Physiochemical and taste characteristics of traditional Chinese fermented food sufu

Sufu shows different taste profiles at different fermentation times. To understand the taste characteristics of sufu at different stages, the changes of the dominant taste substances and the correlation between physicochemical properties and taste substances were investigated. The results showed that 5 '-cytidine monophosphate, bitter amino acids, lactic acid, citric acid, and acetic acid were the dominant taste substances throughout the fermentation process. At the end of fermentation, their contents were 19.15, 251.48, 96.70, 155.23, and 20.68 mg/100 g, respectively. The equivalent umami concentration value of the samples in the curing and post-fermentation stage exceeded about 83.35-240.61% the threshold of monosodium glutamate, which demonstrated that umami taste properties of sufu were intense. Glu, Val, tartaric acid, and acetic acid were considered as active substances in mature sufu, with taste activity values of 2.27, 1.04, 3.33, and 1.95, respectively. Principal component analysis based on physicochemical indexes can effectively distinguish different fermentation stages. Furthermore, there was a significant correlation between active substances and physicochemical indexes. Our findings could help to understand and improve the taste of sufu and provide a certain reference for evaluation of the taste characteristics of sufu. Novelty impact statement The taste substances accumulated were different in fermentation stages. The production of taste substances had a certain correlation with physicochemical indexes. The equivalent umami concentration value was higher than monosodium glutamate threshold in curing and post-fermentation stages. Glu, Val, tartaric acid, and acetic acid were effective active taste substances in the mature sufu.