Abstract:Silver carp protein isolate powder with excellent nutritional and functional properties was prepared by acid/alkali solubilization-isoelectric precipitation.The properties of the protein isolate powder samples produced under different conditions（pH3.0-5.5，pH4.0-5.5，pH11.0-5.5，pH12.0-5.5 and pH13.0-5.5）were compared.The results showed that the protein isolate powder prepared with the alkali method had higher protein content，lower crude fat content，and stronger solubility than that prepared with the acid method.The protein isolate powder prepared with the alkaline method（pH12.0-5.5）had the highest protein content of 81.96 g/100 g and the moisture content of only 9.76 g/100 g.Moreover，the protein isolate powder prepared with the alkaline method（pH12.0-5.5 and pH13.0-5.5）showed the highest yield.The fish protein isolate powder prepared with the acid/alkali solubilization-isoelectric precipitation method had complete amino acid composition，with essential amino acids accounting for more than 42.27%of the total amino acids，which was in line with the ideal protein model proposed by the Food and Agriculture Organization/World Health Organization（FAO/WHO）.The fish protein isolate powder prepared with the alkali method showed higher gel strength，breaking strength，and waterholding capacity than that prepared with the acid method.The product prepared at pH12.0-5.5 had the strongest gel properties and the highest water-holding capacity.In conclusion，the alkali method outperformed the acid method in terms of the yield，and the protein isolate powder prepared at pH12.0-5.5 demonstrated the best quality and good nutritional properties.