Changes in Phenolic Compounds and Antioxidant Activity during Development of 'Qiangcuili' and 'Cuihongli' Fruit

Plums are widely consumed, contain high levels of phenolic compounds, and have strong antioxidant activity. In this study, the main Sichuan cultivars 'Qiangcuili' and 'Cuihongli' were used to study the changes in the appearance, internal quality, phenolic compounds, and antioxidant activities during fruit development and the expression of phenolic-compound-related structural genes. The results showed that, during development of the two plums, the total soluble solid and soluble sugar contents were highest at the mature stage. The phenolic contents (total phenol content (TPC), total flavonoid content (TFC), and total flavanol content (TFAC)) trended gradually downward as the fruits of the two cultivars matured, while the total anthocyanin content gradually increased in 'Cuihongli'. The main phenolic components were neochlorogenic acid, chlorogenic acid, ferulic acid, benzoic acid, rutin, and proanthocyanidin B1. The changes in the DPPH and FRAP scavenging activities decreased with fruit ripening. The antioxidant capacity was positively correlated with the TPC, TFC, and TFAC. In the two cultivars, the total phenols, phenolic components, and antioxidant capacity were higher in the peel than in the pulp. CHS, PAL3, and HCT1 may be the regulatory genes related to the accumulation of phenolic substances in the pericarp and pulp of 'Qiangcuili' and 'Cuihongli'. HCT1 may be an important regulator involved in the accumulation of chlorogenic acid in plums. The changes in the quality of the phenols, phenolic components, and antioxidant activity were elucidated during the development of the main plum cultivars in Sichuan, particularly the changes that provided a theoretical basis for the development of bioactive substances in local plum cultivars.

Automated summary

Plums have high levels of phenolic compounds and strong antioxidant activity. This study investigated the changes in appearance, internal quality, phenolic compounds, and antioxidant activities during fruit development of two main plum cultivars in Sichuan. The results showed that soluble solid and sugar contents were highest at maturity. Phenolic contents decreased as the fruits matured, while anthocyanin content increased in one of the cultivars. The peel had higher phenol, phenolic components, and antioxidant capacity than the pulp. Certain genes were found to be associated with the accumulation of phenolic substances. The study provides a theoretical basis for the development of bioactive substances in local plum cultivars.