| Oriental sweet melon (Cucumis melo var.makuwa Makino), also known as the Chinese melon, oriental melon or cantaloupe, is a class of very important resource of melon varieties, occupies an important position, especially in the areas of Heilongjiang Province. Melon mainly local, and there is a certain distance with the developed countries. In order to better develop and utilize this resource, researchers need to better understand melon physiological changes at different times.This experiment used Hatian No.2 fruit,Yongtian No.3 fruit,and Baiyi No.4 fruit three varieties of oriental sweet melon as the research object,and discussed the fruit respiration rate, hardness, the contents of soluble sugar,soluble solids,vitamin C,titratable acid and aroma components, a series of dynamic changes of physiological characteristics during post-harvest storage process(divided into normal temperature storage and 8℃storage ). Strived to validate and perfect the oriental sweet melon's postharvest physiology theory, to provide the theory basis and the technical support for oriental sweet melon variety breeding and storage processing.The results are as follows:1)The physiological characteristics of the three varieties of oriental sweet melon during postharvest storage are consistent. The respiration rate of oriental sweet melon with storage time gradually decreases, and the respiration rate of the fruits storaged under 8℃conditions maintained at a lower level than the fruits stored under normal temperature conditions.The hardness of oriental sweet melon with the fruit riping and continuous decrease, and the fruits stored under normal temperature conditions occurred significant softening.The vitamin C content of oriental sweet melon has decreasing trend during the fruit storaged period. The soluble solids content, soluble sugar content and titratable acid content during storage of oriental sweet melon tended to increase first, with the extension of the fruit storage time decreased gradually.And low temperature storage may be appropriate to reduce the consumption rate of substances of oriental sweet melon. Comparison the storage properties of oriental sweet melon, medium maturing variety Yongtian No.3 fruit is more appropriate to storage.2)Oriental sweet melon fruits which storaged in the conditions of 8℃can delay ripening about 3-7d and the comprehensive indicators are better than the melon fruits storged in room temperature .Low temperature is conducive to maintaining fruits quality and prolong shelf life of fruit.3)This experiment used SPME and GC-MS technique to determine the volatile aroma compounds of the three varieties of oriental sweet melon. Volatile substances are esters, aldehydes, alcohols, ketones and acids, alkenes, phenols, ethers and other substances.Different varieties of melon has its specific volatile substances, but are different at types and quantites of appeal substances.With the extension of storage time, the number of species of aldehydes and alcohols were decreased ,and the number of species of esters increased at first and then decreased.The fruits storaged in the conditions of 8℃can maintain flavor better than others.4)This experiment found that esters are the main component of the volatile aroma of oriental sweet melon .Comparison of the three varieties of oriental sweet melon. There are 9 kinds of esters which achieve the total material content of 60% or more. The 9 kinds of esters are Methyl acetate; Ethyl Acetate; Acetic acid, isobutyl ester;Acetic acid, butyl ester;2-Methyl-1-butyl acetate;Acetic acid, Hexyl ester; 2,3-Butanedioldiacetate;Acetic acid, phenylmethyl ester and Diisobutyl phthalate. Therefore, they have a greater contribution to the aroma of melon fruits. The changes of relative content of Ethyl Acetate and 2,3-Butanediol Diacetate are significant. The relative content of Ethyl Acetate during the fruit ripening period to reach the largest, but decrease with senescence. The relative content of 2,3-Butanedioldiacetate is proportion to the melon fruits senescence. |
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