Abstract: In this study, the fermentation of kelp (Laminaria japonica) by yeast was carried out to deodorize it. Fermentation conditions were optimized using response surface methodology based on a three-variable, three-level experimental design. The responses were sensory score, pH value, color deference and chlorophyll content. The optimal fermentation conditions were determined as 0.17% inoculums size, 28 ℃ and 100 min. Under these conditions, higher sensory score of 74.6 points and higher total chlorophyll (a + b) content of 2.23 mg/kg were obtained. By monolithic material sorptive extraction coupled with gas chromatography and mass spectrometry (MMSE-GC-MS), a total of 43 volatile compounds, belonging to seven chemical groups, were detected in unfermented and fermented kelp, 11 of which were identified as odor-active compounds with odor activity value (OAV ≥ 1). Compared with unfermented kelp, the number of volatile compounds in fermented kelp decreased from 43 to 23, the total concentration of volatiles from 287.65 to 151.92 ng/g, and summated OAV value from 91.75 to 55.28. The efficiency of deodrization was 39.75%. The findings of this study can provide experimental data for improving kelp processing technologies.

Key words: kelp, yeast fermentation, deodorization, response surface methodology, sensory evaluation, color difference