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1、安徽农业大学 硕士学位论文 机械损伤对采后砀山酥梨生理生化变化的影响 姓名：俞雅琼 申请学位级别：硕士 专业：营养与食品卫生 指导教师：董明 2011-06I 摘 要 砀山酥梨驰名中外， 是历史悠久的地方优良品种。 由于果实肉质酥脆， 含水量高， 在储运过程都不可避免地遭到机械损伤，导致商品价值和食用品质的下降。国内外关 于砀山酥梨的研究主要集中在贮藏上， 在机械损伤引起生理生化变化方面的研究还未 见报道。本试验通过人工模拟机械伤害的方法，选用两种损伤程度，贮藏在两种温度 条件下，研究受伤果实采后生理生化变化，以期对果蔬受机械伤害后生理生化反应的 机制有更深入的了解，为采后果蔬的科学贮运提供理
2、论依据。 试验结果如下： 1机械损伤能明显地诱导受伤果乙烯的产生，乙烯释放量显著高于对照。机械损 伤越严重，乙烯释放量越高，释放高峰越提前到来。低温储藏显著的抑制了乙烯释放 量，防止伤果快速老化。 2机械损伤显著的促进了果实呼吸强度的升高，可溶性固形物含量的下降，果实 硬度的下降，并且当损伤越严重，贮藏温度越高时，变化趋势越明显。在整个贮藏过 程中，伤果的各项生理指标都经历了上升、下降的反复过程。低温贮藏时，变化趋势 基本平缓。其中 18储藏的伤果出现两次呼吸高峰，第二次峰值小于第一次。伤果 的可滴定酸含量前期大幅下降，后期变化幅度变小。Vc 含量前期保持较高，后期缓 慢下降。贮藏温度越高，机
3、械损伤越严重，营养成分下降速度越快。 3机械损伤导致受伤果的纤维素酶活性、PAL 活性和 SOD 活性明显低于对照。 各项指标随贮藏期的延长均显示了不同程度的上升、下降的反复过程。其中纤维素酶 活性在两种贮藏温度下均逐渐降低，PAL 活性在 18贮藏时前期逐渐上升、但后期 缓慢下降，3贮藏时上升下降变化幅度较大。SOD 活性在 3贮藏时保持在较高水 平，说明采后的砀山酥梨果实在低温下贮藏抗氧化能力较强。机械损伤越严重，贮藏 温度越高，酶活性变化越快。低温显著抑制了酶活性。 4伤果的 PPO 活性和 POD 活性在两种贮藏温度下前期上升后期下降。3贮藏 初期，伤果的 PPO活性略高于对照，末期低
4、温贮藏的 PPO活性较低，利于贮藏。伤 果的 POD活性在两种贮藏温度下明显高于对照，随着贮藏时间的延长，POD活性也 都经过了上升、下降的反复过程。低温条件下 POD活性变化得相对缓慢。POD活性 伴随着机械伤害而上升，机械损伤越严重，POD活性越高。 关键词：砀山酥梨，机械损伤，生理生化，乙烯，呼吸强度II Abstract DangShan peer is wellknown all of the world of its long history and the place of local varieties. Because of the peer is crisp and con
5、tent high moisture, when in transportation will lead to mechanical damage inevitably, So lead the commodity value and food quality decline. In domestic and foreign countries the research about DangShan peer are mainly concentrated in how to storage, the research about mechanical damage will cause ph
6、ysiological and biochemical changes have not been reports. This experiment made the method of the mechanical damage by artificial simulation, choosing two different damage degrees and stored in two different temperature conditions, Do the research about physiological and biochemical changes in injur
7、ed area fruits, In order to depth understanding the science of the physiological and biochemical reaction mechanism after the mechanical damage, provide theoretical basis for postharvest fruits and vegetables how to better storage and transport. The results show that: 1The mechanical damage can obvi
8、ously induce the generation of ethylene which are injuries, the releases significant high than control. When damage more serious, the release of ethylene more higher, and the peak of release came early. Low temperature storage can significantly inhibit the ethylene release, and prevent injury fruit
9、aging rapidly. 2The mechanical damage made the fruit respiration rate significantly increased, the soluble solids content gradually decline, fruit firmness decreased, and when injuried more seriously, storage temperature more higher, the changing trends more obvious. In the whole storage process, th
10、e wounds fruit physiological indexes has experienced repeated rise and fall process. When storage at low temperature, the change trend gently. The wounds fruit storage at 18 emerge breathing two peak times, the second lower than the first. Injury fruit acid content greatly decreased, small amplitude
11、 in later time.In the early time the content of Vc maintain higher but later generally decline.When storage in higher temperature,the mechanical damage more serious, the nourishment composition decline more quickly. 3The mechanical damage cause injury fruit cellulose enzyme activity, PAL activity an
12、d SOD activity obviously lower than contrast. In the storage period each index showed the repeated process extension of the different level of rise and fall. The cellulose enzyme activity gradually decline in two different kinds of storage temperature, In the 18 the PAL activity gradually rise in ea
13、rly time storage, but decline slow in later time, WhenIII storage in 3 the up and down change obviously. In 3 storage the SOD activity keep in high levels, So the postharvest DangShan peer storage at low temperature also have stronge antioxidant ability. When the mechanical damage more serious, the
14、storage temperature more higher , the enzymes changed more faster. Low temperature significantly inhibit enzymes activity. 4When storage at two kinds of temperature the PPO activity and POD activity in injuried fruit rises in the early time but late downward. When storage at 3, in early time the PPO
15、 activity in hurt part slightly higher than the control, storage in low temperature the PPO activity lower at end. The POD activity in injuried fruit high than controlled when storage at two different temperature. In all storage time, the POD activity repeated rise and fall process. In low temperature the POD activity changes relatively slow. The POD activity increased with the mechanical damage, when mechanical damage more seriously, the POD activity more higher. Keywords: DangShan peer, mechanical d
