Qin Jianxin, Zhao Yinghan, Zhou Jingwen, Zhang Guoqiang, Li Jianghua, Liu Xiao
Science Center for Future Foods, Jiangnan University, Wuxi, China.
National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, China.
Front Nutr. 2022 Aug 12;9:970010. doi: 10.3389/fnut.2022.970010. eCollection 2022.
At present, the structural changes of extruded materials under thermal-mechanical stress during high-moisture extrusion are still unclear. In this study, the transglutaminase (TG) treatments on the structure of pea protein isolate (PPI) under conditions relevant to high-moisture extrusion processing (50 wt% PPI at 30°C, 120°C and heated to 120°C and subsequently cooled to 30°C) was studied by using a closed cavity rheometer. Strain and frequency sweeping were carried out under various temperature conditions, and the information obtained was drawn into a texture map. Lissajous curves combined with energy dissipation ratio were introduced to characterize the nonlinear response of the samples. The results showed that the storage modulus of PPI increased with the increase of TG concentration during heat treatment. After cooling to 30°C, PPI with 0.25-1%TG could enhance the elasticity, but treating by 2% TG could inhibit the formation of disulfide bonds, the uniform development of the protein network, thus showing the "tough" character. These findings can help to better understand the relationships of material-structure during the extrusion process, and also provide help for further optimization of the quality of meat substitutes.
目前，高水分挤压过程中热机械应力作用下挤压物料的结构变化仍不明确。在本研究中，利用密闭腔流变仪研究了转谷氨酰胺酶（TG）在与高水分挤压加工相关的条件下（30℃、120℃时50 wt%的豌豆分离蛋白（PPI），加热至120℃后冷却至30℃）对豌豆分离蛋白（PPI）结构的影响。在不同温度条件下进行应变和频率扫描，并将获得的信息绘制成纹理图。引入李萨如曲线结合能量耗散比来表征样品的非线性响应。结果表明，热处理过程中PPI的储能模量随TG浓度的增加而增大。冷却至30℃后，0.25 - 1%TG的PPI能增强弹性，但2%TG处理会抑制二硫键的形成，阻碍蛋白质网络的均匀发展，从而表现出“坚韧”的特性。这些发现有助于更好地理解挤压过程中物料 - 结构的关系，也为进一步优化肉类替代品的品质提供帮助。
