| Summary: | 碩士 === 國立屏東科技大學 === 食品科學系所 === 99 === Rice contains about 76% starch, and 7~10% protein. It is considered as a starchy crop. According to the annual report of United States Renal Data System (USRDS) in 2010, the population of dialysis prevalence and incidence rates of Taiwan in 2008 are the highest in the world. The diet therapy of chronic renal failure (CRF) patients focuses on the low protein diet (LPD) to reduce nitrogen wastes and delay the dialysis treatment time. Therefore, rice was studied for the protein content with different levels of milling first, and then with the enzymatic hydrolysis in this study. In enzymatic hydrolysis, the response surface methodology was used to investigate effects of treatments in hydrolysis, i.e., time (1, 4, 7 hours), temperature (50, 60, 70℃) and pH (6.5, 7.5, 8.5), on total nitrogen content, amino nitrogen content, and degree of hydrolysis of rice. Results of the study showed that the total nitrogen content of rice decreased along with the increasing degree of milling. The optimum condition of the enzymatic hydrolysis of rice was found at pH 7.5, temperature 58.15℃ for 5.07 hr, and the lowest total nitrogen content of treated rice was 0.2%. In addition, the temperature in the enzymatic hydrolysis was found the most significant effect on total nitrogen content. Thereafter, the obtained low protein rice was used as raw materials, and processed by an collet extruder for a low protein expanded rice snack. The results showed that low protein, expanded rice snack had higher enthalpy and a-value, but lower solubility, swelling power and L value.
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