In situ crosslinked Schiff base biohydrogels containing Carica papaya peel extract: application in the packaging of fresh berries

Abstract

Although endowed with antimicrobial and antioxidant properties, fruit peel is often regarded as waste. With the focus largely on sustainable development and sustainability, this study explores the valorisation of aforesaid waste. In this work, the influence of C. papaya peel powders on the functional properties of Schiff base hydrogels of chitosan (Cs) and dialdehyde starch (DAS) was investigated for active food packaging. In this work, the hydrogels were fabricated by virtue of in situ crosslinking of –CHO moieties of DAS and –NH₂ groups of Cs. The utilization of C. papaya peel extract in hydrogel films enhanced their thickness, moisture content and opacity. Furthermore, the developed hydrogel film offered versatile performances in terms of antimicrobial and antioxidant activities, water-barrier properties, high tensile strength, stretched/twisted flexibility, anti-puncture resistance, thermal stability and biodegradability. Noteworthy, the shelf life of fresh blueberries, strawberries, gooseberries and Indian jujube was extended by at least one week upon packaging with the fabricated material as compared with unpackaged ones. Thus, our work paves the path for the design of a versatile hydrogel film for potential food packaging and preservation.