Establishment of a novel loach-deodorization technology based on gas chromatography-ion mobility spectroscopy analysis

Fishy odor has been a major limiting factor for the production and commercialization of loach. Herein, this study aims to develop an efficient deodorization process using single-factor experiments and Design-Expert response surface methodology. The deodorization capability is evaluated using gas chromatography-ion mobility spectroscopy (GS-IMS). As a result, the trehalose-sweet wine koji method was selected and the final optimal deodorization conditions were shown as follows: the compound ratio of trehalose to sweet wine koji was 51:1, the content of sweet wine koji was 0.10%, and the deodorization time was 33 min at 17 °C. Under the conditions, the final trimethylamine content of loach was reduced by 89%. A total of 29 volatile compounds in loach samples before and after deodorization were identified by GC-IMS, including 11 aldehydes, 8 alcohol, 7 ketones, 1 ester, and 2 olefins. Volatile compounds responsible for fish-like odor, such as hexanal, pentanal, heptanal, benzaldehyde, octanal, nonanal, n-butanol, pentanol, and acetone, were decreased in intensity. Principal component and fingerprint analysis confirmed the deodorization effect of this process on loach was significant (p < 0.05). Collectively, the study developed an efficient loach deodorization method, which will improve the quality of loach production.