Antifungal whey protein films activated with low quantities of water soluble chitosan

VANDEN BRABER, NOELIA L.; DI GIORGIO, LUCIANA; AMINAHUEL, CARLA A.; DÍAZ VERGARA, LADISLAO I.; MARTIN COSTA, AMADEO O.; MONTENEGRO, MARIANA A.; MAURI, ADRIANA N.

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Año: 2021 vol. 110

0268-005X

The aim of this work was to develop antifungal films from whey protein isolate (WPI) added with low quantities of a water soluble derivative of chitosan (WSCh), which was obtained through a Maillard reaction with glucosamine hydrochloride. Glycerol was used as plasticizer and sodium tripolyphosphate was added to neutralize WSCh charges, at a working pH of 6.4, to avoid coacervation due to the opposite charges interaction of both biopolymers. Nevertheless, this WSCh derivative also acted as a crosslinking agent mainly through hydrogen bonding with whey proteins, which generated a decrease in the films´ solubility and elongation. Possibly a conformational change of the WPI proteins increased the films´ surface hydrophobicity (with contact angles greater than 90°), but there were no increases in their mechanical resistance or in barrier to water vapor. WPI/WSCh films showed excellent fungistatic and barrier effects against the growth of fungus strains associated with food spoilage. Aspergillus niger was 100% inhibited when a suspension containing 1 × 103 spores/mL was inoculated on the films´ surface (barrier effect), while Penicillium roqueforti was the strain more resistant to WSCh activity. The obtained results suggest interesting properties of these materials to use them as active edible coatings.