【作者】 胡亮；

【导师】 王则金；

【作者基本信息】 福建农林大学 ， 农产品加工及贮藏工程， 2008， 硕士

【摘要】 番木瓜（Carica papaya L.）营养丰富,对温度敏感,在低温环境下容易发生冷害,在较高温度下贮藏会快速后熟软化,难以达到贮藏保鲜和长途运输的目的。为此,本文以台湾主栽品种“台农二号”为试材,建立不同成熟度与番木瓜果实色泽、硬度和糖酸比等指标间的数学模型;并通过不同前处理条件、不同贮藏温度、不同成熟度等因素与番木瓜各冷害指标间的相关性分析,揭示出番木瓜果实冷害和抗冷性的一些机制。研究结果如下:1.番木瓜成熟度与相关理化指标间的数学模型以色泽、硬度及总糖和总酸质量分数为指标,考察了番木瓜不同成熟度与指标间的关系。结果显示,随着番木瓜成熟度的提高,L值减小,a、b值逐渐增大,并且成熟度与L、a、b间存在着一定的线性关系;同时,总糖随着成熟度的增加而增加,而总酸却随之减少,糖酸比也因此而急剧增加;另外,成熟度和硬度之间的关系为y=1991.7403x^-3.0754。2.贮藏温度与番木瓜品质和冷害间的关系以七成熟番木瓜为试材,选用（6±0.5）℃、（94±0.5）℃、（12±0.5）℃、（15±0.5）℃、（18±0.5）℃、（21±0.5）℃、（24±0.5）℃不同温度贮藏,考察贮藏温度与番木瓜品质和冷害的关系。结果表明,当贮藏温度低于12℃时,冷害指数会迅速增加;而当贮藏温度高于15℃后,在贮藏后期,番木瓜的外观品质指数也呈下降趋势,因此,可认为12℃左右为番木瓜果实冷害发生临界温度,当贮藏于12℃时,贮藏至第10d出现轻微冷害。3.成熟度与番木瓜品质和冷害间的关系以冷害临界温度12℃为贮藏条件,选用六成熟、七成熟、八成熟和九成熟的番木瓜,考察成熟度与番木瓜品质和冷害的关系。结果表明,成熟度和番木瓜冷害有着密切的关系,成熟度越高,越不易冷害,低成熟度的番木瓜体内保护酶活性较低,抗冷性较差,在冷藏过程中容易遭受冷害。4.冷激处理对番木瓜耐贮性及诱导其抗冷性的影响以未经冷激处理的为对照,采用两种冷激处理方式,定期调查果皮外观品质指数和冷害指数的情况,筛选出最佳冷激处理条件,以此条件考察冷激处理后的番木瓜在12℃下的生理变化,探讨冷激处理对番木瓜果实耐贮性和抗冷性的影响。试验结果表明,冷空气处理3.5h组为最佳番木瓜冷激处理条件,冷激处理可有效地降低番木瓜的呼吸强度,但对呼吸峰值出现的时间却影响不大;同时,冷激对番木瓜的硬度下降有着明显的抑制作用;另外,冷激处理能提高CAT的活性,延缓SOD和AsA-POD活力的降低,因此,冷激处理能够在一定程度上减轻冷藏中冷害的发生。5.热处理对番木瓜耐贮性及诱导其抗冷性的影响在番木瓜冷藏和后熟前选用不同的热处理方式和处理时间,考察热处理对番木瓜果实耐贮性和抗冷性的影响。结果表明,热处理的番木瓜果肉CAT、SOD、AsA-POD活性在冷藏期间均明显高于对照;热处理不但可提高果实的抗冷性,而且也提高了抗病性,减少了腐烂的发生率。6.番木瓜冷害和抗冷性的综合试验选取均匀设计表U₁₂（4³×3）,以热空气处理时间、贮藏温度、贮藏时间和成熟度为因素,探讨它们对番木瓜贮藏期间的冷害和抗冷性的影响,并确定各因素对番木瓜冷害发生的主次作用。结果显示,成熟度是影响外观品质指数的主要因素,而贮藏温度却决定着冷害指数的高低;对番木瓜果肉CAT和POD活性影响的主要因素是贮藏温度,且均随贮藏温度的上升而活性呈上升趋势;热处理可以有效诱导SOD活性的增加。更多还原

【Abstract】 Papaya fruit（Carica papaya L.）is rich in nutrition,which is sensitive to the temperature.Papaya is prone to chilling injury in low temperature environment and rapid ripening and softening under higher temperature storage,so it is difficult to keep fresh and long-distant transport.In this article,a major Taiwan papaya cultivar "Taiwan farmerⅡ" was used to establish the mathematical models of color,firmness and sugar-acid ratio with different maturity,revealing some mechanisms of papaya chilling injury and chilling tolerance through the correlation analysis between different pre-treatment conditions,different storage temperatures,with different factors such as maturity and the indicators of papaya chilling injury.The details are specified as follows:1.Using color,firmness,total sugar and total acid of papaya fruits as reference indicators,the relationship between maturities and indicators were studied.The results show that with the increase of papaya maturity,L value reduced,and a,b value increased gradually,and there exists a certain linear relationship between maturity and the value of L,a,b.At the same time,total sugar accumulates with the maturity increasing,but the acid were reduced thus sugar-acid ratio increases dramatically.In addition,the relationship between maturity and firmness is y=1991.7403x^-3.0754.2.Storing 70%ripening papayas at（6±0.5）℃,（9±0.5）℃,（12±0.5）℃, （15±0.5）℃,（18±0.5）℃,（21±0.5）℃and（24±0.5）℃separately,the effects of storage temperature on papaya quality and chilling injury were studied.Results indicated that chilling injury index rapidly increased when the temperature was below 12℃,but appearance quality index showed a decreased trend during anaphase storage when the temperature was higher than 15℃.Therefore,the critical temperature of papaya chilling injury is 12℃.3.Storing 70%ripening,80%ripening and 90%ripening papaya fruits at 12℃, effects of different maturities on papaya quality and chilling injury were studied.It was found that there was close relationship between maturity and papaya chilling injury.Chilling injury has less influence on papaya qualities at higher maturity.The activities of antioxidant enzymes in low maturity papaya fruits were low and poorly resistant to cold.Therefore,low maturity papaya fruits were prone to chilling injury during lower temperature storage.4.Comparing with the control group without cold shocking,pre-treating by two kinds of cold shock,the optimal cold shock was selected by observing the quality index of papaya pericarp and chilling injury index regularly.Physiological changes of papaya during storing at（12±0.5）℃after cold shocking treatment were studied. Effects of cold shock on papaya quality and chilling resistance were also examined. The results showed that the treatment of 0℃cold air for 3.5h was the best for papaya fruits,which decreased the respiration rate of papaya effectively,but had little impact on the peak respiration time.Meanwhile,cold shock not only inhibited the decline of firmness,delayed the decline of SOD and AsA-POD,but also enhanced the activity of CAT.To certain degree,cold shock can reduce the occurrence of chilling injury of papaya during cold storage.5.Using different heat treatment and different processing times before cold storage and post-ripening,effects of heat treatment on storage property and chilling resistance of papaya fruits were studied.Results explained that the activities of CAT, SOD,AsA-POD during cold storage after heat treatment were higher than the control group.Heat treatment improved chilling resistance of papaya fruits and the resistance of diseases,however,reduced the incidence of decay.6.The combined trails between hot-air treating time,storage temperature, storage time and maturity on papaya chilling injury and chilling resistance were studied by U₁₂（4³×3）uniform design experiment.The primary-secondary roles of factors on papaya chilling injury were obtained.The result showed that maturity was the most significant effect on papaya appearance quality index,but chilling injury index and activities of CAT,POD were determined by storage temperature, meanwhile,the activity of SOD increased by heat treatment.Activities of CAT and POD increased with the rise of storage temperature.更多还原