蓝圆鲹分离蛋白酶解产物的制备及其抗大米淀粉老化特性

Preparation of enzymatic hydrolysate of blue round scad(Decapterus maruadsi)protein isolate and its anti-retrogradation effect on rice starch

为了进一步拓展海洋鱼类蛋白在食品中的应用,以蓝圆鲹分离蛋白为原料,利用酶解改性得到溶解性良好的蓝圆鲹分离蛋白酶解物(BPIH),并研究其对大米淀粉(RS)短期老化的抑制作用。通过响应面法优化酶解改性工艺制备BPIH,并分别按RS的3%、6%、9%(质量百分比)进行添加。通过测定RS的凝沉性、动态黏弹性、热学特性以及微观结构分析评价BPIH的抗淀粉老化活性。结果显示,响应面法确定的最佳条件:酶底比5000;1(U/g)、酶解时间3 h、料液比1.00;3.81、酶解温度46.36℃、酶解pH 6.30,氮溶指数(NSI)实际值为85.41%±0.82%,与预测值86.37%接近。该酶解条件下BPIH水解度达到21.62%。BPIH中小于1000 u的肽占79.94%,主要为小分子低聚寡肽。加入BPIH可以减弱RS的凝沉现象,降低RS在4℃保存过程中的储能模量(G'),显著降低老化后RS的峰值温度(T_(p))和焓值(ΔHr);加入BPIH的大米淀粉,老化后微观结构有较大孔洞,提升了淀粉糊化后保留内部水分的能力。研究表明,BPIH能够抑制RS在4℃保存期间凝胶网络和微晶结构的形成,同时可能限制了淀粉分子间的聚集,抑制或延缓RS的短期老化。本研究为蓝圆鲹分离蛋白酶解物在食品蛋白配料中的应用提供理论参考。

The protein from marine fish is regarded as an ideal resource of high-quality protein thanks to their high nutritional value and good digestibility.The application of fish protein in infant rice flour products can not only give the product a richer flavor,but also improve the nutritional value of the product and meet the nutritional requirements of infants.To further expand the application of marine fish protein in food products,the enzymatic modification of blue round scad(Decapterus maruadsi)protein isolate was carried out to obtain blue round scad protein isolate hydrolysate(BPIH)with good solubility.The inhibitory effects of BPIH on short-term retrogradation of rice starch(RS)was investigated.The enzymatic modification process was optimized by response surface methodology,and was added to RS at concentrations of 3%,6%and 9%(W/W).The measurements of coagulability,dynamic viscoelasticity,and thermal properties and microstructure of RS were carried out to evaluate the antiretrogradation activities of BPIH.The results showed that the optimal conditions determined by response surface methodology were:enzyme bottom ratio of 5000;1(U/g),enzymatic digestion time of 3 h,feed-to-liquid ratio of 1.00;3.81,enzymatic digestion temperature of 46.36℃,and enzymatic pH of 6.30.The actual value of nitrogen solubility index(NSI)was 85.41%±0.82%,which was close to the predicted value of 86.37%.The degree of BPIH hydrolysis reached 21.62%under these enzymatic conditions.The peptides less than 1,000 u in BPIH accounted for 79.94%,which were mainly small oligopeptides.The addition of BPIH attenuated the coagulation phenomenon of RS,reduced the energy storage modulus(G')of RS during storage at 4℃,and significantly reduced the peak temperature(T_(p))and enthalpy(ΔHr)of RS after aging(P<0.05);the rice starch added with BPIH had larger pores in the microstructure after aging,which enhanced the ability of starch to retain internal water after pasting.These results indicate that BPIH can inhibit the formation of gel network and microcrystalline structure of RS during storage at 4℃,and may also limit the aggregation between starch molecules and inhibit or delay the shortterm aging of RS.The present study provides a theoretical reference for the application of the enzymatic hydrolysate of blue round scad protein isolate in food protein ingredients.