Quality and Shelf‐Life Evaluation of Perilla Seed Oil, Sesame Seed Oil, and Their Blended Oil in Dietary Supplements: A Moisture Sorption Isotherm Approach

ABSTRACT Fatty acid composition and storage conditions strongly influence the stability of oil‐based dietary supplements. In this study, the quality, microbiological safety, and shelf‐life of perilla seed oil (PSO), sesame seed oil (SSO), and their 50:50 blend encapsulated in soft gels were evaluated. Fatty acid analysis showed PSO to be rich in omega‐3 fatty acids, whereas SSO contains higher proportions of omega‐9 and omega‐6; blending them resulted in a more balanced fatty acid profile. All formulations complied with microbiological safety standards, with no pathogenic bacteria detected. Moisture sorption isotherms at 25°C exhibited typical Type II sigmoidal behavior, with rapid moisture uptake above 60% relative humidity (RH), indicating critical storage conditions. Shelf‐life prediction revealed that under moderate storage conditions (30°C, 60% RH), PSO, SSO, and the blended oil had respective estimated shelf‐lives of 51.1, 49.9, and 58.0 months. Harsher conditions (35°C and 70% RH) reduced shelf‐life to 23.5, 23.1, and 25.9 months, respectively. Across all conditions, the 50:50 blend consistently showed the greatest stability, demonstrating that oil blending is an effective strategy to improve nutritional balance and extend the storage stability of oil‐based dietary supplements. Practical Applications : The findings demonstrate that combining PSO and SSO in dietary supplements not only balances composition of essential fatty acids but also enhances oxidative stability and extends shelf‐life. The shelf‐life predication in this study could support the industry in setting appropriate expiration dates and selecting suitable storage conditions. Overall, these results have practical applications in the development of functional foods or dietary supplements that deliver both high nutritional value and prolonged stability, ensuring consumer safety and improving market competitiveness.