Study On The Process Optimization, And The Separation,Control Of Spoilage Microorganisms In Soy-Peanut Bean Milk

Soy milk is one of the traditional non-fermented soybean products, with rich nutrition.Soy-peanut bean milk containing a variety of high-quality plant protein, minerals, vitamins,isoflavones, soybean cephalin and daidzin raw, plays a very important role in human health.But the rich nutrition of soy-peanut bean milk is also providing a favorable condition for the growth of microorganisms, so it shelf life is short, and the production, storage and sale of soy-peanut bean milk has been seriously affected. The deterioration of soy-peanut bean milk is harmful to human health, so it is very important to study on the separation and identification of spoilage microorganisms in soy-peanut bean milk.The experimental results show that process of soy-peanut bean milk as follow,weighing peanut and soy bean at the rate of 1:3 separately, cleaning beans at first, soaking the beans together for 4h with 5 times water at 40?.Then grind them, and extracted from the beans a thick chartreuse liquid, grinding conditions are: 12 times water, 100 ?. The liquid was separated with a 100 mesh screen, add 5% into the milk. with twice homogenization, sterilized the milk at 115? for 15 minutes,the product of soy-peanut bean milk was got. Compare with traditional soya bean milk, the product preserved at low temperature had a higher stability and longer storage life.In this paper, the microbial change was tested between the normal and spoilage soy-peanut bean milk. It was found that the pH value of spoilage soy milk dropped from6.40 to 5.40. Three kinds of microorganisms were isolated.them can make the normal soy-peanut bean milk spoilage. The results showed that they were Gram-positive bacteria,Bacillus licheniformis, Bacillus subtilis, Bacillus cereus.The growth characteristics under different conditions of three spoilage microorganisms were studied in the paper. By analysis of the growth under the different storage conditions, pH value and sterilization technology, it was found that, these conditions could affect the growth of them.Inhibition experiments and inhibitor filtration to the three spoilage microorganisms were done. Several gradient concentration of inhibitor solution were selected to confirm the approximate action range of the antimicrobial agent, then the minimum concentration of the final inhibitory concentration were determined. The result showed that three of the selected inhibitors, nisin, polylysine and nipagin complex esters(water soluble). The combination for the highest antibacterial rate is 0.004 % of nisin, 0.008 % of polylysine,0.010 % of nipagin complex esters(water soluble), 100 ?/10 min, all microorganisms could not grow. Using it to soy-peanut bean milk under different storage conditions, the products had a longer shelf life than before.