Preservative Potential of Nanosilver Coatings Biosynthesized from Selected Plant Extracts in Improving Shelf Life of Banana (Musa paradisiaca L.) and Tomato (Lycopersicon esculentum L.) Fruits

Abstract

Fruits’ natural high moisture content affects their postharvest quality and shelf life. Bananas and tomatoes are among the widely consumed horticultural crops worldwide, yet they are prone to huge postharvest loss. Thus, this study aimed to evaluate the preservative potential of nanosilver coatings biosynthesized from selected plant extracts in improving the shelf life of banana and tomato. Accordingly, four Silver nanoparticles (AgNPs) biosynthesized from aqueous extracts of ginger rhizomes (GAgNPs), turmeric rhizomes (TAgNPs), banana peel (BPAgNPs), and orange peel (OPAgNPs) were used. The AgNPs-based coating solutions were then prepared from the AgNPs at concentrations of 30 and 40 µg/mL, in which the fruits were dip-coated. Finally, the disease incidence and changes in physico-chemical composition of the fruits were measured once every 7 days for 28 days. Banana and tomato fruits treated with AgNPs-coatings were observed to have better quality and extended shelf time of at least 7 days, compared to the untreated control. The AgNPs coatings also maintained the physico-chemical properties of the fruits: improved fruit firmness, moisture content, total soluble solids, stable pH and titratable acidity, and ascorbic acid contents throughout the storage time. Generally, the study revealed that the surface application of biosynthesized AgNPs at very low concentrations (endorsed by the WHO) is an effective technique for extending the postharvest shelf life and quality of stored fruits. Therefore, the use of biosynthesized AgNPs-based coatings to extend the shelf life of fruits and vegetables could be suggested as one of the most successful methods.