Effect of co‐fermentation and sequential fermentation of Candida versatilis and Lactococcus lactis subsp. cremoris on unsalted pork hydrolysates components

Growth and metabolism of halophilic Candida versatilis and Tetragenococcus halophilus in simultaneous and sequential fermentation of salted soy whey

This study investigated various strategies: mono-, simultaneous and sequential fermentation of halophilic Candida versatilis and Tetragenococcus halophilus to valorize salted whey, a side stream of salted tofu (pressed beancurd) production, with an ultimate goal of creating a soy sauce-like condiment. Growth, glucose, organic acids were monitored throughout fermentation, while free amino acids and volatile compounds were analyzed on the final days. In monoculture fermentation, both C. versatilis and T. halophilus thrived in salted soy whey. However, in co-culture fermentation, an antagonistic relationship was observed, wherein C. versatilis growth was slightly suppressed and T. halophilus was significantly inhibited. In C. versatilis-involved fermentations, no significant (p > 0.05) differences in key volatile and non-volatile chemical components were found among various fermentation modes. Key soy sauce-like volatile compounds, such as 4-ethylguaiacol and 4-ethylphenol, were detected in all C. versatilis-fermented salted soy whey, while T. halophilus primarily functioned as a lactic and acetic acids producer. This study highlights the potential of mixed culture fermentation involving soy sauce yeast and lactic acid bacteria for eventually developing a soy sauce-like condiment from salted soy whey, with C. versatilis playing a crucial role in flavour development. The findings suggest that fermenting of a single culture of C. versatilis in lactic acid-adjusted salted soy whey could be a viable and efficient choice for future production of soy sauce-like condiment.

Correlation and Difference between Core Micro-Organisms and Volatile Compounds of Suan Rou from Six Regions of China

Suan Rou (SR), a traditional fermented meat, is widely favored by consumers due to its unique flavor and characteristics. To study the relationship between the core differential micro-organisms and differential volatile organic compounds (VOCs) of SR from six regions of China, high-throughput sequencing (HTS) and gas-chromatography−ion mobility spectrometry (GC-IMS) technologies were used to analyze the correlation between micro-organisms and VOCs in SR from Xiangxi of Hunan, Rongshui of Guangxi, Zunyi of Guizhou, Jinping of Guizhou, Congjiang of Guizhou, and Libo of Guizhou. A total of 13 core micro-organisms were identified at the genus level. Moreover, 95 VOCs were identified in the SR samples by GC-IMS analysis, with alcohols, aldehydes, ketones, and esters comprising the major VOCs among all the samples. The results showed a strong correlation (|r| > 0.8, p < 0.05) between the core differential micro-organisms and differential VOCs, including four bacteria, five fungi, and 12 VOCs. Pediococcus, Debaryomyces, Zygosaccharomyces, and Candida significantly contributed to the unique VOCs of SR.