Vitamin E and Oxidative Stability of Soya Bean Oil Prepared with Beans at Various Moisture Contents Roasted in a Microwave Oven
✍ Scribed by Yoshida, Hiromi; Takagi, Sachiko
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 837 KB
- Volume
- 72
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Whole soya beans (Glycine max) at various moistures (96, 382 and 519 g kg-') were roasted by exposure to microwaves at a frequency of 2450 MHz and the effects on the tocopherols of soya beans were studied in relation to chemical changes in the oils. The amounts of a-, I-, y-and &tocopherols in the soya beans before microwave treatments ranged from 62 to 187, 43 to 89, 673 to 757 and 542 to 593 mg kg-' oil, respectively. Increasing moisture contents by soaking prevented, not only the reduction of tocopherols but also, the oxidative deterioration of soya bean oils during microwave roasting. The amounts of tocopherols still remained > 80% of the original level in soaked soya bean oils after 20 min of roasting, and microwave roasting after soaking caused no significant differences (P > 0-05, with few exceptions) in the chemical changes of the oils in comparison with those before soaking. These results implied that microwave roasting after soaking would be effective in making full-fat soya flour with high vitamin E without a burnt odour and browning from raw beans.