Tocol composition and supercritical carbon dioxide extraction of lipids from barley pearling flour.
Samples of whole grain and 35% pearling flour of 20 different barley varieties grown in Alberta were analyzed for their lipid contents. Total lipid contents of whole grains were within 1.9% to 3.0% (w/w), whereas those of the 35% pearling flour were 4.3% to 7.9%. Lipids of 35% pearling flour fraction of Tercel barley were extracted using supercritical carbon dioxide (SC-CO2 ) at different pressures (24, 45, and 58 MPa) and temperatures (40 and 60 °C) for 3 h. Lipid recoveries of 73% to 97% were achieved using SC-CO2 extraction under different operational conditions. Tocol contents and compositions of whole grain, 35% pearling flour, and SC-CO2 extracts were analyzed using HPLC. Tocol content of the whole grain was 53.8 to 124.9 μg/g and that of the pearling flour was 195 to 363 μg/g of flour. The hulless barley varieties were higher in tocols, with waxy, double waxy and Tercel varieties having the highest levels (P < 0.05). The ratios of total tocotrienols to total tocopherols varied within 1.6 to 3.9 range. Tocol concentrations of SC-CO2 extract fractions varied from 1171 to 4391 μg/g extract depending on the operational conditions. Barley oil is a good natural source of different tocol isomers rich in tocotrienols.
Dept. of Agricultural, Food and Nutritional Science, Univ. of Alberta, Edmonton, Alberta, Canada, T6G 2P5.
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F
Temelli
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K
Stobbe
K
K
Rezaei
T
T
Vasanthan
D000416:Alberta; D002245:Carbon Dioxide / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004041:Dietary Fats / Q000032:analysis; D005433:Flour / Q000032:analysis*; D001467:Hordeum / Q000737:chemistry*; D011312:Pressure; D013696:Temperature; D024505:Tocopherols / Q000032:analysis*; D024508:Tocotrienols / Q000032:analysis
D004041:Dietary Fats; D024508:Tocotrienols; D002245:Carbon Dioxide; D024505:Tocopherols; C572520:tocol
barley; lipid; pearling; supercritical carbon dioxide; tocopherol; tocotrienol