| 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... |
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