基于纳米碱式次氯酸镁果蔬抗菌包装膜的制备及保鲜机理研究

Modified atmosphere packaging is one of the main preservation methods for fresh fruits and vegetables. But, modified atmosphere packaging conducted with ordinary plastic still can not completely control the pathogen infection to cause rotting. Antifungal films with moilproof and fungicidal properties can kill or inhibit the reproduction of pathogen sticking on the plastic within a certain time. which greatly improve the effect of preservation for fruits and vegetables. Basic magnesium hypochlorite (BMH) is non-toxic and environmentally friendly. It can use carbon dioxide generating from the respiration of fruits and vegetables to emit Nascent oxygen to kill pathogen. In this project, we have done the following works: Nano BMHs with size controllable was prepared by microemulsion method. The Antifungal films were prepared by casting using polyvinyl alcohol as environmentally friendly material. Furthermore, the relationships between BMHs and membrane barrier or antifungal properties were studied. The antifungal mechanism of nano BMHs and its migration behavior in film were studied to explore antifungal mechanism of antifungal film. Then the application of antifungal film on fruits and vegetables was carried out and some indicators were measured and analyzed to clarify the preservation mechanism of the film. Such as the respiration rate, ethylene production, enzyme active, and so on. The relationships among BMHs amount, the respiration rate, ethylene production, enzyme activity, decay rate were build for the application of antifungal packaging films in fruit and vegetable storage.

气调包装是果蔬保鲜的主要方法之一，但用普通保鲜膜进行的气调包装还是不能完全控制由病原菌侵染而引起的果蔬腐烂。抗菌膜具备抑菌和杀菌性能能在一定时间内将沾在塑料上的病原菌杀死或抑制其繁殖，从而大大提高膜保鲜果蔬的效果。碱式次氯酸镁（BMHs）无毒无污染，可以利用果蔬呼吸作用放出的二氧化碳生成新生态氧对果蔬进行杀菌。本项目采用微乳法制备尺寸可控的纳米BMHs；以环保型聚乙烯醇为成膜材料，采用流延法制备抗菌膜；探索BMHs与膜阻隔性和抗菌性的关系，调节膜的阻隔性和抗菌性，使之适合果蔬保鲜；对纳米BMHs抗菌机理及在膜中的迁移行为进行研究探索抗菌膜的抗菌机理；同时将抗菌膜应用于果蔬保鲜包装，测定和分析果蔬贮藏过程中呼吸速率、乙烯生成量、酶活性等指标，阐明抗菌膜对果蔬保鲜机理；建立BMHs添加量、果蔬呼吸速率、乙烯生成量、酶活性、腐烂率的相互关系，为BMHs抗菌包装膜在新鲜果蔬贮运中的应用奠定基础。

鉴于果蔬采后腐烂严重，而病原微生物侵染是其腐败最主要的原因，但目前常用的普通保鲜膜气调包装还是不能完全控制由病原菌侵染而引起的果蔬腐烂的现状。本项目采用了微乳法制备纳米BMH，以环保型聚乙烯醇为成膜材料，采用流延法制备了抗菌膜；探索BMH与膜阻隔性和抗菌性的关系，调节膜的阻隔性和抗菌性，使之适合果蔬保鲜；对纳米BMH抗菌机理及在膜中的迁移行为进行研究探索抗菌膜的抗菌机理；同时将抗菌膜应用于果蔬保鲜包装，通过测定果蔬储藏过程中感官评分、失重率、腐烂率、维生素C含量、有机酸含量等指标的变化，研究其对果蔬的保鲜效果；通过分析膜阻隔性和抗菌性与保鲜效果的关系，初步阐明抗菌包装膜保鲜机理。结果表明，制备的BMH粒径主要分布在在1~2 μm，属于微米级，其对果蔬病原微生物有很好的抑制作用，对黑曲霉的最小抑菌浓度为75ppm，对其安全性检测结果显示其基本无毒；当BMH在PVA膜中的添加量为6%时，膜具有较好的力学性能、透明性、热封性，膜的阻隔性和抗菌性随BMH在膜中的添加量的增加而增大；BMH在膜中会发生迁移，而且以在4%乙酸中迁移最多；果蔬抗菌包装膜能有效的降低果蔬在贮藏过程中品质的变化，而且以BMH添加量为6%的包装膜保鲜效果最佳。果蔬抗菌包装膜对果蔬有很好的抗菌保鲜效果的机理主要是因为BMH在膜中的迁移以及BMH的添加调整了PVA膜的阻隔性，使其具有抗菌性的同时更有效的控制和调节果蔬的呼吸作用。本项目研究结果为BMHs抗菌包装膜在新鲜果蔬包装贮运中的应用奠定基础。