Chen Junliang, Chen Yao, Cao Weiwei, Yang Tongxiang, Li Linlin, Liu Wenchao, Duan Xu, Ren Guangyue
College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China.
Henan Province Engineering Research Center of Agricultural Products Processing Equipment, Luoyang 471000, China.
Foods. 2025 Aug 21;14(16):2916. doi: 10.3390/foods14162916.
Transglutaminase (TGase) improves protein structure by facilitating cross-linking reactions. However, the effects of TGase on the physicochemical properties of whey protein isolate (WPI)-soymilk complexes and their applications in yuba remain unclear. Therefore, the impacts of TGase concentration on the free sulfhydryl content, free amino content, particle size, and structure of WPI-soymilk complexes and their film-forming properties were studied. The results showed that the physicochemical properties of the composite soymilk were changed by the TGase-induced cross-linking reaction of protein. Compared with the composite soymilk without TGase modification, the particle size of the WPI-soymilk complexes increased from 707.99 ± 9.47 nm to 914.41 ± 2.8 nm as the TGase concentration increased, and the complexes remained relatively stable at low TGase concentrations. TGase modification changed the tertiary structure of the WPI-soymilk complexes. The composite yuba with 0.01% and 0.03% levels of TGase had a higher β-sheet content than composite yuba without addition of TGase. The surface hydrophobicity of composite soymilk was decreased by all the addition levels of TGase. Meanwhile, the TGase-modified composite protein with 0.03% TGase had the lowest free sulfhydryl (35.92 μg/g) and amino groups (0.46). Additionally, the tensile strength of the composite yuba with 0.05% TGase addition reached a peak of 1.66 ± 0.02 MPa, which was 7.8% higher than that of the composite yuba without TGase addition. The SEM results revealed that the composite yuba with 0.01-0.03% TGase addition exhibited a dense and non-porous film structure. Moreover, all the composite yuba with TGase addition had a reduced rate of yuba cooking loss. This study contributes to enhancing the yield and mechanical properties of traditional yuba.
转谷氨酰胺酶（TGase）通过促进交联反应改善蛋白质结构。然而，TGase对乳清分离蛋白（WPI）-豆浆复合物的物理化学性质及其在腐竹中的应用效果仍不清楚。因此，研究了TGase浓度对WPI-豆浆复合物的游离巯基含量、游离氨基含量、粒径、结构及其成膜性能的影响。结果表明，蛋白质的TGase诱导交联反应改变了复合豆浆的物理化学性质。与未经过TGase改性的复合豆浆相比，随着TGase浓度增加，WPI-豆浆复合物的粒径从707.99±9.47 nm增加到914.41±2.8 nm，并且在低TGase浓度下复合物保持相对稳定。TGase改性改变了WPI-豆浆复合物的三级结构。添加0.01%和0.03% TGase水平的复合腐竹比未添加TGase的复合腐竹具有更高的β-折叠含量。所有添加水平的TGase均降低了复合豆浆的表面疏水性。同时，添加0.03% TGase的TGase改性复合蛋白的游离巯基（35.92μg/g）和氨基（0.46）含量最低。此外，添加0.05% TGase的复合腐竹的拉伸强度达到峰值1.66±0.02 MPa，比未添加TGase的复合腐竹高7.8%。扫描电子显微镜结果显示，添加0.01-0.03% TGase的复合腐竹呈现致密无孔的膜结构。此外，所有添加TGase的复合腐竹的腐竹煮失率均降低。本研究有助于提高传统腐竹的产量和机械性能。
