Research Of Crux Technology On Preparing Yoghourt Freeze-dry Starter Culture Of Fermented Meet Product

The flavor of traditional fermented meet product adopt natural fermented, so it is difficult for quality of product to control. In order to obtain the optimum starter and processing parameter of fermented meet product which is fit to Chinese flavor, and to supply theory and practical basis for the industrial production of starter for meet, crux technology on preparing freeze-dry starter culture for fermented meet product were investigated in this study. Firstly, freeze-dry starter culture of Lactobacillus delbrueckii was studied, and then freeze-dry starter culture of Staphylococcus carnosus was studied. Main contents and conclusions are as follows.1.The growth experiment of Lactobacillus delbrueckii in carrot juice, tomato juice, wort which are apt to gain and separate ,was conducted. The result showed that wort was the best base medium for Lactobacillus delbrueckii. The effect of adding 12 kinds of different nutrient factors in wort on the growth of Lactobacillus delbrueckii was studied. The results showed that Soya peptone, Beef Extract, Yeast Extract and the initial pH of the media concentration could promote the growth of Lactobacillus delbrueckii significantly in wort and K2HPO4. And he influence of Soya peptone addition, Beef Extract addition, Yeast Extract addition and the initial pH of the media concentration on the living bacteria number by four elements quadratic currents quadratic current revolving design. The processing technology was optimized, and the optimal processing parameters were obtained. Beef extract 9.99g/l , Yeast extract 5.07g/l, Soya peptone is 5.14g/l and the initial pH of the media is 6.27. Results also indicated Beef extract addition and Yeast extract addition, Beef extract addition and the initial pH of the media have obvious mutual effect.The effect of cultivation temperature, mode and inoculation amount on the growth of Lactobacillus delbrueckii was studied. The optium condition to cultivate Lactobacillus delbrueckii was that the cultivated 37℃, inoculation 5%The effects of centrifuging force, time on the loss rate, survival rate and harvest rate of Lactobacillus delbrueckii was studied. The results showed that the optimum conditions for centrifugation of Lactobacillus delbrueckii was 7500r/min for 10min or 9000r/min for 5min.A complex protectant was screened by orthogonality test L8(2~7) consist, which could protect cell from damaging during freeze-dry and storage, and which at the based of Skim milk 10% was detemined by trail as glycerin 20ml/L,sucrose 30g/L,Tween80 10 ml/L, maltodextrin 10g/L,Glutamate-Na 20g/L, Yeast exeract 20g/L. At the same time, the starter,s character was storaged at -4℃and packaged with air.2.The enrichment of Staphylococcus carnosus was selected by orthogonality test L16(45)consist, and which at the based of MSA was Soya peptone 8 g/L, Yeast Extrac 3 g/L, Grape sugar 8 g/L, K2HPO41.6g/L and the initial pH of the media concentration 6.7.The effect of cultivation temperature, mode and inoculation amount on the growth of Staphylococcus carnosus was studied. The optium condition to cultivate Staphylococcus carnosus was that the cultivated 37℃, inoculation 3%. In the condition, the living-cell number of Staphylococcus carnosus was 17.2×108cfu/mLThe effects of centrifuging force, time on the loss rate, survival rate and harvest rate of Staphylococcus carnosus was studied. The results showed that the optimum conditions for centrifugation of Staphylococcus carnosus was 7500r/min for 10min or 9000r/min for 5min.A complex protectant was screened by orthogonality test L8(2~7) consist, which could protect cell from damaging during freeze-dry and storage, and which at the based of Skim milk 10% was detemined by trail as glycerin 20ml/L,sucrose 30g/L,Tween80 5 g/L, maltodextrin 10g/L,Glutamate-Na 20g/L, Yeast exeract 10g/L. At the same time, the starter,s character was storaged at -4℃and packaged with vacuumize.