30C-8 |
Protein extraction from heat-stabilized defatted rice bran: III. Use of carbohydrases and proteases |
S. Tang and N. S. HETTIARACHCHY. Department of Food Science, University of Arkansas, Fayetteville, AR 72704 Limited information is available in using carbohydrases and proteases to extract proteins from rice bran. During milling of rough rice, rice bran is subjected to heat processing to stabilize the lipids. During this process rice bran proteins get denatured, and bind to cellular components. Carbohydrases can hydrolyze the cellular components and release bound protein, while proteases can hydrolyze proteins into peptides and increase protein solubility in heat-stabilized defatted rice bran (HDRB). The objective of this research was to screen carbohydrases and proteases, and to select suitable enzymes for protein extraction from HDRB. A total of 24 carbohydrases and proteases were evaluated individually for protein extraction from HDRB. Single factorial experimental design with three levels for each enzyme was used. Proteins extracted under recommended pH and temperature were determined by Kjeldahl method. The carbohydrases and proteases with highest protein extractabilities were selected for combination study. Most of the carbohydrases extracted less than 30% of protein, however, carbohydrases a, b and c extracted 36, 33 and 40% of protein from HDRB, respectively. Protease treatments extracted 11-52% of the protein. Protease a, b and c treatments extracted 52, 52, and 52% of the total protein, respectively. Combined enzyme treatments of carbohydrase c and protease a increased protein extraction up to 80%. These results suggest that combined treatments of carbohydrase and protease are effective and more resourceful in extracting protein from HDRB.
Session 30C, Food Chemistry: Proteins
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