Effects of transglutaminase and thyme oil addition on the properties of faba bean protein-based active films.

Abstract

In this study, faba bean (Vicia faba L.) protein concentrate-based biodegradable films were developed using the casting method at two pH levels (6 and 8) and with different microbial transglutaminase (MTGase) concentrations (0, 5 U, and 10 U). Films prepared at pH 8 exhibited improved mechanical properties due to the higher solubility of proteins. Therefore, subsequent experiments were conducted with the films prepared at this pH. The films were evaluated for their barrier properties, color, antioxidant properties, thermal stability, and degree of cross-linking. The incorporation of 5 U MTGase led to random cross-link formation within the film matrix, which negatively impacted the mechanical and barrier properties. In contrast, 10 U MTGase enhanced the physical properties of the films and resulted in a higher degree of cross-linking. Thyme oil (Thymus vulgaris) was incorporated into the film-forming solutions to enhance their antioxidant and antimicrobial properties. While 1 % thyme oil enhanced the active properties of the films, it reduced their mechanical strength, barrier performance, and degree of cross-linking. Despite these challenges, incorporating 1 % thyme oil in films crosslinked with 10 U MTGase is recommended for developing active packaging films with high antioxidant capacity and antimicrobial effectiveness.