Study On Storage And Fresh-keeping Technology Of Brown Rice

Rice is main foodstuff in our country.Every country must have a certain amount of rice reserve in order to guarantee food safefy and people's basic living conditions.But on the traditional reserve condition,rice will occupy larger storage and add the expenses of transport.The deficiency of rice storage can be made up in the shape of brown rice's storage and turnover.But the problems of aging,insect pest and mould make things difficult in the course of storage.Winter time in northeast china is longer and high temperature period in summer is shorter,which is suitable for japonica.Japonica's viscosity is higher than indica's and its flavor is better too.Aiming at weather condition in northeast and main problems in storage period of brown rice,the experiment is conducted with NEAU3418,the relationship between different storage conditions and the quality change of brown rice,the influence on the quality of brown rice that the storage condition has are discussed in the paper.It is also studied in the paper the storage condition of brown rice which has higher moistore content in order to keep brown rice fresh.1 Experimental research method of one-factor is firstly taken to study the effect that controlled atmosphere mode,temperature,moisture content have on germination percentage of brown rice, free fatty acid and viscosity.The study shows:(1) In the experimental conditions,the effect that storage condition(controlled atmosphere mode,temperature,moisture) has on germination rate is:in three controlled atmosphere mode, brown rice with both14.2%to 16.3%moisture content and temperature range of 5℃to 25℃can be stored for 3 months and keep high germination rate under the condition of filling N₂ and vacuum storage.Controlled atmosphere mode of brown rice with 14.2%moisture content has little influence on germination rate,brown rice with 16.3%moisture content has better germination rate under the storage condition of filling N₂,and brown rice with 18.3%moisture content is unsuitable for storage.(2) Under various controlled atmosphere mode,free fatty acid value of brown rice increases with longer storage time,brown rice's storage index of quality demands that free fatty acid value of suitable storage is under 25 KOH mg per 100g,the experiment based on this and derived:brown rice with 14.2%to 16.3%moisture content could be stored for 3 months and it's free fatty acid value could be controled within the suitable storage range under three controlled atmosphere mode.Brown rice with 18.3%moisture content could be stored for 3 months under the condition of both 5℃to 15℃temperature range and filling N₂ and vacuum storage,it is unsuitable for the condition of over 25℃and natural air storage.(3) Brown rice's storage index of quality demands that viscosity value of suitable storage is above 10cSt.The experiment based on this,the brown rice's quality change was studied and derived:brown rice with 14.2%moisture content could be stored for 3 months and kept it's viscosity within the suitable storage range under the condition of three controlled atmosphere mode and three kinds of temperature.Brown rice with 16.3%moisture content could be stored for 3 months under the condition of 5℃and three controlled atmosphere mode and it could be stored for 2 months under the condition of 15℃and filling N₂ and vacuum storage,but it was unsuitable for natural air storage.Brown rice with 18.3%moisture content could be stored for 2 months under the condition of 5℃and filling N₂ and vacuum storage,it was unsuitable for storage under other conditions.2.Base on one-factor study,by three factors and three levels full factor experimental design method,the effect that controlled atmosphere mode,temperature and moisture content have on germination rate,free fatty acid and viscosity is studied and each evaluating indicator and mathematical model of various factors are founded with polyfactors analysis by using Design-Expert software,as well as the analysis of interaction that each factor has on quality of brown rice.The results show:controlled atmosphere mode,temperature,moisture content all affect quality of brown rice and every factor interacts each other,of which the interaction of temperature and moisture content has remarkable influence on every desired value of brown rice's quality, which explains that temperature and moisture content affect quality of brown rice biggest.The lower of moisture content and temperature,the slower that brown rice's quality changes. Controlled atmosphere mode has an adverse effect on decay and mould of brown rice,filling N₂ and vacuum storage have the same effect.3.Base on one-factor analysis,two optimum combinations are obtained by using multi-objective optimization method to optimize and by Design-Expert software to obtain optimal solution.In the combinations,moisture content of brown rice is all between 15%and 16%and it improves 1%to 2%comparing with moisture content of general safe storage,thus can decrease drying cost remarkably and keep the quality of brown rice fresh in the same time.Optimized value is proved to be in the range of allowable error,therefore,the results and the mathematical model can be used for actual brown rice's storage.