| Starch and protein are important components of food.Besides providing rich nutrients,they have a significant impact on the physicochemical properties and edible quality of food.The mixed system(complex,gel,mixture,etc.)formed between starch and protein can improve the physical and chemical properties of starch and protein,and its potential application in the food industry has attracted widespread attention.In the preliminary experiment,the effect of soybean 7S protein in lowering blood sugar was more obvious,so this experiment took rice flour and soybean 7S protein(β-Conglycinin)as the experimental objects.The experimental methods and results are as follows:(1)Different proportions(0%,3%,6%,9%,12%)of soybean 7S protein were added to indica rice flour to explore its effect on Inflluence of gelatinization,thermodynamic,rheological and gel properties of indica rice flour The results showed that the addition of soybean 7S protein reduced the viscosity of the mixed powder paste,increased its fluidity,and showed more liquid properties;the hardness and elasticity of the mixed powder gel gradually decreased,indicating that the addition of soybean 7S protein can effectively control the properties of rice starch-based gel food.(2)Add 0%,3%,6%,9%,12%of soybean 7S protein to the indica rice flour respectively,and use this as a raw material to make rice flour with a single-screw extruder and a twin-screw extruder,respectively.Taking hydration characteristics,water absorption rate,broken strip rate,cooking loss rate,turbidity,sensory evaluation,texture characteristics and color difference as the inspection indicators to explore the effect of soybean 7S protein addition on the quality of rice flour under different extrusion processes.The results showed that with the increase of soybean 7S protein content,the water absorption rate,sensory evaluation and texture properties of rice flour decreased,the broken strip rate,cooking loss rate and turbidity increased,and the quality of rice flour decreased slightly.The amount of soybean added is within 6%,the sensory score of rice flour prepared by single-screw extruder is greater than 80,and the rate of cooked and broken strips and the rate of cooking loss are both less than 10%.The amount of soybean 7S protein added is within 9%,and the rice flour prepared by the twin-screw extruder has a sensory score of more than 80,a broken strip rate of less than 8%,and a cooking loss rate of less than 4%,which meets the standard T/CCOA4-2019.The twin-screw has large shearing force,strong extrusion force,and the rice flour has a dense structure.When the same amount of soybean 7S protein is added,the quality of the twin-screw group rice flour is better than that of the single-screw group.(3)The fast digestible starch(RDS),slow digestible starch(SDS),resistant starch(Resistant starch,RS),starch hydrolysis rate,estimated glycemic index(estimated glycemic index,eGI),Glycemic load(GL)was used as the investigation index to explore the effects of different extrusion processes and different soybean 7S protein additions on the digestion characteristics of rice flour.The results showed that with the addition of soybean 7S protein,the RDS decreased,the total amount of SDS and RS increased,the starch digestibility decreased,and the eGI and GL decreased.When the protein content was 12%,the eGI and GL of rice flour prepared by single-screw extruder and twin-screw extruder were 62.47,73.43 and 40.61,47.74,respectively.Twin screw extruders are less effective than single screw extruders in reducing eGI and GL.(4)No new diffraction peaks were found in the X-ray difraction patterns(XRD)of the two rice noodles,and no new absorption peaks appeared in the infrared patterns;the characteristic absorption peaks of protein and starch did not shift significantly. |
