Effects Of Storage Condition On Rice Aging

Rice was one of the primary grain corps in our food. Due to the features of its consu-mption, rice needed being stored for a period of time before being consumed. Under the impact of the environment and internal factors, its eating and nutrition quality would vary to some extent in the process of be stored. Such as, diminished viscosity, rase hardness, degraded taste, vanished flavour, Lessening content of vitamins and limiting aminoacid etc. All these changed can have a bad impact on its eating quality and economic value, so it was of great importance to research the impacts of storage conditions on rice quality.This paper concernd about the impacts brought by temperature, relative humidity and storage time and the main chemical content changed such as rice Alylum,Lipid and protein.Research show that temperature, relative humidity and storage time all play a role in the aging of rice, while their effects vary.With the prolonging of storage time, the content of amylose will increase to some extent, While the content of amylopectin will diminish. Such as, Amylose content increased 3.36% storaged for 7.5m in environmental condition of 20℃,RH85%. As the content of starch was about 85%, the change was not obvious due to the huge base number,Amylose content increased 0.37%,Amylopectin and starch content decreased 1.11%and 0.74% storaged for 7.5m in environmental condition of 10℃,RH45%. but they were changed 2.4%,8.52%and 6.12% storaged for 7.5m in environmental condition of 30℃,RH85%.However the content of soluble starch declined. The Amylase activity reduced in the storage process, the relationship between the content of a mylose and a mylase was negative association.In storage, with the prolonged of storage time, augmenting of relative humidity and rising of temperature, the starch and Amioco content declining speed increase,the content of amylase increasing speed became higher; the amylase activity declining speed become fast,We can infer that the augmenting of relative humidity and rising of temperature can accelerate the maturing process of rice.Orthogonal analysis and the orthogonal experiment analysis of variance showed that the impacts that effecting the starch content play different roles; temperature>storage time>relative humidity.But the orthogonal analysis showed that these impacts were't remarkable.In storage, with the prolonging of storage time, the content of crude protein stayed almost at the same level, such as the crude protein content only decreased 0.55% storaged for 7.5m in environmental condition of 30℃,RH85%.But the soluble protein reduces; The content of albumin and globulin reduced, Albumin and globulin content all decreased 0.45% storaged for 7.5m in environmental condition of 10℃,RH45%,and they were decreased 1.51%and 0.9% storaged for 7.5m in environmental condition of 30℃,RH85%. While the content of gluten and prolamine are almost unchanged, however the protein structure changes Which was shown as the reducing of-SH and increasing of-S-S-; the content of small molecule protein reduced and the the degree of crosslinking increased; according to these changes, We can infer the textural properties Which affect the rice quality. The content of free a mino acid fluctuated in storage.During the beginning of storage,due to the lower temperature and lower relative humility condition,the content of free acid increased smally.With the storage prolonging,the content of free acid reduced.Under the same storage times,the higher temperature and lager relative humility,the content of free acid was less.Usually the content and category of a mimo acid was one of important meritsesti mating the qulity of protein.Reserch showed that:during the storage,With the time prolonging,the limted acid such as Lysine lost greatly,and the nutritional value of protein reduced..Orthogonal analysis showed that the impacts that effecting the protein and animo acid content paly different roles; temperature>storage time>relative humidity. Orthogonal experiment analysis showed that the impacts on content of rice albumin,Globumin and Lysine achived remarkable level,the impact by relative humility was't remarkable,these three factors brought impacts on the content of animo nitrogen and gluten were't remarkable.With prolonging of storage time, the content of crude fat reduced, fatty acid value increased, Lipase activity wanes. In higher temperature and larger relative humidity environment with longer storage time, the content of crude fat will reduced quicker; The fatty acid value increase rate will be larger.Such as, crude fat decreased 13.8% storaged for 7.5m in environmental condition of 10℃,RH45%,but the content decreased 27.6% storaged for 7.5m in environmental condition of 30℃,RH85%.The fatty acid values were 48.65mg/100g and 49.9mg/100g stored 7.5m,in10℃relative humidity of 45% and 85% conditions.but the fatty acid values were 53.3mg/100g and 56.55mg/100g in 30℃. Orthogonal analysis showed that the impacts that effecting the content of crude fat and fat acid value paly different roles; Storage time>temperature> relative humidity.Orthogonal analysis showed that:during the storage, the impactd on content of rice crude fat,fat acid value brought by storage time achived re markable level,the impact by tempereture was't remarkable,the impact brought by relative humidity was't remarkable. These three factors brought impacts on the content of crude fat were't remarkable.Researches show that storage temperature, time and relative humidity have a great impact on rice quality. The textural properties change a lot in storage. Usually, as the storage time prolonging, the relative humidity augmenting and temperature rase, the hardness of rice was increased, While its adhesivity, flexibility and resilience will reduce.Researches shown that the storage time and temperature played the most important roles in effecting the rice qulity,with prolonging of the storage time and rising of temperature,the rice qulity reduce remarkably,the impact brought by relative humidity was't remarkable.During to these,lower storage time and short storage time have good of remaining the rice qulity and upgrating the economical value.