Thiamine Demonstrates Bio-Preservative and Anti-Microbial Effects in Minced Beef Meat Storage and Lipopolysaccharide (LPS)-Stimulated RAW 264.7 Macrophages

SIMPLE SUMMARY: Thiamine (TA), also known as vitamin B1, is an essential amino acid derived from food sources for normal body function. TA is thought to have antioxidant, antimicrobial, and anti-inflammatory effects in addition to its nutritional benefits. The degree to which a number of microorganisms implicated in food rotting are sensitive to increasing concentrations of thiamine (TA), was examined. TA at increasing concentration was incubated with minced beef and then physicochemical and microbiological assessments were conducted. LPS-stimulated RAW264.7 cells were used to test TA’s anti-inflammatory capabilities. Western blot analysis revealed the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). Finally, the ability of TA to act as a natural preservative was evaluated. ABSTRACT: This study assessed the anti-inflammatory effect of thiamine (TA) in lipopolysaccharide-stimulated RAW264.7 cells and also assessed the preservative properties of TA in minced beef. TA demonstrated a concentration-dependent antimicrobial effect on microbial contaminants. Inhibition zones and MIC from the effect of TA on the tested bacterial strains were respectively within the ranges 15–20 mm and 62.5–700 µg/mL. TA significantly (p < 0.05) decreased all the pro-inflammatory factors [(nitric oxide (NO), prostaglandin E2 (PGE2), TNF-α, IL-6, IL-1β, and nuclear factor-κB (NF-κB)] monitored relative to LPS-stimulated RAW264.7 cells. TA inhibited the expression of both iNOS and COX-2. In minced beef flesh, the growth of Listeria monocytogenes was inhibited by TA. TA improved physicochemical and microbiological parameters of stored minced beef meat compared to control. Principal component analyses and heat maps elucidate the quality of the tested meats.