Fermentation Technology Of Compound Probiotics And Development Of Milk Beverage

Most of probiotic milk beverage market existing way of sterilization is ultra high temperature sterilization,and by 115?¹20?heat 5⁸ min to achieve sterilization effect,this approach can lead to products are brown,and the product of nutrients,such as protein,amino acid,produce adverse effect.In order to reduce fermentation products before the sterilization temperature and time,prevent Browning in raw milk sterilization process,at the same time,using different lactic acid bacteria fermentation characteristics,give play to the role of different strains of synergy,this study first high acid and high living bacterium composite were screened,on this basis,through the optimization of fermentation conditions and in the process of composite stabilizer adding amount,to speed up the fermentation,the increase of the number of living bacterium probiotic products and improve its flavour,this experiment mainly research contents are as follows:?1?In this experiment,six strains of probiotics of different types were screened.Based on the fermentation characteristics of these six strains and considering the symbiotic and synergistic effects among them,the strains with fast fermentation speed and strong acid production capacity were selected.The results showed that streptococcus thermophilus,lactobacillus debrachii Bulgarian subspecies and lactobacillus casei as the mixed starter could achieve the expected goal.In the early stage,acid reduction was rapid,the effect of inhibiting bacteria was obvious,the fermentation cycle was long,and a large number of flavor substances could be produced.In addition,the optimum growth temperature of the dominant strains in each stage was tested,and the best fermentation method was selected.?2?In this study,the effects of probiotics inoculation amount,strain ratio,glucose addition,fermentation temperature,and the addition of skim milk powder on the pH value,acidity and viable count of active probiotics milk beverage after fermentation for 48h were studied.On the basis of single factor and extreme difference analysis and variance analysis by orthogonal optimization test,with the pH of fermentation after 48h,acidity and the number of living bacterium composite scores as examining index,determine the best fermentation technology of probiotics beverage recipe for:glucose 2%,degreasing powder adding quantity 10%,the proportion of probiotics?thermophilic streptococcus:lactobacillus debrachii Bulgarian subspecies:lactobacillus casei?as1:1:1,fermentation temperature of35?.The verified probiotic milk beverage obtained under the optimal fermentation conditions showed that the total number of live bacteria in the original product was1×10^8.5cfu/mL with a pH of 3.43,and the total number of live bacteria after optimization was 1×10^9.74cfu/mL with a pH of 3.35.?3?On the basis of the basic formula,the effect of high-fat pectin,CMC and soluble soybean polysaccharide on the stability and sensory quality of probiotic milk beverage was studied by taking centrifugal precipitation rate and sensory score of probiotic milk beverage as evaluation indexes.By single factor test and response surface optimization test,the optimal ratio of composite stabilizer for probiotic milk beverage was obtained:the addition amount of high-fat pectin was 0.083%,the addition amount of CMC was 0.077%,and the soluble soybean polysaccharide was 0.09%.The final centrifugal precipitation rate and sensory score of the product obtained in the validation test were 2.7%and 85.23 respectively,with ideal indexes.