冬凌草提取物与壳聚糖复合膜物理特性分析和对鸡蛋的保鲜效果研究

为开发新型可降解抗菌包装材料,以壳聚糖和冬凌草提取物为原料制备复合膜,测试了复合膜的物理特性和抑菌活性,并研究了其对鸡蛋的保藏效果。试验结果显示,冬凌草提取物对复合膜抑菌活性、透光率和水蒸气透过率影响显著(P<0.05),当其添加量为0.5 mg/mL时,复合膜具有较好的物理性能和抑菌活性,其抑菌率为89.3%,膜厚度0.036 mm,拉伸强度为30.57 MPa,断裂伸长率为26.94%,水蒸气透过率为0.117 g·mm/m^2·kPa·h,透光率为58.04%;对鲜蛋和污染蛋进行涂膜保鲜,20℃储藏42 d,其失重率为1.40%,蛋黄指数大于0.30,哈夫单位值大于40,pH值为9.2,菌落总数为0.15×10^3 cfu/mL左右。涂膜组鸡蛋的鲜度指标显著优于对照组(P<0.05),这表明冬凌草提取物与壳聚糖复合膜能延长鸡蛋的保藏期。

Physical Properties of Rabdosia rubescens Extract/Chitosan Composite Film and Its Fresh-Keeping Effects on Chicken Eggs

In order to obtain new degradable antimicrobial packaging material,the antimicrobial film was prepared by incorporated different volume fraction Rabdosia rubescens extract into chitosan solution.The physical properties and antimicrobial activities of the composite film were tested,and the fresh-keeping effects of the antimicrobial film on chicken eggs were investigated.The results showed that R.rubescens extract had significant effects on the antibacterial activities,transparency and water vapor permeability of the composite film.The film displayed obvious antimicrobial activities and physical properties when the concentration of R.rubescens extract reached to 0.5 mg/mL.The antibacterial rate reached 89.3%,and the thickness,tensile strength,elongation at break,water-vapor permeability value and transparency were 0.036 mm,30.57 MPa,26.94%,0.117 g·mm/m^2·kPa·h and 58.04%,respectively.The fresh and polluted chicken eggs coated with R.rubescens extract combined with chitosan were stored at 20℃ for 42 day,the weight-loss rate,yolk index,Haugh unit,pH value and total plate count of the chicken eggs were 1.40%,0.30,40,9.2 and 0.15×10^3 cfu/mL,respectively.The freshness of eggs in the coating group was significantly better than that in the control group(P<0.05).The results indicated that the composite film of R.rubescens extract/chitosan could prolong the preservation period of chicken eggs.