Preparation Of Packaging Of Nanocomposite-Based And Its Application On Agaricus Bisporus And Flammulina Velutipes

A nanocomposite-based packaging (NCP) material was prepared with polyethylene (PE), nano-Ag, nano-TiO2, nano-SiO2and attapulgite and its effect on the preservation quality of Agaricus bisporus and Flammulina velutipes was investigated. Mushroom whiteness, weight-loss, membrane permeability, malondialdehyde (MDA), protein and total sugar, activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were measured. The main research results were as follows:1. A mixture of30wt.%of nano-powders(30wt.%of nano-silver,35wt.%of nano-TiO2,25wt.%of montmorillonite and10wt.%of nano-silicon dioxide),68wt.%of LDPE and2wt.%of cross-link reagent KH-570was fed into a co-rotating twin screw extruder and cut into masterbatch nano-granules. Then3.75Kg of the nano masterbatch,3.75Kg of anti-fog masterbatch and92.5Kg of PE granule (25wt.%of2102TN26and75wt.%of DFDA7042) were immingled for0.5h, and afterwards blown into a film of40μm thickness via a plastic extruder.2. The morphological characterization, physical properties and anti-fog effect of NCP were conducted. The results indicated that nano-particles (Ag, TiO2, SiO2and montmorillonite) were evenly distributed which did not impact on the thickness, mechanical strength and physical properties of NCP. Owing to the addition of nanoparticles and anti-fog masterbatch, the anti-fog properties of NCP are enhanced, hence more effective than normal packaging. The study would provide the theoretical and practical basis for the application of NCP on preservation of mushroom.3. Agaricus bisporus are easy to lose their merchandise quality for weight loss and browning. After stored in4℃for12days, Agaricus bisporus packaged with NCP maintained a high level of whiteness, protein and total sugar content, reduced the increases in both membrane permeability and malondialdehyde (MDA) content, and protected body cells from collapse. Furthermore, treated samples showed higher activities of antioxidant enzymes. Activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly (p<0.05) inhibited by7.58%,41.25%and159%respectively, increasing the antioxidant capability, free radical scavenging activity, delaying the senescence of Agaricus bisporus.4. By taking Flammulina velutipes as the research object, the effects of NCP on the preservation quality of Flammulina velutipes were investigated. During the15-day storage at4℃and2-day storage at normal temperature (25℃), Mushroom weight-loss rate, browning degree (BD), membrane permeability, MDA content, VC, protein and total sugar content, activities of SOD, POD and CAT were measured. The results indicated that NCP slowed down the senescence process of Flammulina velutipes by indicating weight loss, BD, membrane permeability and MDA content which were significantly inhibited by31.8%,20.0%,20.8%and27.5%compared with normal packaging. Activities of SOD, POD and CAT were inhibited by6.3%,13.7%and11.5%respectively. In addition, NCP maintained high content of VC, protein and total sugar.The obtained results suggested that NCP enhanced the capacity of anti-oxidation defensive system, and induced the protective enzyme system initiation which eliminated free radicals and inhibited membrane lipid peroxidation. These activities delayed senescence of Agaricus bisporus and Flammulina velutipes.