明胶/壳聚糖层层自组装涂层对樱桃柿子保鲜效果研究

Study on the Controllable Preparation of Gelatin/Chitosan LbL Film and Its Fresh-Keeping Property for Cherry Persimmon

本研究以明胶、壳聚糖为主要原料,考察了采用层层自组装(LbL)技术制备的可食性涂层对樱桃柿子的保鲜效果。通过分析明胶、壳聚糖的浸涂顺序、涂层层数、明胶浓度和壳聚糖浓度等因素对樱桃柿子保鲜效果的影响,筛选出最佳工艺参数。结果表明:明胶和壳聚糖的组装顺序对涂层保鲜效果具有很大影响;壳聚糖在外层时涂层保鲜效果明显优于明胶在外层;当自组装涂层的层数为3层、明胶浓度为1.25%、壳聚糖浓度为1.75%时,涂层保鲜效果较好,在此条件下,樱桃柿子贮存7天依然保持了良好的商品品质,而未经涂层保鲜处理的樱桃柿子样品,不到5天时已基本失去了商品价值。实验证实,与共混膜相比,LbL技术能使壳聚糖的抗菌作用得到更好的发挥,从而延长樱桃柿子的货架寿命。水接触角的分析表明,LbL涂层表面具有疏水性,因此其对樱桃柿子的保鲜效果也更好。明胶/壳聚糖LbL可食性涂层对樱桃柿子具有良好的保鲜效果,为果蔬保鲜提供了一种绿色安全的方法。

In this study,the fresh-keeping effect of edible coating prepared by layer-by-layer self-assembly(LbL)with gelatin and chitosan as the main raw material on cherry persimmon was studied.The optimum process parameters were obtained by investigated the effects of gelatin and chitosan coating sequence,coating layer number,gelatin concentration and chitosan concentration on cherry persimmon fresh-keeping.The results showed that the assembly sequence of gelatin and chitosan has a great influence on the fresh-keeping effect of coating,and the fresh-keeping effect of coating with chitosan in the outer layer is significantly better than that with gelatin in the outer layer.When the LbL coating had three layers and the gelatin concentration was 1.25%and the chitosan concentration was 1.75%,the coating fresh-keeping effect was better than others.Under this condition,the cherry persimmon keeps good quality for 7 days.However,cherry persimmon without coating fresh-keeping has basically lost their commercial value in less than 5 days.Experiments proved that LbL membrane can give better play to the antibacterial effect of chitosan than the blend membrane,thus prolonging the shelf life of cherry persimmon.The analysis of the water contact angle showed that the surface of LbL coating is hydrophobic,so it has a better effect on the fresh-keeping of cherry persimmon.Gelatin/chitosan LbL edible coating has good fresh-keeping effect on cherry persimmon,which provides a green and safe method for the fresh-keeping of fruits and vegetables.