Major triacylglycerol composition of the oil from
Abstract
In this chapter, amaranth seed oil composition will be presented. The main component of this oil is triacylglycerols (TAGs). TAGs are composed of fatty acids, which have an important effect on oil stability, application, and nutritional properties. POL, PLL, POO, OLL, and LOO are the predominant TAGs in the amaranth seed oil. Linoleic acid (C18:2), oleic acid (C18:1), and palmitic acid (C16:0) are the predominant fatty acids present in the amaranth oil. Minor components of this oil are squalene, sterols, tocopherols, carotenoids, phospholipids, etc. Growth conditions of amaranth and extraction conditions can influence oil composition, which will be discussed in this chapter as well. Oil stability and quality parameters will be also discussed. The stability of this oil during different conditions of storage will be a part of this chapter.
Keywords
- triacylglycerol
- fatty acid
- squalene
- tocopherol
- sterol
1. Introduction
Grain amaranth is considered as a gluten-free pseudocereal, which is a non-grass but cereal-like grain (true cereals are classified as grasses). It is suitable to be used as the celiac disease patient diet as it contains no gluten [1]. Among more than 60 species, the grain of
The amaranth grain is mainly composed of about 61.3–76.5% carbohydrate (mostly starch), 13.1–21.5% crude protein, 5.6–10.9% crude fat, 2.7–5% crude fiber, and 2.5–4.4% ash [3]. Proteins and lipids are two nutritiously important macromolecules of the amaranth grain. The content and even the quality of these two macronutrients are different from those with cereals. The amaranth grain has higher protein content in comparison to cereals. Lysine, which is the limiting amino acid in cereals, is found in higher amounts in amaranth grain. The high protein content of the amaranth grain is also evident from its high essential amino acid index (EAAI = 90.4%), which makes it comparable with egg protein [4].
In addition to protein content and special amino acid profile, amaranth grain usually contains 5–8% fat, which is important from the nutritional aspect [5]. However,
The fat content of amaranth grain is two to three times higher than cereals [7]. The oil is usually extracted from the grain by the solvent extraction method with the help of a non-polar organic solvent in a Soxhlet apparatus [8]. Supercritical carbon dioxide can be used as an alternative to traditional organic solvents for the extraction of the oil (supercritical fluid extraction method) [9, 10]. In the accelerated solvent extraction method, high pressure and temperature (even above the boiling point of the organic solvent) are used [6]. The oil yield with the Soxhlet method (62.1–75.7%) and accelerated solvent extraction method (65.1–78.1%) is almost similar; however, the latter is faster and uses lower organic solvent. The supercritical fluid extraction method has the lowest oil yield among the three methods (54.6–61.1%) [8].
Lipid fraction is mainly composed of triacylglycerols (TAGs) as the major component (around 80%) and other minor compounds, such as squalene, sterols, tocopherols, carotenoids, phospholipids, etc. [11]. Lipid fraction can also be divided into two groups: free lipids and bonded lipids. TAGs are the major free lipids, while phospholipids (up to 10.2% of total lipids) and glycolipids (6.4% of total lipid fraction) comprise the main part of the bounded lipids [11].
2. Triacylglycerol profile
TAGs are the major component of the amaranth oil, comprising 78–82% of the lipid fraction [11, 12]. Di- and monoacylglycerols comprise 5.1–6.5 and 3–3.5% of lipid fraction, respectively [11]. They are composed of fatty acids. Although the oxidative stability and the nutritional value of the oil are determined by the fatty acid profile, the functionality of oil is affected by the type and amount of TAGs [13]. The predominant structures in the amaranth oil are diunsaturated TAGs (UUS; 43.4–50.2%) and triunsaturated TAGs (UUU; 33–35.7%) [13].
The major TAG composition of
3. Fatty acid composition
The fatty acid composition of the oil gives information about oxidative stability and nutritional quality. Table 2 presents the fatty acid profile of some species of
C16 | C18:0 | C18:1 | C18:2 | Source | |
---|---|---|---|---|---|
15.8–27 | Tr-4.2 | 20.3–38.9 | 33.6–47 | [7, 13, 15, 16, 17, 18, 19] | |
12.3–20.5 | 2.2–4.7 | 23.8–32.9 | 35.6–49.8 | [11, 18, 20] | |
17.9–24 | 0.9–3.7 | 16.3–33.7 | 38.9–52.5 | [13, 15, 16, 18] | |
18.6–22 | 1.3–4.4 | 18.7–26.3 | 47.4–55.9 | [12, 15, 16, 18] | |
19.5–24.3 | 1–3.6 | 25.9–27.5 | 46.4–51.5 | [15, 16, 21] | |
15.7–25.9 | 0.7–4.1 | 14.8–30.5 | 46.9–53.5 | [15, 18, 21] |
4. Squalene
Squalene is a triterpene (C30H50) with six double bonds at carbon numbers 2, 6, 10, 14, 18, and 22, which is present in the unsaponifiable fraction of the oil (Figure 1). It is an intermediate molecule for the biosynthesis of phytosterols and cholesterol [22]. The main sources of squalene are whale and shark liver oil (40–86%). However, due to the concerns about the extinction of these marine animals, attempts are made to replace the animal source of squalene with a plant one [23].
Vegetable oils can be used as dietary sources of squalene. There is about 0.5% squalene in olive oil; around 0.03% in corn, hazelnut, and peanut oils; and 0.01% in grape seed and soybean oils [24]. The deodorizer distillates of oils such as olive oil, soybean oil, and palm fatty acids have higher amounts of squalene, containing 10–30, 1.8–3.5, and 0.2–1.3%, respectively [25].
Amaranth grain is another natural plant source of squalene. Although amaranth grain has lower oil content compared to the other oil-containing seeds, its oil fraction is a rich source of squalene [26] (Table 3). The high content of squalene in the amaranth grain oil makes it a unique component, which can be used to recover squalene. Although the direct derivation of squalene from amaranth seed is not economically affordable, the recovery of squalene from amaranth oil as a coproduct of starch production is advantageous [26]. An extensive study on 104 genotypes from 30 species of
% Squalene | Reference | |
---|---|---|
6.56 | [7] | |
4.9 | [11] | |
5.74–6.95 | [27] | |
2.26–5.94 | [17] | |
4.2–5.44 | [16] | |
3.32–4.93 | [15] | |
9.16 | [13] | |
6.96 | [14] | |
5.29–6.25 | [28] | |
4.74–6.98 | [15] | |
3.62–5.01 | [16] | |
9.96 | [13] | |
6.05–7.12 | [28] | |
5.23 | [16] | |
2.26–7.3 | [15] | |
0.67–8.19 | [20] | |
4.8 | [11] | |
4.73–5.75 | [15] | |
6.14 | [16] | |
2.72–5.63 | [15] |
5. Phytosterols
Plant sterols (phytosterols) are minor components of the vegetable oils, which comprise a large proportion of unsaponifiable fraction. They contribute to oxidative stability and extended shelf-life and have serum cholesterol-lowering properties [29, 30]. Phytosterols are found as 4-desmethysterols, 4-monomethylsterols, and 4, 4′-dimethylsterols. They can also be classified as free and esterified forms [31]. It has been reported that a large proportion of the phytosterols in amaranth oil are in esterified form and only low amounts are present in the free form (about 20%) [7]. However, in most of the vegetable oils, such as soybean, sesame, olive, cottonseed, safflower, palm and coconut oils, free sterols comprise the predominant form (54–85%) [32].
Total phytosterol content of the amaranth oil is between 1931 and 2762 mg/100 g oil [7, 21, 27, 33]. This level of phytosterol in amaranth oil is much higher than values established by Codex Alimentarius for most of common vegetable oils, such as coconut oil (40–120 mg/100 g), cottonseed oil (270–640 mg/100 g), flaxseed oil (230–690 mg/100 g), palm oil (30–70 mg/100 g), low-erucic acid rapeseed oil (450–1130 mg/100 g), safflower oil (210–460 mg/100 g), sesame oil (450–1900 mg/100 g), soybean oil (180–450 mg/100 g), and sunflower oil (240–500 mg/100 g) [34, 35]. However, wheat germ oil (4240 mg/100 g) and rice bran oil (1050–3100 mg/100 g) have total phytosterol content higher than amaranth oil [34, 36].
The phytosterol composition of the different
I | II | III | IV | V | VI | |||
---|---|---|---|---|---|---|---|---|
Cholesterol | Tr | 0.01 | 0.01 | — | — | — | — | — |
24-Methylene cholesterol | 0.3 | 0.42 | 0.25 | 1.64 | 1.54 | 1.41 | — | — |
Campesterol | 1.6 | 0.76 | 1 | 1.83 | 1.96 | 1.96 | 2.61 | 1.57 |
Stigmasterol | 0.9 | 0.77 | 0.44 | 1.28 | 1.08 | 1.49 | 20.09 | 13.7 |
Δ7-Ergostenol | — | 23.8 | 25.3 | — | — | — | — | — |
α-Spinasterol | — | 34.2a | 26.3a | 44.94b | 53.24b | 56.31b | — | — |
Sitostanol | Tr | 0.25 | 0.18 | 1.18 | 1.35 | 1.09 | — | — |
Δ7-Campesterol | 24.8 | — | — | — | — | — | 31.19 | 24.35 |
Clerosterol | 42 | — | — | — | — | — | 1.58 | 3.71 |
Sitosterol | 1.3 | — | — | — | — | — | 2 | 1.74 |
Δ5-Avenasterol | 2 | 1.68 | 2.34 | 0.79 | 0.74 | 0.35 | 24.27 | 30.76 |
Δ5,24-Stigmastadienol | Tr | 1.89 | 2.26 | 1.92 | 2.04 | 1.45 | 13.66 | 10.73 |
Δ7-Stigmastenol | 15.2 | 22.2 | 24.4 | 15.02 | 14.48 | 11.74 | 0.69 | 1.52 |
Δ7-Avenasterol | 11.9 | 13.4 | 14.9 | 8.56 | 7.27 | 8.09 | 0.15 | 6.11 |
Δ7-Ergosterol | — | — | — | 17.29 | 16.32 | 16.12 | — | — |
Cycloartenol | 1.63 | — | — | 2.26 | 0 | 0 | — | — |
Citrostadienol | 1.3 | — | — | 3.3 | 0 | 0 | — | — |
Total sterol (mg/100 g) | 2460 | 2730 | 2590 | 2490 | 1931 | 2140 | 2488.7 | 2762 |
Reference | [7] | [33] | [33] | [27] | [27] | [27] | [21] | [21] |
6. Tocopherols and tocotrienols
Tocopherols and tocotrienols (i.e., tocols) are a part of unsaponifiable fraction, which are forms of vitamin E and act as natural antioxidants in the vegetable oils. Tocotrienols are structurally similar to the tocopherols, except that tocotrienols have three double bonds within their phytol chains [37]. They have a chromanol ring attached to a phytol chain. Each of tocopherols and tocotrienols is divided into four subclasses, α-, β-, γ-, and δ- forms, which differ from each other as to the number of methyl groups on the chromanol ring [38]. The structure of eight homologs of tocopherols and tocotrienols is presented in Figure 2.
Tocopherols comprise the majority of the tocols in most of the common oils. However, tocotrienols are predominant in palm, rice bran, grape seed, and barely oils [39, 40]. It has been reported that amaranth seed has small or negligible amounts of tocotrienols [7, 18]. However, there are also reports that amaranth seed oil has tocotrienol content higher than some vegetable oils, such as soybean oil, peanut oil, and olive oil [21, 41].
γ-Tocopherol is the dominant tocol in most edible oils such as corn, soybean, rapeseed, sesame seed, and flaxseed oils. While α-tocopherol is the most abundant tocol in some vegetable oils such as safflower, sunflower, and olive oils [40]. Total and individual content of tocol homologs depends on the amaranth species, varieties, variation in analytical and extraction methods, and also growing location and cultivation conditions [18, 42]. The total tocol content of 21 amaranth accessions has been reported to be 31.5–78.3 mg/kg seed (wet basis), with an average of 49.4 mg/kg seed (wet basis) [18].
The study on the effect of dosages of fertilization with macronutrients on the tocopherol profile of two varieties of
7. Carotenoids
Carotenoids are essential photosensitizers, which have an important role in plant photosynthesis. They are also considered as provitamin A and possess antioxidative properties [44]. The two carotenoids lutein (3.55–4.44 mg/kg seeds) and zeaxanthin (trace to 0.32 mg/kg seeds) have been detected in amaranth seeds, lutein being the predominant one. β-Carotene, the most known carotenoid, has not been detected in amaranth seeds [45].
8. Phospholipids
Phospholipids are essential polar lipid materials that have an important role in biological membranes. TAGs are the major components of the nonpolar fraction of the lipid. However, phospholipids are the main compounds of the polar fraction of the lipids, which are considered as bound lipids. The phospholipid content of the amaranth grain oil has been reported to be in the range of 9.1–10.2% of total lipids [11].
9. Oxidative stability
Concerning the high concentration of squalene and tocopherols, the amaranth oil is expected to have good oxidative stability. Oxidative stability of amaranth oil was determined by monitoring the peroxide value at 60°C for 30 days. It has been reported that amaranth oil had good oxidative stability, even better than the oxidative stability of sunflower oil [11]. However, direct investigation of the stability of crude amaranth oil obtained opposite results. It has been reported that although amaranth oil contains high concentrations of squalene and tocopherols, which are strong antioxidants, it did not have good oxidative stability [46].
10. Conclusion
Amaranth grain contains 5–8% oil, which is mainly comprised of triacylglycerols (78–82%). The oil also contains important minor phytochemicals, such as squalene (up to 10%), phytosterols (2–3%), tocopherols, carotenoids, and phospholipids (up to 10%). The high content of tocopherols and squalene, which act as antioxidants, provides high oxidative stability for amaranth oil. The unique composition of amaranth seed oil makes it a useful ingredient in the food, pharmaceutical, and cosmetic industries.
Conflict of interest
The authors declare no conflict of interest.
References
- 1.
Mota C, Santos M, Mauro R, Samman N, Matos AS, Torres D, et al. Protein content and amino acids profile of pseudocereals. Food Chemistry. 2016; 193 :55-61. DOI: 10.1016/j.foodchem.2014.11.043 - 2.
Caselato-Sousa VM, Amaya-Farfán J. State of knowledge on amaranth grain: A comprehensive review. Journal of Food Science. 2012; 77 (4):R93-R104. DOI: 10.1111/j.1750-3841.2012.02645.x - 3.
Mlakar SG, Turinek M, Jakop M, Bavec M, Bavec F. Nutrition value and use of grain amaranth: potential future application in bread making. Agricultura. 2009; 6 (4):43-53 - 4.
Písaříková B, Kráčmar S, Herzig I. Amino acid contents and biological value of protein in various amaranth species. Czech Journal of Animal Science. 2005; 50 (4):169-174. DOI: 10.17221/4011-CJAS - 5.
Gimplinger D, Dobos G, Schonlechner R, Kaul H. Yield and quality of grain amaranth (Amaranthus sp.) in Eastern Austria. Plant Soil and Environment. 2007; 53 (3):105-112 - 6.
Kraujalis P, Venskutonis PR, Pukalskas A, Kazernavičiūtė R. Accelerated solvent extraction of lipids from Amaranthus spp. seeds and characterization of their composition. LWT- Food Science and Technology. 2013; 54 (2):528-534. DOI: 10.1016/j.lwt.2013.06.014 - 7.
León-Camacho M, García-González DL, Aparicio R. A detailed and comprehensive study of amaranth ( Amaranthus cruentus L.) oil fatty profile. European Food Research and Technology. 2001;213 (4-5):349-355. DOI: 10.1007/s002170100340 - 8.
Krulj J, Brlek T, Pezo L, Brkljača J, Popović S, Zeković Z, et al. Extraction methods of Amaranthus sp. grain oil isolation. Journal of the Science of Food and Agriculture. 2016; 96 (10):3552-3558. DOI: 10.1002/jsfa.7540 - 9.
Westerman D, Santos R, Bosley J, Rogers J, Al-Duri B. Extraction of Amaranth seed oil by supercritical carbon dioxide. The Journal of Supercritical Fluids. 2006; 37 (1):38-52. DOI: 10.1016/j.supflu.2005.06.012 - 10.
Shaddel R, Maskooki A, Haddad-Khodaparast MH, Azadmard-Damirchi S, Mohamadi M, Fathi-Achachlouei B. Optimization of extraction process of bioactive compounds from Bene hull using subcritical water. Food Science and Biotechnology. 2014; 23 (5):1459-1468. DOI: 10.1007/s10068-014-0200-7 - 11.
Gamel TH, Mesallam AS, Damir AA, Shekib LA, Linssen JP. Characterization of amaranth seed oils. Journal of Food Lipids. 2007; 14 (3):323-334. DOI: 10.1111/j.1745-4522.2007.00089.x - 12.
Martirosyan DM, Miroshnichenko LA, Kulakova SN, Pogojeva AV, Zoloedov VI. Amaranth oil application for coronary heart disease and hypertension. Lipids in Health and Disease. 2007; 6 (1):1. DOI: 10.1186/1476-511X-6-1 - 13.
Jahaniaval F, Kakuda Y, Marcone M. Fatty acid and triacylglycerol compositions of seed oils of five Amaranthus accessions and their comparison to other oils. Journal of the American Oil Chemists’ Society. 2000; 77 (8):847-852. DOI: 10.1007/s11746-000-0135-0 - 14.
Lyon C, Becker R. Extraction and refining of oil from amaranth seed. Journal of the American Oil Chemists’ Society. 1987; 64 (2):233-236. DOI: 10.1007/BF02542008 - 15.
He H-P, Corke H. Oil and squalene in amaranthus grain and leaf. Journal of Agricultural and Food Chemistry. 2003; 51 (27):7913-7920. DOI: 10.1021/jf030489q - 16.
He H-P, Cai Y, Sun M, Corke H. Extraction and purification of squalene from Amaranthus grain. Journal of Agricultural and Food Chemistry. 2002; 50 (2):368-372. DOI: 10.1021/jf010918p - 17.
Berganza BE, Moran AW, Rodríguez GM, Coto NM, Santamaría M, Bressani R. Effect of variety and location on the total fat, fatty acids and squalene content of amaranth. Plant Foods for Human Nutrition. 2003; 58 (3):1-6. DOI: 10.1023/B:QUAL.0000041143.24454.0a - 18.
Budin JT, Breene WM, Putnam DH. Some compositional properties of seeds and oils of eight Amaranthus species. Journal of the American Oil Chemists’ Society. 1996; 73 (4):475-481. DOI: 10.1007/BF02523922 - 19.
Ogrodowska D, Zadernowski R, Czaplicki S, Derewiaka D, Wronowska B. Amaranth seeds and products–the source of bioactive compounds. Polish Journal of Food and Nutrition Sciences. 2014; 64 (3):165-170. DOI: 10.2478/v10222-012-0095-z - 20.
Bruni R, Medici A, Guerrini A, Scalia S, Poli F, Muzzoli M, et al. Wild Amaranthus caudatus seed oil, a nutraceutical resource from Ecuadorian flora. Journal of Agricultural and Food Chemistry. 2001; 49 (11):5455-5460. DOI: 10.1021/jf010385k - 21.
Z-s Z, Y-j K, Che L. Composition and thermal characteristics of seed oil obtained from Chinese amaranth. LWT. 2019; 111 :39-45. DOI: 10.1016/j.lwt.2019.05.007 - 22.
Huang Z-R, Lin Y-K, Fang J-Y. Biological and pharmacological activities of squalene and related compounds: Potential uses in cosmetic dermatology. Molecules. 2009; 14 (1):540-554. DOI: 10.3390/molecules14010540 - 23.
Popa O, Băbeanu NE, Popa I, Niță S, Dinu-Pârvu CE. Methods for obtaining and determination of squalene from natural sources. BioMed Research International. 2015; 2015 . Article ID: 367202. DOI: 10.1155/2015/367202 - 24.
Frega N, Bocci F, Lercker G. Direct gas chromatographic analysis of the unsaponifiable fraction of different oils with a polar capillary column. Journal of the American Oil Chemists’ Society. 1992; 69 (5):447-450. DOI: 10.1007/BF02540946 - 25.
Naziri E, Mantzouridou F, Tsimidou MZ. Squalene resources and uses point to the potential of biotechnology. Lipid Technology. 2011; 23 (12):270-273. DOI: 10.1002/lite.201100157 - 26.
Sun H, Wiesenborn D, Tostenson K, Gillespie J, Rayas-Duarte P. Fractionation of squalene from amaranth seed oil. Journal of the American Oil Chemists’ Society. 1997; 74 (4):413-418. DOI: 10.1007/s11746-997-0099-8 - 27.
Czaplicki S, Ogrodowska D, Zadernowski R, Derewiaka D. Characteristics of biologically-active substances of amaranth oil obtained by various techniques. Polish Journal of Food and Nutrition Sciences. 2012; 62 (4):235-239. DOI: 10.2478/v10222-012-0054-8 - 28.
Bozorov SS, Berdiev NS, Ishimov UJ, Olimjonov SS, Ziyavitdinov JF, Asrorov AM, et al. Chemical composition and biological activity of seed oil of amaranth varieties. Nova Biotechnologica et Chimica. 2018; 17 (1):66-73. DOI: 10.2478/nbec-2018-0007 - 29.
Azadmard-Damirchi S, Dutta PC. Stability of minor lipid components with emphasis on phytosterols during chemical interesterification of a blend of refined olive oil and palm stearin. Journal of the American Oil Chemists’ Society. 2008; 85 (1):13-21. DOI: 10.1007/s11746-007-1170-1 - 30.
Azadmard-Damirchi S, Emami S, Hesari J, Peighambardoust S, Nemati M. Nuts composition and their health benefits. World Academy of Science, Engineering and Technology. 2011; 5 :544-548. DOI: 10.5281/zenodo.1329785 - 31.
Azadmard-Damirchi S, Dutta PC. Free and esterified 4, 4′-dimethylsterols in hazelnut oil and their retention during refining processes. Journal of the American Oil Chemists’ Society. 2007; 84 (3):297-304. DOI: 10.1007/s11746-006-1025-1 - 32.
Phillips KM, Ruggio DM, Toivo JI, Swank MA, Simpkins AH. Free and esterified sterol composition of edible oils and fats. Journal of Food Composition and Analysis. 2002; 15 (2):123-142. DOI: 10.1006/jfca.2001.1044 - 33.
Berger A, Monnard I, Dionisi F, Gumy D, Hayes K, Lambelet P. Cholesterol-lowering properties of amaranth flakes, crude and refined oils in hamsters. Food Chemistry. 2003; 81 (1):119-124. DOI: 10.1016/S0308-8146(02)00387-4 - 34.
Alimentarius C. Codex standard for named vegetable oils. Codex stan 210-1999. Rome, Italy: FAO/WHO; 2019. pp. 1-13 - 35.
Yang R, Xue L, Zhang L, Wang X, Qi X, Jiang J, et al. Phytosterol contents of edible oils and their contributions to estimated Phytosterol intake in the Chinese diet. Food. 2019; 8 (8):334. DOI: 10.3390/foods8080334 - 36.
Schwartz H, Ollilainen V, Piironen V, Lampi A-M. Tocopherol, tocotrienol and plant sterol contents of vegetable oils and industrial fats. Journal of Food Composition and Analysis. 2008; 21 (2):152-161. DOI: 10.1016/j.jfca.2007.07.012 - 37.
Ahsan H, Ahad A, Siddiqui WA. A review of characterization of tocotrienols from plant oils and foods. Journal of Chemical Biology. 2015; 8 (2):45-59. DOI: 10.1007/s12154-014-0127-8 - 38.
Grilo EC, Costa PN, Gurgel CSS, AFdL B, FNdS A. Dimenstein R. Alpha-tocopherol and gamma-tocopherol concentration in vegetable oils. Food Science and Technology. 2014; 34 (2):379-385. DOI: 10.1590/S0101-20612014005000031 - 39.
Wie M, Sung J, Choi Y, Kim Y, Jeong HS, Lee J. Tocopherols and tocotrienols in grape seeds from 14 cultivars grown in Korea. European Journal of Lipid Science and Technology. 2009; 111 (12):1255-1258. DOI: 10.1002/ejlt.200900058 - 40.
Shahidi F, De Camargo AC. Tocopherols and tocotrienols in common and emerging dietary sources: Occurrence, applications, and health benefits. International Journal of Molecular Sciences. 2016; 17 (10):1745. DOI: 10.3390/ijms17101745 - 41.
Lehmann JW, Putnam DH, Qureshi AA. Vitamin E Isomers in grain amaranths ( Amaranthus spp.). Lipids. 1994;29 (3):177-181. DOI: 10.1007/BF02536726 - 42.
Skwaryło-Bednarz B. Assessment of content of fat and tocopherols in seeds of Amaranthus in relation to diversified fertilization with macroelements. Ecological Chemistry and Engineering S. 2012; 19 (2):273-279. DOI: 10.2478/v10216-011-0021-z - 43.
Kraujalis P, Venskutonis PR. Supercritical carbon dioxide extraction of squalene and tocopherols from amaranth and assessment of extracts antioxidant activity. The Journal of Supercritical Fluids. 2013; 80 :78-85. DOI: 10.1016/j.supflu.2013.04.005 - 44.
Tang Y, Tsao R. Phytochemicals in quinoa and amaranth grains and their antioxidant, anti-inflammatory, and potential health beneficial effects: A review. Molecular Nutrition & Food Research. 2017; 61 (7):1600767. DOI: 10.1021/acs.jafc.5b05414 - 45.
Tang Y, Li X, Chen PX, Zhang B, Liu R, Hernandez M, et al. Assessing the fatty acid, carotenoid, and tocopherol compositions of amaranth and quinoa seeds grown in Ontario and their overall contribution to nutritional quality. Journal of Agricultural and Food Chemistry. 2016; 64 (5):1103-1110. DOI: 10.1021/acs.jafc.5b05414 - 46.
Szterk A, Roszko M, Sosińska E, Derewiaka D, Lewicki P. Chemical composition and oxidative stability of selected plant oils. Journal of the American Oil Chemists’ Society. 2010; 87 (6):637-645. DOI: 10.1007/s11746-009-1539-4