EMULSIFYING PROPERTIES OF HYDROLYSATES MADE BY LIMIT ENZYMATIC HYDROLYSIS OF SWEETPOTATO HEAT-DENATURED PROTEIN

FU Ting-ting1,2 MU Tai-hua1 CHEN Jing-wang1 ZHANG Miao1 TIAN Meng-chen1(1.Institute of Agro-Food Science and Technology,Chinese Academy of Agricultural Sciences,Beijing 100193; 2.College of Food Science and Pharmaceutical Science,Xin Jiang Agricultural University,Urumqi 830052)

sweetpotato heat-denatured protein;limited enzymatic hydrolysis;emulsifying properties

The hydrolysates made by limit enzymatic hydrolysis of sweetpotato heat-denatured protein(SPHP) which treated with five different types of enzymes(Alcalase,As1.398,Neutrase,Pepsin,Trypsin) were investigated.The average droplet size(d4,3),emulsifying activity index(EAI),emulsifying stability index(ESI),emulsion microstructure and apparent viscosity of supernatant and precipitate by centrifugation from each hydrolysates were determined or observed respectively.The results showed that the solubility of supernatants and precipitates were increased,but the solubility of precipitates were increased with less range than that of supernatants.D4,3 of SPHP was 71.96μm as a control,however D4,3 of the hydrolysates including supernatants and precipitates were decreased,and supernatants had a lower D4,3 values than that of precipitates.D4,3 of supernatant of pepsin hydrolysates showed the smallest value(14.94μm).The emulsion droplets of supernatant hydrolysates became more homogenous in size,while the precipitate hydrolysates still retained big size and inhomogeneity.In addition,EAI of SPHP was 11.21m2/g,but EAI of the hydrolysates including supernatants and precipitates were increased markedly(P<0.05),and the supernatant of pepsin hydrolysate had the highest EAI value(70.32m2/g).Furthermore,ESI values of the hydrolysates were increased.Compare with precipates,supernatants had a lower apparent viscosity and all emulsions were shear-thinning non-Newtonian fluids.