Studies On Physical And Chemical Properties Of Starch Of Chalky Rice During Storage

Texture, flavor are the key evaluation indicators of rice, the texture includes structure, degree of polymerization, degree of hydrolysis and conformation of starch chain, flavor affect the taste of rice, including total acid, fatty acids and volatile substances, and so on, It is the key index evaluing the flesh quality of rice. The effect of flesh deeps on ambient temperature, humidity, gas, packaging materials and the substances of the natural flavor of rice, water.The experiment use the chalky rice with different chalky area as the experimental material, to research the indicator change pattern like springness, hardness, amlose content, volume expansion, water absorption, and so on. which relate to the starch metabolism, and hydrolysis. Then fefines the regulation mechanism of rice during storage. In order to provide the theoretical basis for CA storage of rice breeding. The statistics show that:(1)The starch microstructure of rice with different chalky area had significant difference. Amyloid of non-chalky rice put in order and the structure was dense. With the chalky area increasing, amyloid loosely arranged, the interval was larger. After storage, The starch microstructure of rice with different chalky all had changed. Amyloid structure all decame dense, the interval was smaller. Especially under30℃, The tightness of non chalky rice was the largest, following the rice with chalky area<50%.The smaller the chalky area, the larger the degree of crystallinity, the smaller the non-crystalline region, and it was the most difficult for strach to gelatiniza.During different temperature storage, the the onset temperature, toptemperature and TC of chalky rice increased. Among of them the onset temperature, toptemperature and TC under30℃very changed, then it was10℃, then0℃. It showed that high temperature can accelerate the chalky crystallization rate of rice starch.After different temperature storge, the amlose content, water uptake, Volume expansion and hardness increased with varying degrees. With the chalky area increasing, the amlose content increasing larger. water uptake of The no chalky rice changed more significantly than the chalky rice. With the chalky area increasing. Volume expansion also increasing larger. The larger the temperature, hardness increased larger, low temperature delayed the decrease of elastic of Chalky rice(2)Under CA storage, the amlose content, water absorb. Volume expansion and hardness of chalky rice increased slowly with the time increasing and springness decreased. The effect of all8:20treatment were good than the other treatment, overall, the storage effect at10℃8:20is the best.(3)High temperature accelerate the change of quality and flavor. Quality of rice with chalky area>50%changed large under30℃. During different temperature CA storage, rice with chalky area>50%also changed larger than the other treatment. The effect was the best when the chalky rice was storaged at10℃8:20.(4) Zone of inhibition test showed that the ZnO film possessed the inhibition on the growth of bacteria of the chalky rice. So using the ZnO film as packaging can reduce the growth of bacteria.The ZnO film possessed the inhibition on the growth of bacteria, affect the growing trend of bacteria and the trends increased with the storage time.