【作者】 林志强；

【导师】 潘东明；

【作者基本信息】 福建农林大学 ， 果树学， 2004， 硕士

【摘要】 本文以福眼龙眼果实为试验材料，经不同蓟剂处理，在不同温度条件下研究了其在采后贮藏过程中蛋白质组分以及自由基的代谢和脂肪酸含量、内源多胺含量的变化。同时探讨了它们之间的关系，以期进一步了解龙眼果实的采后生理。 1、在采后贮藏过程中，福眼果皮和果肉的蛋白质组分比较丰富，其中果肉含有26种可溶性蛋白质、32种总蛋白质；果皮含有34种可溶性蛋白质。在室温条件下，随着采后贮藏时间的延长，既有新蛋白质组分的出现，也有些蛋白质降解。在果肉的可溶性蛋白质组分中，采后第3d、第4d、第5d新出现了分子量为138.68KD的蛋白质，分子量为87.50KD的蛋白质在采后第5d开始降解消失；在果肉的总蛋白质组分中，采后第6d新出现了分子量分别为41.30KD和27.93KD的蛋白质，同时分子量为42.36KD的蛋白质含量增大；在果皮的可溶性蛋白质组分中，有14种蛋白质在采后逐渐降解(分子量分别为629.51KD、333.43KD、302.69KD、181.97KD、149.28KD、133.66KD、77.62KD、70.47KD、63.97KD、49.55KD、44.36KD、23.07KD、19.95KD、18.92KD)，5种蛋白质组分的含量在采后逐渐增大，其分子量分别为94.62KD、59.57KD、55.46KD、41.30KD。随着贮藏时间的延长，果实的蛋白质总体呈不断降解的趋势，并且主要集中表现在采后第4d和第5d，即果实开始出现大量腐烂前。果实的衰老腐烂，伴随着蛋白质的大量降解，且果皮的蛋白质降解时间先于果肉2d，其降解程度也大于果肉。从蛋白质水平上可以认为，龙眼果实的衰老腐败是从果皮开始的，这与龙眼果实贮藏保鲜实践的观察是一致的。因此，要解决龙眼果实的贮藏保鲜问题，关键在于保持果皮的正常生命代谢。 2、福眼果实中果肉的多胺含量明显高于果皮，采收当天的果肉中Put、Spd和Spm的总量为4.27μg／g·FW，而果皮的Put、Spd和Spm的总量仅为2.35μg／g·FW，前者是后者的1.82倍。在室溫条件下，随着贮藏时间的延长，果皮的内源多胺(Put、Spd、Spm)均呈不断下降的趋势，而果肉中只有Put含量不断下降，Spd和Spm含量变化不明显；在低温条件下，随着贮藏时间的延长，果皮的内源多胺在采后前期迅速下降，接着保持在较稳定水平，而果肉中只有Put含量跟果皮的变化趋势一致，Spd和Spm含量变化不明显。采后贮藏过程中，果皮的内源多胺变化趋势大于果肉，果皮的衰老腐烂亦早于果肉。伴随着采后果实的衰老变质，内源多胺总体呈不断降低的趋势。在果皮中，Put、Spd和Spm的含量差别较小；而在果肉中，Put是多胺的主要组分，其含量占3种多胺总量的89.0％。由此可见，果皮中的多胺含量低可能也是果皮易衰老腐败的原因 摘要乙一。 3、福眼果肉中所含的脂肪酸主要有豆范酸(14:O)、棕搁酸(16:O)、硬脂酸 (18:O)、油酸(18:一)不11亚油酸(18:2)，亚麻酸的含量很少未检出。所含){旨肪酸中亚油酸的含量最高，棕搁酸和油酸的含量次之，硬脂酸和豆范酸的含量最少。随着龙眼采后贮藏时间的延长，不饱和脂肪酸(油酸、亚油酸)和饱和脂肪酸(豆范酸、棕搁酸、硬脂酸)的含量变化不明显。果皮中的脂肪酸含量很少检出。在采后贮藏过程中，果肉所含LOX活性较低。随着贮藏时间延长，室温下的LOX活性不断上升，低温下LOX活性在前期迅速上升，接着保持在较稳定水平，到后期又升高，活性变化呈双峰型。但LOX的变化幅度总体来说不明显。LOX氧化脂肪酸是以亚油酸和亚麻酸为主要底物，本试验的结果表明，在果实采后贮期脂肪酸和LOX活性的变化都不明显，推测脂肪酸代谢可能不是引起龙眼果实衰老变质的主要因素。 4、在福眼果实采后贮藏过程中，随着贮藏时间的延长，果皮的质膜透性逐渐增大，MDA含量、超氧阴离子自由基含量逐渐增加，但HZO:未能检出;保护物质抗坏血酸和谷肤甘肤的含量呈先上升后下降的趋势;过氧化物酶POD的活性逐渐上升，多酚氧化酶PPO的活性先上升后下降，SOD的活性呈上升趋势，且果皮的变化趋势比果肉明显;但同样未能检测到过氧化氢酶CAT的活性。福眼果实在采后随贮期延长，自由基代谢加强，使自由基及其代谢产物逐渐积累，膜透性增大。研究还表明，在3口低温条件下，3种不同药剂(疫霜灵、S.ASP、水杨酸)处理对龙眼采后贮藏过程中自由基的代谢影响不明显。 综上所述，在福眼果实采后贮藏过程中，随着贮藏时间的延长，果实中既有新蛋白质组分的产生也存在一些蛋白质的降解，但从总体上看，果实的蛋白质呈不断降解的趋势，果实的衰老腐败与果实中的蛋白质组分变化关系密切。并且，果皮中蛋白质的降解变化先于果肉，这是果皮比果肉先衰败的重要原因。福眼果肉的多胺中Put含量占绝大多数，而果皮中Put、Spd和Spm的含量相差较小，其内源多胺含量也明显低于果肉，而这可能也是导致果皮比果肉先腐败变质的原因之一。因此，在龙眼采后贮藏保鲜的实践中，应着重于果皮生理生化特性的研究，使之能保持较长的生理寿命，从而延长贮藏期。试验结果还表明，在采后贮藏过程中，福眼果皮的脂肪酸含量很少，未检出，而果肉中的脂肪酸含量变化不大，LOX活性较小且变化不明显，、推测脂肪酸的代谢可能不是福眼果实更多还原

【Abstract】 Variations on protein composition, contents of fatty acids and endogenous polyamines, metabolism of free radicals in Fuyan’s fruits treated with different chemicals and stored under different temperatures after harvesting were studied and probed their interrelationships to father understand postharvest physiology of Longan’s fruits. The results were as follow.In the process of storing after harvest, composition of proteins in peel and flesh was abundant. There were 26 and 34 types of soluble proteins in flesh and peel, respectively; there were 30 types of total proteins in peel. Under room temperature, with delay of store time, new protein compositions would emerge and some proteins would degrade in fruits after harvest. Among the compositions of soluble proteins in flesh, the protein with the molecular weight of 138.68KD appeared at 4th day, 5th day, 6th day after harvest, and the protein with the molecular weight of 87.50KD started to degrade and disappear at 5th day after harvest. Among the compositions of total proteins in flesh, both new proteins with the molecular weight of 41.3KD and 27.93KD appeared at 6th day after harvest, and the contents of protein with the molecular weight of 42.3KD increased; Fourteen types of proteins were gradually degraded after harvest, their molecular weights were 629.51KD, 333.43KD, 302.69KD, 181.97KD, 149.28KD, 133.66KD, 77.62KD, 70.47KD, 63.97KD, 49.55KD, 44.36KD, 23.07KD, 19.95KD, 18.92KD separately, and the contents of five types of proteins increased by degrees after harvest, their molecular weights were 94.62KD, 59.57KD, 55.46KD, 41.30KD separately. Therefore, with delay of storing time, proteins in fruit overall trend to degrade consistently, and mainly focus on 5th day, 6th day after harvest, before which the fruit began to rot largely. The senescence and rotting of fruit companied with proteins degrading largely, and degrading time of proteins in flesh delayed 2 days compared with in peel, its degrading extent was less than peel. From the level of protein, it was thought that The senescence and rotting of fruit in Longan started with peel, which was consistent with observation results in practices of storing and fresh-keeping for Longan’s fruit. Summarily, the key to storing and fresh-keeping for Longan’s fruit was keeping peel regular metabolism.The contents of polyamines in flesh was apparently higher than that in peel, at the day of harvest, total sum of the contents of Put, Spd, and Spm was 4.27 ug/g.FW, but that in peel was 2.35 ug/g.FW, the former was 1.82 times of the latter. Under room temperature, withdelay of storing time, the contents of endogenous polyamines (put, Spd, Spm) in peel trended to decrease consistently, but in flesh, only the contents of Put decreased continuously, variation on the contents of Spd and Spm was not apparent; Under low temperature, with delay of storing time, the contents of endogenous polyamines sharply decreased at the beginning of postharvest, then maintained at steadier level, but in flesh, only variation on the contents of Put was consistent with that in peel, variation on the contents of Spd and Spm was not apparent; in the process of storing after harvest, range of endogenous polyamines in peel varied larger than that in flesh, and earlier than senescence and rotting in flesh. In peel, difference of the contents of put, Spd, Spm was little, but in flesh, Put was main composition of polyamines, its contents was 89.0% in total contents. Therefore, low contents of polyamines in peel was probably one of causes that peel was liable to senescence and rotting.The main fatty acids in flesh were Myristic acid, Linoleic acid, Oleic acid, Palmitic acid, Stearic acid,but the contents of Linolenic acid was lower and was determined, the contents of Linoleic acid among all fatty acids was highest , that of Palmitic acid and Oleic acid was lower, that of Stearic acid and Myristic acid was lowest, with delay of storing time, variation of unsaturated fatty acids(Oleic acid, Linoleic acid)and saturated fatty acids(Myristic acid, Palmiti更多还原