Development and Application of Intelligent Release Fresh-Keeping Composite Packaging Films

Abstract

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.

Extending the Shelf Life of Victoria Table Grapes by High Permeability and Fungicide Packaging at Room Temperature

“…The outer and inner layers are both made of modified low‐density polyethylene (LDPE) films, which contain 5–10% of zeolite to increase the oxygen transmission rate (OTR) . Polyurethane adhesive with additives forms a bond between the two layers, including sodium metabisulfite, calcium sulfite and citric acid, which can release sulfur dioxide . The APF bag (measuring 300 × 300 mm) was punctured with 10 pinholes on one side to obtain an OTR value of ~20 000–30 000 ml/m 2 ·day·atm, to maintain high respiration rate for grapes in ambient temperatures of 25 ± 1°C.…”

Triggered and controlled release of active gaseous/volatile compounds for active packaging applications of agri‐food products: A review

“…Bisulfite salts (e.g., sodium metabisulfite) can be used as a precursor for sulfur dioxide. Upon contact with water/moisture, bisulfite can be converted into SO 2 according to Equation (4) (Lichter et al., 2008; Xing et al., 2011; Xu et al., 2011). Also, calcium sulfite can release SO 2 under acidic conditions (Xu et al., 2011).…”

“…Upon contact with water/moisture, bisulfite can be converted into SO 2 according to Equation (4) (Lichter et al., 2008; Xing et al., 2011; Xu et al., 2011). Also, calcium sulfite can release SO 2 under acidic conditions (Xu et al., 2011). …”

“…This delivery system, however, is inconvenient for postharvest and plant growth regulation applications due to safety concerns. Chlorine dioxide (ClO 2 ), sulfur dioxide (SO 2 ), and ethanol are broadly used in the food industry (including food packaging applications) as antimicrobial agents against pathogenic and spoilage microorganisms in perishable products, such as meat, poultry, fish, and bakery products (Chen et al., 2020; Kaliyan et al., 2007; Latou et al., 2010; Xu et al., 2011). These gases/volatiles are chemically unstable due to their high reactivity, flammability, explosiveness, or corrosiveness at high concentrations.…”

A Comparative Study of Monomers on the Preparation of Permselective Functional Packaging Materials

“…Such preservation condition is easy to breed bacteria and multiply rapidly and thus cause fruit decay. Therefore, a large number of fruits rots and suffered rather high losses every year [1].…”