采后生物学(精品)

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Chapter,4,Post-harvest Diseases,(Physiological Disorders),Professor,Dr.Lin Hetong,College of Food Science,Fujian Agriculture and Forestry University,Fuzhou,Fujian 350002,China,E-mail:,Post-harvest Diseases,采后病害包括由温度、水分和气体胁迫等生理因素引起的,生理性病害,。,Physiological Disorders,Chilling Injury,、,Freezing Injury,、,Heat Injury,、,Transpiration,、,Gas injury,由微生物引起的,病理性病害,两种，与农产品采后损失密切相关。,Post-harvest,Pathology,(Post-harvest Diseases),Post-harvest Diseases,Objects:,1.To know types of post-harvest disorders and diseases of plant products.,2.To know relationship between physiological disorders and shelf-life of post-harvest plant products.,Post-harvest Diseases,Objects:,3.Learn controlling physiological disorders and keeping quality in post-harvest plant products.,4.Learn controlling post-harvest diseases and keeping quality in post-harvest plant products.,Post-harvest Diseases,Contents:,1.Introduction,2.Temperature Stress,2.1 Heat Stress,2.2 Chilling Injury,2.3 Freezing Injury,Post-harvest Diseases,Contents:,3.Transpiration,3.1 Transpiration and its role in post-harvest loss and quality deterioration of post-harvest plant products.,3.2 Factors Affecting Transpiration,3.3 Controlling Transpiration Action,Post-harvest Diseases,Contents:,4.Gas Injury,4.1 Oxygen Stress(Low O2 Injury),4.2 Carbon Dioxide Stress(High CO2 Injury)4.3 Ethylene Stress,5.Post-harvest Diseases,Introduction,植物产品在高于或低于正常温度的环境中发生着生理和生化代谢的调整，热激蛋白和冷冻蛋白的诱导产生有利于防御这种不良的温度环境。温度变化过度就会导致生化代谢和细胞膜结构的严重伤害。,Introduction,水分以气态方式离开产品表面，造成品质和生理代谢的改变。产品种类和表面特性是影响蒸腾作用的最主要内部因素。通过改变环境温度、湿度、通风状况、气压、包装和光照条件可以调节产品的蒸腾作用。,Introduction,降低氧气浓度或提高二氧化碳水平能抑制产品的呼吸作用、抑制乙烯的合成和作用。过多或过少的氧气或二氧化碳对产品造成伤害。环境中的乙烯则会刺激产品的成熟和衰老过程。,Introduction,由微生物引起的腐烂是农产品采后损失最主要的原因。通过了解引起采后农产品腐烂的病原菌种类、侵染方式、病原菌控制的条件，为控制农产品采后病害、减少采后腐烂损失、延长农产品贮藏保鲜期有重要的科学意义，同时为农产品贮藏保鲜提供生产指导。,1.,Temperature Stress(,温度胁迫,),高温胁迫,(Heat Stress/Heat Injury),低温冷害,(Chilling Injury),低温冻害,(Freezing Injury),1.1 Heat Stress,Effects of heat treatment on maintaining quality and control of diseases and pests of post-harvest fruits and vegetables,改善果蔬贮藏期间的品质,增强抗逆性,(,如抗冷性的诱导,热激蛋白的产生,),防治病虫害,(,热处理防治果蔬贮藏期间病虫害,-,如直接作用于病菌、害虫与提高果蔬的抗病虫性等,),1.1 Heat Injury,破坏细胞结构,热损伤褐变，严重影响产品的外观品质,易引起病原菌的侵入,缩短产品的贮藏期,1.2,Chilling Injury,C,hilling injury(,低温冷害,),冷害：农产品低温贮藏时，由冰点以上的不适宜低温（,0-15,）所造成的生理病 害，其结果使农产品的耐藏性和抗病性下降，品质劣变，贮藏期和货架期缩短。,热带、亚热带农产品对低温敏感，在低温贮藏时容易发生低温冷害。,1.2,Chilling Injury,Chilling sensitivity,(,冷敏性，易感性,),农产品（果蔬）受冷害后发生一系列不正常的生理变化，产品对这些变化具有一定的抵抗能力或适应能力，称为冷敏性或易感性。,冷敏型植物和抗冷型植物,冷敏型植物：起源于热带或亚热带的果蔬,抗冷型植物（非冷敏型植物）：,起源于温带的果蔬,1.2,Chilling Injury,Chilling injury symptoms,低温冷害的常见症状,Surface lesions,表面伤害，在表面发生下陷（或凹陷）的病斑，变色,Water-soaking of the tissue,表面组织呈水浸状，易被微生物侵入,Internal discoloration,果肉、维管束和种子内部变色,组织崩溃,1.2,Chilling Injury,Chilling injury symptoms,Failure to ripen normally,果实不能后熟,促进衰老，但外观正常,容易腐败,组织发生变化，影响风味,失去生长或萌芽能力，特别是繁殖器官,影响低温冷害发生的因素,The factors affecting chilling injury,种类,、品种,产地,发育阶段和成熟度,影响低温冷害发生的因素,The factors affecting chilling injury,膜脂肪酸饱和度,可溶性固形物、糖和钙含量,脯氨酸含量,影响低温冷害发生的因素,The factors affecting chilling injury,温度的高低和低温持续的时间,湿度,环境气体组成,The possible mechanism of occurrence of chilling injury(,冷害发生的机理,),冷害发生的生理生化反应,冷害的初始反应,(Primary response),生物膜的物理相改变,即液晶态、固晶态,(,凝胶态,),的改变。,The possible mechanism of occurrence of chilling injury(,冷害发生的机理,),冷害的次级反应,(Secondary response),膜的透性变化,细胞和亚细胞结构的变化,原生质流动异常,The possible mechanism of occurrence of chilling injury(,冷害发生的机理,),冷害的次级反应,(Secondary response),呼吸代谢失调,能量产生和利用被干扰,刺激乙烯的产生,蛋白质和酶活性的变化,有毒物质积累,The possible mechanism of occurrence of chilling injury(,冷害发生的可能机理,),呼吸代谢失调,有毒物质积累,膜的透性增加,The methods of alleviating chilling injury,减轻冷害发生的技术措施,贮藏前的预处理,贮藏前预冷处理（低温锻炼）：,热处理：贮藏前热处理（高温锻炼）,中途加温处理,(Intermittent warming),The methods of alleviating chilling injury,减轻冷害发生的技术措施,湿度和环境空气成分调节,化学处理,The methods of alleviating chilling injury,减轻冷害发生的技术措施,植物激素,基因工程技术,1.3 Freezing Injury,低温冻害,(,Freezing Injury),2 Transpiration,蒸腾作用,(Transpiration,),水分胁迫的作用,失重和失鲜,干扰正常的生理代谢,耐藏性和抗病性下降,产品的贮藏期缩短,The factors affecting transpiration,影响蒸腾的因素,（,1,）内在因素,种类、品种,比表面积,:,表面的保护结构,The factors affecting transpiration,影响蒸腾的因素,（,1,）内在因素,种类、品种,细胞的持水能力：持水能力越高失水越小。,成熟度,成熟度越低失水越大。,The factors affecting transpiration,影响蒸腾的因素,（,2,）外界贮运条件,温度,相对湿度,空气流速,The factors affecting transpiration,影响蒸腾的因素,（,2,）,外界贮运条件,气压,包装,涂蜡,The methods of control transpiration for keeping quality in post-harvest plant products,(,水分胁迫的控制,),低温贮藏,Low temperature storage,Pre-cooling before storage,高湿度贮藏,Storage at low humidity,涂蜡,Surface coating,waxing,塑料薄膜包装等,Modified atmosphere storage,Modified atmosphere packaging(MAP)storage,Film packaging,The methods of control transpiration for keeping quality in post-harvest plant products,结露,(,出汗,),结露,(,出汗,)Condensation,果蔬等农产品在贮藏过程中，果蔬的表面或库顶、墙壁和薄膜袋包装的内侧等处凝结水珠的现象。,农产品贮藏环境中的温度降到露点以下，过多的水蒸汽从空气中析出附着在农产品的表面，凝结成水珠的现象。,产生结露的原因,当空气温度降到露点以下，即农产品表面与贮藏环境存在温度差，或者库房贮藏温度不稳定，过多水气从空气中析出而在物体冷热界面凝结成水所致。,The methods of control transpiration for keeping quality in post-harvest plant products,结露,(,出汗,),防止结露产生的方法,保持库房温度稳定；,合理堆垛，有利于通风，降温循环使各部位温度一致；,包装前须预冷