NUTRITIONAL EVALUATION OF POWDERED GOAT'S MILK PROTEIN / 营养学报

ABSTRACT

This study is conducted to evaluate the protein quality of the spray-dried goat's milk powder made from milk of Qingdao's Laoshan dairy goats. Chemical analysis and rat experiment are included in the study with spray-dried powdered cow's milk and isolated soy protein as comparative substances and chemical pure casein as reference protein.The content of crude protein in the powdered goat's milk is 26.01% and the protein's limitting amino acid is sulphur containing amino acids with the AAS and CS being 0.91 and 0.52 respectively, similar to those of cow's milk protein. The percentage of EAA and the EAA index are 49.1% and 96.96%, as high as those of cow's milk. The results of the rat experiment designed according to AOAC showed that the PER, NPR, AD, TD, BV, NPU of the protein are 3.01, 4.62, 90.49%, 96.75%, 86.02 and 83.22% respectively. Except that the AD of goat's milk protein is slightly higher than that of cow's milk protein, there is no significant difference between two milk proteins on other nutritional parameters. The present study gives the conclusion that the protein of powdered goat's milk is at least as nutritious as that of powdered cow's milk, but more nutritious than chemical pure casein and far more nutritious than isolated soy protein.