Evaluation of the Storage Stability of Starch-Based Films Containing Grape Seed Oil
Abstract
The increasing environmental concerns associated with petroleum-based packaging materials have accelerated the development of biodegradable alternatives, with starch-based films emerging as promising candidates. This study investigates the influence of grape seed oil (5–15 wt.%) and storage time (up to 5 months) on the mechanical, thermal, structural, and surface properties of potato-starch-based films for biodegradable packaging applications. Oil incorporation improved the initial film performance, increasing tensile strength (1.27–3.11 MPa), enhancing thermal stability (melting temperature up to ~118 °C), and promoting higher surface hydrophobicity (contact angle up to ~87°). The differential scanning calorimetry (DSC) analysis indicated time-dependent changes in the thermal transitions associated with the reorganization of ordered starch domains with oil addition, from 39.96% for samples with 5% oil to 36.40% for samples with 15% oil. After three months, all oil-containing samples exhibited a substantial reduction in ultimate tensile strength, with normalized stress values decreasing to 0.74–1.18 depending on oil content. However, after 5 months, the evaluated properties had values close to or above the reference. Statistical evaluation confirmed that storage time is the dominant factor governing property evolution, exceeding the influence of oil concentration.