Studys On The Non-destructive Pre-cooking Processes For Red Kidney Beans

Red kidney beans are nutritious and taste mellow after cooked.Due to their compact structures and long cooking time,cooking with rice at the same time will often appears "Rice is cooked beans but beans are not ripe or beans are cooked but rice has been well-cooked" phenomena.As the pace of life in modern society continues to accelerate,people's choices of food and food materials have been developed towards convenience and the production of all kinds of grains and beans with rice cooking ripe at same time can meet the practical needs of people's daily life.In this study,three kinds of pre-cooking processes methods : high pressure cooking,microwave heating and explosion puffing drying are used to optimize the pre-cooking processes of red kidney beans and maintain the appearance of red kidney beans to the maximum extent.In order to achieve the goal of "rice and beans cooked ripe at the same time",to improve of the national healthy diet structure in China provides certain technical support,and make a contribution to the enhancement of the level and market competitiveness of China's new grain and oil industry,the experimental results are as follows:(1)On the basis of a single factor test,the optimal process parameters of each method are optimized by a response surface test.The optimal technological parameters of high pressure cooking are: cooking pressure is 20 k Pa,cooking time is 10 min,bean-water ratio is 1:3.The optimal technological parameters for microwave heating are: the microwave power is 450 w,the microwave time is 4 min,and the water content of red kidney bean is 25 %.The explosion puffing drying are: the heating temperature is 80 ?,the heating time is 120 min,and the water content of red kidney beans is 30 %.All of the three methods can produce red kidney beans with non-destructive appearance,good sensory quality,strong flavor and the ability to cooked with rice at the same time.(2)To investigate the effects of the three methods: high pressure cooking,microwave heating and explosion puffing drying on the texture characteristics,color difference and microstructure of red kidney beans before and after pre-cooking processes.The hardness of the first cycle is in the order of microwave heating > explosion puffing drying > high pressure cooking method;the elastic elastic is in the order of high pressure cooking method > microwave heating > explosion puffing drying method.The chewiness is in the order of explosion puffing drying > high pressure cooking > microwave heating.The degree of cohesion is in the order of the microwave heating > high pressure cooking > explosion puffing drying method.The large pits of starch grains in red kidney beans after high pressure cooking.Large pits appeared in some starch grains of red kidney beans heated by microwave,and the small changes of some starch grains reflected the inhomogeneity of microwave heating energy release.Compared with the other two methods,the damage degree of starch in explosion puffing drying is lower.(3)To investigate the gelatinization characteristics and digestibility of red kidney bean starch before and after pre-cooking processes by the three methods: high pressure cooking,microwave heating and explosion puffing drying.RVA results showed that the gelatinization time and gelatinization temperature of red kidney beans decreased after the pregelatinization,and the gelatinization temperature of the pre-cooking processes method is in the order of explosion puffing drying > microwave heating > high pressure cooking,which demonstrated the effectiveness of the pre-cooking processes.DSC results showed that after the enthalpy value of the red kidney beans treated by the three methods,the starting paste temperature and the ending temperature all decreased by the three methods,indicating that pre-cooking processes reduced a certain degree of gelatinization difficulty.The contents of rapidly digestible starch in red kidney bean starch were significantly increased,the contents of slowly digestible starch were slightly decreased,and the contents of resistant starch were significantly decreased.Among them,the explosion puffing drying method has the highest content of resistant starch,which is more suitable for low GI food material.(4)On the whole,the three kinds of pre-cooking processes methods can reduce the gelatinization difficulty,and can produce red kidney beans with good sensory quality which can achieve "rice and beans cooked ripe at the same time".High pressure cooking method is time-saving and efficient,avoiding energy waste.The microwave heating method is easy to operate and the time is the shortest.Explosion puffing drying is a new method of pre-cooking processes.Red kidney beans are boiled with rice with moderate hardness and highest sensory score,which is more suitable for mass production in factories.It's better for high blood sugar people to eat with its lower digestibility and provides a new way of thinking for the processing of coarse grains.