【作者】 王波；

【导师】 王则金；

【作者基本信息】 福建农林大学 ， 农产品加工及贮藏工程， 2008， 硕士

【摘要】 龙眼（Dimocarpus longan Lour.）是我国南方著名的特产水果,也是福建_省的主要水果之一,种植面积和产量均居世界前列。龙眼果实营养丰富,具有较高的食用价值和保健作用,自古以来就被视为果中珍品,营养分析表明:龙眼肉富含葡萄糖、蔗糖、蛋白质、脂肪、多种维生素和腺嘌呤、胆碱等成份。但是由于龙眼成熟于高温、高湿的夏季（8～9月份）,鲜果采后生理代谢旺盛,在常温下很容易失水、褐变和腐烂,影响了龙眼的贮藏和销售。为此,本文采用微冻保鲜的方法对龙眼的贮藏进行了研究,探讨了龙眼果实的冻结规律和龙眼微冻贮藏的最适温度,在此基础上,研究了褐变抑制剂处理、臭氧处理、气调包装对龙眼微冻保鲜效果的影响。主要研究结果如下:1.龙眼果实的冻结规律通过对乌龙岭、福眼、泉州本、普明庵、东壁、石硖等6种福建主栽龙眼品种的冻结规律进行探讨,结果表明,不同品种龙眼果实的结冰点在-2.6℃～-3.2℃之间,结冰点与龙眼果实的可溶性固形物含量和含水率有关,并呈现显著的线性关系。龙眼果实冻结过程中的三个阶段并不明显,最大冰晶生成区为-2℃～-14℃。2.最佳微冻贮藏温度的研究以乌龙岭品种作为实验材料,其冻结点为-2.7℃,以果实好果率、褐变指数、呼吸强度、可滴定酸（TA）和果皮PPO活性为主要指标,研究了不同贮藏温度-3℃、-4℃和-5℃对龙眼贮藏品质的影响。结果表明,微冻保鲜在抑制龙眼的呼吸作用、酶活性和减缓营养物质的损耗等方面的效果显著。-3℃下贮藏的龙眼果实,此时只是轻微的冻结,结冰率仅为7%,可以更好地保持龙眼的品质,保鲜期限可达40d以上。3.褐变抑制剂处理对龙眼微冻保鲜效果的影响研究龙眼在微冻保鲜过程中的主要问题是果皮的褐变,果肉品质变化较小。为此,本试验对5种褐变抑制剂的防褐变效果进行了探讨,并采用L₁₆（4⁵）正交实验确定了复合褐变抑制剂的适宜配比和最佳浸泡时间。4.O₃处理对龙眼微冻保鲜效果的影响研究以无处理的果实为对照组,采用O₃对龙眼分别进行前处理5min、10min和15min,考察不同O₃处理时间对龙眼贮藏品质的影响。在本试验范围内,以O₃处理10min对龙眼贮藏保鲜的效果较为显著。5.O₃处理结合气调包装对龙眼微冻保鲜效果的影响研究通过O₃处理结合气调包装,研究其对龙眼保鲜效果的影响。采用L₉（3⁴）正交实验分别探讨了氧气浓度、二氧化碳浓度及每盒装载量对龙眼贮藏品质的影响。结果表明:龙眼经过处理后（O₃处理10min+1%O₂+6%CO₂+每盒装载量450g）,能延缓龙眼果皮褐变的发生,保持较高的好果率和果实TSS含量,抑制果皮的PPO活性,保持果皮细胞的完整性,减缓膜脂过氧化产物MDA的生成,延长了贮藏期。更多还原

【Abstract】 The Longan（Dimocarpus longan Lour.）,is a specialty fruit in the southern China.It is one of the main fruit in the Fujian.The planting area and output of Longan in China is premier in the world.Longan fruits have an abundance of nutrition,high edible value and medicinal value.It has been regarded as treasures among the fruits since ancient times.Nutrition analysis showed that:there were rich glucose,sucrose, protein,fat,vitamins and a variety of adenine,choline in longan meat.The physiology metabolism of Longan is strong after post-harvest due to the fruits were ripened in high temperature and humidity summer（August～September）.Thus,the storage and sale of longan has a serious of problems,such as water loss easily at normal temperature,browning and decay.In this thesis,freezing fresh was used in the Longan storage.The Longan’s freezing and the optimum storage temperature were discussed.Base on above,we also investigated the effects of Browning inhibitor treatment,ozone treatment,and modified atmosphere packaging on fresh longan freezing.The results were as follows:1.The Wulongling,Fuk eyes,the Quanzhou,pumingan,Dongbi,Shek Kip were selected to discuss.The results showed that the freezing point of varieties of fruit longan is between -2.6℃and -3.2℃,the freezing point of longan fruit related closely to soluble solids content and the rate of the aquifer.Three stages of Longan fruit freeze was not obvious,the largest ice formation zone -2℃～-14℃.2.Take Wulongling species as experimental sample,its freezing point is -2.7℃. Taking good fruit rate,browning index,respiratory rate,titratable acid（TA）and PPO activity peel as indexes,we discussed the effects of different storage temperature -3℃,-4℃and -5℃on the storage quality of Longan.The results showed that freezing significantly inhibited the respiration and enzyme activity,slowed nutrient loss.The longan fruit stored in -3℃,has only slightly frozen,and its ice rate was only 7%.It is in this temperature that the quality of longan can be better maintained.3.The main problems during subfreezing fresh longan were pericarp browning,small changes in pulp quality.Therefore,the test investigated the effects of five kinds of browning inhibitors,and determined of the optimum composite browning inhibitors and the best immersion time by L₁₆（4⁵）orthogonal experiments.4.Compared with the non-treating fruits,we respectively adopt ozone 5 min,10min and 15 min to pre-treat the longan,and studied the effects of different ozone treatment time on the storage quality of longan.Results indicated that the effect of ozone treatment 10min was more obvious.5.Combining ozone treatment with modified atmosphere packaging,we investigated the effects on fresh Logan.We investigated the effects of concentration of oxygen, carbon dioxide concentration and loading of the pack on the storage quality of longan. by L₉（3⁴）orthogonal experiment.The results showed that:the treatment（ozone 10 min,1%O₂,6%CO₂ pack loading 450 g）could retard the occurrence of longan pericarp browning,maintain a relatively high rate of good fruit and fruit TSS level, inhibit the peel PPO activity,and maintain the integrity of skin cells,reduce formation of lipid peroxidation product MDA to extend the storage period.更多还原