Research On Preparation And Properities Of Oxygen Scavenging Packaging Film Based On Gallic Acid

In many case, the food is easily corrupt with the presence of oxygen, since oxygen can cause oxidation of food components, the proliferation of molds and aerobic bacteria. Vacuum packaging and modified atmosphere packaging have been widely used to exclude oxygen in the head space, but which cannot completely remove the oxygen and there is always0.1%-2.0%oxygen remains in the packaging, in particular in the porous food. Furthermore, this two methods cannot exclude the oxygen which penetrated through the film into the packaging during the storage. Active oxygen packaging is a new technology after vacuum packaging and modified atmosphere packaging.In this study, we used natural oxygen Gallic acid as active ingredient, an alkali metal salt as the oxygen additive to prepare the single-layer oxygen scavenging film and multi-layer composite oxygen scavenging film. Multi-layer composite oxygen scavenging film with three layer structure were prepared by the inspergation of solid powder and the suspension of polyurethane glue, which out layer were KBOPP(PVDC coated on BOPP) and inner layer were LDPE/EVA blend film. The influence of process technology, oxygen additive added ratio, structure of inner layer and relative humidity in package on oxygen scavenging performance were studied by single factor experiment. At last, take orange juice as the research object, the preservation effect of this film on orange juice was evaluated.(1) The influence of process technology on the oxygen scavenging performance of oxygen scavenging film is obvious. The oxygen scavenging capacity of the single-layer film which prepared by melt extrusion is relative small, mainly due to the low addition ratio of the oxygen scavenger, and the amount of increase will affect the processing properties of the resin. After oxygen scavenger through the high temperature environment of processing, the oxygen performance of oxygen scavenger would weaken.(2) The aim of the ratio between GA and oxygen additives is mainly to provide a suitable environment, so that it can reaches the maximum oxygen scavenging. When the addition ratio is0.5of food grade Na2CO3, oxygen scavenger can get the maximum oxygen absorption, and the composite oxygen scavenging film can reach the maximum oxygen capacity of860mL/m2.(3) The inner layer of the multi-layer composite oxygen scavenging film play a key role in the whole oxygen scavenge system, which not only determine the moisture penetration of activator of oxygen scavenge react, but also determine the oxygen content which permeated into the middle layer. When the addition ratio of EVA is40%, the amount of oxygen permeability and water vapor permeability was3506.8cm3/(m2·atm·24h) and14.7g/(m3·24h), which helps to achieve the maximum oxygen scavenge of the multi-layer composite oxygen scavenging film.(4) The oxygen scavenger packaging system based on water-activated have the special requirement of water activity of the packaged food. The results showed that the oxygen capacity of the oxygen scavenger will increase with the relative humidity rising, and when the RH exceeded85%, the oxygen capacity will not suppress by RH.(5) Study the influence of the multi-layer composite oxygen scavenging film on the preservation of orange juice, and the result showed that oxygen scavenging packaging material can effectively remove oxygen, and the oxygen scavenging rate sufficient to slow the degradation of the Vc in orange juice and to delay the orange juice browning and quality decline, so the oxygen scavenging packaging material could help to extend the shelf life of orange juice.