The Studies On Fermentation Technology Of Fermented Soymilk And HACCPS' Application

There are rich improved varieties,resources and long-standing cultivating history of soybean in China. The soybean has very good value of nutrition, and it is titled "plant meat".Besides plentiful plant protein and vegetable fat, soybean contains bioactive compounds good for one's health, for example: soybean oligosaccharide, isoflavones,phosphatide,saponin, peptide,dietary fiber,vitamin E.The main material of the researchment is soybean, and the test is about optimum seeking of lactic acid bacteria fermentation technology for fermented soymilk. Through unifactor and orthogonal design experiments about the recipe of materials and mixed starter,inoculum size,fermentation temperature and time,pressure and time of homogenization, the paper researched these factors' influences to acid production, pH,flavor and texture of fermented soymilk, and the changes of its physics properties of biology,mouth feel at the shelf life. The optimum parameters of fermented technology and formula were obtained. Then the test achievements were researched in medium-scale test of fermented soymilk processing, and HACCPS' application on fermented soymilk production was inquired. The company (internal control) standard of fermented soymilk was worked out.The fermentation technology of fermented soymilk was selected for optimization: selecting mixed starter of Lactobacillus bulgaricus and streptococcus thermophicus, the ratio 1:1, fermentation temperature 42.5℃,fermentation time 3-3.5 h,inoculum size 3%,sucrose content 8%; After using microwave heating, the majority of lipoxygenase is inactivated,and soybean smelling of seafood is removed. The microwave baking temperature is controlled for 70-80℃, meanwhile, the baking time is 2-3min; By soaking soybean in rational quantity of 0.25% NaHCO₃, the texture of soybean can be softened effectively, and its time in NaHCO₃ solution is less than in water. The ideal soaking time is 8-10h under normal atmospheric temperature, and the weight of NaHCO₃ solution is three times of dry soybean. The NaHCO₃ solution is replaced every three hours; After finishing soakage, the soybean is milled with boiling water (five times of soaked soybean weight) , as milling with boiling water can inactivate lipoxygenase and removing soybean smelling of seafood to considerable extent for ensuring the flavor of fermented soymilk products. Adding a rational milk will benefit mutual nutrient supplement, but also the optimum flavor. The test defined the optimum ratio of soymilk to milk is 85:15; Rational addition of powdered whey,sodium phosphatic tribasic,honey,stabilizer to soymilk can improve fermentation property of lactic acid bacterium,flavor,taste and stabilization of the product,and the adding ratio of powdered whey,sodium phosphatic tribasic,honey,stabilizer are respectively 0.50%,0.05%,2.0%,0.3% (0.15%PGA+0.15%pectin); The homogenization pressure has a great influence on the quality of products, and the test defined the pressure of homogenizing is 25 Mpa, the temperature of soymilk before homogenizing is above 85℃. The test selected homogenization of high pressure twice; The sterilization temperature and time should be strictly controlled, and the optimum parameters are 95℃,15min; After-ripening of product's cold storage for 12-20h will benefit the formation of flavor substance. The larger the quality of flavor substance is, the better the flavor is.In the storage period of fermented soymilk, pH value will become smaller, and at the same time, the acidity will be going up. The change of acidity accords with the one of pH value.The amount of total baceria became a lower value after 9 days of urgented drop, then the drop is smooth and steady, and the taste of products is also changed; General speaking, the fermented soymilk can be store at 2-6℃, and the test suggests the shelf life of fermented soymilk is 9 days. Only within these days, can the taste,quality and nutrient value of products be ensured.Through medium-scale researchment, the HACCPS' application on fermented soymilk production was probed. The test analysed harmful elements existent and potential in the processing, and the key controlling points that influence the quality of products were found out. By using correspording controls, the production of best fermented soymilk has the assurances.