| Summary: | 碩士 === 輔仁大學 === 食品科學系碩士班 === 104 === Rice bran is a by-product of rice milling. It is rich in lipid with unsaturated fatty acid and antioxidant compounds, hypoallergenic protein with well-balanced amino acids, and dietary fiber with beneficial effects against cardiovascular diseases and colon cancer. However, rice bran is usually not consumed as food because of high fiber content. Ball milling is a low-cost and environmental-friendly micronization method which can modify the physicochemical properties of material. The aging population grows rapidly in recent years. Dysphagia is a common symptom of elders and usually causes problems of malnutrition and constipation. Therefore, foods with texture modification and nutrients improvement are crucial to increase the life quality of elders and dysphagia patients. The aims of this research were to investigate the effect of micronization on the yield and physicochemical properties of rice bran extracts (RBE) and to study the effect of micronized rice bran (MRB) addition on the physicochemical properties of bean-curd. These bean-curd products were further classified based on the standanders for texture-modified foods used in dysphagia management. Rice bran was micronized at different times using a ball miller to obtain RBE and MRB. Results showed that the partical size of rice bran decreased with increasing the micronization time. The yield and carbohydrate contents of RBE increased while the protein contents decreased with increasing the micronization time. The molecular weight of proteins in RBE was in the range of 0.02-216 kDa and it decreased with increasing the micronization time. RBE had better solubility at higher pH. The foaming and emulsifying abilities of RBE increased with its concentration and milled with 60 min had significant increase. The MRB micronized for 10 min had higher protein and dietary fiber contents and was further added to the bean-curd. The bean-curd prepared with MRB had higher water holding capacity. The cohasiveness, adhesiveness, gumminess and chewiness of MRB added bean-curd increased significantly (p<0.05) with increasing the addition concentration. The hardness of the bean-curd was in the range of 7.8×104-8.5×104 N/m2 which was classified to the Japan standard 2. The 6% MRB added bean-curd could not form gel that was classified to the Japan standard 4. Therefore, ball milling could effectivly modify the fiber and improve the functional nutrients extraction in rice bran, thus extend its application. Moreover, micronized rice bran possesses special functionality and could be added to bean-curd as dysphagia diets with high nutrient value and water-holding capacity, and proper texture.
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