Effects of chitosan, aqueous extract of ginger, onion and garlic on quality and shelf life of stewed-pork during refrigerated storage.

Effects of 1% or 0.5% chitosan (CHI), 10% or 5% aqueous extract of ginger, onion and garlic (GOG) and their composite solutions (1% CHI+10% GOG, 0.5% CHI+5% GOG) on quality and shelf life of stewed-pork were evaluated. Microbiological (total bacterial count), chemical (pH, total volatile basic nitrogen (TVB-N), peroxide value (POV), 2-thiobarbituric acid (TBA)) and sensory characteristics were analysed periodically during refrigerated storage at 4 °C for 12 days. CHI and/or GOG treatments retarded the increases in pH, TVB-N, POV, TBA and total bacterial count. CHI showed better antibacteria but weaker antioxidation than GOG. Composite treatment had possible synergistic effect while the high concentration of composite solution (Mix1) had adverse effect on odour and overall acceptance. Mix2, the diluted solution of Mix1, could be a natural promising preservative for the stewed-pork considering the comprehensive effects of antioxidation, antibacteria and sensory quality, which could extend the shelf life for about 5-6 days.