Recently, the researchers from Food Nutrition and Functional Foods Innovation Team at the Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (IFST-CAAS), has significantly improved the flavor and safety of red sour soup through co-fermentation with specific strains of Lactiplantibacillus plantarum and Pichia membranifaciens. The related findings were published in the international journal Food Chemistry (JCR Q1, IF = 9.8). Zhang Pengfei, a master’s student at IFST, is the first author, while Prof. Li Shuying and Prof. Wang Fengzhong are the corresponding authors. This work was supported by the National Key Research and Development Program of China (2023YFE0104900–3-2) and the National Natural Science Foundation of China (32372285).

Red sour soup, a traditional fermented food of Guizhou Province, is made from tomatoes and chili peppers as the main raw materials, with garlic, ginger, and glutinous rice added for fermentation. It is known for its unique flavor and rich functional ingredients. However, traditional natural fermentation suffers from disadvantages such as long fermentation cycles, unstable quality, and potential safety risks.

In this study, a fixed-inoculation fermentation strategy was applied, which markedly enhanced fermentation efficiency and product quality. The results showed that inoculation with Lactiplantibacillus plantarum MX14 and Pichia membranifaciens PY33 shortened the fermentation period to 5-7 days. The pH decreased from 4.01 to 3.06, total acid content increased to 21.00 g/kg, and nitrite levels dropped from 7.64 mg/100 g to 2.97 mg/100 g, significantly improving food safety. Multi-dimensional sensory analyses using an electronic tongue and electronic nose revealed that sourness and sweetness were notably enhanced, bitterness was reduced, and overall flavor quality improved. Characteristic flavor compounds such as glutamic acid, arginine, lactic acid, succinic acid, linalool, ethyl hexanoate, and eucalyptol were identified, and 20 key biomarkers were screened to distinguish samples at different fermentation stages. Moreover, the study confirmed that microbial sugar metabolism is the core mechanism driving flavor formation and quality improvement in red sour soup.

This research provides a scientific basis for the standardized production of red sour soup and promotes the modernization of traditional fermented foods. Through industrial demonstration, it also explores new pathways for leveraging science and technology to support rural specialty industries and contribute to rural revitalization.

Article link: https://www.sciencedirect.com/science/article/pii/S0308814625027244?via%3Dihub