| The living standards have a great improvement with the development of economic and social in recent years, so people’s consumption patterns and attitudes are undergoing great changes which pay more attention to food safety, nutrition and health. The consumption of fruits、vegetables and aquatic products are growing very fast for its fresh、delicious and high nutritional value, the huge demand is growing rapidly which has become a necessity of residents’ life and occupy a large share in total agricultural products.In this research active packaging films that 2% grape seed oil、2% clove essential oil 、1% grape seed oil+1% clove essential oil were selected as active ingredients, ethylene/vinyl alcohol copolymer(EVOH) was selected as membrane material was prepared by extrusion blow molding. The effect of the active packaging films on preservation properties of grass carp and cherry tomatoes during cold storage and the basic properties of the films were investigated. The main experiment results are followed:(1) Ethylene vinyl alcohol copolymer(EVOH) films containing Clove oil and grape seed oil respectively were successfully prepared by extrusion. Clove oil and grape seed oil had a good compatibility with the basic membrane material EVOH, the incorporation of essential oil made the film more dense and homogeneous, increased the tensile strength of the film, reduced the water vapor permeability coefficient and produced no adverse effects on their thermal resistance. Escherichia coli and Staphylococcus aureus bacteria inhibition zone test results showed that theexperimental group presented a strong inhibition on this two tested bacteria, the film contained clove oil exhibited a most effective antibacterial effect among the experimental group films. DPPH radical scavenging rate which represented the antioxidant ability results indicated that experiment active films possessed more perfect oxidation resistance than control group, and the film added grape seed oil presented the best performance.(2) The effect of the active packaging films on preservation properties of cherry tomatoes during cold storage were investigated. The freshness indicators such as weight loss rate, Vc content, hardness, titratable acid content and rot rate were analyzed periodically in cherry tomatoes during cold storage. The results showed that the active packaging film treatment groups presented significantly higher preservation effect than the control group. And the film that included 1% grape seed oil and 1% clove essential oil could keep the cherry tomatoes fresh more effectively than any other group. The advantages of this film were strong barrier, can suppress fruit respiration, can inhibit microbial reproduction and oxidation of organic matter, so it has an effective preservation effect.(3) The EVOH active packaging films were applied to keep the quality of grass carp during cold storage. The total volatile basic nitrogen(TVB-N), aerobic plate count, p H, TBA, water holding capacity(WHC) and texture properties were analyzed periodically in grass carp. The results showed that all the freshness indicators reflected the simultaneous addition of clove oil and grape seed oil into the film had the best preservation effect on grass carp. In terms of total number of colonies less than 5 lg(CFU/g) as edible criteria, the film that included 1% grape seed oil and 1% clove essential oil could effectively keep the fish fresh and extend the shelf life to 8 days, which compared with the control group can be extended to 3~4d. Experiments show that the development of EVOH active packaging film could effectively extend the shelf life of grass carp,which had a good application prospect in the preservation of grass carp. |
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