30C-6 |
Protein extraction from heat-stabilized defatted rice bran: I. Physical processing with aids of enzymes |
S. Tang1, N. S. HETTIARACHCHY1, and T. H. Shellhammer2. (1) Department of Food Science, University of Arkansas, Fayetteville, AR 72704, (2) Department of Food Science and Technology, Ohio State University, Columbus, OH 43210 Rice bran is an under-utilized co-product of rice milling. It contains about 17-22% high quality protein. The nutraceutical functionality of these proteins has been recognized for many years. However, rice bran protein from heat-stabilized defatted rice bran (HDRB) is not commercially available due to a lack of appropriate extraction procedure. Physical processing provides a suitable micro-environment to extract and solubilize proteins and increase protein extraction. The objective of this research was to evaluate sonication, freeze-thaw, high pressure, and high-speed homogenization with or without enzymes on protein extraction from HDRB. HDBR was suspended in water with varying water bran ratios, and subjected to sonication, freeze-thaw, high pressure or high-speed homogenization. These physical treatments were followed with carbohydrase and /protease, and the amount of protein extracted was determined by Kjeldahl method. Sonication, freeze-thaw, high pressure and high-speed homogenization extracted 15%, 14%, 11% and 16% protein from HDRB, respectively. Energy levels of sonication, 0, 20%, 40%, 80%, and 100% output of 750W, extracted 25.6-33.9% of protein from HDRB with carbohydrase, and 54.0-57.8% with both carbohydrase and protease treatments. No significant difference was observed among the treatments (P>0.05). High pressure treatments of 0, 200, 500, or 800Mpa, extracted 10.5-11.1% protein with water, and 61.8-66.6% protein with carbohydrase and/protease. High-speed homogenization extracted about 5% more protein in comparison with the untreated control (9.9%). These results suggest that physical processing in combination with enzyme treatments can be used to extract protein from HDRB.
Session 30C, Food Chemistry: Proteins
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