Analysis of nutrient composition and antioxidant characteristics in the tender shoots of Chinese toon picked under different conditions

Abstract Chinese toon is a woody plant whose shoots are a seasonal vegetable, and the nutritional and sensory quality of Chinese toon products could be greatly impacted by picking conditions. To address this problem, a rational picking strategy of Chinese toon was established by the comparison analysis of different picking conditions. The results indicated that the contents of total protein, total amino acids and essential amino acids was higher at earlier picking times and shorter lengths. The highest contents of K, Ca, Mg and highest K/Na ratio were found in group I-A, while the lowest contents of Na and the highest contents of Fe were observed in group II-A and III-A, respectively. Obvious rising tendencies of the crude fat and fiber content were observed with the prolonging of the picking time and shoot lengths. Moreover, the content of total phenols showed a stronger correlation with antioxidant activity than total flavonoids at each picking condition. Specifically, gallic acid and methyl gallate might play the key role in the high antioxidant activity of Chinese toon shoots at each picking condition. Taken together, these findings provide a guidance for the harvesting and deep processing of Chinese toon.