Development of antimicrobial defatted soybean meal-based edible films incorporating the lactoperoxidase system by heat pressing

• The first report on agricultural byproduct-based edible film formation by pressing.
• Defatted soybean meal (DSM)-based edible films were developed using heat pressing.
• Films can be formulated to obtain the desired tensile and moisture barrier properties.
• Antimicrobial DSM films were developed by incorporating the lactoperoxidase system.
• Temperature and aw of coated food affected antimicrobial diffusion in the coating.

Antimicrobial edible films were developed using defatted soybean meal (DSM), a lactoperoxidase system (LPOS), and heat pressing. DSM-based films were formed at 70–90 °C and 40–50 MPa for 3 min, varying with the concentrations of DSM, xanthan, glycerol, and water in the formulation. The tensile strength, elongation, elastic modulus, and moisture vapor permeability of the DSM films were 1.2–5.4 MPa, 0.7–19.5%, 19.6–505.4 MPa, and 2.6–6.8 g mm kPa−1 h−1 m−2, respectively. The LPOS-DSM film inhibited Salmonella Typhimurium by 1.5 log CFU/disk. The diffusion coefficients for the diffusion of antimicrobial hypothiocyanite (OSCN−) in the LPOS-DSM film coated on ham and a gel foodwere 1.8–10.7 × 10−15 m2 s−1. As the water activity of the food or storage temperature increased, the coefficient also increased. These results demonstrated the feasibility of producing edible films from DSM on a large scale, which can potentially be used as a food coating to decontaminate S. Typhimurium on food surfaces by controlled release of antimicrobials.