Removal of fishy flavor in kelp (Laminaria japonica) by natural antioxidant soaking combined with microbial fermentation

Kelp ( Laminaria japonica ) is rich in resources and a variety of active substances. However, its fishy flavor, which is hard to remove, poses challenges to consumer preferences. This study investigated the removal of fishy odor from Saccharomyces cerevisiae SK1.008 fermented kelp and kelp treated with fermentation combined natural antioxidant soaking through gas chromatography -mass spectrometry (GC -MS), odor activity values (OAVs) and gas chromatography -ion mobility spectrometry (GC-IMS). A total of 79 and 72 substances were identified in kelp using GC -MS and GC-IMS analysis, respectively. There were 16 volatile compounds (VOCs) with OAV >1 which were identified as key contributors to fishy odor, including ( E,Z )-2,6-nonadienal, 1-octen-3-one, ( E,E )-2,4-octa- dienal, ( E,E )-2,4-decadienal and ( E )-2-nonenal et al. The GC -MS analysis revealed that the removal efficiency of unsaturated aldehydes and ketones was 73.3% in kelp treated by fermentation combined soaking. The hierarchical cluster analysis and principal component analysis (PCA) constructed by GC-IMS revealed that the blank kelp, fermented kelp and kelp treated with fermentation combined soaking can be distinguished by volatile compounds. This study provides a reference for establishing a long-term effective deodorization method.