Study On Enzymatic Hydrolysis Of Lamb Myofibrillar Protein Fermented Beverage

Livestock meat and meat products are important sources of high-quality protein for human beings,of which myofibrillar protein(Myofibrillar proteins,MP)accounts for about 50%-55%of muscle protein.At present,due to the aging of the body,it is difficult for the elderly and sick people to ingest meat products due to the decline of body function,which limits the acquisition of animal meat protein by the elderly and sick people to a great extent.In this thesis,myofibrillar protein from mutton was hydrolyzed by enzyme and then fermented by lactic acid bacteria to obtain polypeptides,oligopeptides,free amino acids and flavor substances.On this basis,a meat protein beverage which is easy to digest and absorb is made to facilitate the intake of meat protein by the elderly and sick people,and at the same time help to maintain the nutritional balance and health of the human body.This thesis is divided into the following three parts:1.Research on enzymatic hydrolysis process:extract myofibril protein from lamb and determine its protein concentration and amino acid composition.Neutral protease,flavor protease,and alkaline protease were used to hydrolyze myofibrillar protein separately to obtain three protease hydrolysates.Determine the degree of hydrolysis and bitterness value of the hydrolysate,and select the most suitable from the three proteases The protease used in this experiment.The selected protease was subjected to single-factor and orthogonal experiments to optimize the process conditions of myofibril proteolysis.The results showed that neutral protease is the best choice for enzymatic hydrolysis of myofibril protein;based on the single-factor test,the orthogonal test The optimal technological conditions for hydrolysis of myofibrillar protein by neutral protease were optimized as follows:the amount of enzyme added was 2000 U/g,the pH value was 7.5,the enzymolysis temperature was 50?,and the enzymolysis time was 8h.2.Selection of Lactobacillus compound strains:Choose Lactobacillus bulgaricus(LB),Lactobacillus sake(LS)and Lactobacillus plantarum(LP)to determine the growth curve of the three strains,and then follow LP:LS(1:1)),LB:LS(1:1)and LP:LS:LB(1:1:1)with a total bacterial count of 107cfu/g,respectively inoculated into mixed skimmed milk powder and myofibril with 4%white sugar In the protein liquid(dissolve skimmed milk mixed protein ratio 1:1 at 50?).Fermented at a constant temperature at 37?,the acidity and pH of the fermented myofibrillar protein were measured,and the fermented product was sensory evaluated.The fermentation characteristics of different combinations of strains in the myofibril protein fermentation process and the fermented muscle were compared.For the flavor state of fibrillin,the most suitable strain combination for myofibril protein fermentation in this experiment was finally selected:LB:LS combination.3.Determination of fermentation process parameters of myofibrillar protein and preparation of beverage:with pH value and titratable acidity as the main index,through single factor and orthogonal experiments,the optimum fermentation process parameters of fermented beverage were determined as follows:inoculation amount 3%,sugar addition 5%,fermentation temperature 39?.Beverage preparation:the amount of ?-cyclodextrin directly affects the taste of fermented beverage.The experiment shows that the taste of fermented beverage is good when 0.02%?-cyclodextrin is added.