Study On The Quality Stability Technology Of Embryo Rice Based On Microwave And UV Treatment

During the storage of embryo rice,due to the loss of the protection of the rice husk,the lipids in the embryo rice come into contact with oxygen to oxidize and decompose under the action of lipase,which is easy to oxidize and rancidity,resulting in the deterioration of the quality of the embryo rice.In recent years,there have been studies showing that microwave and ultraviolet irradiation treatments can kill bacteria,but there are few reports on the effects of microwave and ultraviolet radiation on the inactivation of embryo rice lipase.In this subject,the untreated sample was used as a blank control,and microwave treatment and ultraviolet treatment were used as a comparison to study the effect of microwave treatment and ultraviolet treatment on passivation of embryo rice lipase activity.Factor experiment and orthogonal and response surface analysis were used to study the influence of lipase inactivation rate,and the changes of quality characteristics such as moisture loss rate,broken rice rate and burst waist rate of the embryo rice were investigated.And the food storage period accelerated test method ASLT(Accelerated shelf-life testing)storage,select ASLT temperature is 35 ℃;45 ℃,during which regular inspection of its food quality indicators and storage quality indicators.Through the study of the change law of the quality indicators of the embryo rice and the research on the storage quality of the embryo rice,the research is intended to provide a new theoretical method for extending the storage period of the embryo rice.The main research contents and results are as follows:(1)Microwave treatment of embryo rice.The effect of microwave on lipase activity in rice was studied by setting single factor experiment,choosing microwave time,microwave power and material thickness as single factors.Taking the lipase inactivation rate as the main index,taking into account the water dispersion loss rate,waist bursting rate and rice breaking rate of embryo rice,the optimal parameters were selected for orthogonal experiment,and the optimal conditions were obtained: microwave action power 595 w,microwave action time 20 s,material thickness 0.5cm,lipase inactivation rate about 79.81%.(2)The embryo rice treated by UV irradiation.Through setting up a single factor experiment,the influence of UV on the lipase activity in embryo rice was investigated by selecting the UV action time,the distance between the material and the UV lamp,and the initial moisture content of the material as single factors.Based on the experimental results,the irradiation time(A),irradiation distance(B),and initial moisture content(C)were selected for a three-factor,three-level,central combination experiment design.The data was collected using the Box-Benhnken design method in Design-Expert V8.0.6 software.Regression analysis was conducted to study the effect of ultraviolet irradiation conditions on the lipase inactivation rate in embryo rice,and the best conditions were obtained: the irradiation time was 11.50 min,the irradiation distance was 4.5 cm,the initial moisture content was 12.87%,and the lipase inactivation rate reached 66.73 %.(3)The changes of rice texture(hardness,viscosity,chewability and cohesiveness),basic nutrients(protein,fat,amylose,calcium,etc.),gelatinization characteristics and crystal properties were studied by microwave treatment and ultraviolet radiation.The results showed that microwave treatment could affect gelatinization characteristics of rice,but not basic nutrients,texture and crystal structure.UV irradiation did not affect the texture,basic nutrients and crystal structure of rice.(4)In order to realize the marketization of preserved rice,the method of accelerated shelf life testing ASLT(Accelerated shelf-life testing)was used in this experiment to test the storage period of untreated and irradiated rice.By analyzing the trend of sensory evaluation,fatty acid value content and gelatinization characteristics of rice during storage,it is concluded that UV can better maintain the quality of rice with embryo,and microwave treatment can effectively delay the deterioration of quality of rice with embryo.