Application of Wickerhamomyces anomalus and Pichia fermentans to improve the aroma of fermented sour fish

Novel yeasts have been developed in recent years to help reinforce and improve food aroma. This study aimed to investigate the possibilities for aroma improvement using two non-Saccharomyces strains with strong aroma production in sour fish fermentation. Two yeasts, Wickerhamomyces anomalus (Wa) and Pichia fermentans (Pf), screened by growth and environmental tolerance, were used to replace Saccharomyces cerevisiae in the mixed starter for sour fish fermentation. Gas chromatography-mass spectrometry, gas chromatography-ion mobility spectrometry and electronic nose were used to analyze the aroma of sour fish inoculated with different starter cultures. Moisture, pH, colony numbers, and content of free amino acids, organic acids and free fatty acids were monitored during the fermentation. Compared with the Sc group, the Wa group and Pf group had no significant effect on microbial composition, moisture content and free amino acids (P > 0.05) at the end of fermentation, while the Pf group had higher levels of organic acids, free fatty acids and alcohol acyltransferases (P < 0.05). Sensory evaluation revealed that the aroma of the Wa group was more similar to that of the Sc group, with a strong flowery and fruity aroma. Generally, W. anomalus was found to be capable of boosting the blossom-like aroma of sour fish.