α-lipoic acid maintains quality by modulating phenolic metabolism and antioxidant capacity in postharvest strawberry

Abstract

Postharvest strawberry is susceptible to mechanical damage and fungal attack, which poses serious storage challenges. In this study, senescence of strawberry fruit was successfully delayed using 0.25, 0.5 and 1 g L⁻¹ α-lipoic acid (α-LA), and microbial proliferation was effectively inhibited during the storage. In particular, the treatment at with 0.5 g L⁻¹ α-LA was the most effective, significantly reducing the decay rate and weight loss, while sustaining the firmness, TSS content and color. Strawberry fruit treated with α-LA showed higher total phenolics, total flavonoids, total anthocyanin, ascorbic acid, and individual phenolic compounds content compared with the control. α-LA attenuated strawberry membrane lipid peroxidation by inhibiting MDA and H₂O₂ production, and increasing antioxidant capacity. Transcriptomic analysis revealed significant enrichment of genes related to phenylpropanoid biosynthesis, and the transcription factors FaMYC2 and FaMYB308 might act as negative regulators in phenolic metabolism. In addition, α-LA remarkably enhanced the expression of key genes related to phenolic metabolism and anthocyanin synthesis. In summary, α-LA maintained quality by modulating phenolic metabolism and antioxidant capacity in postharvest strawberry.