| Summary: | 碩士 === 國立宜蘭大學 === 食品科學系碩士班 === 102 === Rice has been a staple food in the world, which is consumed principally as a whole grain. The rice consumption in Taiwan is declining in decades since the diversity of diets and the western culture impact. There has been a considerable interest in the development of rice processed products to enhance the rice consumption. In application, rice is usually milled by different methods to the preparation of rice flour, thus the milling methods might affect the ultimate physicochemical properties of the rice flour and the qualities of related products. The objective of this research was to study the in vitro hydrolysis along with the digestibility of different rice species (indica: TCS10, CS22, TCN1, japonica: TC192, KH145, and glutinous: TCSnGl2, TCGlu70, TKGlu3) milled by three milling methods (dry milling, and wet milling followed by hot air drying at 45oC and/or freeze drying). In addition, the influence of adding difference percentage oil on the physical and physiological characteristics of indica rice cakes was selected as a case study of rice product. The results showed that the indica species of TCN1 appeared to have the highest resistance on enzymatic hydrolysis than the others, while the glutinous ones got the least resistance (best digestibility). The equilibrium concentration ( ) and kinetic parameter (k) of TCN1 were smaller than the others. This result turned to increase the resistant starch (RS) as well as to decrease the estimated glycemic index (eGI). For the different milling methods, wet-milled raw flour followed by hot air drying at 45oC performed the best enzymatic resistance to hydrolysis. In addition, gelatinized freeze-dried wet flour got a lower starch digestibility. For indica rice cakes, the height, specific volume and white index of TCN1 rice cake were significantly higher than those of TCS10 and CS22 cakes. As the addition level of butter increased the hardness of rice cakes increased simultaneously. According to the in vitro digestion study, rice cake with addition of 25% soybean oil and 75% butter showed the highest starch digestibility than the other rice cakes, and rice cake of whole soybean oil performed the least starch digestibility. In general, rice cakes were the foods of middle-to-low glycemic index.
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