Production of chitosan and poly (vinyl alcohol) films functionalized with hop extract (Humulus lupulu L. var. Cascade) for food packaging application

Abstract

In this study, chitosan and poly(vinyl alcohol) (PVOH) films functionalized with hop (Humulus lupulus L. var. Cascade) extracts were produced for food packaging application. The film form solution was prepared by the casting technique, adding 30%, 50%, and 70% of PVOH (2% w/w) in chitosan (2% w/w), and then, functionalized with 10%, 20%, and 40% (v/v) of hop extracts. The mechanical, color, morphological, thermal, and antioxidant properties were investigated. The results indicated that the addition of PVOH improved the flexibility of the films, and the functionalization with hop extracts produced more rigid films. The addition of hop extracts decreased the luminosity, resulting in yellow and green colored films. High antioxidant capacity by DPPH and ABTS assays was observed in the films containing hop extracts. The release study demonstrated that the films can release antioxidant compounds in aqueous and acid food simulant. In conclusion, the physicochemical, mechanical, and antioxidant properties of chitosan/PVOH films were improved with the addition of the hop extracts, indicating that the functionalized material is a promising alternative for active packaging in food system.