Evaluation Of The Germinated Soybean Variety Specifically For Soybean Milk Characteristics And Correlation With Soybean Milk Quality

Soybean milk is produced by the process of soaking,grinding,boiling,and filtering soybean.With the increasing popularity of soybean milk machines,more people make soybean milk themselves.Soybean milk machines have also appeared on the market which can be used to make soybean milk from unsoaked soybeans.Although it is convenient to make,the soybean milk tastes bad,which has low protein content,and it is not easy to absorb by human body.In this case,people still choose the traditional way of soaking the original beans for more than ten hours,although the process is a little complicated.Therefore,to exploit the soybean variety specifically for soybean milk shows the great potential market and commercialization prospect.The paper has a systematic study of the soybean variety specifically for soybean milk,germination conditions,passivation methods of anti-nutritional factors,quality index of soybean milk,storage period of germinated beans,and the relationship between physical and chemical indexes of soybean varieties and quality of soybean milk.The results are shown below:(1)The paper has taken 29 soybean varieties from the main production area of Heilongjiang as the research object.Firstly,the physicochemical properties of soybean(content of water,fat,total sugar,protein,calcium,protein subunit 7S,11 S,11S/7S)and the quality index of soybean milk(protein content,stability,yield of soybean milk,grain size,protein transfer rate,sensory score)are analyzed;then using principal component analysis,and the results of principal component analysis show that the variance contribution rate of 6 principal component factors(comprehensive indicator)reach 84.973%,the top five varieties with comprehensive scores are: Heinong 85,Heinong 66 and Heinong 71,Heike 56,Heihe 33;Finally,the results of cluster analysis show that 29 varieties of soybean milk are divided into four categories,the five selected varieties are all in category II,this variety of soybean milk has the characteristics of high protein content,protein transfer rate,high sensory score and medium soybean milk yield,which meets the technical requirements of soybean milk products.(2)The soybean varieties selected above were germinated at different temperatures(15,20,25,30 ℃)for 4,8,12,16,20,24 h,the nutrient content of soybean(content of reducing sugar,total sugar,protein),the anti-nutritional factors(content of urease,lipoxygenase)and the main beany flavor(content of Hexaldehyde,Hexyl alcohol,1-Octen-3-Octenol)are analyzed.The experiment results show that the content of reducing sugar increased with the extension of storage days and the content of total sugar,which is up 0.95% at most and the content of total sugar,protein,anti-nutritional factors,and main beany flavor decreased,which is falling8.59 %、1.78 %、25.04 %、49.78 % at most respectively.The varieties after germination with low anti-nutritional factors and high nutrient content were selected for the germinated soybean variety specifically for soybean milk.(3)Three methods: baking,microwave,boiling water blanching were used to passivate the anti-nutritional factors.By comparison,the passivation of anti-nutritional factors effect of boiling water blanching is the best among all the three methods,and the passivation suitable conditions has been determined as follows: boiling water blanching for 40 s.(4)In the process of the germinated soybean variety specifically for soybean milk stored at 4 ℃,with the extension of storage days(0～28 days),the physicochemical properties of germinated soybean(content of reducing sugar,total sugar,protein,anti-nutritional factors,beany flavor),microbiological index(total numbers of colony)had no apparent changes.(P>0.05).When the germinated soybeans has been stored for 28 days,the total numbers of colony were close to the limit,and the total numbers of colony exceeded the limit at 35 days;With the extension of storage days,the content of α-helix in secondary structure of protein decreased and the content of β-sheet increased,the protein tertiary structure was stable;the decrease in protein content of soybean milk produced by the germinated soybeans was not significant(P>0.05),when the germinated soybean variety specifically for soybean milk has been stored for 21 days,the decrease in the stability of soybean milk produced by them was not significant(P>0.05);Therefore,the longest storage time of the germinated soybean variety specifically for soybean milk at 4 ℃ was 21 days.The results from a series of studies on the germinated soybean variety specifically for soybean milk can provide a technical reference for its commercial production and storage.