Study On Physiological And Biochemical Characteristics Of Thompson Seedless Raisin In The Different Storage Environments

Xinjiang is the main producing areas of Thompson Seedless raisins in China, but the quality decreased and economic benefit reduced due to the improper Storage way of Thompson seedless raisin in the long-term storage process.In this paper, Thompson Seedless raisin from Turpan was taken as experimental material(moisture content is about 12%), the effects of different gas components on the storage quality were studied.It explored the change trend of physiology, color,function components and aroma components under different storage conditions through the test and analysis of physiological index and quality index. Then selected good storage conditions under the experimental conditions to provide a theoretical basis for improving the level of science and technology for Thompson Seedless raisin.The main results are as follows:1. Study on the physiological changes of Thompson Seedless raisinThe results showed that ethylene release and respiration activity of Thompson Seedless raisin were still exist.The end of storage, physiological metabolic activity reduced in the low temperature treatment(5?) compared with the normal treatment, in which the ethylene release and respiration were 0.021 ?L/(kg�h) and 0.528 mg CO2/(kg�h), respectively. Moisture content, vitamin C(VC),sugar, acids and other substances consumption reduced as well.The amount of ethylene release of Thompson seedless raisin decreased, appearance of respiratory peak lagged and the peak value was lower; vitamin C content, total sugar content decreased slowly, storage time prolonged under the conditions with Nitric oxide(NO) treatment.2. Study on changes of color for Thompson Seedless raisinThe results showed that the green gradually subsided, the effect of green maintaining followed by low temperature(5?), nitric oxide(NO), room temperature(CK) treatment as the time extended during storage of Thompson seedless raisin.Polyphenol Oxidase(PPO) and ascorbate peroxidase(AAO) were detected in the Thompson Seedless raisin, other related enzymes not detected due to the activities of enzymes were weak.Degradation rate of chlorophyll was mitigated in the conditions with low temperature(5?) the chlorophyll content was 0.120mg/g, at the end of storage.3. Study on changes of functional components for Thompson Seedless raisinThe results showed that flavonoids, tannin, proanthocyanidins and resveratrol content of Thompson seedless raisin decreased during storage, the content of functional ingredients declined more slowly before the 180 th day, decreased rapidly after 180 th day. Differences reflected between different treatments after the 180 th day.Low temperature(5 ?) processing could better maintain the functional components of Thompson seedless raisin, because that the content of functional components reduced slower, although decreased in the storage period.4. Study on changes of aroma components for Thompson Seedless raisinThe test results showed that the main aroma components of Thompson Seedless raisin were esters, acids, alcohols, aldehydes and ketones;The proportion of aroma components from high to low were: aldehydes, esters, alcohols, acids, ketones before storage; The proportion of aroma components from high to low were: alcohols, acids, esters, ketones, aldehydes after 360 days.Storage for 360 days, 26 and 30 kinds of aroma components were detected respectively in Thompson Seedless raisin under the conditions with nitric oxide(NO) treatment and low temperature(5 ?) treatment, and aroma components were maintained by the way of low temperature(5?) treatment.There were 9 mutual aroma components in the comparison of aroma components bet ween before and after the storage, what's more, the relative contents were relatively high.Changes were larger in aldehydes, esters and ketones, aldehydes: reduced from 12 to 3 ki nds, a mutual component was hexanal; esters: increased from 10 to 11, mutual component s were ethyl acetate, gamma-Butyrolactone, ethyl hexanoate, Palmitic acid ethyl ester; keto ne:reduced from 6 to 4,mutual compositions were 3-Hydroxy-2-butanone,As-Indacen-1(2H)-o ne, 3,6,7,8-tetrahydro-3,3,6,6-tetramethyl-.