| Longchang beanstalk has a long history and is one kind of high quality products of soybean which can provide a balanced energy and nutrition for the humans.The traditio na l beanstalk is usual y dehydrated.It needs to rehydration treatment before cooking,which would take a long time,and not convenient.The pre-soaking soybean gulten is one kind of beanstalk product which be cut and drained after rehydration treatment,and finished with vacuum packaging and sterilization.Since pre-soaking gulten not only contains rich nutrients such as protein,fat and sugar,but also has a high water content which could easily breed microorganisms and lead to the deterioration.To solve this problem,this study used beanstalk as raw material to study the influence of sterilization conditions on the pre-soaking soybean gulten quality.The optimum process conditions were optimizing by the orthogonal experiment.Finally,the storage stability of pre-soaking soybean gulten products had been tested.The main research results were as follows:1.It investigated the effects of soaking temperature,soaking time,vacuum degreeand,bactericidal temperature and bactericidal time factors on the processing of pre-soaking soybean gulten product.The total number of colonies and sensory score were as evaluatio n indexes to determine the optimum conditions for each single factor.Based on single factor experiment,the orthogonal test was used to optimize process conditions,the optimum process conditions were as follows: soaking temperature was at 20 ?,soaking time was 4h,vacuum degree was at 0.09 MPa,bactericidal temperature was at 105 ?,bactericidal time was 15 min.The total number of colonies and sensory score of pre-soaking soybean gulten measured under the optimum process conditions were 30cfu/g and 89.75.2.The results showed that the colony lump-sum of the sample decreased from 8.72×108 cfu/g to 50 cfu/g or less,and coliform bacteria in the sample decreased from 1.6×105 MPN/g to 3 or below,when the temperature above 105 ? and the sterilization time over 10 min.Pathogenic bacteria was not detected.Sterilization temperature and time had no significa nt effect on fat content,pH and springiness(P>0.05),but had a significant effect on moisture,protein,color and lustre,hardness and chewiness(P<0.05).It could make a conclusion that 105 ? and 15 min,110 ? and 10 min can effectively maintain the quality,and inactive the microorganism of pre-soaking soybean gulten.3.The changes of main microorganism,sensory and physicochemical indices during shelf life of the pre-soaking soybean gulten treated with the two sterilization conditions 105? for 15 min and 110? for 10 min were investigated,and the correlation between the related indices were analyzed too.The results showed that with the prolongation of storage time,the total number of colonies,hardness and chewiness of the immersion-free beanstalk treated with the two conditions significantly increased(P < 0.05);the moisture content,pH,sensory score and L* significantly decreased(P < 0.05);there was no significant difference in the change of protein content,fat content and springiness during the storage(P > 0.05).Through the correlation analysis on the indexes of the two sterilizing conditions,correlation analysis and the variation tendency of all indexes in the storage period are basically coincident.The apparent indexes and the interior physicochemical indexes of pre-soaking soybean gluten have prominent correlation,and the correlation among all indexes are affected by the sterilization temperature and time.The conclusion was that the pre-soaking soybean gulten treated with the sterilization condition at 110? for 10 min could better preserve the quality during shelf life. |
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