Effect of Alginate Oligosaccharides on Oxidative Reactions in Sweet Basil During Low-Temperature Storage

This study aimed to investigate the antioxidant effect of alginate oligosaccharides (AOS) on sweet basil leaves preserved at low temperatures. This investigation was divided into 3 treatments and 3 replications using a completely randomized design (CRD) experiment. Specifically, the effects of dipping basil leaves in AOS solutions at different concentrations (100 and 200 mg L−1) and in distilled water (control) for 1 min were compared. Cell deterioration due to cold storage was investigated based on the variation in oxidative reactions in the cells, causing an accumulation of free radicals. The AOS-treated sweet basil leaves had a 12-day shelf life, compared to just 9 days for those in the control group. Those treated with AOS at 100 mg L−1 exhibited the lowest levels of phenylalanine ammonia-lyase, lipoxygenase, hydrogen peroxide, peroxidase and malondialdehyde content. On the contrary, the contents of phenolic compounds, polyphenol oxidase, catalase and superoxide dismutase increased in the treated leaves during storage compared to those observed in the control treatment. HIGHLIGHTS Alginate oligosaccharides (AOS) enhanced antioxidant effects in sweet basil leaves stored at low temperatures. Basil leaves treated with AOS at 100 and 200 mg L⁻¹ had an extended shelf life of 12 days, compared to 9 days for untreated controls. AOS treatment reduced oxidative stress markers, including phenylalanine ammonia-lyase, lipoxygenase, hydrogen peroxide, peroxidase, and malondialdehyde. AOS-treated leaves showed increased phenolic compounds, polyphenol oxidase, catalase, and superoxide dismutase activity. AOS treatment may mitigate chilling injury and improve postharvest quality in sweet basil leaves. GRAPHICAL ABSTRACT