高酯果胶对豌豆淀粉凝胶糊化及流变特性的影响

Effects of high methoxyl pectin on pasting and rheological properties of pea starch gel

为研究高酯果胶(high methoxyl pectin,HMP)对豌豆淀粉凝胶特性的影响,以豌豆淀粉为原料,加入不同比例的HMP后考察豌豆淀粉的糊化和流变特性的变化。结果表明,豌豆淀粉的峰值黏度、崩解值以及回生值随着HMP添加量的增加而逐渐降低,当豌豆淀粉/HMP的配比(质量比)为8∶2时,复配体系具有最低的峰值黏度、崩解值和回生值;糊化温度随HMP的增加而升高,当豌豆淀粉/HMP的配比(质量比)为8. 5∶1. 5时,糊化温度增加至75. 85℃。HMP的添加并未改变豌豆淀粉凝胶的流体性质,豌豆淀粉/HMP复配体系仍为典型的假塑性流体。HMP对豌豆淀粉的储能模量(G')的影响大于对损耗模量(G″)的影响,随着HMP添加量的增加,复配体系的G'逐渐下降,淀粉凝胶的黏性逐渐增强,复配体系表现出弱凝胶的动态流变特征。HMP降低了豌豆淀粉凝胶的硬度,豌豆淀粉/HMP的配比(质量比)为8∶2时,复配体系的硬度达到最低;但弹性和黏着性随HMP的增加而升高。扫描电镜观察到添加HMP后,豌豆淀粉凝胶内部结构更加均匀稳定,网络结构更致密。

The effects of high methoxyl pectin( HMP) on the gelling properties of pea starch were explored. The changes in pasting and rheological properties of pea starch were investigated by adding HMP in different ratios. The results showed that the peak viscosity,breakdown value,and setback value of pea starch gradually decreased with increasing HMP. Besides,they were the lowest when the ratio of pea starch to HMP was 8∶ 2. The gelling temperature increased with increasing HMP,and it increased to 75. 85 ℃ when the ratio of pea starch to HMP was 8. 5 ∶ 1. 5.However,HMP did not change the rheological properties of pea starch gel. The pea starch/HMP mixed system was still a typical pseudoplastic fluid. The effect of HMP on the energy storage modulus( G’) of the mixed system was greater than that of the loss modulus( G″). The G’ of mixed system decreased with increasing HMP,and the viscosity of pea starch gel increased gradually,and the mixed system showed dynamic rheological characteristics of a weak gel.HMP lowered the hardness of pea starch gel,and it was the lowest when the ratio of pea starch to HMP was 8 ∶ 2.However,the elasticity and adhesiveness of pea starch gel increased with HMP. Scanning electron microscope showed that the internal structure of pea starch gel was more uniform and stable after adding HMP,and the network structure was denser.