Recently, the website of the Tianjin Municipal People's Government published the "Decision of the Tianjin Municipal People's Government on Promulgating the 2024 Tianjin Science and Technology Awards", and six achievements of our university won the Tianjin Science and Technology Progress Award. Among them, the project "Key Technological Innovation and Application of Microbial Directional Regulation for Brewing High-Quality and High-End Soy Sauce" led by Professor Zhao Guozhong's team from our institute won the second prize of Tianjin Science and Technology Progress Award in 2024.

Soy sauce is an indispensable condiment in every household. The brewing of soy sauce is confronted with industry challenges such as low raw material utilization rate, impure flavor, and dark color. Zhao Guozhong led his team to develop for the first time a method of adding Lactobacillus plant-based to regulate flavor during the post-fermentation stage of soy sauce by using microbial directional regulation technology, and established a technical system to enhance the ester aroma of soy sauce and inhibit spoilage microorganisms. Adding Lactobacillus plantarum to fermented soy sauce increases its abundance from 4% to 18%-24%, and the detection rate of spoilage microorganisms during the fermentation process is 0. Moreover, a method for improving the germination rate of soy sauce starter culture and evaluating the spore rate of abnormal microscopic morphology was established, which solved the problems of difficulty, long time and complex process for enterprises to evaluate the quality of soy sauce starter culture, and improved the stability of soy sauce starter culture and the fermentation efficiency. During the project implementation, a technology was also developed to enhance the germination rate of the starter culture by promoting the expression of growth factors of Aspergillus oryzae. The germination rate of the starter culture reached over 96%, far exceeding the industry standard.

In addition to the method of enhancing the flavor of soy sauce by adding Lactobacillus plantarum during the post-fermentation stage, to improve the color of soy sauce, for the first time, the method of adding yeast complex strains during the fermentation stage for regulation has improved the color of soy sauce, solving problems such as poor flavor, black color, and insufficient red-brown color of soy sauce.

Zhao Guozhong introduced, "The yeast complex strain has extremely high salt tolerance. During the fermentation process of soy sauce, it can synthesize carotenoids, which is conducive to the formation of the red-brown color of soy sauce." This project regulated the fermentation through yeast complex strains, enhancing the reddish-brown color of the soy sauce. The red color value reached the level of top-grade soy sauce stipulated in the national standard "GB/T 18186-2000 Brewed Soy Sauce", which is "reddish-brown or light reddish-brown, with bright color and luster". At present, the relevant research results have been applied in soy sauce production-related enterprises such as Tianjin Limin Condiment Co., LTD., Shandong Qiaoxifu Food Co., Ltd. and Angel Yeast Co., LTD., promoting technological innovation in the brewing of high-quality soy sauce in China, breaking through the bottleneck of traditional soy sauce brewing processes, and promoting the protection and development of traditional brewing techniques.

This is an important and landmark achievement cultivated by our college in implementing the school's "Pioneer Plan", promoting the deep integration of scientific and technological innovation and industrial innovation. Next, the college will further promote organized scientific research, intensify efforts to tackle key core and frontier technologies, and accelerate the transformation of scientific and technological achievements.

Editor: Li Tong, Intern Editor: Zhao Tiantong