壳聚糖涂膜罗伯逊脐橙保鲜效果的研究.docxVIP

壳聚糖涂膜罗伯逊脐橙保鲜效果的研究摘要：本实验研究了在4.0±0.5℃，85%-90%RH的贮藏条件下，不同浓度（0.1 %、0.2 %、0.3 %、0.4 %、0.5 %）的壳聚糖溶液对罗伯逊脐橙采后贮藏品质和生理代谢的影响。结果表明，0.3%、0.4%、0.5%壳聚糖涂膜处理能够有效延缓脐橙果实可溶性固形物含量的上升，可滴定酸和还原糖含量的下降，减少果实的重量损失; 0.2%、0.3%、0.4%的壳聚糖处理，能降低脐橙果实贮藏期间的丙二醛含量，延缓超氧化物歧化酶活性的下降，使过氧化物酶活性保持在较高水平，抑制果实贮藏期间超氧阴离子产生速率。并以0.3%壳聚糖处理效果最好。关键词：罗伯逊脐橙，壳聚糖，涂膜，贮藏Study on the Effect of Chitosan Coatingfor the Fresh-keeping Robertson Navel OrangesCao Wanxiu Food science and engineering, Grade 2007Directed by Chen Anjun (Associate Prof. Ph. D)Abstract:Navel oranges were treated with chitosan solution and then stored at 4.0 ± 0.5℃, 85%-90% RH. The effects of these treatments on storage characteristics, quality and physiological metabolisms of navel oranges were then evaluated during storage period. The reasults showed that, the increase of soluble solid contentand the decrease of ascorbic acid were effectively inhibited by 0.3%、0.4%、0.5% chitosan coating treatment, reducing of sugar and fruit weight were also effectively inhibited. 0.2%, 0.3% and 0.4% chitosan coatingcould inhibited the production of malondialdehyde, the increase of membrance permeability during storage . Results frombiochemical determinationsshowed that superoxide dismutase, peroxidasewere remarkedly enhanced, the levels of superoxide radicals were effectively reduced.In addition,the effect of 0.3% chitosan was the best.Keywords: Robertson navel oranges, chitosan,coating,storage1 前言罗伯逊脐橙又名鲁滨逊脐橙，是四川柑橘的主要栽培品种之一，经济效益良好。但其采后易受物理、生理和病理等因素的影响而腐败变质，造成巨大的经济损失。在我国，由于保鲜技术落后，果品每年产后损耗率高达25％～30％[1]。因此，搞好脐橙的贮藏保鲜对满足内销和外贸市场的需求，十分重要。目前，我国广泛用于脐橙保鲜的技术主要有简易贮藏法、温度调节法、气调贮藏法及保鲜剂涂膜法等[2]。其中，保鲜剂涂膜法因其简单、高效、造价低等优点，已作为常温下的一项独立技术而得到广泛应用。保鲜剂可分为化学防腐保鲜剂、生理活性调节剂和天然防腐保鲜剂。其中化学防腐保鲜剂的使用更为广泛，但传统使用的一些化学保鲜剂毒性较大且易残留，危害人体健康。因而高效、天然、无毒的新型保鲜剂已成为保鲜界研究与开发的热点。本实验中应用的壳聚糖即属于天然保鲜剂范畴。壳聚糖又称脱乙酰甲壳素、甲壳胺，是通过甲壳素一定程度的脱乙酰而制得[3]，具有无毒、可生物降解、成膜性好、来源丰富等优点，并能有效地延长蔬菜的保鲜期[4]。有关壳聚糖涂膜保鲜效果的研究，国内外进行的均很早，并取得了较大的进展。胡文玉等[5]对苹果，J M Du等[6]对梨和猕猴桃，A El Ghaouth等[7]对黄瓜和青椒的实验结果表明，壳聚糖具有良好的成膜性和抑菌作用，可在果蔬表面形成一个半透膜，阻碍果蔬的蒸腾作用，减少果蔬水分的散失，抑制呼