Preservation Effect of Natural Composite Preservative Coating Liquids on Pot-Stewed Duck's Neck

To assess the preservation effect of natural composite coating liquid on pot-stewed Duck's neck. First,effects of sodium alginate,nisin and natamycin on the quality of the pot-stewed duck's neck were investigated by single factor experiments with the bacterial count,total volatile base nitrogen (TVB-N),pH and thiobarbituric acid reactive substances (TBARS). Second,the three different ratios of natural preservatives were compared by L₉ (3⁴) orthogonal experiment to obtain the optimal combination of coating liquid on pot-stewed duck's neck. The results showed that the preservation effects of the three natural preservatives were better than those of the blank group,among which nisin showed strong antibacterial effect,and the coating formed by sodium alginate had better antioxidation effect. When the concentration ratio of the three preservatives was 1.0 g/100 mL of sodium alginate,0.9 g/100 mL of nisin,and 0.18 g/100 mL of natamycin,the coating liquid had the best preservation effect on the quality of the pot-stewed duck's neck. The total bacterial count,TVB-N,pH,TBARS and color difference at the 15th day after cold storage at 4℃ were (5.37±0.08) lg CFU/g, (20.86±0.79) mg/100 g, (5.85±0.06), (2.68±0.08) mg/kg, (1.51±0.07),respectively. All data were significantly better than the control group (p<0.05). Thus,the coating liquid could effectively extend the shelf life of the pot-stewed duck's neck.