Flavor and quality enhancement of miiuy croaker (Miichthys miiuy) surimi by co-fermentation with Monascus purpureus and Actinomucor elegans

Co-fermentation technology is expected to improve the flavor and quality properties of fermented surimi products. Effects of fermentation with Monascus purpureus (M. purpureus) and Actinomucor elegans (A. elegans) at different inoculation ratios on the volatile profiles and physicochemical properties of surimi were investigated. Generally, fermentation resulted in significant surimi protein hydrolysis as indicated by increased amino acid nitrogen, TCA-soluble peptide and free amino acid contents, simultaneously accompanied by decreases in hardness, gumminess and chewiness of surimi. Co-fermentation effectively improved the volatile profiles of surimi. Comparatively, a higher inoculation ratio of M. purpureus was favorable for the production of esters and ketones, whereas a higher proportion of A. elegans reduced the aldehyde contents, especially nonanal with fishy odor. Taken together, a 1:1 inoculation ratio of M. purpureus and A. elegans was more conductive to improve the aroma profiles of surimi, with a 77.2% reduction of aldehyde compared to unfermented surimi.