Study On Preparation And Influence Factors Of Yuba

Traditional preparation technics of dried bean milk cream in tight rolls (namely, yuba) wasdiscussed. The optimum conditions for yield were: soluble solid content 5%, soymilktemperature 85℃ and pH8.5;the optimum conditions for quality were: soluble solid content 5%,soymilk temperature 85℃ and pH8.0. The quality and the yield were 77.5 and 48.2% respecti-vely under the optimum conditions.On the basis of corresponding authority vectors, a new synthetical quality index was firstlybuilt, which included mechanical properties and colors. Relevant blur math theory was appliedfor this quality index. It was proved in the experiment that it was feasible to investigate thequality of yuba using this method.The content of protein, fat, soluble sugar and soluble solid vary with the time increasingduring the heating. Relevant mathematical model were built to observe the changes. Thecomponents of the soybean had a great effect on the mechanical properties and yield. Theresults indicated: high 11S/7S ratio would increase the tensile strength. It was better for thepreparation of yuba at fat/protein ratio 0.3, the soluble sugar/protein ratio 0.35 and pH8.0. Abackpropagation neural network system(ANNS) was built according to quality and yield inwhich fat/protein, sugar/protein and pH were the effective factors and the results can beforecasted in any conditions.The studies on different additives showed: NaSO3 was the excellent reducing agent andbleacher while the ferulic acid was a better cross-linking agent.Further studies indicated: the optimum addition time of NaSO3 and ferulic acid were 2.0hours and 3.0 hours respectively after the milk was boiling. The optimum reaction conditionsby surface analysis were: NaSO3 0.06%, ferulic acid 6.4%, glycerol 60%. The quality and theyield were 84.61 and 54.1% respectively under the optimum conditions. Compared with thetraditional techics, the quality and the yield improved 9.17 %and 12.2% respectively.