Effects Of Rice Steam-Microwave Combined Pretreatment On Edible Quality And Storage Quality Of Brown Rice

As an important food crop in my country,rice is partly used for food after harvest,and the other is used for storage to cope with food shortages caused by extreme natural disasters and other emergencies.During the storage process,the quality of rice is prone to deteriorate under the action of its own endogenous enzymes and other factors,which affects the storage period of rice.Rice stabilization technology is widely used as an important means to effectively improve the storage characteristics of rice.In this experiment,the steammicrowave stabilization technology was applied to the treatment of rice,and the edible quality and storage characteristics of brown rice were studied,in order to provide technical support for the stabilization of rice and the improvement of the storage quality of brown rice.The main findings are as follows:1.Steam-microwave stabilization treatment can be effectively used in the treatment of rice.The steam-microwave stabilization treatment of rice does not change its moisture distribution.The factors affecting the broken rice rate and fatty acid enzyme activity of rice during the treatment process are microwave power,steam time,microwave time and rice moisture content in order.The best steam-microwave stabilization process finally obtained with No.1 as the raw material was as follows:the steam time was 10 min,the microwave time was 1.5 min,the microwave power was 1 w/g,the broken rice rate after treatment was 8.18%,and the fatty acid activity was 8.63%.2.Steam-microwave stabilization of rice(Longkezao No.1,Longjingyou No.1,Longjing Youdizhan)has a significant effect on the processing and eating quality of brown rice.After the rice was stabilized by steam-microwave,the color difference values such as L*value,a*value and b*value and appearance of the brown rice did not change significantly.Intracellular fractures increased and intercellular fractures decreased,resulting in a certain increase in the broken rice rate of rice.Among them,Longjing Youdizhan increased the broken rice rate most obviously due to the higher aspect ratio,from 15.85%to 25.67%.;The lipase activity of brown rice was significantly reduced after the stabilization treatment,among which the Youzhan variety decreased most obviously,from 14.28(mg/g)to 7.21(mg/g);the fatty acid content also decreased significantly,from 31.07(mg/100g))20.68(mg/100g)decreased to 10.74(mg/100g)-6.88(mg/100g);the malondialdehyde content increased slightly.In terms of physical and chemical properties,after steammicrowave stabilization treatment,the elasticity,hardness and chewiness of brown rice were reduced,and the gelatinization temperature of brown rice flour was different due to the influence of raw materials.The gelatinization temperature increased,while the gelatinization temperature of Longjing Youdizhan decreased,but the overall gelatinization enthalpy decreased significantly;the peak viscosity and valley viscosity increased significantly,and the retrogradation value decreased significantly.3.Steam-microwave stabilization treatment of rice(Longkezao 1,Longjingyou 1,Longjing Youdizhan)can significantly improve the storage quality of its brown rice.Compared with untreated brown rice,the endosperm intercellular fracture of rice after steam-microwave stabilization treatment was reduced;the increase in color difference such as L*,a*and b*values of brown rice decreased,which slowed down the color of brown rice.The deepening of the degree of brown rice inhibits the bran phenomenon of brown rice to a certain extent;the combination of steam-microwave stabilization treatment and vacuum storage can significantly inhibit the increase of the number of molds,lipase activity,fatty acid value,and malondialdehyde in the three varieties of brown rice,effectively Delay the deterioration of brown rice quality.In terms of physical and chemical properties,after steammicrowave stabilization treatment,the increase in hardness,recovery,stickiness,chewiness,etc.,and decrease in viscosity of brown rice during the storage period of gelatinization temperature were effectively delayed.