p-CA treatment influences the accumulation of anthocyanin and flavonoids and enhances the fruit quality and storage characteristics of blood orange during storage

Anthocyanin content determines the nutritional and colour quality of blood orange. This study examined effects of p -coumaric acid ( p -CA) on anthocyanin accumulation and storage traits of blood orange. Compared with control, p -CA significantly accelerated anthocyanin accumulation, and increased juice colour index and anthocyanin content. Total flavonoids and its components (flavanol, flavonol, flavanone, flavone) were also elevated. p -CA-treated fruit had higher titratable acid (TA) and total soluble solids (TSS), and lower weight loss. The treatment enhanced superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) activities, 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) scavenging ability, hydrogen peroxide (H 2 O 2 ) and superoxide anion (O 2 − ·) contents, while reducing malondialdehyde (MDA) content. It also increased phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H) and 4-coumarate: CoA ligase (4CL) activities. Transcriptomic analysis showed ethylene-responsive transcription factor (AP2/ERF) and C2H2-type zinc finger (C2H2-ZF) were significantly correlated with anthocyanin content. This study provides a safe and effective technique to improve postharvest quality of blood orange.