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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. [ABSTRACT FROM AUTHOR]

Multiple antimicrobial peptides (designated brevilaterin) were extracellularly produced by Brevibacillus laterosporus S62-9, five brevilaterins were purified by liquid chromatography, and characterized by MALDI-TOF/TOF MS and 2D-NMR. The results suggested that brevilaterin A-E (Mw 1568.9753, 1555.0334, 1601.0044, 1569.0189, 1583.0946 Da) showed similar primary structures exhibiting small variation of three amino acid substitutions at residue 3, 5, 7. Every brevilaterin contained a fatty acid (2-hydroxy-3-methylpentanoic acid) at the N -terminus and 13 amino acids including three modified amino acids: 2-amino-2-butenoic acid, ornithine and C -terminal residue of valinol, of which brevilaterin D was a new compound. Brevilaterins showed broad antimicrobial activities against bacteria and fungi, and were resistant to heat (retained over 80% antimicrobial activity at 121 °C for 20 min) and pH (no significant loss at pH 2 to 12). They effectively killed Staphylococcus aureus in milk. Collectively, these findings evidenced a promising application of brevilaterins in food preservation. • Five AMPs were extracellularly produced by Brevibacillus laterosporus. • The primary structures of brevilaterins were purified and elucidated by 2D-NMR. • Brevilaterins showed broad antimicrobial spectrum and good resistance to heat and pH. • Brevilaterins showed promising application potential in food preservation. [ABSTRACT FROM AUTHOR]