| The major cultivars of sweet cherry (Prunus avium L.) in China,such as the early-mature cv. 'Hongdeng',the middle-mature cv. 'Satohnishiki' and the late-mature cv. "Napoleon1,'Lapins' and 'Summit',were studied their postharvest physiological properties,quality and storability during storage periods,in order to determine the suitable concentrations of O2 and CO2 in controlled atmosphere and storage time for the fruit. In the experiment,peroxidase (POD),polyphenol oxidase (PPO),superoxide dismutase (SOD) and malondialdehyde (MDA) content of sweet cherries were analyzed during different storage conditions,and the relationship between them and senescence,browning and storability of sweet cherries were revealed. The ethanol content,color,firmness,soluble solids content,acid,vitamin C of the fruit stored in different CA conditions were measured in all storage periods. Meanwhile,the structure of peel tissue in different cultivars was examined,as well as physiological response of sweet cherry fruits with different maturity to controlled atmospheres and the changes in their quality attributes were also evaluated in storage. The results will be beneficial to provide integrative technologies for commercial storage of sweet cherries.This experiments included following contents:(1) Effect of CA with different CO2 concentrations on postharvest physiological properties and quality attributes of sweet cherries. (2) Effects of CA with high O2 or with CO2 concentrations onbrowning,senescence and quality attributes of sweet cherry. (3) Changes of postharvest physiology,quality and storability of sweet cherry in the comparative experiment of dynamic controlled atmospheres (DCA) and static controlled atmospheres (SCA). (4) Effects of different mature stages and cultivars on the storability of sweet cherry. (5) Effects of different fungicides and packing treatments on storability and quality of sweet cherry. The results showed as following:1. CA with high-CO2 concentrations was beneficial for sweet cherry storage. CA (5% O2 + 5% CO2 or 5% O2+ 10% CO2) could delay fruit senescence,reduce fruit decay and browning,maintain quality and prolong storage period as long as 1.5-2 times in comparison with MAP. Especially the latter was the optimal condition for sweet cherry storage,in which early-mature "Hongdeng" can be kept for 60 days,and middle- or late-mature cultivars,such as 'Satohnishiki','Napoleon','Lapins' and 'Summit',for 80-100 days with shift time of 2-3 days at 25 C,or more than 6 days at 3-5C,respectively.2. CA with high-O2 concentration was harmful to sweet cherry. CA with 70% O2 + 0% CO2 caused some O2 toxicity in sweet cherry. High concentration of oxygen stimulated the accumulation of MDA and aggravated fruit browning even though this level obviously controlled fruit rot and reduced the content of ethanol in pulp during the early storage periods.3. DCA was more adaptable for sweet cherries. Comparative experiment of DCA and SCA indicated that DCA storage,namely,high CO2 concentration (20%) was adapted during the early period of storage,effectively maintained Vitamin C content,obviously inhibited the accumulation of MDA and significantly reduced fruit browning and rot.4. Sweet cherry fruits with high-maturity were better for CA storage. Fruit with high-maturity (dark red color for cv "Hongdeng") was more optimal for CA storage than that with lower-maturity (red color for cv "Hongdeng").5. Structure of peel tissue of sweet cherry was related to its storability. Fruit,having a good storability,usually showed small and compact cells in epidermis tissue.6. In combination MAP with bio-fungicide was beneficial for storing sweet cherries. Bio-fungicide No.l in combination with thiabendazole (TBZ) polyethylene film showed to be better result for controlling decay,inhibiting the production of ethanol and ethylene,maintaining quality attribute and prolonging storage life in comparison with other fungicide and package treatments.7. MDA was a major factor influencing fruit browning. The result of thi... |
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