Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P. R. China.
State Key Laboratory of Food Nutrition and Safety, Tianjin, P. R. China.
J Sci Food Agric. 2021 Aug 15;101(10):4154-4160. doi: 10.1002/jsfa.11052. Epub 2021 Jan 13.
Although Streptomyces mobaraense transglutaminase (MTG) has been extensively applied to enhance the functional characteristics of soy protein isolate (SPI) through cross-linking, various transglutaminases (TGs) in nature may provide more choice in the food industry. Previous research reported that TG derived from Bacillus subtilis (BTG) exhibited better pH stability and thermostability than MTG.
An attempt was made to study the influence of BTG induced cross-linking on the properties of SPI. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results indicated that almost all protein constituents (α', α, β, AS, and BS) in SPI could be cross-linked with BTG treatment. The BTG treatment also resulted in a significant increase (*P < 0.05) in SPI mean particle size. Emulsifying activity and stability were improved from 0.11535 m g and 48.3% for native SPI to 0.13252 m g and 83.9% for SPI treated with BTG at 6 h. Similarly, the modified SPI showed better foam activity (1.32 mL) and stability (87.6%) than the original SPI (0.93 mL and 56.8%). The water-holding capacity of SPI gel was found to increase with time, with a value of 95.43% at 6 h. Furthermore, SPI gel's texture profiles were greatly improved by adding BTG (*P < 0.05).
The results of the present study indicated that BTG could be a promising cross-linking agent for improving the functional characteristics of SPI. As a substitute for MTG, BTG could thus potentially be used for food structure engineering to enhance the functional characteristics of multiple proteins to advance the development of food chemistry. © 2020 Society of Chemical Industry.
尽管来自 Streptomyces mobaraense 的转谷氨酰胺酶（MTG）已被广泛应用于通过交联来增强大豆分离蛋白（SPI）的功能特性，但自然界中各种转谷氨酰胺酶（TGs）可能在食品工业中提供更多选择。先前的研究报道，来自枯草芽孢杆菌（BTG）的 TG 表现出比 MTG 更好的 pH 稳定性和热稳定性。
尝试研究 BTG 诱导交联对 SPI 特性的影响。十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）结果表明，SPI 中的几乎所有蛋白质成分（α'、α、β、AS 和 BS）都可以与 BTG 处理交联。BTG 处理还导致 SPI 平均粒径显著增加（*P<0.05）。与天然 SPI（0.11535 m g 和 48.3%）相比，BTG 处理 6 h 后 SPI 的乳化活性和稳定性分别提高到 0.13252 m g 和 83.9%。同样，改性 SPI 表现出比原始 SPI 更好的泡沫活性（1.32 mL 和 87.6%）和稳定性（0.93 mL 和 56.8%）。发现 SPI 凝胶的持水能力随时间增加，6 h 时达到 95.43%。此外，通过添加 BTG，大大改善了 SPI 凝胶的质构特性（*P<0.05）。
本研究结果表明，BTG 可作为一种有前途的交联剂，用于改善 SPI 的功能特性。作为 MTG 的替代品，BTG 可能用于食品结构工程，以增强多种蛋白质的功能特性，从而推动食品化学的发展。
