The Effect Of Milk Solids Concentration And Starter On The Quality Of Sour Goat Milk

Goat milk has high nutritional value,is regarded as a fine product in dairy products.However,in the production of yogurt using goat milk as a raw material,it is often easy to show a defect of Long curd,poor curd,whey easily precipitated.In order to solve the problems of curd and poor stability of goat milk curd,this experiment mainly studied the influence of solids concentration and starter on goat milk yoghurt,and provided a theoretical basis for improving the quality of goat milk.(1)Effects of different total solids of goat milk on quality of goat milk yogurtIn this study,goat milk was concentrated by vacuum concentration to study the effect of different concentration of goat milk(12%,14%,16%and 18%)on the quality of yogurt.The quality of goat milk yogurt was analyzed by determination of the coagulation characteristics,texture etc.The results showed that the fermentation time decreased with the increase of goat milk concentration,accompanied by the increment in acidity and water holding capacity;High concentrations of 2,3-butanedione and acetaldehyde were recorded in yogurt fermented with goat milk with solids of 16%,the viable counts of lactic acid bacteria in the yogurt was 6.35×109 cfu/mL which is the highest among different milk concentration.The most compact microstructure was measured in yogurt fermented with 16%goat milk with pore diameter of 2.75 p.m.Yogurt fermented with goat milk with solids of 16%displayed with good texture characteristics evaluated by the hardness,adhesiveness and gumminess and cohesiveness;The viscosity of goat milk yogurt increased by 149.07%with the total solids of goat milk increased.By simulating transportation experiments and studying the storage characteristics,when the goat milk's solids content was 16%,the goat milk yogurt showed better anti-jump ability and storage stability.(2)Effect of starter on the quality of goat milkThrough the selection of starters with different sticky properties,making goat milk yogurt to study the effect of starter on the quality of goat milk yogurt.The results showed that there was a small amount of whey precipitated in the goat milk yogurt produced by using the YO-MIX187 starter,but the yogurt produced by the YO-MIX300 and the YO-MIX 495 starter was precipitated without whey;The difference in the curd time of goat milk yogurt with different starter was not significant;With the increase of sticky ability of the starter,the acidity of goat milk yogurt gradually increased;There was a significant difference in the water holding capacity of goat milk yogurt made from starters with different sticking properties,the goat milk yogurt produced by the YO-MIX300 starter has high water holding capacity;The goat milk yogurt produced by using the YO-MIX300 starter had the highest hardness and the finest taste,the goat milk yogurt produced with the YO-MIX 495 starter had the highest viscosity and adhesive viscosity;The high content of diacetyl and acetaldehyde in goat milk yogurt produced by the YO-MIX495 starter;The structure of the goat milk yogurt produced using the YO-MIX300 starter was the most compact;With the increase of sticky ability of the starter,the total number of lactic acid bacteria increased gradually in goat milk yogurt;Goat milk yogurt showed the best storage stability when using the YO-MIX300 starter.