【作者】 李继兰；

【导师】 刘兴华；

【作者基本信息】 西北农林科技大学 ， 食品科学， 2008， 硕士

【摘要】 猕猴桃是一种营养丰富、深受消费者喜爱的保健型水果。因其是成熟后果肉仍为鲜绿色、叶绿素含量较高的少数水果种类之一,近年来猕猴桃中叶绿素成为研究的热点。本文以“秦美”猕猴桃为试材,在0℃±1℃下,研究果实后熟衰老过程中叶绿素的降解规律及其与果实品质、活性氧和膜脂过氧化代谢、细胞壁和叶绿体超微结构的关系;研究猕猴桃加工中相关因素对叶绿素稳定性的影响。取得以下试验结果:（1）猕猴桃属乙烯高峰出现在果实完熟之前的“早峰型”果实;在0℃±1℃下,可以保鲜75d左右。（2）猕猴桃在0℃±1℃下贮藏,叶绿素含量与硬度呈极显著正相关,与可溶性固形物含量呈极显著负相关,与pH值呈显著负相关,与Fv/Fm值呈显著正相关。说明硬度、可溶性固形物含量、pH和Fv/Fm值都可以作为猕猴桃叶绿素含量变化的指示性指标。（3）猕猴桃在冷藏过程中,活性氧及其酶系统均参与了叶绿素代谢,O₂^-·的积累可加速叶绿素的降解,SOD活性提高可延缓叶绿素的降解,而POD对叶绿素的降解起双重作用;果实膜脂过氧化作用产物MDA的含量与叶绿素含量呈显著负相关,其相关系数达到0.93。（4）叶绿素酶和脱镁螯合酶活性在猕猴桃冷藏过程中呈峰型变化,酶活性大时,叶绿素降解速度快。（5）冷藏90d时猕猴桃果肉细胞壁已基本丧失其原有的结构,60d时叶绿体已经崩解,结构解体破坏了叶绿素降解酶与叶绿素在空间上的分隔,从而增加了叶绿素降解的可能性。（6）加工条件中,不同温度和pH值的猕猴桃果浆,其A*值、叶绿素含量和Vc含量有极显著差异（p<0.01）;试验时间（48h）内,不同的光照和空气条件下没有显著差异;漂烫温度越高、时间越长,POD失活越多,当漂烫温度为90℃、95℃、100℃,时间超过1min时,则POD大部分失活。更多还原

【Abstract】 Kiwifruit is a kind of popular fruit which is accepted by mostly customer for its nourishment. It is getting research hotspot recently for its green pulp and high chlorophyll contents.“Qinmei”Kiwifruit was as the material of experiment , in 0℃±1℃, studied on the relativity between the law of chlorophyll catabolism and fruit quality, active oxygen, membrane lipid peroxidation, cell wall ultrastructure, chloroplast ultrastructure during senescence. Studied on the effect of different factors to the contents of chlorophyll during processing. All the results are showed below:（1） kiwifruit belonged to“early apex”with ethylene apex present ahead full ripe; kiwifruit could be keep fresh about 75days in 0℃±1℃.（2） In 0℃±1℃,the contents of chlorophyll and firmness were terribly significant plus relativity, with SSC terribly significant negative relativity, with pH value significant negative relativity ,with Fv/Fm significant plus relativity. So firmness, SSC, pH value and Fv/Fm were all as the indicative index of chlorophyll change.（3） Active oxygen and its enzyme system both entered into catabolism of kiwifruit chlorophyll during cold-storage , the accumulation of O₂^-·could accelerate the speed of chlorophyll catabolism, activity of SOD increased, the speed of chlorophyll catabolism was slowed; but POD had double effects to chlorophyll catabolism; contents of MDA and chlorophyll were significant negative relativity, related coefficients was to 0.93.（4） Activity of chlorophyllas and Mg-dechelatase were apex changes, while the activity of enzymes was high, the speed of chlorophyll catabolism was accelerated.（5） Cell wall of kiwifruit losed its intrinsic structure in cold-storage 90 days, in 60 days chloroplast was already disintegration, structure disintegration damaged the space separation between chlorophyll and enzyme of chlorophyll catabolism, so the possibility of chlorophyll catabolism was accelerated.（6） In process condition ,the effects of temperature and pH to A* value, chlorophyll and Vc contents had very significant difference（p<0.01）;within 48 hours, the different conditions of illumination and air had no significant difference to A* value, chlorophyll and Vc contents; while the temperature of float burn was high and time was long, POD losed its more activity, while the temperature were 90℃,95℃,100℃, the time exceeded 1 minute, then the mostly activity of POD had been losed.更多还原