ABSTRACT Identifying the appropriate harvesting stage of jujube fruit is of high interest since the changes in physiological indicators during the fruit maturation may influence the fruit nutritional quality. The present study aimed at assessing the effect of the maturation stages on the nutritional composition and quality of the Chinese jujube variety ‘Dongzao.’ Fresh fruits were harvested at three consecutive maturity stages: white (W), semi-red (SR), and full-red (R) stage, for analyzing a wide range of nutritional constituents. Our results showed significant effects of the maturity stage on the fruit nutritional constituents. Soluble sugars and dietary fibers (mainly lignin and hemicellulose) highly increased in the fruit. Total flavonoids, carotenoids, and saponin contributing to the antioxidant capacity of the fruit were fairly decreased over the maturity stages. Except for citric, ascorbic, and succinic acids, all the organic acids increased in the fruit. Interestingly, jujube fruit is a good source of essential amino acids (26% of the total amino acids), and also gradually accumulated cyclic nucleotides (cAMP and cGMP) during the maturation. From our results, the semi-red stage seems to be the most appropriate for harvesting the jujube fruit in order to preserve its bioactive compounds.

中文翻译：

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枣果实（Ziziphus jujuba Mill.）在成熟阶段营养成分的变化

摘要 由于枣果实成熟过程中生理指标的变化可能会影响果实的营养品质，因此确定合适的枣果实收获阶段具有重要意义。本研究旨在评估成熟阶段对大枣品种“冬枣”营养成分和品质的影响。在三个连续的成熟阶段收获新鲜水果：白色 (W)、半红色 (SR) 和全红色 (R) 阶段，用于分析广泛的营养成分。我们的结果表明成熟阶段对水果营养成分有显着影响。水果中的可溶性糖和膳食纤维（主要是木质素和半纤维素）大量增加。总黄酮、类胡萝卜素、在成熟阶段，有助于果实抗氧化能力的皂苷和皂苷均显着降低。除柠檬酸、抗坏血酸和琥珀酸外，果实中所有有机酸均增加。有趣的是，枣果实是必需氨基酸的良好来源（占总氨基酸的 26%），并且在成熟过程中逐渐积累了环核苷酸（cAMP 和 cGMP）。从我们的结果来看，半红阶段似乎最适合收获枣果实以保存其生物活性化合物。