无核君迁子果实发育成熟过程中生理指标变化规律

  目的  探讨无核君迁子Diospyros lotus果实发育成熟过程中生理指标的变化规律，为无核君迁子果实资源的进一步开发利用提供参考。  方法  以不同时期无核君迁子果实为材料，测定单宁、总酚、黄酮、花青素、糖和果胶组分以及果胶降解酶活性的变化规律，并分析其相关性。  结果  无核君迁子果实发育成熟过程中，可溶性单宁和花青素不断降低，不溶性单宁、淀粉、果糖、葡萄糖、糖酸比、水溶性果胶、离子结合果胶逐渐上升，总酚、黄酮、可滴定酸和共价结合果胶先升后降；多聚半乳糖醛酸酶和果胶裂解酶活性在果实软熟期显著上升(P＜0.05)。相关性分析表明:水溶性果胶、离子结合果胶与多聚半乳糖醛酸酶、果胶裂解酶活性呈极显著正相关(P＜0.01)，共价结合果胶与多聚半乳糖醛酸酶、果胶裂解酶活性呈显著负相关(P＜0.05)，淀粉、果糖、葡萄糖与水溶性果胶、离子结合果胶及多聚半乳糖醛酸酶、果胶裂解酶活性呈极显著正相关(P＜0.01)。  结论  无核君迁子果实发育成熟过程中，可溶性单宁逐渐下降至可食用阈值以下，多聚半乳糖醛酸酶和果胶裂解酶参与催化细胞壁果胶组分降解，进而引起无核君迁子果实果胶组分变化、可溶性糖升高以及活性成分变化。图4表2参29

Variation patterns of physiological indices of seedless Diospyros lotus during fruit development and ripening

  Objective  This study, with an investigation of the variation patterns of physiological indices of seedless Diospyros lotus during fruit development and ripening, is aimed to provide a theoretical basis for the further utilization of such resources.   Method  With fruits of seedless D. lotus of different stages collected, a survey was conducted of the variation patterns of tannin, total polyphenols and flavonoids, anthocyanins, sugar and pectin composition, as well as the activity of pectin degrading enzyme before an analysis was conducted of the correlation.   Result  During the fruit development and ripening there was a constant decrease in the contents of soluble tannin and anthocyanin and a gradual increase in the contents of insoluble tannin, starch, fructose, glucose, sugar-acid ratio, water soluble pectin and ironic soluble pectin whereas there was first an increase and then a decrease in the contents of total polyphenols, flavonoids, titratable acids and covalent soluble pectin content. There was a significant increase in the activities of polygalacturonase and pectate lyase at the later stage of fruit ripening (P＜ 0.05). There was a significant positive correlation between the contents of water soluble pectin and ironic soluble pectin and the activities of polygalacturonase and pectate lyase (P＜0.01), a significant negative correlation between the contents of covalent soluble pectin and the activities of polygalacturonase and pectate lyase (P＜ 0.05) and a significant positive correlation between the contents of starch, fructose and glucose and the contents of water soluble pectin, ironic soluble pectin as well as the activities of polygalacturonase and pectate lyase (P＜ 0.01).   Conclusion  During the development and ripening of seedless D. lotus, the content of soluble tannin gradually decreased to below the edibility threshold while polygalacturonase and pectate lyase enzymes were involved in the catalytic degradation of pectin components in the cell wall, which led to the change of pectin components, the increase of soluble sugar content and the change of active components in the fruit. Ch, 4 fig. 2 tab. 29 ref.]