Study on improving color quality of purifying casein made from Yak Qula

“Qula”was used as raw material for the production of casein,the chroma value( L*,a*,b*) of dried products were taken as target parameters,and the three factors were scored by the comprehensive evaluation using the data standardization method.Based on the single factor test,the response surface methodology was adopted to discuss the influence caused by the dissolution p H,the dissolution temperature and the dissolution time.Before drying different pressure gradients were put on wet casein clot to complete the pre- dewatering process.The results showed that orders of significance among these three factors were: dissolution p H,dissolution temperature,dissolution time.“Qula ” dissolved optimum condition was that the dissolution p H was 9.37,the dissolution temperature was 54.21 ℃,and the dissolution time was 29.73 min.The optimal pre- dehydration pressure was 850 N,at this pressure the L*value was 91.95,the a*value was 0.13,the b*value was 6.27.The casein color quality was improved,and the casein color was significantly better than the industry level.