金丝小枣在生长成熟过程中理化特性的变化规律

本文研究了6个不同生长成熟期(S1~S6)金丝小枣果实的色泽、叶绿素、可溶性糖及其代谢酶活性、有机酸及氨基酸的动态变化,以明确其代谢规律。研究结果表明:枣果生长成熟过程中,叶绿素含量降低,枣果由绿变红;葡萄糖、果糖均逐步积累,而山梨醇含量逐渐降低,蔗糖则在生长发育初期未被检出,其积累主要发生在枣果成熟后期,且其含量最高,金丝小枣为蔗糖积累型果实,蔗糖磷酸合成酶是蔗糖积累的关键酶;金丝小枣为苹果酸型果实,苹果酸随枣果的成熟而积累,而柠檬酸含量先上升后降低;Pro和Asp在枣果成熟过程中被大量合成,是成熟枣果中最主要的两种氨基酸。全红枣的可溶性总糖、糖酸比以及游离氨基酸总量最高,可作为金丝小枣鲜食的最佳采收时期。

Changes in Physicochemical Properties of Jujube (Zizyphus jujuba) Fruit cv. Jinsixiaozao during Growth and Maturity Stages

The dynamic changes in color, chlorophylls, soluble sugars, metabolic activity, organic acids, and free amino acids in jujube fruit cv. jinsixiaozao during six different growth and maturity stages (S1~S6) were studied in order to understand fruit metabolism. The results indicated that as growth and maturity progressed, the chlorophyll content decreased and the fruit color changed from green into red in jujube fruit. The contents of fructose and glucose gradually increased, while the sorbitol content decreased gradually. Sucrose was not detected at early growth stages, but it accumulated at the late maturity stage and showed the highest content. Jujube fruit cv. jinsixiaozao is a sucrose accumulation-type fruit and sucrose phosphate synthase is the key enzyme for accumulating sucrose. Jujube fruit cv. jinsixiaozao is also a malic acid-type fruit, malic acid accumulated along with fruit maturation, and the citric acid content showed a declining trend after the initial increase. Asparagine and proline were synthesized in large amounts during fruit maturation, and are the two main amino acids in mature jujube fruits. The total soluble sugars, ratio of sugar to acid, and total free amino acids of jujube fruit at the S6 stage were the highest among all growth stages. So S6 can be considered as the suitable harvest stage for fresh edible jujube fruits cv. jinsixiaozao.