Fan Xuyao, Wang Yanli, Bai Yuxiang, Jin Zhengyu, Svensson Birte
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; International Joint Research Laboratory for Starch Related Enzyme at Jiangnan University, Wuxi, Jiangsu, 214122, China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu, 214122, China; International Joint Research Laboratory for Starch Related Enzyme at Jiangnan University, Wuxi, Jiangsu, 214122, China.
Int J Biol Macromol. 2022 Jun 1;209(Pt A):1-8. doi: 10.1016/j.ijbiomac.2022.03.153. Epub 2022 Mar 26.
4-α-glucanotransferase is used to produce thermoreversible starch gels to alleviate limitations to use of starch gels in repetitively heat-processed foods. However, the gel strength was weakened after this enzyme modification. In the present study, treatment by amylosucrase (NpAS) of corn starch and sucrose was applied to retain the gel thermoreversibility and eliminate the shortcoming caused by 4-α-glucanotransferase (TuαGT). Changes in molecular structure, rheological and retrogradation properties of modified starch were investigated after NpAS and TuαGT sequential and one-pot treatment, respectively. The apparent amylose content was reduced and increased by sequential and one-pot treatments, respectively, compared to single TuαGT modification. Chain length profiles showed higher proportion of degree of polymerization (DP) ≥ 13 by sequential treatment, whereas DP 6-12 was higher after one-pot treatment. All modified starches had reduced molecular weight. G' and G" increased by dual enzyme compared to single TuαGT treatment having little effect on retrogradation. Interestingly, starch subjected to 3 h one-pot treatment caused G' and G" temperature curves to cross-over, improving thermoreversible properties. The results indicate that NpAS treatment compensated for loss of starch gel strength caused by TuαGT and offered possibility to provide a wider range of thermoreversible starches.
4-α-葡聚糖转移酶用于生产热可逆淀粉凝胶，以缓解淀粉凝胶在反复热处理食品中使用的局限性。然而，经过这种酶改性后，凝胶强度会减弱。在本研究中，采用支链淀粉酶（NpAS）处理玉米淀粉和蔗糖，以保持凝胶的热可逆性，并消除4-α-葡聚糖转移酶（TuαGT）造成的缺点。分别对经过NpAS和TuαGT顺序处理和一锅法处理后的改性淀粉的分子结构、流变学和回生特性进行了研究。与单一TuαGT改性相比，顺序处理使表观直链淀粉含量降低，而一锅法处理使其增加。链长分布表明，顺序处理后聚合度（DP）≥13的比例更高，而一锅法处理后DP 6-12更高。所有改性淀粉的分子量均降低。与单一TuαGT处理相比，双酶处理使G'和G"增加，对回生影响不大。有趣的是，经过3小时一锅法处理的淀粉使G'和G"温度曲线交叉，改善了热可逆性能。结果表明，NpAS处理弥补了TuαGT导致的淀粉凝胶强度损失，并为提供更广泛的热可逆淀粉提供了可能性。
