Optimisation of disinfection and packaging methods for the preservation of Persian shallot (Allium hirtifolium L.)

Abstract

This study optimised disinfection methods and packaging solutions for preserving Persian shallot corms. It involved two phases: disinfection using gamma irradiation (5, 10, and 15 kGy) and cold plasma (17, 20, and 23 kV—1, 5, and 10 min), followed by evaluating various packaging materials (four gas-barrier nanocomposite films), storage conditions (atmospheric and vacuum-sealed), and durations (3, 6, and 9 months). The studied traits were: total phenolic content (TPC), colour characteristics, essential oil (EO) content, and composition and allicin content. The results demonstrated that cold plasma preserved the qualitative characteristics more effectively than gamma irradiation. The highest TPC was recorded in cold plasma at 20 and 23 kV for 1 min. In contrast, the highest EO content was observed in cold plasma at 17 kV for 10 min. Increasing the gamma irradiation intensity from 5 to 15 kGy resulted in a 51% reduction in allicin content. Among cold plasma treatments, the highest allicin content was observed at 23 kV. Extended storage durations across all packaging types resulted in a decline in TPC and decreases in the L* colour indices and EO content. Analysis of the EOs revealed that the dominant compounds were dimethyl disulphide, (methylthio) acetic acid, and tetradecane.