【作者】 柳艳霞；

【导师】 刘兴华；

【作者基本信息】 西北农林科技大学 ， 食品科学， 2003， 硕士

【摘要】 本试验以甘肃省庆阳地区栽培的籽用南瓜(C. Mixia. Pang)主栽品种为试材，于2001年和2002年分两个年度对籽用南瓜采后的贮藏特性、籽粒的成熟特性、生理生化特性及采后温度对果肉、瓜籽品质的影响等进行研究，分析比较了10℃、5℃、室温三个温度和贮藏时间之间的差异性，探讨了籽用南瓜采后生理生化变化规律和成熟衰老机制，提出了掏籽最佳时间的概念，为籽用南瓜进行综合开发提供了理论依据和技术参数。 籽用南瓜贮藏过程中呼吸强度和乙烯释放量总体上都呈现出上升趋势，但是二者的最大值并不是同时出现；方差分析后发现，贮藏时间对呼吸强度有显著性影响、对乙烯释放量不存在这种影响，温度对呼吸强度和乙烯释放量都不存在明显影响。采后的衰老变化会引起籽用南瓜组织的相对电导率和膜脂过氧化程度的提高。SOD活性、MDA含量、细胞膜透性三个指标之间具有密切关系，随着SOD活性降低，MDA含量逐渐积累，细胞膜的通透性不断增大。不同部位的各项衰老指标之间差异显著，各部位的抗衰老能力存在很大差异，果肉的活性氧清除能力＞瓜瓤，MDA含量和可溶性蛋白含量的累积量则恰恰相反：瓜瓤＞果肉。籽用南瓜的POD活性在果肉和瓜瓤中分别呈现出下降和上升的趋势。 研究结果表明，籽用南瓜采后的腐烂指数总体呈现出增加趋势，10℃的腐烂指数大于5℃和室温；三个温度的失重率关系为5℃＞室温＞10℃；籽肉重量比一直在0.04％～0.06％的范围内变化，未表现出明显的增加趋势；瓜籽的特征指标范围：纵径14.3mm～21.3mm、横径6.9mm～11.3mm、厚度为2.1mm～3.6mm，纵横径比在1.8～2.2间波动，厚度不断增大，外形尺寸发生很大变化；瓜籽的千粒重范围为240g～340g，而且三个温度都在贮藏到30d时达到最大值。 籽用南瓜籽的蛋白质含量在贮藏期间表现出明显的差异，呈现总体下降的趋势；粗脂肪含量由最初的47.8％逐渐下降到37％；瓜籽水分含量的变化趋势与蛋白质、粗脂肪相似，由36.6％降到30.3％。果肉的外侧硬度逐渐增大，内侧硬度逐渐减小；果肉中的可溶性固形物含量呈现出前期升高后期下降的单峰变化；总酸含量、水分含量随着贮藏时间的延长而逐渐降低。 本试验的新见解：在国内率先对籽用南瓜采后生理及贮藏特性进行了比较系统地研究，初步判定籽用南瓜属于呼吸跃变型果实，提出掏籽的最佳时间为采后贮藏30天。更多还原

【Abstract】 Based on seed-used pumpkin of QingYang area in GanSu Province, storage characteristic, mature characteristic of pumpkin seed, physiological & biochemical characteristic and influence to flesh and seed quality by temperature after harvest were studied in 2001 and 2002. The difference between 10 , 5 , room temperature and storage time were analyzed, physiological & biochemical rule and mature & senescence mechanism of seed-used pumpkin were discussed. The best time of drawing out seeds was brought forward. All results would be theoretical basis and technology for full using of seed-used pumpkin.In the course of storage of seed-used pumpkin, respiration rate and release of ethylene is up trended in collectivity. But the highest is not appearing at the same time. By analysis of variance, storage time have marked influence to respiration rate but not to release of ethylene, the temperature have no marked influence to respiration rate and release of ethylene.Seed-used pumpkin relative electrical conductivity and membrane peroxidation increased because of senescence after harvest. There are affinity between activities of SOD, contents of MDA and cell membrane permeability. Along with decrease of activities of SOD, contents of MDA were accumulated; cell membrane permeability was increase incessantly. Senescent indexes and anti-senescence abilities have marked difference of different part, activities of SOD in flesh were higher than that in pulp, but contents of MDA and accumulation of soluble protein were on the contrary. Increase and decrease tendency of activities of POD were found in flesh and pulp of seed-used pumpkin.Study proved that cankered index of seed-used pumpkin showed increased tendency. Cankered index in 10 was higher than 5 and room temperature; weightlessness rate connection is 5 >room temperature>10 ; weight ratio with seed and flesh is between 0.04%~0.06%, there were no obvious increased tendency; characteristic index of seeds were between 14.3mm and 21.3mm in vertical length,6.9mm~11.3mm in transverse length, 2.1mm~3.6mm in thickness, 1.8~2.2 in vertical and horizontal length ratio, thethickness increased ceaselessly, formal dimension changed obviously; weights of 1000 seeds were between 240g and 340g, the highest weight in three temperatures was when they were stored to 30 days.The content of protein in seed showed obviously different, and behaved decreasing; content of fat decrease from 47.8% to 37%; water content decreased from 36.6% to 30.3%. Rigidity of flesh outside increased ceaselessly, but inside decrease; the content of soluble solid in flesh show single apex; the content of total acid and water decrease constantly alone with the increasing of the storage time.The paper was first systematically studied on the post-harvest physiology and storage characteristic of seed-used pumpkin in China. It brought forward seed-used pumpkin belonging to respiration climacteric. The best time of drawing out seeds was storaging 30 days after harvest.更多还原