General differences could result from the different locations where samples were obtained, which could affect the chemical composition of the oil.31 Lavedrine et al.25 also reported that these differences could be due to geographical differences. Various researchers report that caper seed oil could be a new vegetable oil source in terms of pharmaceutical, industrial and nutritional aspects.1,3,31,41
wileyonlinelibrary.com/jsfa
CONCLUSIONS 1. As caper seed crude oils have high free fatty acidity (6.36–7.23), peroxide (2.82–1.37 meq kg−1 ) and colour (L* 39.66–43.13, a* 10.53–20.55, b* 0.17–24.20) values, they are unsuitable for consumption by humans. Therefore it is advised that they be consumed only after refinement to conform to Turkish Food Codex standards. 2. Specific gravity (0.929–0.934 g L−1 ), refractive index (nD 1.463–1.466), iodine (104.51–121.70) and saponification (193.31–192.13 mg g−1 ) values of caper seed oils showed parallelism with those of other vegetable oils such as sunflower, maize, nut, canola and cotton oils. 3. In terms of fatty acid composition, caper seed oils are rich in unsaturated fatty acids (82–91%) and essential fatty acids. Because of these properties, caper seed oils are thought to be important in terms of nutritional, cosmetic and industrial aspects. 4. Average sterol contents of seed oils of C. spinosa and C. ovata species were 3220 and 3298 mg kg−1 respectively, showing that caper seeds are a good phytosterol source in terms of nutritional, health and economic aspects. 5. Caper seed oils are rich in 𝛼-tocopherol (2.63–10.81 mg per 100 g) and thus are a natural potential vegetable oil source in terms of health, oil stability and resistance to oxidation.
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
www.soci.org
Table 4. Sterol and tocopherol contents of caper seed oils
Variety
Harvest year
C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010
Total sterols (mg kg−1 ) 3272g ± 0.16 3266f ± 0.02 3259f ± 0.15 3173b ± 0.03 3216d ± 0.19 3235e ± 0.07 3140a ± 0.05 3199c ± 0.05 3312i ± 0.14 3275g ± 0.05 3294h ± 0.12 3312i ± 0.11
Sitosterol (%) 71.69g ± 0.200 69.04c ± 0.040 70.40de ± 0.045 69.01c ± 0.090 67.45b ± 0.050 66.19a ± 0.190 71.14f ± 0.140 70.60e ± 0.300 70.20d ± 0.200 70.53e ± 0.170 70.51e ± 0.090 71.670g ± 0.200
Campesterol (%)
Stigmasterol (%)
18.66e ± 0.160 18.97fg ± 0.030 19.04g ± 0.040 16.68c ± 0.180 14.11b ± 0.080 13.32a ± 0.080 18.69e ± 0.180 17.99d ± 0.150 20.05h ± 0.200 18.78ef ± 0.120 18.93fg ± 0.070 18.00d ± 0.050
9.65a ± 0.100 11.99f ± 0.200 10.55cd ± 0.300 9.91a ± 0.090 13.64g ± 0.140 20.49h ± 0.110 10.17b ± 0.170 11.41e ± 0.040 9.75a ± 0.200 10.69d ± 0.090 10.56cd ± 0.050 10.33bc ± 0.130
𝛼-Tocopherol (mg per 100 g) 2.20e ± 0.12 3.76f ± 0.09 1.30bc ± 0.20 4.62g ± 0.04 5.41h ± 0.18 10.81j ± 0.11 1.86d ± 0.15 1.03ab ± 0.06 6.87i ± 0.11 1.43c ± 0.08 0.84a ± 0.02 1.39c ± 0.16
Values are mean ± standard deviation.
6. All physical and chemical properties (except specific gravity) of caper seed oils varied according to the location where seeds were collected and the year in which they were harvested (P < 0.01).
ACKNOWLEDGEMENT This work was supported by Selçuk University Scientific Research Project (S.U.-BAP. Konya-Turkey).
REFERENCES 1 Rodrigo M, Lazaro M, Alvarruiz A and Giner V, Composition of capers (Capparis spinosa): influence of cultivar, size, and harvest date. J Food Sci 57:1152–1154 (1992). 2 Özcan M, Composition and pickling product of capers (Capparis spp.) flower buds. PhD Thesis, Department of Food Engineering, Selçuk University, Konya (1996). 3 Özcan M and Akgül A, Influence of species, harvest date and size on composition of capers (Capparis spp.) flower buds. Nahrung 42:102–105 (1998). 4 Alvarruiz A, Rodrigo M, Miquel J, Girer V, Feria A and Vila R, Influence of brining and packing conditions on product quality of capers. J Food Sci 55:196–198, 227 (1990). 5 Tlili N, Nasri N, Saadaoui E, Khaldi A and Triki S, Sterol composition of caper (Capparis spinosa) seeds. Afr J Biotechnol 9:3328–3333 (2010). 6 Ivanov SA and Aitzetmüller K, Untersuchungen über die Tocopherolund Tocotrienolzusammensetzung der Samenöle einiger Vertreter der Familie Apiaceae. Eur J Lipid Sci Technol 97:24–29 (1995). 7 Gutteridge JM, Rowley DA and Halliwell B, Superoxide-dependent formation of hydroxyl radicals in the presence of iron salts. Biochem J 199:263–265 (1981). ˘ NM and Nas S, The phenolic compounds in vegetables 8 Nizaml𝚤oglu and fruit; structures and their importance. Electron J Food Technol 5(1):20–35 (2010). 9 Vanhanen HT, Blomqvist S, Ehnholm C, Hyvonen M, Jauhiainen M, Torstila I, et al., Serum cholesterol, cholesterol precursors, and plant sterols in hypercholesterolemic subjects with different apo-E phenotypes during dietary sitostanol ester treatment. J Lipid Res 34:1535–1544 (1993). 10 Law M, Plant sterol and stanol margarines and health. Br Med J 320:861–864 (2000). 11 Awad AB and Fink CS, Phytosterols as anticancer dietary components: evidence and mechanism of action. J Nutr 130:2127–2130 (2000). 12 National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Final report. Circulation 106:3143–3421 (2002).
J Sci Food Agric (2015)
13 Hendricks HFJ, Weststrate JA, Vabvliet T and Meijer GW, Spreads enriched with three different levels of vegetable oil sterols and the degree of cholesterol lowering in normocholesterolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr 53:319–327 (1999). 14 AOCS, Official Methods and Recommended Practices (4th edn), Vol. 1. American Oil Chemists’ Society, Champaign, IL (1990). 15 CIE, Official Recommendations of the International Commission on Illumination. Publication CIE No.15 (E-1.3.1). Bureau Central de la CIE, Paris (1976). 16 Anupama D, Bhat K and Sapna V, Sensory and physicochemical properties of commercial samples of honey. Food Res Int 36:183–191 (2002). 17 Encyclopedia Britannica (15th edn). Encyclopedia Britannica, London (1994). 18 Singleton VL and Rossi JA, Colorimetry of total phenoloics with phosphomolybdic–phosphotungstic acid reagents. Am J Enol Vitic 16:144–158 (1965). 19 Lee SK, Mbwambo ZH, Chung HS, Luyengi L, Games EJC and Mehta RG, Evaluation of the antioxidant potential of natural products. Combin Chem High Throughput Screen 1:35–46 (1998). 20 H𝚤¸s𝚤l Y, Enstrümantal G𝚤da Analizleri – II (4. Bask𝚤). Yay𝚤n No. 45. Ege Üniversitesi Mühendislik Fakültesi ders Kitaplar𝚤, ˙Izmir (2004). 21 Özkaya H, Analitik G𝚤da Kontrolü. Yay𝚤n No. 1068, Ankara Üniversitesi Ziraat Fakültesi, Ankara (1988). 22 Balz M, Schulte E and Thier H-P, Trennung von Tocopherolen und Tocotrienolen durch HPLC. Eur J Lipid Sci Technol 94:209–213 (1992). 23 Phillips KM, Ruggio DM and Ashraf-Khorassani M, Phytosterol composition of nuts and seeds commonly consumed in the United States. J Agric Food Chem 53:9436–9445 (2005). 24 Özdamar K, SPPS ile Bioistatistik. Yay𝚤n No. 3. ETAM A.¸S. Matbaa Tesisleri, Eski¸sehir (1999). 25 Lavedrine F, Ravel A, Poupard A and Alary J, Effect of geographic origin, variety and storage on tocopherol concentrations in walnuts by HPLC. Food Chem 58:135–140 (1997). 26 Özcan M and Akgül A, Some compositional characteristics of capers (Capparis spp.) seed and oil. Grasas Aceites 50:49–52 (1999). ˘ tohumlarda kalite kontrolü [Quality control in oil seeds]. 27 Y𝚤lmaz M, Yagl𝚤 [Online]. (2008). Available: www.gidacilar.net [21 February 2012]. 28 Georing CE, Schwab AW, Daughurty MJ, Pryde EH and Heakin AJ, Fuel properties of eleven vegetable oils. Trans ASAE 25:1472–1477 (1982). ˘ T and Karaali A, Türk Bitkisel Ya˘glar𝚤n𝚤n Ya˘g Asitleri Bile¸simleri. 29 Yaz𝚤c𝚤oglu Yay𝚤n No. 70. Tübitak Marmara Bilimsel ve Endüstriyel Ara¸st𝚤rma Enstitüsü Beslenme ve G𝚤da Teknolojisi Bölümü, Gebze (1983) (in Turkish). 30 Tlili N, Saadaoui E, Sakouhi F, Elfalleh W, El Gazzah M, Triki S, et al., Morphology and chemical composition of Tunisian caper seeds: variability and population profiling. Afr J Biotechnol 10:2112–2118 (2011).
© 2014 Society of Chemical Industry
wileyonlinelibrary.com/jsfa
www.soci.org 31 Tlili N, Munné-Bosch S, Nasri N, Saadaoui E, Khaldi A and Triki S, Fatty acids, tocopherols and carotenoids from seeds of Tunisian caper Capparis spinosa. J Food Lipids 16:452–464 (2009). 32 Morrison WH, Variation in the wax content of sunflower seed with location and hybrid. J Am Oil Chem Soc 60:1013–1014 (1983). 33 Carelli A, Frizzera LM, Forbita PR and Crapiste GH, Wax composition of sunflower seed oils. J Am Oil Chem Soc 79:763–768 (2002). 34 Mailer RJ, Ayton J and Graham K, The influence of growing region, cultivar and harvest timing on the diversity of Australian olive oil. J Am Oil Chem Soc 87:877–884 (2010). 35 Ak𝚤n A and Akdi¸sli A, Emir, Gök Üzüm ve Kara Dimitri üzüm çe¸sitlerinin ˘ çekirdek yaglar𝚤n𝚤n yag˘ asidi kompozisyonu ve fenolik madde içeriklerinin belirlenmesi. Akademik G𝚤da 8(6):19–23 (2010). ˘ H and Özçelik B, Memecik zeytinyaglar𝚤n𝚤n ˘ 36 ˙Ilyasoglu biyokimyasal karakterizasyonu. G𝚤da 36(1):33–41 (2011). 37 Gupta AS and Chakrabarty MM, Composition of the seed fats of the Capparidaceae family. J Sci Food Agric 15:69–73 (1964).
wileyonlinelibrary.com/jsfa
D Erman, MM Özcan 38 Ul’chenko NT, Bekker NP and Glushenkova AI, Neutral lipids from seeds of Asteraceae plants. Chem Nat Comp 44:147–150 (2008). ˘ 39 Haciseferogullar𝚤 H, Özcan MM and Duman E, Biochemical and technological properties of seeds and oils of Capparis spinosa and Capparis ovata plants growing wild in Turkey. J Food Process Technol 2:129–135 (2011). 40 ˙Ilisulu K, Oil Plants and Breeding. Caglayan Bookshop, Istanbul (1973). 41 Matthäus B and Özcan M, Glucosinolates and fatty acid, sterol, and tocopherol composition of seed oils from Capparis spinosa var. spinosa and Capparis ovata Desf. var. canescens (Coss.) Heywood. J Agric Food Chem 53:7136–7141 (2005). 42 Westrate JA and Meijer GW, Plant sterol-enriched margarines and reduction of plasma total- and LDL-cholesterol concentrations in normocholesteolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr 52:334–343 (1998). 43 Abbassi AR, Hajırezeaı M, Hofıus D, Sonnewald U and Voll LM, Specific role of a- and g-tocopherol in abiotic stres responses of transgenictobacco. Plant Physiol 143:1720–1738 (2007).
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
Revised: 7 April 2014
Accepted article published: 8 December 2014
Published online in Wiley Online Library:
(wileyonlinelibrary.com) DOI 10.1002/jsfa.7040
Physicochemical properties of caper species seed oils collected from two different harvest years Erman Dumana and Mehmet Musa Özcanb* Abstract BACKGROUND: In this study the physicochemical properties, fatty acid composition and sterol and tocopheol contents of caper species seed oils were determined. RESULTS: Brightness (L* ) values of oils obtained from caper seeds ranged between 36.76 and 53.48. Viscosity values of oils of Capparis spinosa species were between 41.1 and 48.6 mPa. While oleic acid levels were high in C. spinosa species oils, linoleic acid levels were high in Capparis ovata species oils. Sterol contents of crude oils were between 3140 and 3272 mg kg−1 (mean 3220 mg kg−1 ) for C. spinosa species and between 3275 and 3312 mg kg−1 (mean 3298 mg kg−1 ) for C. ovata species. 𝜶-Tocopherol contents of C. spinosa and C. ovata oils averaged 3.87 and 2.63 mg per 100 g respectively. Radical-scavenging activities of crude oils averaged 29.78% (C. spinosa species) and 26.09% (C. ovata species). Total phenolic concentrations in crude oils averaged 0.642 mg g−1 for C. ovata species (P < 0.01). CONCLUSION: Caper seeds are a natural source of vegetable oils that are beneficial in terms of health, oil stability and resistance to oxidation. © 2014 Society of Chemical Industry Keywords: caper seed; varieties; harvest year; oil; fatty acid composition; sterol; 𝛼-tocopherol
INTRODUCTION Caper is a plant with medicinal and aromatic properties. It is a long-lasting shrubby plant belonging to the Capparaceae family, occurs in numerous types (>350) and grows naturally on all continents in many different regions of the world.1,2 It is a tropical/subtropical plant.1,3 Caper, which is called bubu, gebre, gabar, gevil, kapari, keper, kebere, tur¸suotu and ¸sebellah in different parts of Turkey, is an economically valuable plant. In various regions of the world, different organs of caper species have been used in a variety of ways since ancient times. Young shoots, flower buds and fruits are used in human nutrition. Caper has an important role in the food industry; for instance, its flower buds are stored in brine and have become an expensive product during recent years2,4 Caper is a perennial shrub of the Mediterranean Basin.5 Its oils contain high levels of tocopherols, which contribute to oil stability and oxidation resistance.6 Reactive oxygen species such as superoxide and hydroxyl radicals occur in the respiratory chain in the human body. Hydroxyl radicals are the most reactive and are responsible for free radical damage in the body. Living organisms do not have a specific molecule or enzyme to scavenge hydroxyl radicals. However, hydroxyl radicals can be scavenged by dietary antioxidants. Therefore measurement of the hydroxyl radical-scavenging activity of antioxidants is important.7 Phenolic compounds are secondary metabolities found widely in plants. Phenolic compounds prevent oxidation through their antioxidant properties, stop the reactions caused by free radicals and hinder the development of many diseases.8 Sterols are an important J Sci Food Agric (2015)
class of organic molecules. The sterols found in vegetable oils are important for nutrition and health. Sitosterols play a role in decreasing the serum cholesterol of patients with breast cancer or hypercholesterolaemia.9 – 11 Also, it is advised that foods containing sterols should be consumed to decrease the risk of cardiovascular disease.12 Research on biologically active materials is increasing for production of neutraceutics and functional foods.13 Caper seeds are good source of phytosterols in terms of nutritional, medicinal and economic aspects. The aim of this study was to compare the physicochemical properties, fatty acid composition and sterol and tocopherol contents of caper species seed oils collected from different locations in Turkey.
MATERIALS AND METHODS Materials This research was performed with six different sample groups (Capparis spinosa var. spinosa, C. spinosa var. aegyptia, C. spinosa
∗
Correspondence to: Mehmet Musa Özcan, Department of Food Engineering, Faculty of Agriculture, University of Selcuk, 42031 Konya, Turkey. E-mail: [email protected]
a Department of Food Engineering, Faculty of Engineering, University of Afyon Kocatepe University, Afyonkarahisar, Turkey b Department of Food Engineering, Faculty of Agriculture, University of Selcuk, 42031 Konya, Turkey
www.soci.org
© 2014 Society of Chemical Industry
www.soci.org var. inermis, C. spinosa var. herbaceae, Capparis ovata var. canescens ˘ and C. ovata var. palaestina) at six different locations (Mugla-Milas, Antalya-Kepez, Antalya-Serik, Mardin-Midyat, Ankara-Beypazar𝚤 and Mardin-Savur) harvested in two different years (2009 and 2010) and all analyses were conducted in triplicate. Thus each parameter was analysed according to a factorial design in the form of 6 × 6 × 2 × 3 = 216. Physicochemical methods Specific gravity, viscosity, melting point, peroxide value, free fatty acidity, iodine value, saponification value, waxy substance value and unsaponifiable matter value were analysed according to AOCS methods.14 Colour determination Colour measurement (L* , a* and b* values) of caper oil samples was performed using a D65 illuminated chromameter (CR-400, Konica Minolta, Osaka, Japan) with 8 mm clarification range in diffuse 10 mode with 2∘ observer. L* (brightness), a* (red/green) and b* (yellow/blue) colour coordinates were determined according to the CIEL* a* b* system. Measurements were made by performing three different readings for each caper oil sample.15 – 17 Total phenolics Total phenolic contents were determined according to Singleton and Rossi18 using the Folin–Ciocalteu calorimetric method. Free radical-scavenging effect To determine the antioxidant activity of caper oil samples, the method proposed by Lee et al.19 was used Fatty acid composition The fatty acid composition of seed oils was determined by the AOCS method.14 Fatty acid methyl esters were prepared by treating the oils with KOH and n-heptane and then analysed by gas chromatography (GC).20,21 An RTX-2330 column (Schımadzu, Tokyo, Japan) (60 m length × 0.25 mm diameter, 0.2 mm film thickness) was used. Column, injector and detector temperatures were 180, 200 and 200 ∘ C respectively. Carrier gas (N2 ), flammable gas and dry air flow rates were 30, 28 and 220 mL min−1 respectively. The amount of sample injected was 1 μL. 𝜶-Tocopherol analysis A high-performance liquid chromatography (HPLC) analysis method developed by Balz et al.22 was used. The mobile phase comprised 970 mL L−1 hexane and 30 mL L−1 1,4-dioxan at a flow rate of 1 mL min−1 . Maxsil 5 (250 mm × 400 mm, 5 μm), PINO OOG0053.DO Phenomenex and Chromosorb 5160 (250mm × 400mm, 5 μm) columns were used. Excitation and emission wavelengths of 293 and 326 nm respectively were employed in the fluorescence detector. Sterol analysis For sterol analysis of caper oil samples, first Zn KOH and 1000 PPM s. A. Choleston 3.𝛽.01 as internal standard was prepared. Then 0.5 g of caper oil sample was taken and 5 mL of KOH and 1 mL of internal standard were added to it. This solution was left for 1 h in a water bath at 80 ∘ C, with mixing every 15 min. Thereafter, 5 mL of water was added and the solution was cooled
wileyonlinelibrary.com/jsfa
D Erman, MM Özcan to room temperature and mixed with 5 mL of hexane. After phase separation, the upper phase was transferred into a separate vessel and N2 gas was used to blow away the hexane. Then 5 mL of water was added and the mixture was vortexed. In this process, water remained in the lower phase; the process was performed with 5 mL of hexane three times. Then hexane was blown away until the volume reached 10 mL, and the sample was transferred into a 10 mL volumetric flask. To remove any remaining water in the sample, a little sodium sulfate was added. To prepare the chelating solution, 4 units of bis(trimethylsilyl)trifluoroacetamide and 1 unit of chlorotrimethylsilane were mixed. A 500 μL aliquot was taken from the sample in the 10 mL volumetric flask and mixed with 250 mL of chelating solution and 250 mL of pyridine. This solution was left for 15 min in a drying oven at 60 ∘ C and then subjected to GC for sterol analysis.23 An Agilent Santa Clara, CA, USA SE-54 column (30 m length × 0.32 mm i.d., 0.25 μm film thickness) and a Perkin Elmer Boston, MA, USA GC autosystem were used. All gas (He, He-2 and air) flow rates were 45 mL min−1 . The column temperature was increased from 0 to 60 ∘ C (2 min) and then from 60 to 220 ∘ C (18 min) and finally held at 220 ∘ C (35 min). Statistical analysis A completely randomised experimental design was used (6 species × 6 locations × 2 years × 3 repetitions). Obtained data were statistically evaluated using SPSS 10.0 (SPSS Inc., Chicago, IL, USA), with significant differences between groups being determined by variance analysis and Duncan’s multiple comparison test.24
RESULTS AND DISCUSSION Physical properties Brightness (L* ) values of oils ranged between 36.76 (C. ovata var. palaestina from Mardin-Savur) and 53.48 (C. ovata var. canescens from Ankara-Beypazar𝚤) (Table 1). Average L* values of C. spinosa and C. ovata seed oils were 39.66 and 43.13 respectively. The brightness value of caper seed oil can vary according to species/variety, location, harvest year, soil and climatic conditions.25 The effect of ‘sample group and harvest year’ interaction with variety and location on the redness (a* ) value of crude oils was statistically significant (P < 0.01) (Table 1). The average a* value of C. ovata seed oils (15.04) was higher than that of C. spinosa seed oils (12.29). Seed oils of C. ovata var. canescens from Ankara-Beypazar𝚤 and C. spinosa var. aegyptia from Antalya-Kepez had the highest (20.55) and lowest (10.53) a* values respectively. The redness value of caper seed oil can vary according to species/variety, location and harvest year. Seed oils of C. ovata var. canescens from Ankara-Beypazar𝚤 and C. spinosa var. aegyptia from Antalya-Kepez had the highest (24.20) and lowest (0.17) yellowness (b* ) values respectively (Table 1). In addition, blueness was observed in seed oils collected from Mardin-Savur in 2009 (b* = −0.82) and 2010 (b* = −0.79). This result shows that blue colour can be present to some degree in caper seed oil as well as in other oil-bearing seed oils. The effect of ‘sample group and harvest year’ interaction with variety and location on the specific gravity of crude oils was statistically non-significant (P > 0.01) (Table 1). Specific gravitys varied between 0.929 and 0.934 g L−1 . Average specific gravitys of C. spinosa and C. ovata seed oils were 0.931 and 0.929 g L−1 respectively. Özcan and Akgül26 reported specific gravitys of 1.1045 and
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
www.soci.org
Table 1. Physical properties of caper seed oils
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
Harvest year 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010
L* colour value (brightness) 44.40i ± 0.150 38.87e ± 0.075 38.46cd ± 0.170 37.27b ± 0.181 39.12ef ± 0.017 38.53d ± 0.090 41.43g ± 0.170 39.22f ± 0.095 53.48j ± 0.009 44.09h ± 0.121 38.19c ± 0.150 36.76a ± 0.006
a* colour value (red) 14.04f ± 0.118 12.34c ± 0.032 10.53a ± 0.098 10.75a ± 0.020 13.35e ± 0.106 12.98d ± 0.159 11.60b ± 0.125 12.76d ± 0.025 18.47g ± 0.010 20.55h ± 0.104 10.64a ± 0.104 10.75a ± 0.119
b* colour value (yellow/blue) 8.28h ± 0.221 0.74c ± 0.012 0.29b ± 0.035 0.17b ± 0.070 2.33e ± 0.109 2.02d ± 0.106 2.65f ± 0.032 3.11g ± 0.105 24.20j ± 0.019 12.41i ± 0.221 −0.82a ± 0.055 −0.79a ± 0.012
Specific gravity (g L−1 ) 0.933a ± 0.023 0.932a ± 0.006 0.934a ± 0.007 0.931a ± 0.003 0.930a ± 0.005 0.930a ± 0.005 0.930a ± 0.005 0.932a ± 0.009 0.925a ± 0.002 0.929a ± 0.007 0.933a ± 0.007 0.929a ± 0.003
Refractive index (nD ) 1.465bc ± 0.02 1.466c ± 0.02 1.464abc ± 0.03 1.463a ± 0.04 1.464abc ± 0.03 1.466c ± 0.03 1.465bc ± 0.07 1.464ab ± 0.02 1.465abc ± 0.13 1.466c ± 0.20 1.463ab ± 0.06 1.464abc ± 0.05
Viscosity (mPa) 41.1d ± 0.045 41.5e ± 0.041 48.6j ± 0.037 42.1f ± 0.023 48.4j ± 0.185 43.3h ± 0.025 43.0g ± 0.062 47.1i ± 0.135 35.9b ± 0.045 43.1g ± 0.058 34.7a ± 0.090 36.3c ± 0.070
Melting point (∘ C) −17.0b ± 0.20 −16.8b ± 0.30 −15.2a ± 0.60 −15.7a ± 0.20 −15.4a ± 0.40 −15.7a ± 0.70 −15.7a ± 0.10 −15.5a ± 0.50 −17.3b ± 0.40 −17.2b ± 0.60 −17.1b ± 0.40 −17.2b ± 0.30
Values are mean ± standard deviation.
1.0840 g L−1 for C. spinosa L. var. spinosa and C. ovata Desf. var. canescens (Coss.) Heywood seed oils respectively. Our values are lower than those of Özcan and Akgül,26 probably owing to filtration of sediments and impurities. Specific gravitys of vegetable oils generally range between 0.910 and 0.932, with only castor oil showing higher values (0.950–0.970). Specific gravity is determined to get an idea about the source of oils.27 The specific gravity of caper seed oil shows parallelism with that of other vegetable oils. Average refractive indices (nD ) of crude oils obtained from C. spinosa and C. ovata seeds are given in Table 1. Values ranged between 1.463 and 1.466. Among C. spinosa species, seed oils of ˘ C.spinosa var. herbaceae from Mugla-Milas (2010) and C. spinosa var. inermis from Antalya-Serik (2010) had the highest refractive indices. Seed oil of C. ovata var. canescens from Ankara-Beypazar𝚤 (2010) had the highest refractive index (1.466) among C. ovata species. The refractive index of caper seed oil can vary according to species/variety, location, soil and climatic conditions.25 Özcan and Akgül26 reported refractive indices of 1.462 and 1.473 for C. spinosa L. var. spinosa and C. ovata Desf. var. canescens oils respectively. Our results show parallelism with those of Özcan and Akgül.26 Refractive index is examined to determine the source of oils.27 It is seen that the refractive index of caper seed oil shows parallelism with that of other edible vegetable oils. While viscosity values of C.spinosa species oils were between 41.1 and 48.6 mPa, those of C. ovata species oils ranged from 34.7 to 43.1 mPa (Table 1). Seed oils of C. spinosa var. aegyptia from Antalya-Kepez (2009) and C. ovata var. palaestina from Mardin-Savur (2009) had the highest (48.6 mPa) and lowest (34.7 mPa) viscosity values respectively. The viscosity of caper seed oil can vary according to location and harvest year. Viscosity is an important physical property that can be defined briefly as the opposition of a liquid to flow because of its internal resistance. Generally, the viscosity of oils containing low-molecular-weight fatty acids is lower than that of oils containing high-molecular-weight fatty acids that have the same unsaturation degree.17,26 Melting points of oils obtained from caper seeds varied between −15.2 and −17.3 ∘ C (Table 1). Average melting points of C. spinosa and C. ovata crude oils were −15.8 and −17.2 ∘ C respectively. Among C. spinosa species, C .spinosa var. spinosa J Sci Food Agric (2015)
˘ oil from Mugla-Milas (2009) had the lowest melting point (−17.0 ∘ C). Among C. ovata species, both C. ovata var. palaestina from Mardin-Savur (2010) and C. ovata var. canescens from Ankara-Beypazar𝚤 (2010) had a melting point of −17.2 ∘ C. Melting points of vegetable oils such as sunflower, cotton, soybean, canola and sesame oils vary between −9.4 and −31.7 ∘ C.28 The melting point of caper seed oil is lower than that of some vegetable oils (peanut, soybean and sesame oils). Chemical properties Free fatty acidity values of crude oils averaged 6.36% for C. spinosa species and 7.23% for C. ovata species (Table 2). Seed oil of C. ovata var. canescens from Ankara-Beypazar𝚤 (2009) had the highest free fatty acidity value (7.69%), while seed oils of C. spinosa var. herbaceae from Mardin-Midyat (2010) and C. spinosa var. aegyptia from Antalya-Kepez (2010) had the lowest (6.10%). The free fatty acidity of caper seed oil can vary according to location and harvest year. Özcan and Akgül26 reported free fatty acidity values of 5.48 and 6.90% for oils from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds respectively. Although somewhat higher, our free fatty acidity values generally show parallelism with those of Özcan and Akgül.26 Peroxide values of crude oils averaged 2.82 and 1.37 meq kg−1 for C. spinosa and C. ovata species respectively (Table 2). Seed oil of C.spinosa var. inermis from Antalya-Serik had the highest peroxide value (4.49 meq kg−1 ), while that of C. ovata var. palaestina from Mardin-Savur had the lowest (0.30 meq kg−1 ). The peroxide value of caper seed oil can vary according to location and harvest year. Özcan and Akgül26 reported that the peroxide value of oils obtained from both C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds was 4.4 meq kg−1 , which is somewhat higher than our values. This may be due to the high free fatty acidity or fast oxidation of crude oils in the holding period before analysis. Our results show that the peroxide value of caper seed oil is higher than that of other usable oils. Iodine values of crude oils averaged 104.51 for C. spinosa species and 121.70 for C. ovata species (Table 2). Seed oils of C.spinosa ˘ var. spinosa from Mugla-Milas (2010) and C. spinosa var. aegyptia from Antalya-Kepez (2009) had the highest (128.54) and lowest (96.16) iodine values respectively. Özcan and Akgül26 reported
© 2014 Society of Chemical Industry
wileyonlinelibrary.com/jsfa
www.soci.org
D Erman, MM Özcan
Table 2. Chemical properties of caper seed oils
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
Variety
Harvest year
Free fatty acidity (%)
Peroxide value (meq kg−1 )
Iodine value (Wijs)
Saponification value (mg KOH g−1 )
Unsaponifiable matter value (%)
2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 Harvest year
6.29ab ± 0.15 6.20ab ± 0.08 6.40abc ± 0.19 6.10a ± 0.25 6.80c ± 0.08 6.40abc ± 0.05 6.60bc ± 0.09 6.10a ± 0.08 7.69e ± 0.25 7.30d ± 0.25 7.20d ± 0.11 6.75c ± 0.12 Total saturated fatty acids (%)
4.00h ± 0.11 1.20c ± 0.05 4.19h ± 0.07 1.10bc ± 0.13 4.49i ± 0.20 2.40e ± 0.09 3.50g ± 0.05 1.70d ± 0.09 3.09f ± 0.08 1.19c ± 0.03 0.90b ± 0.10 0.30a ± 0.04 Total unsaturated fatty acids (%)
122.15h ± 0.04 128.54k ± 0.06 96.16a ± 0.04 98.04d ± 0.06 98.53e ± 0.03 98.64e ± 0.06 97.20c ± 0.05 96.85b ± 0.15 124.36j ± 0.36 123.08i ± 0.04 119.19f ± 0.12 120.18g ± 0.08 Radical-scavenging activity (%)
192.07b ± 0.070 191.99b ± 0.500 194.91c ± 0.080 193.49a ± 0.490 193.61a ± 0.390 193.26a ± 0.260 193.71a ± 0.200 193.47a ± 0.470 192.25b ± 0.200 192.27b ± 0.280 191.92b ± 0.200 192.10b ± 0.340 Waxy substance value (mg kg−1 )
2.36abcd ± 0.188 2.32abcd ± 0.030 2.29abcd ± 0.140 2.13a ± 0.026 2.21abc ± 0.297 2.19abc ± 0.061 2.11a ± 0.065 2.14ab ± 0.056 2.51cd ± 0.135 2.45abcd ± 0.045 2.48bcd ± 0.134 2.59d ± 0.119 Total phenolics (mg g−1 )
217ab ± 26877 214ab ± 47362 215ab ± 41584 213ab ± 41464 210ab ± 18384 205a ± 21855 209ab ± 45108 211ab ± 18354 235b ± 41529 229ab ± 41338 229ab ± 16.28 233ab ± 23.18
2.180k ± 0.009 1.403i ± 0.017 0.675de ± 0.009 0.728f ± 0.006 0.565c ± 0.004 0.648d ± 0.015 1.062h ± 0.031 1.557j ± 0.021 0.466a ± 0.004 0.507b ± 0.012 0.714ef ± 0.028 0.881g ± 0.014
C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010
10.455f ± 0.062 8.471a ± 0.014 16.934j ± 0.020 17.353i ± 0.057 16.791h ± 0.017 16.428g ± 0.02 1 16.916i ± 0.076 17.144k ± 0.062 9.418d ± 0.035 9.102b ± 0.030 10.098e ± 0.029 9.234c ± 0.001
89.544g ± 0.078 91.528i ± 0.015 83.065c ± 0.014 82.646a ± 0.006 83.088d ± 0.049 83.571f ± 0.035 83.517e ± 0.011 82.855b ± 0.002 90.581i ± 0.072 90.907k ± 0.026 89.901h ± 0.004 90.765j ± 0.044
58.71k ± 0.07 25.17c ± 0.02 17.45a ± 0.05 23.90d ± 0.01 24.45e ± 0.01 24.82f ± 0.06 18.00b ± 0.01 45.78j ± 0.01 31.75i ± 0.03 20.50c ± 0.02 23.90d ± 0.09 28.22h ± 0.02
Values are mean ± standard deviation.
iodine values of 154 and 102 for oils obtained from C. spinosa L.var. spinosa and C. ovata Desf. var. canescens seeds respectively. Our results do not show parallelism with those of Özcan and Akgül.26 Also, iodine values of vegetable oils such as sunflower, maize, canola, nut and cotton oils vary between 99 and 141.29 The iodine value of caper seed oil shows parallelism with that of other vegetable oils. Saponification values of crude oils averaged 193.31 mg g−1 for C. spinosa species and 192.13 mg g−1 for C. ovata species (Table 2). Seed oils of C. spinosa var. aegyptia from Antalya-Kepez (2009) and C. ovata var. palaestina from Mardin-Savur (2009) had the highest (194.91 mg g−1 ) and lowest (191.92 mg g−1 ) saponification values respectively. The saponification value of caper seed oil can vary according to species/variety and location. Özcan and Akgül26 reported much lower saponification values of 122.02 and 103.79 mg g−1 for oils obtained from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds respectively. On the other hand, saponification values of vegetable oils such as sunflower, maize, canola and cotton oils vary between 187 and 195 mg g−1 .29 The saponification value of caper seed oil shows parallelism with that of other vegetable oils. Unsaponifiable matter values of crude oils averaged 2.21% for C. spinosa species and 2.50% for C. ovata species (Table 2). Seed oils of C. ovata var. palaestina from Mardin-Savur (2010) and C. spinosa var. herbaceae from Antalya-Kepez (2009) had the highest (2.59%) and lowest (2.11%) unsaponifiable matter values
wileyonlinelibrary.com/jsfa
respectively. In a previous study, unsaponifiable matter values of oils obtained from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds were determined as 1.13 and 1.21% respectively.26 Unsaponifiable matter values of C. spinosa seed oils from Tunisia were reported as 1.7% minimum, 2.5% maximum and 2.05% on average.30 Our results show parallelism with these results. In terms of their unsaponifiable matter values, caper seed oils can be a new oil source for food and industrial applications. Radical-scavenging activities of crude oils averaged 29.78% for C. spinosa species and 26.09% for C. ovata species (Table 2). Seed oils ˘ of C. spinosa var. spinosa from Mugla-Milas (2009) and C. spinosa var. aegyptia from Antalya-Kepez (2009) had the highest (58.71%) and lowest (17.45%) radical-scavenging activities respectively. Waxy substance values of crude oils averaged 211 mg kg−1 for C. spinosa species and 231 mg kg−1 for C. ovata species (Table 2). Seed oils of C. ovata var. canescens from Ankara-Beypazar𝚤 (2009) and C. spinosa var. inermis from Antalya-Serik (2010) had the highest (235 mg kg−1 ) and lowest (205 mg kg−1 ) waxy substance values respectively. In a study carried out by Özcan and Akgül,26 waxy substance values of oils obtained from C. spinosa L. var. spinosa and C. ovata Desf. var. canescens seeds cultivated in Turkey were determined as 209 and 221 mg kg−1 respectively. Our values are higher than those of Özcan and Akgül.26 The difference may be due to samples being collected from different locations, thus affecting the chemical compositions of the oils.31 Morrison32
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
www.soci.org found that waxy substance values of sunflower oil samples varied between 200 and 3500 mg kg−1 . In a similar study by Carelli et al.,33 it was reported that waxy substance values of crude and refined sunflower oils were between 366 and 965 mg kg−1 . Mailer et al.34 determined wax rates ranging from 20 to 130 mg kg−1 in olive oils obtained from various locations in Australia, indicating that the wax rate of oils could vary according to climate and variety. Total phenolic contents of crude oils averaged 0.642 mg g−1 for C. ovata species (P < 0.01) (Table 2). Seed oils of C. spinosa ˘ var. spinosa from Mugla-Milas (2009) and C. ovata var. canescens from Ankara-Beypazar𝚤 (2009) had the highest (2.180 mg g−1 ) and lowest (0.466 mg g−1 ) total phenolic contents respectively (P < 0.05). The total phenolic content of crude caper oil can vary according to location and harvest year. Ak𝚤n and Akd𝚤¸sl𝚤35 reported total phenolic contents of grape seed oils between 71.192 and 87.031 mg g−1 . In a study on the biochemical characterisation of Memecik olive oils, total phenolic contents ranging from 106.89 ± 17.59 to 171.34 ± 16.80 mg kg−1 were found.36 In terms of their total phenolic contents, caper seed oils can be a new oil source for food and industrial applications. Fatty acid composition The fatty acid composition of caper seed oils from different locations is given in Table 3. Fatty acid compositions were similar in the two varieties, except for specific fatty acids. Oleic and linoleic acid contents were high in C. spinosa and C. ovata species respectively. Seed oils of C. spinosa var. aegyptia from Antalya-Kepez (2010) ˘ and C. spinosa var. spinosa from Mugla-Milas (2010) had the highest (17.353%) and lowest (8.471%) saturated fatty acid contents respectively. The amount of saturated fatty acids was higher in C. spinosa species than in C. ovata species. ˘ Seed oils of C. spinosa var. spinosa from Mugla-Milas (2010) and C. spinosa var. aegyptia from Antalya-Kepez (2010) had the highest (91.528%) and lowest (82.646%) unsaturated fatty acid contents respectively. The amount of unsaturated fatty acids was higher in C. ovata species than in C. spinosa species. Gupta and Chakraborty37 determined the major fatty acids in caper seeds as palmitic (21%), oleic (57%) and linoleic (1%) acids. Özcan and Akgül26 determined the fatty acid composition of oils obtained from C. spinosa L.var. spinosa and C. ovata Desf. var. canescens seeds cultivated in Turkey. They found palmitic (13.2 and 11.3% respectively), palmitoleic (4.6 and 1.8%), stearic (3.2 and 2.7%), oleic (49.87 and 34.66%), linoleic (25.2 and 24.5%) and linolenic (1.0 and 0.3%) acids as the main fatty acids, with unsaturated fatty acids accounting for 15% of total fatty acids. Ul’chenko et al.38 extracted (Soxhlet) the oil from seeds of C. spinosa L. fruits collected in the Jizak region of Uzbekhistan and determined the major fatty acids of the oil by GC as 16:0, 18:1 and 18:2. In a study of fatty acids found in C. spinosa fruits, Tlili et al.31 determined the fatty acid composition by GC/mass spectrometry (MS). They found that 90.09% of fatty acids in the fruit oil were unsaturated fatty acids, the dominant one being 9,12-octadecadienoic acid (49.13%). In another study, the major fatty acids of C. spinosa and C. ovata seed oils were found to be palmitic (10.23 and 8.41% respectively), stearic (2.61 and 2.07%), oleic (38.45 and 44.62%), linoleic (23.75 and 18.26%) and linolenic (1.17 and 0.56%) acids.39 In parallel with our results, those of other researchers showed that the fatty acid composition of seed oils could change according to variety/species of plant and cultivation, harvesting and postharvest conditions.40 Also, when we compared the fatty acid J Sci Food Agric (2015)
composition of commonly used sunflower oil with that of caper seed oil, it was seen that the major fatty acids of sunflower oils were palmitic (7.9–12.0%), stearic (4.5–6.7%), oleic (34.4–45.5%) and linoleic (36.9–47.9%) acids,29 while those of caper seed oils were palmitic (5–6%), stearic (2–3%), oleic (32–49%) and linoleic (28–56%) acids. This comparison shows that the fatty acid compositions of caper seed oil and sunflower oil show parallelism. In particular, unsaturated fatty acids found in C. spinosa and C. ovata seed oils have some nutritional and industrial properties. In addition, Tlili et al.31 found that C. spinosa seed oils were rich in linoleic (>20%) and linoleic (1%) acids and other essential fatty acids which are important in terms of nutritional and industrial aspects. Sterol and tocopherol contents Sterol contents of crude oils ranged between 3140 and 3272 mg kg−1 (average 3220 mg kg−1 ) for C. spinosa species and between 3275 and 3312 mg kg−1 (average 3298 mg kg−1 ) for C. ovata species (Table 4). Seed oils of C. ovata var. palaestina from Mardin-Savur (2010) and C. ovata var. canescens from AnkaraBeypazar𝚤 (2009) had the highest sterol content (3312 mg kg−1 ), while seed oil of C. spinosa var. herbaceae from Mardin-Midyat (2009) had the lowest sterol content (3140 mg kg−1 ). The sterol content of caper seed oil can vary according to variety and location. In addition, sterol contents of vegetable oils such as sunflower, maize, canola, nut and cotton oils range between 0.2 and 1%.29 Thus the sterol content of caper seed oil (0.32–0.33%) shows parallelism with that of other vegetable oils. Seed oils of C. spinosa and C. ovata contain high levels of sitosterol, stigmasterol and campesterol, which increases the nutritional and pharmacological value of caper seeds. Matthäus and Özcan41 reported sterol contents of seed oils of C. ovata and C. spinosa species of 4875.5–12189.1 and 4961.8–10009.1 mg kg−1 respectively. They also reported that the sterols consisted of 60% sitosterol, 16% campesterol and 10% stigmasterol as well as high levels of Δ5 -avenasterol (138.8–599.4 mg kg−1 ). Tlili et al.5 determined 12 different sterols in the analysis of C. spinosa seed oils by GC, with total sterol contents ranging between 2068 and 2470 mg kg−1 (average 2240.4 mg kg−1 ). On average, these sterols comprised 1289.54 mg kg−1 sitosterol (57.53%), 382.37 mg kg−1 campesterol (17.05%), 265.31 mg kg−1 stigmasterol (11.85%) and 141.63 mg kg−1 Δ5 -avenasterol (6%) as well as low amounts of cholesterol. In their analysis of sterols in C. spinosa seed oils, Matthäus and Özcan41 found an average Δ5 -avenasterol level of 336 mg kg−1 . Our results show that contents of sterols, the most important minor components in oils, are high in C. spinosa and C. ovata oils, and these substances have a role in decreasing human serum cholesterol levels.25,42 Statistical analysis results for 𝛼-tocopherol contents of oils obtained from caper seeds collected from different locations are given in Table 4. Average 𝛼-tocopherol contents were 3.87 and 2.63 mg per 100 g for C. spinosa and C. ovata species respectively. Seed oils of C. spinosa var. inermis from Antalya-Serik (2010) and C. ovata var. palaestina from Mardin-Savur (2009) had the highest (10.81 mg per 100 g) and lowest (0.84 mg per 100 g) 𝛼-tocopherol contents respectively. Matthäus and Özcan41 studied the tocopherol composition of seed oils of C. ovata and C. spinosa collected from 11 different locations in Turkey and found 𝛾-tocopherol levels of 124.3–1944.9 mg per 100 g, 𝛿-tocopherol levels of 2.7–269.5 mg per 100 g and 𝛼-tocopherol levels of 0.6–13.8 mg per 100 g. They also determined that 88% of the
© 2014 Society of Chemical Industry
wileyonlinelibrary.com/jsfa
www.soci.org
D Erman, MM Özcan
Table 3. Fatty acid composition (%) of caper seed oils
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovate var. canescens C. ovate var. palaestina
Variety C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovate var. canescens C. ovate var. palaestina
Harvest year
Lauric (C12:0)
Myristic (C14:0)
Palmitic (C16:0)
Margaric (C17:0)
Stearic (C18:0)
Arachidic Behenic Lignoceric (C20:0) (C22:0) (C24:0)
∑
SFA
Palmitoleic (C16:1)
2009
0
0.116
5.854
0
2.833
0.721
0.760
0.170
10.455
1.392
2010 2009
0 0.078
0.07 0.369
4.927 11.435
0 0.055
2.173 3.418
0.506 0.711
0.663 0.763
0.126 0.102
8.471 16.934
1.264 4.517
2010 2009
0.047 0.055
0.249 0.286
11.907 11.534
0 0
3.603 3.368
0.761 0.708
0.684 0.745
0.099 0.093
17.353 16.791
4.411 4.732
2010 2009
0 0.074
0.257 0.352
11.130 11.489
0 0
3.388 3.423
0.791 0.710
0.762 0.765
0.097 0.100
16.428 16.916
4.624 4.594
2010 2009 2010 2009 2010
0.069 0.070 0.059 0 0
0.317 0.261 0.234 0.078 0.069
11.846 5.428 5.933 5.859 5.441
0 0 0 0.060 0
3.283 2.267 1.878 2.435 2.393
0.710 0.571 0.416 0.669 0.570
0.805 0.657 0.465 0.772 0.610
0.111 0.163 0.113 0.221 0.149
17.144 9.418 9.102 10.092 9.234
4.701 1.052 1.278 1.847 1.861
∑ MUFA
∑ PUFA
Harvest Heptadecenoic Oleic Eicosenoic year (C17:1) (C18:1) (C20:1)
Erusic (C22:1)
Eicosadienoic (C20:2)
Linoleic (C18:2)
Linolenic (C18:3)
∑
UFA
2009
0.192
36.219
0.535
0.063
0
50.409
0.730
38.404
51.140
89.544
2010 2009
0.231 0
32.945 49.257
0.458 0.694
0 0.066
0 0.009
55.981 28.323
0.646 0.176
34.900 54.555
56.627 28.509
91.528 83.065
2010 2009
0.427 0
46.956 48.076
0.357 0.166
0 0.060
0 0
30.075 29.522
0.418 0.530
52.152 53.036
30.494 30.052
82.646 83.088
2010 2009
0.489 0
47.845 48.356
0.399 0.663
0 0.061
0 0.663
29.695 29.004
0.517 0.173
53.358 53.675
30.213 29.841
83.571 83.517
2010 2009 2010 2009 2010
0.467 0.177 0 0.266 0.207
48.410 35.823 38.449 41.042 41.517
0.408 0.602 0.296 0.555 0.465
0 0.097 0.049 0 0
0 0.040 0.024 0 0
28.369 52.126 50.206 45.530 46.202
0.498 0.662 0.601 0.658 0.511
53.987 37.752 40.074 43.711 44.051
28.867 52.829 50.832 46.189 46.714
82.855 90.581 90.907 89.901 90.765
SFA, saturated fatty acids; MUFA, monounsaturated fatty acids; PUFA, poly unsaturated fatty acids; UFA, unsaturated fatty acids.
total tocopherol content in C. spinosa seed oils was 𝛾-tocopherol (average 581 mg per 100 g). Abbasi et al.43 reported 𝛼-tocopherol contents of 10.9–39.7 mg per 100 g (average 29.09 mg per 100 g) and 𝛽-tocopherol contents of 10.4–24.5 mg per 100 g (average 18.28 mg per 100 g). In an HPLC study on the tocopherol composition of leaves, flowers and buds of C. spinosa from Tunisia, it was determined that leaves had an 𝛼-tocopherol content of 20.19 ± 10 mg per 100 g, while flowers and buds had 𝛼-tocopherol contents of 49.12 ± 17.48 and 28.68 ± 9.13 mg per 100 g respectively and 𝛾-tocopherol contents of 48.13 ± 15.08 and 27.8 ± 16.01 mg per 100 g respectively.31 Tlili et al.31 established the fatty acid, tocopherol and carotene contents of C. spinosa seed oils collected from seven different locations in Tunisia. According to their research, the average tocopherol content of seed oils was 6.28 mg per 100 g. Caper seed oils are rich in 𝛼-tocopherol, 𝛾-tocopherol and 𝛿-tocopherol, which are isoforms of tocopherol compounds.5,31 Our 𝛼-tocopherol results were similar to those of Matthäus and Özcan.41 General differences could result from the different locations where samples were obtained, which could affect the chemical composition of the oil.31 Lavedrine et al.25 also reported that these differences could be due to geographical differences. Various researchers report that caper seed oil could be a new vegetable oil source in terms of pharmaceutical, industrial and nutritional aspects.1,3,31,41
wileyonlinelibrary.com/jsfa
CONCLUSIONS 1. As caper seed crude oils have high free fatty acidity (6.36–7.23), peroxide (2.82–1.37 meq kg−1 ) and colour (L* 39.66–43.13, a* 10.53–20.55, b* 0.17–24.20) values, they are unsuitable for consumption by humans. Therefore it is advised that they be consumed only after refinement to conform to Turkish Food Codex standards. 2. Specific gravity (0.929–0.934 g L−1 ), refractive index (nD 1.463–1.466), iodine (104.51–121.70) and saponification (193.31–192.13 mg g−1 ) values of caper seed oils showed parallelism with those of other vegetable oils such as sunflower, maize, nut, canola and cotton oils. 3. In terms of fatty acid composition, caper seed oils are rich in unsaturated fatty acids (82–91%) and essential fatty acids. Because of these properties, caper seed oils are thought to be important in terms of nutritional, cosmetic and industrial aspects. 4. Average sterol contents of seed oils of C. spinosa and C. ovata species were 3220 and 3298 mg kg−1 respectively, showing that caper seeds are a good phytosterol source in terms of nutritional, health and economic aspects. 5. Caper seed oils are rich in 𝛼-tocopherol (2.63–10.81 mg per 100 g) and thus are a natural potential vegetable oil source in terms of health, oil stability and resistance to oxidation.
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
www.soci.org
Table 4. Sterol and tocopherol contents of caper seed oils
Variety
Harvest year
C. spinosa var. spinosa C. spinosa var. aegyptia C. spinosa var. inermis C. spinosa var. herbaceae C. ovata var. canescens C. ovata var. palaestina
2009 2010 2009 2010 2009 2010 2009 2010 2009 2010 2009 2010
Total sterols (mg kg−1 ) 3272g ± 0.16 3266f ± 0.02 3259f ± 0.15 3173b ± 0.03 3216d ± 0.19 3235e ± 0.07 3140a ± 0.05 3199c ± 0.05 3312i ± 0.14 3275g ± 0.05 3294h ± 0.12 3312i ± 0.11
Sitosterol (%) 71.69g ± 0.200 69.04c ± 0.040 70.40de ± 0.045 69.01c ± 0.090 67.45b ± 0.050 66.19a ± 0.190 71.14f ± 0.140 70.60e ± 0.300 70.20d ± 0.200 70.53e ± 0.170 70.51e ± 0.090 71.670g ± 0.200
Campesterol (%)
Stigmasterol (%)
18.66e ± 0.160 18.97fg ± 0.030 19.04g ± 0.040 16.68c ± 0.180 14.11b ± 0.080 13.32a ± 0.080 18.69e ± 0.180 17.99d ± 0.150 20.05h ± 0.200 18.78ef ± 0.120 18.93fg ± 0.070 18.00d ± 0.050
9.65a ± 0.100 11.99f ± 0.200 10.55cd ± 0.300 9.91a ± 0.090 13.64g ± 0.140 20.49h ± 0.110 10.17b ± 0.170 11.41e ± 0.040 9.75a ± 0.200 10.69d ± 0.090 10.56cd ± 0.050 10.33bc ± 0.130
𝛼-Tocopherol (mg per 100 g) 2.20e ± 0.12 3.76f ± 0.09 1.30bc ± 0.20 4.62g ± 0.04 5.41h ± 0.18 10.81j ± 0.11 1.86d ± 0.15 1.03ab ± 0.06 6.87i ± 0.11 1.43c ± 0.08 0.84a ± 0.02 1.39c ± 0.16
Values are mean ± standard deviation.
6. All physical and chemical properties (except specific gravity) of caper seed oils varied according to the location where seeds were collected and the year in which they were harvested (P < 0.01).
ACKNOWLEDGEMENT This work was supported by Selçuk University Scientific Research Project (S.U.-BAP. Konya-Turkey).
REFERENCES 1 Rodrigo M, Lazaro M, Alvarruiz A and Giner V, Composition of capers (Capparis spinosa): influence of cultivar, size, and harvest date. J Food Sci 57:1152–1154 (1992). 2 Özcan M, Composition and pickling product of capers (Capparis spp.) flower buds. PhD Thesis, Department of Food Engineering, Selçuk University, Konya (1996). 3 Özcan M and Akgül A, Influence of species, harvest date and size on composition of capers (Capparis spp.) flower buds. Nahrung 42:102–105 (1998). 4 Alvarruiz A, Rodrigo M, Miquel J, Girer V, Feria A and Vila R, Influence of brining and packing conditions on product quality of capers. J Food Sci 55:196–198, 227 (1990). 5 Tlili N, Nasri N, Saadaoui E, Khaldi A and Triki S, Sterol composition of caper (Capparis spinosa) seeds. Afr J Biotechnol 9:3328–3333 (2010). 6 Ivanov SA and Aitzetmüller K, Untersuchungen über die Tocopherolund Tocotrienolzusammensetzung der Samenöle einiger Vertreter der Familie Apiaceae. Eur J Lipid Sci Technol 97:24–29 (1995). 7 Gutteridge JM, Rowley DA and Halliwell B, Superoxide-dependent formation of hydroxyl radicals in the presence of iron salts. Biochem J 199:263–265 (1981). ˘ NM and Nas S, The phenolic compounds in vegetables 8 Nizaml𝚤oglu and fruit; structures and their importance. Electron J Food Technol 5(1):20–35 (2010). 9 Vanhanen HT, Blomqvist S, Ehnholm C, Hyvonen M, Jauhiainen M, Torstila I, et al., Serum cholesterol, cholesterol precursors, and plant sterols in hypercholesterolemic subjects with different apo-E phenotypes during dietary sitostanol ester treatment. J Lipid Res 34:1535–1544 (1993). 10 Law M, Plant sterol and stanol margarines and health. Br Med J 320:861–864 (2000). 11 Awad AB and Fink CS, Phytosterols as anticancer dietary components: evidence and mechanism of action. J Nutr 130:2127–2130 (2000). 12 National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Final report. Circulation 106:3143–3421 (2002).
J Sci Food Agric (2015)
13 Hendricks HFJ, Weststrate JA, Vabvliet T and Meijer GW, Spreads enriched with three different levels of vegetable oil sterols and the degree of cholesterol lowering in normocholesterolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr 53:319–327 (1999). 14 AOCS, Official Methods and Recommended Practices (4th edn), Vol. 1. American Oil Chemists’ Society, Champaign, IL (1990). 15 CIE, Official Recommendations of the International Commission on Illumination. Publication CIE No.15 (E-1.3.1). Bureau Central de la CIE, Paris (1976). 16 Anupama D, Bhat K and Sapna V, Sensory and physicochemical properties of commercial samples of honey. Food Res Int 36:183–191 (2002). 17 Encyclopedia Britannica (15th edn). Encyclopedia Britannica, London (1994). 18 Singleton VL and Rossi JA, Colorimetry of total phenoloics with phosphomolybdic–phosphotungstic acid reagents. Am J Enol Vitic 16:144–158 (1965). 19 Lee SK, Mbwambo ZH, Chung HS, Luyengi L, Games EJC and Mehta RG, Evaluation of the antioxidant potential of natural products. Combin Chem High Throughput Screen 1:35–46 (1998). 20 H𝚤¸s𝚤l Y, Enstrümantal G𝚤da Analizleri – II (4. Bask𝚤). Yay𝚤n No. 45. Ege Üniversitesi Mühendislik Fakültesi ders Kitaplar𝚤, ˙Izmir (2004). 21 Özkaya H, Analitik G𝚤da Kontrolü. Yay𝚤n No. 1068, Ankara Üniversitesi Ziraat Fakültesi, Ankara (1988). 22 Balz M, Schulte E and Thier H-P, Trennung von Tocopherolen und Tocotrienolen durch HPLC. Eur J Lipid Sci Technol 94:209–213 (1992). 23 Phillips KM, Ruggio DM and Ashraf-Khorassani M, Phytosterol composition of nuts and seeds commonly consumed in the United States. J Agric Food Chem 53:9436–9445 (2005). 24 Özdamar K, SPPS ile Bioistatistik. Yay𝚤n No. 3. ETAM A.¸S. Matbaa Tesisleri, Eski¸sehir (1999). 25 Lavedrine F, Ravel A, Poupard A and Alary J, Effect of geographic origin, variety and storage on tocopherol concentrations in walnuts by HPLC. Food Chem 58:135–140 (1997). 26 Özcan M and Akgül A, Some compositional characteristics of capers (Capparis spp.) seed and oil. Grasas Aceites 50:49–52 (1999). ˘ tohumlarda kalite kontrolü [Quality control in oil seeds]. 27 Y𝚤lmaz M, Yagl𝚤 [Online]. (2008). Available: www.gidacilar.net [21 February 2012]. 28 Georing CE, Schwab AW, Daughurty MJ, Pryde EH and Heakin AJ, Fuel properties of eleven vegetable oils. Trans ASAE 25:1472–1477 (1982). ˘ T and Karaali A, Türk Bitkisel Ya˘glar𝚤n𝚤n Ya˘g Asitleri Bile¸simleri. 29 Yaz𝚤c𝚤oglu Yay𝚤n No. 70. Tübitak Marmara Bilimsel ve Endüstriyel Ara¸st𝚤rma Enstitüsü Beslenme ve G𝚤da Teknolojisi Bölümü, Gebze (1983) (in Turkish). 30 Tlili N, Saadaoui E, Sakouhi F, Elfalleh W, El Gazzah M, Triki S, et al., Morphology and chemical composition of Tunisian caper seeds: variability and population profiling. Afr J Biotechnol 10:2112–2118 (2011).
© 2014 Society of Chemical Industry
wileyonlinelibrary.com/jsfa
www.soci.org 31 Tlili N, Munné-Bosch S, Nasri N, Saadaoui E, Khaldi A and Triki S, Fatty acids, tocopherols and carotenoids from seeds of Tunisian caper Capparis spinosa. J Food Lipids 16:452–464 (2009). 32 Morrison WH, Variation in the wax content of sunflower seed with location and hybrid. J Am Oil Chem Soc 60:1013–1014 (1983). 33 Carelli A, Frizzera LM, Forbita PR and Crapiste GH, Wax composition of sunflower seed oils. J Am Oil Chem Soc 79:763–768 (2002). 34 Mailer RJ, Ayton J and Graham K, The influence of growing region, cultivar and harvest timing on the diversity of Australian olive oil. J Am Oil Chem Soc 87:877–884 (2010). 35 Ak𝚤n A and Akdi¸sli A, Emir, Gök Üzüm ve Kara Dimitri üzüm çe¸sitlerinin ˘ çekirdek yaglar𝚤n𝚤n yag˘ asidi kompozisyonu ve fenolik madde içeriklerinin belirlenmesi. Akademik G𝚤da 8(6):19–23 (2010). ˘ H and Özçelik B, Memecik zeytinyaglar𝚤n𝚤n ˘ 36 ˙Ilyasoglu biyokimyasal karakterizasyonu. G𝚤da 36(1):33–41 (2011). 37 Gupta AS and Chakrabarty MM, Composition of the seed fats of the Capparidaceae family. J Sci Food Agric 15:69–73 (1964).
wileyonlinelibrary.com/jsfa
D Erman, MM Özcan 38 Ul’chenko NT, Bekker NP and Glushenkova AI, Neutral lipids from seeds of Asteraceae plants. Chem Nat Comp 44:147–150 (2008). ˘ 39 Haciseferogullar𝚤 H, Özcan MM and Duman E, Biochemical and technological properties of seeds and oils of Capparis spinosa and Capparis ovata plants growing wild in Turkey. J Food Process Technol 2:129–135 (2011). 40 ˙Ilisulu K, Oil Plants and Breeding. Caglayan Bookshop, Istanbul (1973). 41 Matthäus B and Özcan M, Glucosinolates and fatty acid, sterol, and tocopherol composition of seed oils from Capparis spinosa var. spinosa and Capparis ovata Desf. var. canescens (Coss.) Heywood. J Agric Food Chem 53:7136–7141 (2005). 42 Westrate JA and Meijer GW, Plant sterol-enriched margarines and reduction of plasma total- and LDL-cholesterol concentrations in normocholesteolaemic and mildly hypercholesterolaemic subjects. Eur J Clin Nutr 52:334–343 (1998). 43 Abbassi AR, Hajırezeaı M, Hofıus D, Sonnewald U and Voll LM, Specific role of a- and g-tocopherol in abiotic stres responses of transgenictobacco. Plant Physiol 143:1720–1738 (2007).
© 2014 Society of Chemical Industry
J Sci Food Agric (2015)
