Effect of Microbial Fermentation on the Fishy-Odor Compounds in Kelp ().

Kelp () is an important marine resource with low cost and rich nutrition. However, its fishy odor has compromised consumer acceptance. In this study, the effects of fermentation with FSB7, CICC 21862 and SK1.008 on fishy notes in kelp was studied using gas chromatography-mass spectrometry (GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS) and odor activity values (OAVs). Forty-four volatile organic compounds (VOCs) were identified in unfermented kelp, most of which were aldehydes, followed by alkanes, alcohols and ketones. Among them were 19 volatile compounds with OAV greater than one. Substances containing ,-unsaturated carbonyl structure (1-Octen-3-one, (,)-2,6-nonadienal, (,)-2,4-decadienal, etc.) are the main contributors to kelp fishy odor. The number of VOCs in kelp samples fermented by , and were decreased to 22, 24 and 34, respectively. GC-IMS shows that the fingerprint of the fermented sample had the most obvious changes. The disappearance of 1-octen-3-one and a 91% decrease in unsaturated aldehydes indicate that was the most effective, while and only reached 43-55%. The decrease in kelp fishy notes was related to the decrease in ,-unsaturated carbonyl groups. The experimental results show that odor reduction with fermentation is feasible.