Changes in sugars and organic acids in wolfberry (Lycium barbarum L.) fruit during development and maturation

Wolfberry (Lycium barbarum L.) fruits of three cultivars (‘Damaye’, ‘Baihua’ and ‘Ningqi No.1’) were harvested at five different ripening stages and evaluated for sugars and organic acids. Fructose, glucose and total sugar contents increased continually through development and reached their maxima at 34 days after full bloom (DAF). Fructose and glucose were the predominant sugars at maturity, while sucrose content had reduced by maturity. L. barbarum polysaccharides (LBP) content was in the range of 13.03–76.86 mg g−1 FW during ripening, with a maximum at 20 DAF. Citric, tartaric and quinic acids were the main organic acid components during development, and their levels followed similar trends: the highest contents were at 30, 14 and 20 DAF, respectively. The significant correlations of fructose and total sugar contents with LBP content during fruit development indicated that they played a key role in LBP accumulation.