【作者】 丁四兵；

【导师】 朱碧岩；

【作者基本信息】 华南师范大学 ， 植物学， 2004， 硕士

【摘要】 本文以臭氧水（Ozone Water）和超声波（Ultrasound）为主要保鲜手段，研究其对冷藏荔枝（Litchi chinensis Sonn.cv.Guiwei）生理变化的影响。主要涉及以下几个方面的内容：（1）初步考查了超声波对荔枝失水率的影响；（2）研究了臭氧水前处理对荔枝贮藏过程中关键酶活性以及营养变化的影响；（3）在超声波、臭氧水处理的基础上，施以生物保鲜剂前处理，研究荔枝在贮藏过程中的生理变化对其的响应程度。主要结果如下： 一、超声波对荔枝失重率的影响 用超声波作用60s后，低强度（1200W^*300W）的超声波能降低荔枝果实的失重率，而其它强度的超声波对荔枝荔枝果实失重率的影响不明显，未能减缓荔枝果实失重率。 用超声波作用90s后，高强度（1200W^*1200W）的超声波加重了失重率；相反，其它强度（1200W^*300W，1200W^*600W，1200W^*900W）的超声波有利于保持荔枝果实的水分。 二、臭氧水对冷藏荔枝生理变化的影响 臭氧水处理“桂味”荔枝后，延缓了果皮花色素苷含量的下降，抑制了类黄酮含量的下降，有效地保持了荔枝果皮地颜色。其中以0.5mg.L^-1和0.25mg.L^-1处理效果较为显著。 臭氧水处理诱导了“桂味”荔枝果皮的过氧化物酶（POD）活性的升高，各个处理均显著高于对照（CK），其中以浓度1.0mg.L^-1（T1）处理最为明显。结果表明，臭氧抑制了多酚氧化酶（PPO）活性，其中以浓度1.0mg.L^-1（T1）处理后，荔枝在贮藏期间的PPO活性明显低于CK。结果说明，臭氧对PPO和POD具有不同的作用方式。 臭氧水处理对“桂味”荔枝果实的可溶性固形物含量（SSC）无显著影响，但能抑制可滴定酸（TA）含量的下降。说明臭氧对荔枝果实影响无明显的负面影响。 三、超声波和臭氧水结合生物保鲜剂综合预处理对荔枝贮藏保鲜的影响 超声波和臭氧水以及生物保鲜剂对荔枝处理后，减缓荔枝的腐烂及其果皮华南师范大学硕_卜研究生学位论文超声波和臭氧水在荔枝贮藏保鲜中的应用研究的褐变，有效地保持了荔枝果皮的颜色，其中以Tl和T2两个处理效果较好。受生物保鲜剂低pH值的影响，花色素昔含量在贮藏保鲜期间下降缓慢。 各个处理均抑制了PPO活性，其中T2处理最为明显，其次为Tl处理。综合处理后，明显诱导了POD活性的升高，以T2处理的POD活性最高。结果说明处理对两种酶的影响机理存在差别。联系综合处理对荔枝果皮褐变指数影响的结论，发现POD活性的升高对荔枝果皮的褐变并没有起到明显的促进作用，表明POD是否在荔枝果皮褐变的过程中起的作用还有待商榷。 综合处理对降低荔枝果皮细胞膜相对透性和果实失重率的作用不显著，但失重率高的处理并没有表现出较高的褐变指数，说明冷藏条件下荔枝失水对荔枝果皮褐变的影响不明显。 综合处理采后荔枝以后，能有效的保持荔枝果实的营养物质，其中以Tl处理能显著抑制荔枝果实内TA和SSC的下降。 整体上来看，本文所采用的综合处理手段具有很好的保鲜效果，利于荔枝的贮藏保鲜，并适宜于生产应用，是值得进一步研究和探讨的荔枝贮藏保鲜手段。更多还原

【Abstract】 Using the ozone water and ultrasound as the main keeping fresh means to study their effects on physiology and quality of Litchi (Litchi chinensis Sonn.cv.Guiwei) in this paper. The paper involves: 1) to investigate the effects of ultrasound on the weight loss rate of litchi fruits in the preservation; 2) to study the effects of ozone water on the main enzyme activity related to browning and quality of litchi; 3) to study the responses of the physiological changes of litchi to ultrasound and ozone water combined with bio-antistaling agents during the preservation of litchi. The results are as follow:1, Effects of ultrasound on the weight loss rate of litchi fruitsLow ultrasonic intensity (1200W*300W) can cause to decreasing of the weight loss rate of litchi fruits after processed for 60s by ultrasound. However, Effects of high ultrasonic intensity (1200W*600W, 1200W*900W, 1200W1200W) are not significant on the weight loss rate of litchi fruits, these processes can not reduce the weight loss rate.High ultrasonic intensity (1200W*1200W) for 90s aggravates the weight loss rate of litchi fruits. However, other ultrasonic intensity (1200W*300W, 1200W*600W, 1200W*900W) is of benefit to holding water of litchi.2, Effects of ozone water on physiological changes of litchi during the cool preservation.The results show that ozone water can retard the decreasing of anthocyanogen and flavonoids content, holding effectively the red color of pericarp litchi (cv Geiwei). The results also suggest the process has significant effective by 0.5mg.L-1.Ozone water induce to the raising of peroxidase (POD) activity of litchi pericarp. The POD activity of litchis treated with ozone water is higher significantly than CK’s, one of which processed with l.0mg.L-1 of concentration is most significant. However, ozone water restrain polyphenol (PPO) activity, which is lower significantly than CK’s by l.0mg.L-1 of concentration of ozone water. These results suggest ozone effect by different mechanisms on PPO and POD activity.The study all shows that ozone water affect un-significantly on the soluble solids content (SSC) of litchi fruits, but it can retard the declining of tiratable acidity (TA)content. These suggest the nutritional quality of litchi fruits isn’t badly affected by the process of ozone water.3, Effects of ultrasound and ozone water combined with bio-antistaling on the preservation of litchiProcessed by ultrasound and ozone water combined with Tl and T2 bio-antistaling, the browning index of litchi is reduced during the preservation. The results suggest the two treatmeotal means can effectively retard browning of litchi pericarp. Because of low PH value of bio-antistaling, anthocyanogen content of litchi pericarp dropped slowly in the storage.All treatments can retard the PPO activity of litchi pericarp, effect of T2 treatment on the enzyme activity is most distinct, the next is Tl treatment. The PPO activity is rising because of these treatments. The effect of T2 treatment on PPO activity is most distinct, enzyme activity of the T2 treatment is most high. The results indicate that the treatments effect by different mechanisms on PPO and POD activity. Considering the front the results relating to the effects of these treatments on browning index of litchi pericarp, the author consider that the rising of PPO activity does not accelerate the browning of litchi. Therefore, the function of PPO to the T2rowning of litchi is required to discussed further.The actions of the treatments are not observed on the reducing the relative permeability of cell membrane in pericarp and weight loss rate of fruits. The results indicate that the treatments with high-weight loss rate of fruits do not present high index of browning. Therefore, the author considers that the losing water of litchi fruits isn’t main factor of browning in cool preservation.After processed by ultrasound and ozone water combined with Tl and T2 bio-antistaling, the nutritive materials are maintained significantly. The results show that th更多还原