Aloe vera Gel–Reinforced Biodegradable Starch–PVA Blends for Sustainable Packaging of Green Chillies

Abstract

ABSTRACTThe objective of the current study was to evaluate the feasibility of Aloe vera gel as a plasticizer and crosslinker in improving the properties of starch–polyvinyl alcohol blends that could find applications in packaging. The concentration of Aloe vera gel was varied (1%, 3%, 5% and 7% wt/wt) to produce SPA‐1, SPA‐3, SPA‐5 and SPA‐7 films, respectively. The plasticizing and crosslinking characteristics associated with Aloe vera gel had a positive influence on the mechanical properties of the films. Addition of Aloe vera gel increased the tensile strength of films from 27.45 MPa (control) to 32.98, 32.53 and 32.32, for SPA‐1, SPA‐3 and SPA‐5 films, respectively. Among all the films, highest elongation at break (20.62%) was observed for SPA‐3 films. Due to crosslinking, degree of swelling, water solubility and water vapour permeability for SPA‐3 films decreased by 5.58%, 38.29% and 21.44%, respectively, compared to control films. The contact angle of the SPA‐3 film significantly increased by 49.25% when compared to control samples. Scanning electron microscope images revealed compact and smooth surface microstructure of control films, and crosslinking was evident in presence of Aloe vera gel. The rate of degradation for SPA‐3 films in soil after 40 days was enhanced by 32.25% compared to control films. SPA‐1 and SPA‐3 films were tested for use as packaging material for storage of green chillies. Chillies under unpacked conditions, in control and SPA‐1 films, turned red in 3 days. Those stored in films with 3% Aloe vera gel began to change colour later (after 5 days) with no visual evidence of microbial or fungal growth. In summary, starch–polyvinyl alcohol matrix films with 3% Aloe vera gel (SPA‐3) were effective as a sustainable alternative in increasing shelf life of foodstuff.