Effect and mechanism of ferulic acid inclusion complexes on tyramine production by Enterobacter hormaechei MW386398 in smoked horsemeat sausages

Abstract

Ferulic acid inclusion complexes (FA-HP-β-CD) effects on tyramine accumulation and gene expression of Enterobacter hormaechei MW386398 in traditional smoked horsemeat sausages were studied. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to identify the expression of tyrosine decarboxylase (TDC) clusters in the tyramine producing pathway. In addition, relevant parameters such as microbial growth, moisture content, pH, and tyramine accumulation in pure cultures and during fermentation of smoked horsemeat sausages were evaluated. Ferulic acid (FA) and FA-HP-β-CD inclusion complexes both significantly decreased tyramine accumulation, as well as significantly inhibited tyrosine decarboxylase (tdcA) and tyrosine/tyramine antiporter (tyrP) genes expression (p < 0.05). Furthermore, FA and FA-HP-β-CD inclusion complexes both reduced the number of Enterobacteriaceae in smoked horsemeat sausages, but did not alter the main microbiota. However, FA-HP-β-CD inclusion complexes exhibited stronger ability in hindering TDC related gene expression, reducing tyramine accumulation and antibacterial properties. These results indicate that FA-HP-β-CD inclusion complexes are able to reduce tyramine accumulation in smoked horsemeat sausages by inhibiting Enterobacteriaceae growth and gene expression.