Improving the quality and shelf-life of strawberries as coated with nano-edible films during storage

Abstract

Strawberry is a non-climacteric fruit but exhibits very limited postharvest life due to its rapid softening and decay. Therefore, the current study was carried out to evaluate the effect of edible coatings using chitosan (CH) and chitosan nanoparticles (CHNPs) to improve the quality and extending the shelf life of strawberries during storage. Chitosan nanoparticles (CHNPs) were prepared by an ionic gelation method. The size and shape of the synthesized CHNPs were observed by transmission electron microscopy (TEM) technique. The strawberry samples were stored (after coating) at ambient temperature (25±3°C) and cold temperature (6±2°C) then, we evaluated the effectiveness of edible coating for physicochemical and microbiological properties, as well as the shelf-life during storage. The results of the TEM showed that the average particle size was 18.8-21.8 nm. At the different temperatures of storage, the samples coated with CHNPs had lower values of weight loss, decay, total soluble solids, and malondialdehyde concentrations. The same treatment had higher levels of total acidity and anthocyanin compared to the CH and uncoated treatments, that lead to preserving their quality properties and extending the shelf-life. Also, counts of total aerobic, mold, and yeast for strawberry samples treated by CHNPs were lower than those for CH and control treatment during the storage. In conclusion, the antimicrobial edible coating by CHNPs improved the qualitative characteristics and increased the shelf-life from 2 to 6 days for fruits stored at 25±3°C and from 8 to 16 days for samples stored at 6±2°C.