| ’Dongbi’ longan and ’Fuyan’ longan were used as test materials to study their physiologicy of longan maturation in this paper.Changes in mature characteristics, related metabolism such as active oxygen metabolism and cell wall metabolism as wll as the basic characteristics of lignification after postharvest were studied. The theroies of longan maturation are discussed in this paper. The results of the research can be applied in making sure the best harvest time for longan and postponement of longan lignification to provide theoretical support. Main results are as follows:1.’Dongbi’ and ’Fuyan’ longan fruit changes both internal and external quality during maturation. With the maturity continuously improved,longan fruit increased gradually, by nearly round fruit to oblong fruit, fruit quality and pulp qudlity increased,and the color of peel gradually turned to brown,meanwhile,the thickness of pulp becomes thicker.The correlation analysis showed that the fruit quality, shape index, peel thickness, pulp edible ratio and pulp TSS, total sugar, sucrose, vitamin C contents, TSS/TA ratio and sugar/TA ratio were significant positive correlation or very significant positive correlation, therefore may use above index as the parameters of the longan pulp maturity.2. During longan maturation, chlorophyll content declined. The correlation analysis showed that change in color was mainly due to the decrease of chlorophyll and the color of carotenoid begane to come out.3.’Dongbi’pulp contented more superoxide than ’Fuyan’ during maturation, and its MDA content showed obviously higher than that of ’Fuyan’ during later maturation period. Superoxide produce rate increases in former period, inducing APX and CAT activity enhanced. Internal antioxidant material content (sunch as ascorbic acid and reduced glutathione) incresd before reactive oxygen species growth.4. As fruit matured,, original pectin content decrease and water-soluble pectin content increased, cellulose and hemicellulose content were reduced, and the cell wall material content that does not change significantly during cell longan mature.Changes of various components of the pulp were different. May be became other products.5. With the fruit mature gradually, total phenols content of ’Dongi’ and ’Fuyan’ longan pulp showed up then declined, lignin content showed a rising trend, which was closely related to with phenolic lignin synthesis.Longan phenols took a part in lignin synthesis, resulting in phenols compounds decreased while content of lignin rised. The correlation coefficient of ’Fuyan’ and ’Dongbi’ longan pulp total phenols to lignin content respectively were0.78**and0.08, stated that phenols of Fuyan fruits major involved in lignin synthesis, and phenolic substances of Dongbi longan pulp may be involved in other substances synthesis in addition to participate in the of lignin synthesis. Longan pulp CAD activity had no significant correlation to total phenols content, lignin content and the fiber content, thus CAD may not afford main role in longan pulp lignification process. Fuyan flesh POD activity had a very significant positive correlation with lignin content,and was tending to a significant negative correlation with fiber content and hemicellulose content, showed that in Fuyan longan pulp POD activity and lignin synthesis exist high correlation, and POD activity of Dongbi had no significant correlation with the index all above, in addition to POD participated in lignin synthesis in Dongbi pulp,other enzymes involved.6.The reducing sugar content in ’Dongbi’ and ’Fuyan’ longan pulp had a very significant positive correlation with lignin, which showed that the accumulation of all kinds of sugar accumulated material base for late rapid growth of lignin, and there existed transform relationship. |
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