Effect of montmorillonite and starch nanocrystals based biodegradable films loaded with lemongrass oil nanoemulsion on quality, enzymatic activity and shelf life of strawberry

The present study aims to determine the influence of montmorillonite (1.5% w/v MMT) and starch nanocrystals (1% w/v SNCs) based corn starch films loaded with lemongrass oil nanoemulsion (2% v/v LNE) on the shelf life and quality characteristics of strawberries (variety Tioga) stored at 4ºC for 8d. Results revealed that MMT and SNCs reinforcement enhanced tensile properties while reducing the WVTR of the films. Active nanocomposites provided superior shelf stability whereas control (unpackaged strawberry) demonstrated the highest quality deterioration in strawberries throughout storage. Amongst nanocomposites utilized, MMT/LNE based films exhibited the best preservative effects on the quality of strawberries, owing to their better barrier properties than SNCs/LNE. On the 8th day, MMT/LNE based films demonstrated highest retention of the physicochemical properties, phenolic content (69.50%), anthocyanin content (86.76%) and DPPH scavenging activity (67.60%). The activity of antioxidant enzymes (superoxide and catalase) was also preserved best with the MMT/LNE based films. Active nanocomposites reduced microbial growth with MMT/LNE films showing the least microbial progression. MMT/LNE and SNC/LNE loaded nanocomposites increased the strawberries' shelf life up to 8 and 6 days, respectively in comparison to the control (4 days), illustrating the effectiveness of nanocomposites in maintaining postharvest quality of strawberries.