Development of antimicrobial starch-based composite films reinforced with soybean expeller for sustainable active packaging applications

Abstract

In this study, the influence of glycerol and sonicated soybean expeller (SSE) on composite edible films supporting natamycin and nisin was investigated using Response Surface Methodology. Assessments were conducted on mechanical properties, moisture content, water solubility (SW), and color. Optimal results were achieved with 0.46% SSE and 1.4% glycerol, yielding a maximum tensile strength (TS) of 1.0 ± 0.1 MPa and a minimum SW of 19.0 ± 0.3%. SSE had no impact on Tg values (82–89 °C), while antimicrobials reduced Tg (70–73 °C) due to increased water retention. Water vapor permeability was (2.5 ± 0.2) × 10–9 −1 s−1 Pa−1. FTIR analysis revealed strong component interactions. The composite films demonstrated biodegradability in compost after seven days and effective action against Listeria innocua and Saccharomyces cerevisiae. These findings suggest that these materials hold promise as active films for food preservation.