The Effect Of Six Different Preparation Processes Of Tofu On The Yield And The Distribution And Residue Of Trypsin Inhibitor

In order to optimize the soymilk processing technology to obtain the high yield,high quality,low activity of trypsin inhibitor product.Six different processing method was used to process the soymilk and tofu with 5 variety soybean as raw material: soaked soybean-boiling before filtration(SS-BBF soymilk),soaked soybean-boiling after filtration(SS-BAF soymilk),half dry soybean-boiling before filtration(HDS-BBF soymilk),and half dry soybean-boiling after filtration(HDS-BAF soymilk),germination soybean-boiling before filtration(GS-BBF soymilk)and germination soybean-boiling after filtration(GS-BAF soymilk).The soymilk yield,soluble protein content in soymilk,protein recovery rate and the yield of tofu were analyzed.The texture and color of tofu by different variety and processing method also was determined in the next step.The trypsin inhibitor activity was measured in raw beans,soymilk,bean curd,bean curd refuse,yellow serofluid in order to research on the distribution and change regulation of soybean trypsin inhibitors content.The results showed that:1.The yield from high to low of different processing method when the soybean variety is same is as following: SS-BBF soymilk,SS-BAF soymilk,HDS-BBF soymilk,HDS-BAF soymilk,GS-BBF soymilk,GS-BAF soymilk.2.The sequence(from high to low)of water-soluble protein content of soymilk is as following: SS-BBF soymilk,SS-BAF soymilk,HDS-BBF soymilk,HDS-BAF soymilk,GS-BBF soymilk,GS-BAF soymilk.3.The trypsin inhibitor activity from high to low in different processing method is as following: SS-BAF soymilk,HDS-BBF soymilk,SS-BAF soymilk,SS-BBF soymilk,GS-BAF soymilk,GS-BBF soymilk.The activity from high to low in different processing method of bean curd refuse is as following: GS-BBF soymilk,SS-BBF soymilk,HDS-BBF soymilk,GS-BAF soymilk,SS-BAF soymilk,HDS-BAF soymilk.4.The maximum average grain diameter is 128.64?m when the HDS-BBF soymilk processing method was used.And it is not significant different(P>0.05)in the other five processing methods.5.In the texture determination of tofu,it can be found that the TPA(tofu hardness,elasticity,glue viscosity,chewiness,cohesiveness)was affected by different processing method and variety significantly.The hardness and restoring force of boiling before filtration tofu are less than that of boiling after filtration tofu.In the comparison of the chewing,adhesiveness,cohesion and elasticity of tofu,the tofu made by the boiling after filtration method is greater than that produced by boiling before filtration method.6.It was found that different processing technology affect on the L*,a*,b* and the ?E value.The L*,a*,b* value of tofu made from SS-BAF soymilk method is higher than all the other processing technology.