Anti-discoloration of Tuna Fillet Through the Lactic Acid Bacteria Treatment: Interpretation by Metabolomic Analysis.

Abstract

This study considered the potential application of lactic acid bacteria (LAB) specifically Leuconostoc citreum M8 (M8) as a natural preservative that could retard discoloration of tuna fillets. Tuna fillets treated with M8 cell-free supernatant were stored at 10 °C. Through the color analysis, it was established that the red color was maintained and color changes prevented in M8-treated samples as opposed to controls. Besides that, antioxidant activities revealed that M8-treated fillets had greater catalase, superoxide dismutase, and peroxidase activity. Also, through metabolic profiling using GC-MS, there were observed significant metabolic differences, which were dominated by increases in amino acids such as tyrosine that are associated with improved quality preservation. Pathway analysis revealed the enrichment of biosynthetic pathways of tryptophan, tyrosine, and phenylalanine at significant levels, reflected in the discoloration effects observed. These findings interpret the metabolites of lactic acid bacteria, in this case, L. citreum M8, as a promising and natural tool for tuna shelf life and quality extension by inhibiting oxidation and discoloration.