99A-5 |
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Z. WANG1, S. Y. Xu2, and Y. Wang1. (1) School of Food Science and Technology, Southern Yangtze University, 170# Huihe Road, Wuxi, 214036, China, (2) School of Food Science & Technology, Southern Yangtze University, 170 Huihe Rd., Wuxi, Jiangsu Province, 214036, China Aqueous enzymatic extraction is a safe and efficient oil extraction process that may produce edible protein simultaneously. In order to improve the oil yield, one must not only consider the yield obtained in the extraction step, but also the break of resulting emulsion. Our objective was to study the effects of the enzyme treatment on the extraction yield of free oil and protein hydrolysates and to seek the demulsification operation to improve the total free oil yield. Blanched peanut splits were ground and dispersed in 4 parts (wt/vol) of water. The extraction was done at 60 degree(C), pH 8.25 for 1hr. The solid phase and liquid phase were separated by centrifugation. The liquid phase was submitted to an enzymatic reaction step to obtain free oil and protein hydrolysates. The resulting emulsion was heated at 90 degree(C) for 5min for demulsification. The molecular weigh distributions of the peptides in protein hydrolysates and the protein adsorbed at the emulsion interface were studied by gel filtration chromatography. Results showed that the relative order of enzyme efficiency in enhancement of free oil yield was papain>alcalase>neutrase. Considering economic factors, alcalase, a food grade subtilisin, was chosen. An enzyme level of 2.5%, pH8.0, 60 degree(C) and 5hr incubation represented the optimal extraction conditions with an oil yield of 80.2% and hydrolysates yield of 90.2%. The emulsion was partly broken and oil yield was improved to 91.2%-92.4%. The molecular weight of the peptides in protein hydrolysates was less than 1 kDa. But the gel filtration of the protein adsorbed at the emulsion interface showed 3 main peaks with molecular weight of 727 kDa, 232 kDa and 108 kDa. These results suggest that the aqueous enzymatic extraction should be a valuable technology to obtain oil and protein hydrolysates from oilseeds.
Session 99A, Biotechnology: General
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