Development and Application of Intelligent Release Fresh-Keeping Composite Packaging Films
A kind of intelligent release fresh-keeping composite packaging films with its preparation methods and experimental results were introduced. This novel fresh-keeping film has three structural layers: the inner layer to control the release which are formed by a certain proportion of EVA/LDPE blended resins; the interlayer to generate SO2 fresh keeping agent which are composed of blended polyurethane binder, sodium metabisulfite and calcium sulfite served as adhesive layer; the outer designed as barrier layer to avoid SO2 diffusion to outside. The film properties varied with different inner layer components were characterized including film polarity, water vapor transmission rate and oxygen transmission rate tests. The film crystallinity and grain size of the inner layer with different LDPE/EVA blend proportions were analyzed by differential scanning calorimeter (DSC). Also, the effects of different inner layer components on the relations of SO2 concentration and release cycles were investigated. The experimental results showed that the film could not only control the SO2 release amount with the need of various fruits so as to inhibit the growth of mould on fruits, but also restrain fruit respiration, reduce water loss and nutrients consumption, and thus extend the fruit storage period effectively.
OUYANG Yun, XU Min and YANG Li
W. C. Xu et al., "Development and Application of Intelligent Release Fresh-Keeping Composite Packaging Films", Advanced Materials Research, Vol. 174, pp. 480-485, 2011