Carnauba wax as a strategy to produce improved ulvan films for sustainable food packaging

Abstract

Abstract Ulvan biopolymers originate from algae and are promising alternatives for sustainable food packaging, however, their hydrophilic nature limits their applications. In this study, different carnauba wax levels (0%, 5%, 10% and 15% w/w) were incorporated into ulvan film-form solutions to modify its hydrophilic nature. The ulvan extraction by hot water yield was 18.9%. Based on FTIR, the characteristic vibrational frequency bands of ulvan: carboxyl groups of uronic acid, ester sulfate groups and the vibration of C-O groups in the glycosidic bond between rhamnose and glucuronic acid were identified. Moreover, lower intensity of transmission peaks between 3500 cm− 1 and 3200 cm− 1 were attributed to the increase in the hydrophobicity of the films by the addition of carnauba wax. Contributing to the convergence of evidence regarding increased hydrophobicity, a significant decrease in solubility was observed in films containing 10% carnauba wax, compared to films without wax. The tensile strength and elongation at break of the films remained significantly unaffected when compared to compositions without carnauba wax. In short, the present study suggests that the addition of carnauba wax has a hydrophobizing effect on the ulvan films without affecting its mechanical properties, and, therefore, is promising for application in the field of food packaging.