There is a significant drive towards the development of edible biocompatible films for food packaging application due to the environmental and health impacts of synthetic packaging materials. This has inspired the exploration of biodegradable natural polymers as packaging materials. To address the instant water disintegration of most natural polymers, polymers with conditional water solubility, such as chitosan (needing acidic conditions for dissolution in water), have gained significant research attention. To this end, chitosan has been blended with different natural proteins, including whey protein isolates, to prepare edible food films. However, consumption of whey protein isolates in their natural form has been proposed in the literature to prolong processing (digestion) time upon consumption. To circumvent this limitation, here we report the development of chitosan/whey protein hydrolysate-based edible films with additional antioxidant properties. The developed films revealed that the inclusion of whey protein hydrolysate improved physicochemical properties and mechanical strength of the films with tensile strength of 26.3 MPa at 1 wt% WPH loading compared to 10.9 MPa in control neat chitosan films (0 wt% WPH). Furthermore, chitosan/whey protein hydrolysate exhibited a significant (whey protein hydrolysate) dose-dependent antioxidant response with a maximum value of 83% DPPH in chitosan/WPH (1 wt%) films assessed using two different antioxidant assays. Based on the results from this study, we envisage the exploration of whey protein hydrolysate-based films for commercial food packaging application in future.

In the present investigation, aloe vera gel (AVG)-based edible coatings enriched with anthocyanin were prepared. We investigated the effect of different formulations of aloe-vera-based edible coatings, such as neat AVG (T1), AVG with glycerol (T2), aloe vera with 0.2% anthocyanin + glycerol (T3), and AVG with 0.5% anthocyanin + glycerol (T4), on the postharvest quality of fig (Ficus carica L.) fruits under refrigerated conditions (4 °C) for up to 12 days of storage with 2-day examination intervals. The results of the present study revealed that the T4 treatment was the most effective for reducing the weight loss in fig fruits throughout the storage period (~4%), followed by T3, T2, and T1. The minimum weight loss after 12 days of storage (3.76%) was recorded for the T4 treatment, followed by T3 (4.34%), which was significantly higher than that of uncoated fruit (~11%). The best quality attributes, such as the total soluble solids (TSS), titratable acidity (TA), and pH, were also demonstrated by the T3 and T4 treatments. The T4 coating caused a marginal change of 0.16 in the fruit titratable acidity, compared to the change of 0.33 in the untreated fruit control after 12 days of storage at 4 °C. Similarly, the total soluble solids in the T4-coated fruits increased marginally (0.43 °Brix) compared to the uncoated control fruits (>2 °Brix) after 12 days of storage at 4 °C. The results revealed that the incorporation of anthocyanin content into AVG is a promising technology for the development of active edible coatings to extend the shelf life of fig fruits.