壳聚糖/纳米蒙脱土涂膜对清洁鸡蛋的保鲜效果

Preservation Effects of Chitosan/Nano-montmorillonite Coating on Clean Eggs

目的在壳聚糖基材中添加纳米蒙脱土制备纳米复合涂膜,探究其对鸡蛋的保鲜效果。方法分别添加质量分数为1%,5%,9%的MMT到壳聚糖乙酸溶液中,超声分散后对鸡蛋进行涂膜处理。将空白对照组与各涂膜组的鸡蛋样品在25℃、相对湿度为60%的条件下贮存,定期测定其感官指数、失重率、蛋黄指数、蛋清pH值、哈夫单位等理化指标。结果当MMT的质量分数为1%时,纳米复合涂膜可显著改善鸡蛋的外观品质,降低其失重率,并能较好地维持鸡蛋品质。综合比较各指标发现,该处理组的鸡蛋在贮存7周时的品质与空白对照组贮存3周时的品质相当。MMT的添加量过高时,由于MMT的团聚影响了涂膜的阻隔性,对复合涂膜保鲜效果反而有不利影响。结论 MMT质量分数为1%的壳聚糖基纳米复合涂膜可有效延长鸡蛋在常温下的货架期,且安全可降解,具有良好的应用前景。

The work aims to study the effects of nano-composite coating （prepared by adding nano- montmorillonite （MMT） to chitosan （CS） on the preservation of eggs. CS/MMT composite coating solution was prepared by addition of 1%, 5% and 9% MMT into CS solution, respectively. After ultrasonic dispersion, coating was applied on eggs. Then the egg samples of blank control group and coating group were stored at 25 ℃ with the relative humidity of 60%. The physi- cochemical indexes of eggs, including sensory index, weight loss ratio, yolk index, albumen pH value and Haugh unit were measured regularly. When MMT content was 1%, the nano-composite coating could significantly improve the exte- rior quality, reduce the weight loss ratio, and effectively maintain the quality of eggs. With comprehensive comparison of all indices, it was found that the quality of eggs with composite coating stored for 7 weeks was almost equivalent to that of the control group stored for 3 weeks. However, when MMT content was excessively high, the barrier property of coat- ing was affected adversely by the aggregation of MMT, which compromised their preservation effects on eggs. CS-based nano-composite coating with 1% MMT is able to extend the shelf life of eggs considerately under ambient conditions. As a safe and biodegradable coating material, it shows great potential to be applied in fresh-keeping of eggs.