江津甜橙3 个变异品种的果实品质及酸组分分析

以江津甜橙的优选品种锦橙及其低酸变异品种长叶橙和高酸大果芽变品种大果锦橙为试材，测定果实膨大至成熟期的多项品质指标及其果汁中柠檬酸、奎宁酸和苹果酸含量的变化趋势。结果表明，在果实发育过程中，各品种果实大小于10月下旬基本定型，可溶性固形物含量逐渐增加、可滴定酸含量逐渐下降。在所测酸组分中，柠檬酸为主要有机酸；在果实发育过程中，柠檬酸含量逐渐降低，苹果酸含量呈相反的变化趋势，奎宁酸含量呈先下降后上升再下降的趋势，最大值出现在11月中旬。在果实成熟阶段，锦橙平均单果质量和柠檬酸含量介于长叶橙和大果锦橙之间，可溶性固形物含量为最高；长叶橙单果质量最小（155.27 g），可滴定酸含量最低（0.55%），其中柠檬酸组分含量为6.95 mg/g；大果锦橙则相反，单果质量达311.92 g，可滴定酸含量为1.02%，其中柠檬酸含量为11.72 mg/g。3 个品种总体上呈酸度越高，柠檬酸含量越高，奎宁酸含量越低的趋势。

Analysis of Fruit Quality and Acid Constituents of Three Bred Cultivars Selected from Jiangjin Sweet Orange

Three elite Jincheng varieties selected from Jiangjin sweet orange, including a low-acid (long-leaf), a normalacid
(Jincheng) and a high-acid (Daguo) cultivar, were used as materials to analyze the dynamic changes in fruit quality and
organic acids including citric acid, quinic acid and malic acid in their juice after the expanding phase. Results showed that the
size of fruit of three cultivars almost reached the maximum in late October and the total soluble solids (TSS) was gradually
increased with a decrease in titratable acid (TA). Of three organic acids, citric acid was the most dominant. During fruit
development, the content of citric acid gradually declined while malic acid showed the opposite trend; the content of quinic
acid was greatly fluctuated as it was increased in the earlier stage and then decreased, and finally reached the maximum in the
middle of November. At maturation, the fruit weight and the citric acid content of Jincheng were both in between ‘Long-leaf’
orange and ‘Daguo’ Jincheng orange, and its TSS content was highest. The fruit weight of Long-leaf was lowest (155.27 g),
and the same was true for the TA (0.55%) and the citric acid content (6.95 mg/g); on the contrary, the fruit weight (311.92 g),
TA (titratable acidity) (1.02%) and citric acid content (11.72 mg/g) of ‘Daguo’ Jincheng orange were highest among three
cultivars. These data showed a tendency that the higher TA was, the higher citric acid content and the lower quinic acid
content occurred.