Changes in tannins, ascorbic acid and sugar content in astringent persimmons during on-tree growth and ripening and in response to different postharvest treatments

• Published in: Journal of food composition and analysis Vol. 22; no. 7; pp. 668 - 677
• Main Authors: Del Bubba, M., Giordani, E., Pippucci, L., Cincinelli, A., Checchini, L., Galvan, P.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.11.2009
• Subjects: antioxidant activity; antioxidants; Antiradical activity; ascorbic acid; Diospyros kaki; Diospyros spp; Food analysis; Food composition; free radical scavengers; fructose; fruit composition; fruit extracts; fruits (food); glucose; mature plants; Maturity stage; Persimmon; persimmons; physicochemical properties; Postharvest treatment; sugar content; Sugars; Tannins; Vitamin C; Diospyros spp; Tannins; Persimmon; Vitamin C; Maturity stage; Food composition; Antiradical activity; Food analysis; Postharvest treatment; Sugars
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2009.02.015

Changes in tannins, ascorbic acid and sugars in astringent persimmons ‘Rojo Brillante’ and ‘Kaki Tipo’ were investigated during fruit maturation and after postharvest treatments. Soluble tannins exhibited a significant initial increment, followed by a marked constant decrease that led to values between 0.2 and 0.3 g/100 g fresh weight (FW) in the last stage of maturity studied. During the entire period monitored, insoluble tannins represented the minor component of the total tannic fraction, accounting for 9–27% (Rojo Brillante) and 17–32% (Kaki Tipo) of total tannins; levels of insoluble tannins were comparable to or higher than the soluble tannins in softer fruits. Total vitamin C decreased from 0.18–0.20 to about 0.08 g/100 g FW during fruit development owing to fruit growth rather than to degradation processes. Total sugars increased from about 4 g/100 g FW at the early stage of fruit development to 17 g/100 g FW after reaching the commercial stage of maturity. Glucose and fructose increased during the entire period monitored, while sucrose reached a maximum and then gradually decreased, probably owing to a strong invertase activity. Antiradical activities were significantly related to the corresponding tannic fraction. In both ‘Rojo Brillante’ and ‘Kaki Tipo’, postharvest treatment with CO 2 was more effective than with ethylene in reducing soluble tannin concentration (0.031–0.067 and 0.220–0.262 g/100 g FW, respectively).