Study On Brown Rice Processing Optimization And Physicochemical Properties

China was the world's largest producer and consumer of rice, annual output of rice was about 2 million tons, making up the world rice yield 1/3, the national food production two-fifths. There were about 800 million people of China who feed on rice, direct edible rice and its products were about 1.2 million tons annually. So the development of rice products consumer market would have huge potential. The nutritional value of brown rice had greatly improved after germination, especiallyγ-aminobutyric acid (GABA) content was significantly increased. Thus the development and utilization of brown rice had great significance on improving people's diet structure, improving people's health level, promoting the sustainable development of country's rice and agricultural productions.Non glutinous rice was used as material in this paper to optimize the germination process conditions which could maximized the amount of GABA in brown rice, and on this condition, the effect of physicochemical properties on brown rice of germination was further discussed. The main results are shown as follows.:In order to maximize the amount of GABA concentration in brown rice, the extraction content of GABA was used as indexes for single factors test to make certain the germinant conditions of brown rice. Then the germinant conditions of brown rice were optimized by the orthogonal tests initially. According to the results of the orthogonal tests, three main factors were determined. The germinant conditions of brown rice were optimized by response surface analysis finally. Results showed that the optimal conditions were as follows: germination time 25.8h, germination temperature 32.9℃, pH of soaking solution 5.11, soaking temperature 30℃. On these conditions, the germinant brown rice's GABA concentration reached 149.42mg/100g, which was about 2.8 times compared with the brown rice without germination.With the optimal germination conditions on brown rice of GABA enrichment, the changes of the internal structure of brown rice and physicochemical properties after germination were studied. The properties included swelling power, transparency, freeze-thawed stability, last subsidence, pasting properties and textural characteristics. The results showed that: After germination, the swelling power was increased, and the swelling power was increased with temperature increasing; the transparency was increased by 20% after germination; the retrogradation was inhibited obviously and the freeze-thawing stability was enhanced strongly after germination, it indicated that the germination of brown rice was not easy to aging, and contributed to extend the food shelf life; peak viscosity was reduced, pasting temperature basically unchanged; the adhesiveness of brown rice was increased after germination, hardness and gumminess were both decreased; electron microscopy analysis showed that the grain structure become more loose after germination. The brown rice amylase activity was increased after germination. It showed that germination could improve the physicochemical properties of brown rice.In order to further study the physicochemical properties of brown rice, two-step by alkali and enzyme was used to extract the starch from brown rice, and the changes of starch structure of brown rice and physicochemical properties after germination were studied. The results showed that: The swelling power was increased after germination, and increased with the temperature rising; the transparency was increased by 57.14%; the retrogradation was inhibited obviously and the freeze-thawing stability was enhanced strongly after germination; the hardness, adhesiveness and gumminess of starch trends were consistent with the brown rice; iodine blue value was decreased, it indicated that the amylose content or the degree of polymerization decreased after germination; electron microscopy analysis showed that germinated brown rice starch granules were round, and the angular were not obvious after germination. It showed that germination could improve the physicochemical properties of brown rice starch.