Effects of Temperature on Bacterial Biodiversity and Qualities of Fermented Yucha Products

Yucha is a home-made, fermented fish product in South China. The quality of yucha can vary depending on environmental factors. In order to determine the effects of temperature on bacterial biodiversity and quality of fermented yucha products, in the present study, yucha was fermented at 15°C, 20°C, 25°C, and 30°C. Bacterial cells in all yucha samples grew from 3.7 log CFU/g at the onset of the fermentation and reached growth over 7.0 log CFU/g within 1 week. Lactobacillus plantarum was predominated in the 20°C and 25°C fermented yucha products, while Lactobacillus sakei and Lactobacillus brevis were the most abundant in the yucha products fermented at 15°C and 30°C, respectively. Predominant bacterial species are presumed to be potential starters to drive yucha fermentation. Evaluation of yucha qualities demonstrated that lower biogenic amine contents, better texture properties, and more desirable volatile compounds were identified in yucha products fermented at 20°C. Therefore, this temperature is recommended for industrial yucha processing in the future.