揉混时间对酸化面团中玉米醇溶蛋白的影响

以玉米醇溶蛋白（zein）、玉米淀粉、沙蒿胶为原料，制备了zein基无麸质模拟面团（Z面团）。基于粉质检测，比较了不同乳酸含量的zein模拟面团在揉混成型时（扭矩达1.1Nm；设为ZS面团）与揉混12 min时（设为ZL面团）面团的揉混扭矩、水分组成情况，以及蛋白分布状态；研究耐揉混面团的最佳乳酸添加量，通过一定时长揉混作用下，不同乳酸含量的面团中zein理化性质，讨论了经长时间揉混面团逐渐弱化的原因，为zein模拟面团的加工、相关谷物制品的制备提供参考。结果表明，添加少量乳酸能促使zein在面团中构建起蛋白质网络，但长时间的揉混会导致酸化面团强度下降，破坏面团中zein网络连贯性，降低zein对淀粉颗粒包裹水平，面团中弱结合水占比下降、游离水占比增加，zein发生脱酰胺反应、表面疏水性上升、相对分子质量下降。面团经长时间的揉混逐渐弱化，是因为揉混作用会扩大乳酸对面团中zein的作用效果，促使蛋白质表面疏水性增加、蛋白质碎片化，进而导致zein网络连贯性下降。

Effect of Kneading Time on the Properties of Zein in Acidified Model Dough

In this study, zein-based gluten-free model dough (Z dough) was prepared with zein, corn starch, and wormwood gum. Based on the flour quality test, the kneading torque, water composition and protein distribution of the zein simulated dough with different lactic acid content were compared when finish dough (torque up to 1.1 Nm; set as ZS dough) and kneading for 12 minutes (set as ZL dough) conditions. The optimal amount of lactic acid added to kneadable dough was explored, and the physical and chemical properties of zein in dough with different lactic acid content were discussed under the action of kneading for a certain period of time, which could and provide reference for the preparation of related cereal products. Studies have shown that adding a small amount of lactic acid could promote zein to build a protein network in the dough, but long-term kneading would lead to decreasing the strength of the acidified dough, destroying the continuity of the zein network in the dough, reducing the level of zein wrapping on starch granules and weak bonding in the dough. The proportion of water decreased and the proportion of free water increased. The surface hydrophobicity increased and the relative molecular weight decreased, when the deamidation reaction of zein occurred. The analysis showed that the dough gradually weakened after a long time of kneading, because the kneading effect would expand the effect of lactic acid on zein in the dough, which would increase the hydrophobicity of the protein surface and fragment the protein, and lead to a decrease in the coherence of the zein network.