Selection of Lactic Acid Bacteria Isolated from Thai Traditional Fermented Foods to use as Starter Cultures Based on Antioxidant Activity and no Histidine Production

Four strains of lactic acid bacteria (LAB), isolated from various Thai traditional fermented foods, were investigated on free radical scavenging activity of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2-Azino-bis-3-ethylbenzothiazoline-6-sulfonic Acid (ABTS). Antioxidant activity by all isolated LAB in intracellular cell free ex- tracts (ICFE) was higher than in intact cells. The LAB strains FF and FB, isolated from fermented foods (fish and sliced beef), their (ICFE) showed the highest radical- scavenging activity for DPPH and ABTS at 65% and 60%, respectively for the former strain. The detection of amino acid decarboxylase of LAB were investigated by growing on decarboxylase medium and quantitatively evaluated by confirmation of amine forming capacity using an HPLC procedure. In this work, all tested LAB strains were tyramine producer; however, the weakest strain was FF followed by strain FB. In contrast, all of them did not produce histamine. Based on 16S rRNA genes, strain FF was identified as Lactobacillus fermentum, while strain FB was Lactobacillus plantarum. Both are potential starter cultures for producing fermented meat sausages.