Effect of temperature and time during steam treatment on the protein quality of full-fat soybeans from different origins
✍ Scribed by Qin, G X; Verstegen, M W A; van der Poel, A F B
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 177 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Soybeans (Glycine max) of Argentinian and Chinese origin were steamprocessed at 102¡C, 118¡C and 136¡C for various durations with the use of a laboratory-scale steam toaster. Samples of raw and processed soybeans were analysed for dry matter (DM), crude protein (CP), trypsin inhibitor activity (TIA), protein dispersibility index (PDI) and reactive lysine content. Chinese raw soybeans showed higher levels of CP, TIA and PDI, and a lower level of reactive lysine than Argentinian raw soybeans (366 vs 357 g kg~1, 20.6 vs 15.2 mg g~1, 87.6 vs 85.6% and 17.4 vs 19.4 g kg~1, respectively). Both the TIA and PDI of the two soybean samples were decreased following a logarithmic pattern with the lengthening of the heating time when beans were steam heated at various temperatures. The reduction rates for TIA and PDI, however, were di †erent between the two origins of soybeans. Chinese soybeans required a longer time or a higher temperature to reduce their TIA to a safe level in comparison with Argentinian soybeans. In the case that the beans were heated at 136¡C, the di †erence in PDI between Chinese and Argentinian soybeans was smaller. It is concluded that the two soybeans origins need di †erent processing conditions to improve their protein properties.
1998 SCI.