预热超声对菠萝蜜种子分离蛋白起泡性及结构的影响

Study on the foaming properties and structure of Jackfruit Seed Protein Isolate by preheated ultrasound

采用预热超声技术改善菠萝蜜种子分离蛋白(Jackfruit Seed Isolate Protein,JSPI)起泡性,探究起泡性与结构的关系。对预热温度,超声功率,超声时间进行了优化,得到最佳条件:预热温度60℃,超声功率600 W,时间20 min。结果得出,与JSPI相比,60℃+600 W处理的JSPI起泡性增加了58.44%(P<0.05),高于600 W(45.25%)和60℃(29.64%)。相比JSPI,泡沫稳定性没有提高(P>0.05)。SDS-PAGE凝胶电泳结果表明,600 W超声处理没有改变JSPI的分子量,60°C处理使JSPI的部分可溶性蛋白分子聚集,出现了新的蛋白条带。相关性结果表明,起泡性与JSPI的β-折叠和无规则卷曲含量成正相关。与JSPI相比,600 W,60℃,60℃+600 W处理后的荧光强度增强、表面疏水性(H 0)提高,说明JSPI结构变松散,内部疏水基团暴露出来,疏水性增加,导致起泡性增加。电位结果表明,与JSPI相比,600 W处理的电位从-22.03增强至-24.53 mV(P<0.05)。60℃,60℃+600 W处理电位减弱,导致溶液体系不稳定。粒径结果表明,与JSPI相比,600 W处理粒径减小,60℃处理粒径增加。蛋白粒径减小、或占较低比例存在的粒径较大的蛋白群体均可以提高JSPI的起泡性。

The technology of preheated ultrasound was used to investigate the foaming property of the Jackfruit Seed Protein Isolate(JSPI),with the relationship between the foaming property and the structure being explored.The preheating temperature,ultrasound power and time were optimized so that the preheating temperature was 60℃,Ultrasound power was 600W and the Ultrasound time was 20 min.Compared with JSPI,the foaming capacity increased by 58.44%after 60℃+600 W treated(P<0.05),higher than that of 600W(45.25%)and 60℃(29.64%).Compared with JSPI,the foam stability was not improved(P>0.05).SDS-PAGE showed that the 600 W ultrasonic did not change the molecular weight of JSPI.A new larger band appeared due to the aggregation of soluble protein molecules after 60℃.The correlation indicates that the foaming was positively correlated with theβ-Turns and the unordered content of JSPI.Compared with JSPI,the enhanced fluorescence intensity and the surface hydrophobicity(H 0)treated after 600 W,60℃,60℃+600W treated showed that the structure became looser and the hydrophobic groups was exposed so that the hydrophobicity and the foaming property were increased.Compared with JSPI,the zeta was enhanced from-22.03 mV to-24.5 mV after 600 W treated(P<0.05)but weakened after 60℃,60℃+600 W treated,leading to instability of solution system.Compared with JSPI,the particle size decreased after 600 W treated,but increased after 60℃treated.Either the particle size decreased or at a lower ratio the protein population with higher size improved the foaming property of JSPI.