Abstract:【Objective】In this study, the suitable harvest time and storage temperature of W. Murcott was cleared, so as to extend the market supply time and relieve the pressure of sales, and provide reference for the collection and storage period of W. Murcott fruits in Guangxi.【Method】Testing W.Murcott fruits were picked at 4 harvest dates (November 29th, December 22nd, January 19th and March1st) and stored at 3 temperatures (2~4℃,6~8℃and room temperature).The changes of weight loss, color, soluble solid, titratable acid, Vc, reducing sugar, citric acid, methanol, ethanol and acetaldehyde of the fruits during storage and simulated shelf life were analyzed.【Results】During storage, L * , A * , B * of W. Murcott fruits tended to level off after rapid rise. L * , A * , B * of fruits stored at 6~8℃ were the highest, followed by those stored at room temperature, and those stored at 2~4℃ were the lowest.On the 60th day of storage, the A * values of the fruits stored at 2~4℃、6~8℃and room temperature were 12.94, 26.51 and 21.46, respectively, low temperature storage can significantly reduce the rate of weight loss and delay the decrease rate of titratable acid and Vc content, and the longer the storage time, the lower the temperature, the more significant the effect was.On the 90th day of storage, the weight loss rate of fruits stored at 2~4℃, 6~8℃ and room temperature were 1.73%, 2.12% and 3.37%, respectively. The content of titratable acid was 0.95% , 0.78% and 0.63% , respectively, the contents of Vc were 16.00, 15.13 and 12.64 mg·100mL-1, respectively. The contents of reducing sugar increased first and then decreased, and the contents of reducing sugar in fruits stored at low temperature were higher than those stored at room temperature.The contents of ethanol and acetaldehyde rose in fluctuation, with the highest at 2~4℃, the second at 6~8℃, and the lowest at room temperature.The contents of ethanol and acetaldehyde were lower at the first 60 days stored at 2~4℃ and 6~8℃ and significantly higher at 2~4℃ than at 6~8℃ after 75 days at storage. L*, A* and B* of W. Murcott fruits gradually increased and reached the peak in phaseⅢ with the delay of harvest date. During 6~8℃ storage, L * and a * increased continuously and then tended to level off, PhaseⅢ, Phase Ⅳ> PhaseⅡ>PhaseⅠ, and the difference was significant. The value of B * increased first and then decreased, and the later the harvest, the earlier the peak value of B * appeared. The rate of weight loss was the fastest in phaseⅣ and the slowest in phaseⅢ.The content of soluble solid increased with the delay of harvest, and was significantly higher in phaseⅢ and phaseⅣ than that in phaseⅠ.The content of titratable acid and Vc decreased with the delay of harvest, with the highest in phaseⅠand the lowest in phaseⅣ.The content of reducing sugar first increased and then decreased with the delay of harvest, and was significantly higher in phaseⅡ and phaseⅢ than that in phaseⅠand phaseⅣ during storage.The content of citric acid decreased with the delay of harvest and fluctuated during storage,and the lowest content was in phaseⅣof 6~8℃ storage .The contents of ethanol and acetaldehyde increased with the delay of harvest time. During the storage of 6~8℃, the rising rate of ethanol and acetaldehyde contents in four phases was as follows: phaseⅠ< phaseⅡ,phaseⅢ< phaseⅣ. At the 60th day of storage, the ethanol contents of fruits in phaseⅠ, phaseⅡ,phaseⅢ, phaseⅣwere 285.61, 894.79, 654.68 and 1311.58 mg·L-1, respectively. The contents of ethanol, acetaldehyde and methanol were significantly higher in the shelf-life than those in storage period.The ethanol content exceeded the threshold of 1500 mg·L-1 after stored 120 days in phaseⅠand turned to room temperature store, and exceeded the threshold in phaseⅡ, phaseⅢ and phaseⅣ after 60 or 75 days of storage.【Conclusion】 Compared with room temperature storage, low temperature storage could reduce the weight loss rate significantly and delay the decreasing rate of titratable acid and Vc content,increase the soluble sugar content of W. Murcott fruits.Compared with 6~8 ℃and2~4 ℃storage, 6~8 ℃storage is more suitable for low temperature storage because of better color change , lower rate of ethanol and acetaldehyde production and no freeze injury of stored fruits. When the green color of the fruit basically fades, the soluble solids reach 11%, and the titratable acid is greater than 0.8% (about late December to late January of the following year in Guilin area), it is the suitable harvest period for storing W. Murcott. 6~8 ℃is a suitable low temperature for storage The fruits of W. Murcott should not be stored for more than 90 d at 6~8 ℃and should not be out of storage at room temperature after 60 days stored at low temperature.
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