Development and characterization of mung bean starch and citric acid active packaging combined with terpinen-4-ol and its application to strawberry preservation

Harvested fresh produce is prone to massive losses during storage associated with fungal infection, and the shelf-life of seasonal nutritious strawberries is only a few days. Biodegradable antimicrobial active packaging has been suggested as a potential strategy to prolong the shelf-life of perishable products. Here, we developed a novel antimicrobial active packaging based on mung bean starch (MBS) modified with citric acid (CA) for cross-linking, and terpinen-4-ol (TP4O) as an antimicrobial additive for preservation. We found that the MBS with CA and TP4O increased film thickness, and enhanced moisture content (MC). Using MBS as the solution base maintained low water vapor permeability (WVP) in the film, this was not affected by TP4O (p > 0.05). Adding TP4O significantly reduced the total color difference (ΔE) of MBS films. The microstructure of films was assessed using scanning electron microscopy (SEM) and cross-linking was verified by Fourier transform infrared spectroscopy (FTIR). The SEM results showed increasing roughness with the incorporation of TP4O, and FTIR analysis showed that CA was well cross-linked. The results of storage tests at 20 ^oC under 80% RH showed that the incorporation of 0.25% TP4O led to a non-significant (p > 0.05) increase in weight loss, whereas the incorporation of 0.5% TP4O, the weight loss of the strawberries increased significantly (p < 0.05). MBS/CA/0.25% and MBS/CA/05% TP4O significantly (p < 0.05) reduced the lesion diameter of strawberries inoculated with Botrytis cinerea. The uncoated, MBS/CA/0.25%, and MBS/CA/05% TP4O each showed favorable highlights of different quality parameters of stored strawberries. Weight loss, firmness, and fungal decay were considered key parameters that greatly affect the postharvest degradation of fruits.