Effects of pickle brine and glycine addition on biogenic amine production in pickle fermentation

This study investigated the effects of different pickle brines and glycine additions on biogenic amine formation in pickle fermentation. The results showed that the brines with higher biogenic amine content led to the production of more biogenic amines in the simulated pickle fermentation system. This was related to the abundance of biogenic amine-producing microorganisms in the microbial communities of the brines. Metagenome analysis of the brines and metatranscriptome analysis of the fermentation systems showed that putrescine was primarily from Lactobacillus, Oenococcus, and Pichia, while histamine and tyramine were primarily from Lactobacillus and Tetragenococcus. Addition of glycine significantly reduced the accumulation of biogenic amines in the simulated pickle fermentation system by as much as 70 %. The addition of glycine had no inhibitory effect on the amine-producing microorganisms, but it down-regulated the transcription levels of the genes for enzymes related to putrescine synthesis in Pichia, Lactobacillus, and Oenococcus, as well as the histidine decarboxylase genes in Lactobacillus and Tetragenococcus. Catalytic reaction assay using crude solutions of amino acid decarboxylase extracted from Lactobacillus brevis showed that the addition of glycine inhibited 45 %-55 % of ornithine decarboxylase and tyrosine decarboxylase activities. This study may provide a reference for the study and control of the mechanism of biogenic amine formation in pickle fermentation.