33G-21 |
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F. TEMELLI, T. Vasanthan, K. Stobbe, and K. Rezaei. Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB T6G 2P5, Canada Tocopherols and tocotrienols (referred to as tocols) are the family of vitamin E compounds with antioxidant activity. Barley contains a high concentration of tocols. Lipids are concentrated in the outer layers of the barley kernel. Therefore, the pearling flour is a suitable starting material for lipid extraction using supercritical CO2 (SC-CO2). The objectives were: (a) to determine the tocol content and composition of barley varieties grown in Alberta, (b) to extract barley lipids from pearling flour using SC-CO2 and analyze for tocols. Samples of whole grain and 35% pearling flour of 20 different barley varieties were analyzed for their lipid content. Lipids of 35% pearling flour fraction of Tercel barley were extracted using SC-CO2 at different temperatures (40oC and 60oC) and pressures (24.1, 44.8 and 58.6 MPa) for 3 h in duplicate. Tocol content and composition of whole grain, 35% pearling flour, and SC-CO2 extracts were analyzed using HPLC in triplicate. The total lipid content of whole grain was 1.92-3.01%, whereas that of 35% pearling flour was 4.33-7.90%. In general, the lipid content of hulless varieties was higher especially in the pearling flour fraction. Tocol content of the whole grain was 53.8-124.9 mg/g and that of the pearling flour was 194.9-363.0 mg/g of flour. The hulless varieties were higher in tocols, with the waxy, double waxy and Tercel barleys having the highest levels (p<0.05). a-Tocotrienol was the most abundant making up 38.6-50.1% (w/w) of the total tocols, followed by a-tocopherol (17.7-33.9%) and g-tocotrienol (10.4-20.2%). The ratio of total tocotrienols to total tocopherols was 1.6-3.9. Lipid recovery of 73-97% was achieved using SC-CO2 extraction under different conditions. Tocol concentration of extract fractions ranged from 1344-2890 mg/g extract. Barley pearling flour can be a feasible starting material for the recovery of lipids rich in tocols with a favorable distribution of tocotrienols and tocopherols.
Session 33G, Nutraceuticals & Functional Foods: Lipid and probiotic functional foods
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