Studies On The Processing Technology And The Postacidification Of The Active Lactic Bacteria Beverage

The active lactic acid bacteria beverage not only has rich nutrition and many health functions, but also has good flavor and high digestion and absorption rate, so it wins warm praise from customers. At present, as a new fermentation dairy beverage, the problem of processing technology of the active lactic acid bacteria beverage is not solved completely. In shelf life, product have many problems, such as precipitation, serious post-acidification, the number of active lactic acid bacteria can not get the industry standard, and etc. The impact of these questions hindering the popularizaton of the active lactic acid bacteria beverage. On account of the existing problems in the active lactic acid bacteria beverage, such as processing technology, stability, post-acidification, further discussion and investigation have been carried out in this dissertation. Results are as follows:When the temperature of reconstituted milk sterilization was 5℃and the time was 20min, the stability of the active lactic acid bacteria beverage is the best. Based on single factor experiment, fermentation temperature, fermentation time and inoculation amount are used as factors of the response surface experiment to optimize the fermentation process. When the fermentation temperature was 39.86℃, fermentation time was 3.94h and inoculation amount was 3.14%, the sensory value of the fermented milk is highest. Compared with different homogenization conditions, when the temperature of homogenization was 15℃and the pressure was 20MPa, the effect of homogenization to the stability of the active lactic acid bacteria beverage is the best.During storage, the viscosity of the active lactic acid bacteria beverage decreases continuously. The active lactic acid bacteria beverage is pseudoplastic fluid, the bad viscosity is, the bad fluidity is. The active lactic acid bacteria beverage deviates from newtonian fluid and the much addition amount of stabilizer, the higher apparent viscosity. When the concentration of mixed emulsifiers(sucrose ester:monoglyceride=l:l) is 1%, compared with other different emulsifiers, the effect of mixed emulsifiers to the stability of the active lactic acid bacteria beverage is the best. The addition quantity of acidic CMC-Na, PGA and xanthan gum are used as factors of the response surface experiment to optimize the composite stabilizer of the active lactic acid bacteria beverage. When the addition quantity of acidic CMC-Na was 0.3%, PGA was 0.1%and xanthan gum was 0.06%, the stability of the the active lactic acid bacteria beverage is the best.By the study of the effects on the lactic acid fermented beverage's postacidification, the results showed that the higher the storage temperature is, the more serious the postacidification and the faster the decrease of viable count lactobacillus will be. And the optimization storage temperature is 1℃-6℃. Lactobacillus bulgaricus is the main starter lead to postacidification of the lactic acid fermented beverage. Otherwise it showed that the postacidification can be effectively controlled by decreaseing the proportion of Lactobacillus bulgaricus in Starter. When the concentration of Nisin reached lOOIU/ml, it can inhibit the postacidification in some extent. At the same time, we can increase the permeability of the cell to inhibit the postacidification. Lysozyme can inhibit the postacidification in some extent, but the using of it leads to high cost. We also can change the soluble solids content of the the active lactic acid bacteria beverage to inhibit the postacidification.