Effect Of Harvesting Stage On Storage Property Of Orah Mandarin In Guangxi

Guangxi is the largest citrus-producing area in China,with the largest area and yield all over China.However,the large proportion of late-ripening citrus make it a significant challenge when they were all for sale.The Orah mandarin(Citrus reticulata Blanco ‘Orah’)is a primary late-ripening citrus variety in Guangxi.Inadequate fresh-keeping technology and imperfect storage equipment have become the key problems that restrict the quality of citrus industry in Guangxi.This study used Guangxi Orah mandarin as the experimental material to systematically explore the changes in fruit quality during different harvest stages under low temperatures.This study aimed to clarify the how different harvest stage affected the storage time of citrus under cold conditions,optimize the key parameters of citrus storage,construct the whole cold chain technology system,extend the storage stage of Guangxi Orah mandarin,and improve the economic benefits of fruit farmers.The main findings were as follows:1.The suitable harvest stage for low-temperature storage of Orah mandarin in Guilin was late January to late February,which in Nanning was mid-January to midFebruary.The experiment set seven harvest stages(Harvesting stages I-VII were November 25,December 14,January 4,January 24,February 28,March 15,and April 8,respectively)in Guilin and six harvest stages(Harvesting stages I-VI were December 2,December 22,January 14,February 16,March 11,and March 31,respectively)in Nanning.In both Guilin and Nanning,the color index(CI)and soluble solids(TSS)of fruits harvested before January remained low level during storage.The fruits harvested on January 24 and February 28 in Guilin and January 14 and February 16 in Nanning showed low decay rate,best color performance,and different degrees of TSS and sugar content during storage.The fruits harvested on March 15 and April 8 in Guilin and March 11 and March 31 in Nanning showed a significant improvement in sugar-acid flavor quality,but the content of ascorbic acid(ASA)was low,and the fruit decay rate,ethanol,and acetaldehyde contents increased during storage.In Guilin,after 140 days of storage of fruits harvested on January 4,January24,February 28,March 15,and April 8,the ethanol contents were 381.79 mg/L,311 mg/L,1,703.04 mg/L,and 1,301.14 mg/L,respectively.In Nanning,after 140 days of storage of fruits harvested on January 14,February 16,March 11,and March 31,the decay rates were0%,1%,7%,and 9.33%,respectively.Overall,Orah mandarin harvested from late January to late February in Guilin and from mid-January to mid-February in Nanning could maintain better color,accumulate fewer off-flavored substances,and decay more slowly during low-temperature storage.2.The Orah mandarin at 6-8℃ was better than stored at 2-4℃.In the case of Orah mandarin from Guilin and Nanning,cold damage occurred in stored fruits at 2-4℃,and decay rates,ethanol,and acetaldehyde content increased.Storage at 6-8℃ can promote the color change of the fruit,maintain fruit quality with a decay rate of less than 3%,and alleviate the accumulation of off-flavored substances such as ethanol and acetaldehyde.This temperature range was considered suitable for storage.When stored at 6-8℃,Orah mandarin harvested in Guilin before early January,late January,late February,mid-March,and early April can be stored until early July,early July,late July,early August,and late August,respectively.Orah mandarin harvested in Nanning before January,mid-January,mid-February,mid-March,and late March can be stored until early June,mid-May,midJune,late June,and early July,respectively.3.The quality of Orah mandarin fruit with a shelf life was better stored at 6-8℃ as compared to 2-4℃.To compare the quality of Orah mandarin fruit stored at 6-8℃ and 2-4℃,which were harvested during the same stage,a 7-day shelf-life analysis was conducted.The results showed that storing the fruit at 6-8℃ slowed down the accumulation of offflavor substances such as ethanol and acetaldehyde during the shelf-life stage.Furthermore,suitable storage temperature nodes were identified for each harvesting stage,indicating that Orah mandarin harvested before early January,late January,and late February can be stored for up to 100 d,80 d,and 60 d respectively in Guilin.On the other hand,the whole cold chain is recommended for Orah mandarin harvested after mid-March.In Nanning,Orah mandarin harvested before early January and mid-February can be stored for up to 80 d and40 d respectively,whereas the whole cold chain is recommended for Orah mandarin harvested after March.In summary,the suitable harvest stage for low-temperature storage of Orah mandarin in Guilin was late January to late February,which in Nanning was mid-January to midFebruary.The storage effect of Orah mandarin in an environment of 6-8℃ was better than that of 2-4℃.Additionally,the shelf-life quality of Orah mandarin fruit stored at 6-8℃ was better than that stored at 2-4℃.This study provides a reference and theoretical basis for post-harvest production of Orah mandarin in Guangxi and helps the citrus industry in Guangxi to develop high-quality products.