Bioactive compounds and fruit quality of Chinese raspberry, Rubus chingii Hu varied with genotype and phenological phase

Abstract

The unripe fruit of Chinese raspberry, Rubus chingii Hu, is a traditional medicinal herb for benefiting kidney, antioxidant, liver care and anti-cancer, and the mature fruit is a prestigious “super food” due to higher nutrition. Thereby, deeply understanding the changes in medicinal component accumulation and fruit quality with genotypes and phenological phases could provide a scientific basis for R. chingii cultivation and fruit harvest. As yet, little information has been available on it. The effects of genotype on phenological phase, bioactive compounds, and fruit quality of R. chingii were first investigated by multivariate analyses in this study. The results showed that the fruit developmental period differed from 42 to 61 d among the 17 genotypes, with the double “S” curve. The contents of soluble solids content (SSC), titratable acidity (TA), Vitamin C (Vc), and total monomeric anthocyanins (TMA) varied from 13.42 %–15.80 %, 0.83 %–1.61 %, 36.02–67.59 mg/100 g Fw (fresh weight), and 12.7–58.6 mg/100 g Fw, respectively. Moreover, the accumulations of total terpenoids (TT), ellagic acid (EA) and kaempferol-3-O-rutinoside (K3R) in medicinal fruits at the green-to-yellow (GY) stage ranged from 2.29 %–4.97 %, 9.46–30.70 mg/100 g Fw and 1.09–5.43 mg/100 g Fw, respectively. Altogether, three promising groups with excellent fruit quality and health-promoting values were selected out using principal component analysis (PCA): 1) L1, L2, L8, L16, L18 and L19 were characterized by big fruits with higher firmness, contributing to the higher yields and handle resistance; 2) L7 tasted best with the highest ratio of soluble solids content and titratable acidity (SSC/TA) and soft receptacle, and L7 together with L4, L14 enriched total sugar (TS) and Kaempferol-3-O-rutinoside (K3R), presenting the optimum genotypes for edible fruit; 3) L3 (thornless), L6, L8 and L16 had higher values of soluble solids content (SSC), total monomeric anthocyanins (TMA), and ellagic acid (EA), indicating the predominant genotypes for medicinal materials. Our findings establish the fundamental data and provide diverse choices for R. chingii breeding and processing industry.