Insights into the potential quality markers of Rubus chingii Hu fruit at different growth stages

Rubus chingii Hu fruit (RHF) is a medicinal and edible resource with excellent biological activities. Currently, the existing identification markers can't meet the needs of RHF quality control. This study collected RHF from cultivation fields of three origins [Qiandaohu (QDH), Lishui (LS), and Fuyang (YF)] at green, green to yellow, yellow to orange, and mature stages (G, G to Y, Y to O, M). The physicochemical information of RHF was examined. Water migration and characteristic volatile compounds of RHF at growth stages from different origins were investigated by low field-nuclear magnetic resonance (LF-NMR) technology and gas chromatography-ion mobility spectrometry (GC-IMS) technology. It showed that samples from QDH possessed the highest antioxidant activity at the first three growth stages (e.g.

, dpph: 0.062 ± 0.000, 0.059 ± 0.004 and 0.037 ± 0.002 mmol Trolox/100 g), while FY had the highest at the mature stage (e.g.

, dpph: 0.026 ± 0.001 mmol Trolox/100 g). The total carbohydrates content ranged from 15 % to 43 %. Besides, in the first two stages, the total acidity value was lower (e.g.

, qdh: 2.69 ± 0.04 and 2.45 ± 0.04 in g citric acid/L). Furthermore, three origins had the same water migration rule, and finally, 10 compounds, including 5 from the G growth stage, 4 from the G to Y growth stage, and 1 from the Y to O growth stage, were highly correlated with antioxidant activity and can significantly indicate RHF quality from different origins, so they can potentially serve as Q-markers for RHF. Identifying Q-markers provides a research direction for the quality control of RHF, promoting the development of the RHF industry.