Study On The Stabilization System Of Fermented Milk Drinks Induced By Skimmed Milk Power Of Different WPNI

In order to research the effect of milk powder with different degree of thermal denaturation on the fermented milk beverage system, this experiment uses skimmed milk powder as raw material, fermented milk beverage is prepared by long and short fermenting process according to the classification of fermented milk beverage on the market respectively. Focus on the changes of fermented milk beverage in sensory physicochemical Parameters during storage time, the shelf life model of long and short fermented milk beverages was established according to Arrhenius equation,and the effect of different heat denatured skim milk powder on the stability of fermented milk beverage was studied. The specific research contents and conclusions are as follows:The single factor experiment and orthogonal experiment were used to obtain the optimum parameters of the fermentation process, along with the centrifugal sedimentation rate. The optimum process parameters were sterilization under95? for 60min, homogeneity at 30MPa, and the sugar and acid ratio was 8 % / 3.8, and the additive amount of compound stabilizer2158-1Bwas 0.20%. According to the range analysis, the main order of each factor was sterilization process parameter>2158-1B dosage>sugar acid ratio>homogeneous pressure. The optimum parameters for the short-time fermented milk beverage were as follows: sterilization process parameters were 95 ? ,15min,the additive amount of compound stabilizer 2158-1B was 0.30% , homogeneous pressure was 25MPa, sugar and acid ratio was 6% / 3.8. According to the range analysis and along with the centrifugal sedimentation rate, the main order of each factor was reached, the sterilization process parameters>sugar acid ratio>2158-1B dosage> homogenization pressure.The sensory difference, centrifugal sedimentation rate, particle size, viscosity, TSI(dynamic stability index) values of fermented milk beverage during storage period were measured. The regression analysis of sensory difference with centrifugal sedimentation rate,particle size, viscosity, TSI values for two kinds of fermented milk beverage were built.The TSI value was regarded as parameters to establish the stability prediction model because of its high relevance. The shelf life prediction model for LT and ST were gained through the analysis of thermodynamic and kinetic by Arrhenius equation.Verify the results of two equations showed that the average relative error of the predicted value and the actual measured value of LT and ST were both less than 10 %, so the shelf life prediction model has a good accuracy.By means of the model of the shelf life of fermented milk beverages, we can find that the shelf life of fermented milk beverages with low and medium thermal skim milk powder as raw materials was longer than that of hot skim milk powder, and the shelf life of the two fermented milk beverages shorten with the increase of heating degree of the skim milk.Through the determination of TSI, particle size and ?BS of raw skim milk reconstituted milk and two kinds of fermented milk beverage products, we can find that the stability of product was decreased with the increase of WPNI value of raw skim milk powder. The results of SDS-PAGE showed that the precipitated substances were mainly casein, ?-lg,a-La and a little Lf and BSA.