Researches On The Mechanism Of Rice Aging And Regulation

Rice is the first yield crop in china, Production and storage of rice related to the state's food supply system security directly. The rice stock of the year's total is about 40% in china now, Long time will inevitably lead to the storage of rice quality deterioration Compared with aging rice with fresh rice,edible quality decreased obviously. With the improvement of people's living, the quality of rice and a higher requirement the main reason of impeding their access to normal flow is aging rice edible quality fell to.Research on ageing mechanism, development of effective control measures to solve aging rice lower edible quality, to meet people's needs, reducing the storage losses and increase farmer's income is of great significance.The internal factors of rice aging have tow facts their own cell structure and chemical composition injury, The chemical composition of which is to change the structure of cell injury and a series of physiological changes as the fundamental reasons. The research based on predecessors resultsin this pape, studies of the aging process rice lipid, protein, starch, and other major changes in chemical composition, explored changes in the chemical composition of the starch properties, the texture of the rice, Using scanning electron microscope to observe before and after the pasting office endosperm,In a study of brown rice germination process amylase and antioxidant enzymes activity to further improve the rice and add the aging mechanism, The paper also study on the gas storage environment conditions on rice storage effect preliminary.Research indicate:in the rice stored process, the main reasons of changing composition of starch is amylopectin debranching in the role of debranching enzyme.Amylose and amylopectin content decline made starch molecules arranged in an orderly, tend to strengthen aggregation, made rice starch RVA spectrum have the highest peak value,breakdown value decreased setback value increased, starch paste is not easy. With the extension of storage time, change of starch make rice hardness and sediment increases gradually.In the storing rice process, crude fat content decrease, fatty acid values increase. With the extension of storage time longer, various fatty acid content increased, the fatty acid composition and changes of NSL is same with brown fat basicly.Fatty acid group of SL remained unchanged basically. Lipid acid increased and the echoed bodies of starch formation enhance the starch paste the enthalpy value (â–³H), and have bigger impact on paste thermal stability of starch Promote aging rice to setback. With the storage time longer, the changes in lipid and starch synergy made the rice rigid increase, and adhesion reduce.In the rice storage process, total protein and cereal protein content remained unchanged, the glutenin sulfhydryl reduced, disulfide band increase, low molecular weight protein change to high molecular weight protein by disulfide-through in the crosslinking role formation.High molecular weight increase in the protein matrix and raising the temperature range of paste and enthalpy value (â–³H), improve the starch paste viscosity. With the storage time longer, the changes in protein and starch synergies made rice viscoelastic gradually weaken, rigid increase gradually. Protein make rice relaxation increased markedly, cohesion dropped significantlyUsing scanning electron microscope observate rice endosperm structural changesafter paste can described impact on aging rice rice edible quality directly. After aging rice 10minutes' boiling, the bright region is extending slowly compared with the fresh rice, The new rice absorbs water fast, whose cell breaks and the content comes out more during cooking, the old rice has the tendency of melting and forms the platy structure owing holes.With the storage time extension longer, brown germination rate lower, the amylase activity and antioxidant enzyme activity decrease, of CAT and SOD of fresh brown rice activity decreased during germination, the basic activity of aging rice remained unchanged, in the rice germination storage process, activity POD of show an upward trend, as the same as rapid increase performance of bud growth shows POD may be related to the growth of the brown bud.Fill N₂ gas adjustment preserve is advantageous to the brown rice quality maintenance, under low temperature condition, the effect is more remarkable. Under atmospheric pressure condition, filling N₂, CO₂ has same effect to the brown ricequality maintenance. However, in high temperature conditions undersmall-conditioning packaged rice storage of CO₂ have the best effect, N₂ and vacuum packaging followed, high moisture content in rice effect is even more evident.