Effect of visible light treatments on postharvest senescence of broccoli (Brassica oleracea L.)

BACKGROUND: Broccoli (Brassica oleracea L.) is a rapidly perishable vegetable crop. Several postharvest treatments have been applied in order to delay de‐greening. Since light has been shown to have an effect on pigment accumulation during development and darkness is known to induce senescence, the effect of continuous and periodic exposure to low‐intensity white light at 22 °C on postharvest senescence of broccoli heads was assayed. RESULTS: Exposure to a constant dose of 12 µmol m^?2 s^?1 was selected as the most suitable treatment and was employed for subsequent experiments. During the course of the treatments, hue and L* values as well as chlorophyll content and visual observation of florets indicated an evident delay in yellowing in treated samples compared with controls. No statistically significant differences in total protein content were found, but soluble protein content was higher in treated samples. Total and reducing sugar as well as starch levels decreased during postharvest senescence, with lower values in control samples. CONCLUSION: The results of this study indicate that storage under continuous low‐intensity light is an efficient and low‐cost treatment that delays postharvest senescence while maintaining the quality of harvested broccoli florets. Copyright © 2010 Society of Chemical Industry     

茉莉酸甲酯诱导的采后果蔬抗病性及其机制研究进展

茉莉酸甲酯(methyl jasmonate, MeJA)是一种广泛存在于植物中的天然植物激素,参与植物的许多代谢过程包括生长、发育、成熟、衰老、抵御生物和非生物胁迫等。由病原真菌侵染引起的果蔬采后病害是导致果蔬贮藏和运输过程中品质劣变和腐烂的原因之一,不仅对生产者和消费者造成巨大经济损失,还会在组织体内产生危害人体健康的有毒次生代谢产物。因此,开发绿色安全的果蔬采后病害控制技术具有重要意义。本文总结了采前和采后MeJA单独或与其他物理、生物方法复合处理对果蔬采后主要真菌性病害的控制作用,并从活性氧代谢、病程相关蛋白的积累、苯丙烷代谢、多胺代谢、能量代谢、细胞壁物质代谢、转录调控等方面详细阐述了其诱导抗性机制,以期为MeJA广泛用于控制果蔬采后病害提供实践参考和理论依据。     

低温维持果蔬采后活性氧代谢平衡的抗氧化转录调控机制研究进展

果蔬采后活性氧（reactive oxygen species,ROS）代谢失衡造成氧化胁迫,加速品质劣变,破坏其商业价值。文章以ROS代谢与果蔬贮藏品质的关系为切入点,探讨低温诱导抗氧化酶活性延缓果蔬采后品质劣变的作用;同时,从转录调控角度综述bHLH、WRKY及NAC等低温响应转录因子参与果蔬采后抗氧化作用,进而揭示低温延缓果蔬品质劣变的抗氧化转录调控作用的可能机制,旨在为开展果蔬采后品质生理生化及分子生物学等基础研究及进一步阐明果蔬采后成熟衰老和品质劣变机制提供新的理论依据。     

微酸性电解水对采后西兰花贮藏品质的影响

为了探究微酸性电解水（Slightly acidic electrolyzed water,SAEW）对采后西兰花贮藏品质的影响,本研究首先进行了微酸性电解水浓度的筛选,将西兰花切成均等的小花球,随机分成五组,以自来水浸泡15 min后晾干作为对照,以25、50、75和85 mg/L的微酸性电解水浸泡15 min后晾干作为不同处理组,置于15±1 ℃贮藏4 d,依据不同浓度微酸性电解水对采后西兰花外观品质、总叶绿素及丙二醛（MDA）含量的影响筛选最适宜的浓度。结果表明,与对照和其它浓度的SAEW处理相比,50 mg/L SAEW可更好地维持采后西兰花的外观品质及总叶绿素含量,并抑制其MDA含量的积累。进一步研究显示,与对照组相比,50 mg/L SAEW可有效维持采后西兰花的感官品质,抑制其菌落总数的升高,延缓其维生素C、可溶性糖、可溶性蛋白、可滴定酸、总硫苷和萝卜硫素含量的下降,并可有效抑制组织中亚硝酸盐含量的升高。这些结果表明50 mg/L SAEW可作为一种维持采后西兰花贮藏品质、延缓其衰老进程的有效处理方法。     

鲜黄花菜衰老机制与采后贮藏保鲜技术研究进展

黄花菜是我国传统的特色蔬菜,具有较高的营养价值和经济价值,但是其采后极易衰老腐烂。本文系统综述了近年来有关鲜黄花菜衰老的生物学变化、生理生化代谢机制、影响因素及采后贮藏保鲜技术等方面的研究进展,为深入认识鲜黄花菜衰老机制、提高采后鲜黄花菜贮藏保鲜效果提供参考。     

硫化氢在采后果蔬贮藏保鲜中的应用

硫化氢作为植物体内的一种气体信号分子,可以调节植物的代谢,影响采后果蔬贮藏期间的生理活动及营养品质。硫化氢能够参与调控果蔬的成熟衰老,激发防御基因的表达,诱导植物的病伤害反应、抗性的形成,延缓其采后衰老,延长货架寿命。本文综述了国内外关于硫化氢在采后果蔬贮藏保鲜中的研究进展,从采后生理学角度出发,对硫化氢在果蔬的代谢过程中的作用进行阐述,主要对感官品质、能量代谢、呼吸强度、乙烯生成、褐变和病害6个方面进行探讨,以期为今后硫化氢在果蔬保鲜上的研究及应用提供参考依据。     

能量状态在果蔬采后衰老中的作用及其调控研究进展

能量是采后果蔬维持正常生理代谢活动的基础。近年来的研究表明,能量亏缺是导致采后果蔬衰老的重要因素。本文从采后果蔬的呼吸代谢、活性氧和细胞膜完整性与能量状态的关系等方面阐述能量状态在果蔬采后衰老中的作用,并对采后果蔬能量状态的调控措施以及调控机制等方面的研究进展进行综述。此外,从能量合成、转运、耗散和感知相关基因在转录和蛋白水平的表达与调控,采后果蔬衰老的起始因子,能量亏缺的应激反应等方面进行展望,旨在为从能量角度探究采后果蔬衰老的机制和研发果蔬采后保鲜新技术提供参考。     

褪黑素调控果蔬采后保鲜研究进展

褪黑素是一种广泛存在于生物体中的吲哚胺类化合物,已经被证实广泛分布在高等植物的组织和器官中,具有调节植物种子萌发、生长发育、抗逆性以及成熟衰老等重要作用。最新研究表明褪黑素在延缓果蔬采后衰老和品质劣变中具有显著的调控作用。本文首先简述植物中褪黑素合成途径、部分果蔬中褪黑素的含量及其影响因素,重点综述褪黑素对果蔬采后生理（呼吸作用、乙烯生成、抗氧化酶活力）和品质（色泽、生物活性物质、抗氧化活性）的调控作用,并对其可能的调控机制进行详细解析,最后归纳褪黑素在果蔬采后保鲜研究中存在的问题和将来的研究重点,为今后褪黑素在果蔬采后保鲜中的研究和应用提供参考。     

Lipoxygenase activity associated to fruit ripening and senescence in chayote (Sechium edule Jacq. Sw. cv. “virens levis”)

Lipoxygenase (LOX) enzyme activity and their putative isoforms were investigated during postharvest life in chayote fruit (Sechium edule Jacq. Sw. cv. “virens levis”). Possible associations of LOX with fruit quality parameters are discussed. Five LOX isoforms were identified (SeLOX‐1 to ?5) displaying different activity patterns during ripening and senescence as well as in roots, stems, and leaves. The probable role of SeLOX‐5 as a specific isoform linked to senescence was examined. The highest relative activity of LOX was registered in fruit tissue, followed by leaves, stem, and roots. Correlations were found between LOX and fruit composition variables such as the contents of linoleic (LA) and linolenic (LNA) acids, weight loss, CO₂ and ethylene production rates. LOX activity, and LA and LNA concentration decreased from Day 1 to Days 13–17, when early seed germination events became visible, indicating a transition stage between late fruit ripening and early senescence characterized by a deteriorative process.

Practical applications

Detrimental effects on fruit composition variables such as dehydration, weight loss, wilting, and sprouting symptoms, have been reported as the main causes that reduce the commercial quality and shelf life in chayote fruit and prevent their export to distant markets. To the best of our knowledge, the association of lipoxygenase (LOX) enzymes to non‐climacteric fruit ripening—like chayote—or their loss of commercial quality during prolonged shelf life has not yet been described. This is the first study that explores the role of chayote LOX activity in fruit, identifies various specific LOX isoforms associated to ripening or to the senescence process and provides new evidence that supports the hypothesis that putative LOX isoforms might be related to several postharvest detrimental effects on chayote fruit. This information could be useful to food processors or packers to pursue better profitability and consumer satisfaction.     

Postharvest Heat Treatment for Mitigation of Chilling Injury in Fruits and Vegetables

Low-temperature storage is widely used as a postharvest treatment applied for delaying senescence in vegetables and ornamentals and ripening in fruits, upholding their postharvest quality. But the refrigerated storage of tropical and subtropical crop plant species provokes a set of physiological alterations known as chilling injury (CI) that negatively affect their quality and frequently renders the product not saleable. The increasing demand for consumption of fresh fruits and vegetables, along with restriction on the use of synthetic chemicals to reduce CI, has encouraged scientific research on the use of heat treatments as an environment-friendly technology for CI mitigation. Membrane damage and reactive oxygen species production are multifarious adverse effects of chilling as oxidative stress in sensitive fruits and vegetables. Chilling mitigation in heat-treated fruits and vegetables could be attributed to (1) enhancement of membrane integrity by the increase of unsaturated fatty acids/saturated fatty acids (unSFA/SFA) ratio; (2) enhancement of heat shock protein gene expression and accumulation; (3) enhancement of the antioxidant system activity; (4) enhancement of the arginine pathways which lead to the accumulation of signaling molecules with pivotal roles in improving chilling tolerance such as polyamines, nitric oxide, and proline; (5) alteration in phenylalanine ammonia-lyase and polyphenol oxidase enzyme activities; and (6) enhancement of sugar metabolism. In the present review, we have focused on the impacts of heat treatments on postharvest chilling tolerance and the mechanisms activated by this environment-friendly technology in fruits and vegetables.     

Effect of chitosan on incidence of brown rot,quality and physiological attributes of postharvest peach fruit

The effect of chitosan (5.0 and 10.0 mg ml ⁻¹) on the incidence of brown rot (caused by Monilinia fructicola), quality attributes and senescence physiology of peaches was investigated. It was found that both concentrations of chitosan reduced the incidence of brown rot significantly and delayed the development of disease compared with the control, but were less effective than the fungicide prochloraz. Chitosan‐treated peaches were firmer and had higher titratable acidity and vitamin C content than prochloraz‐treated or control peaches. Compared to control (water‐treated) peaches, chitosan‐treated peaches showed lower respiration rate, less ethylene and malondialdehyde (MDA) production, higher superoxide dismutase (SOD) activity and better membrane integrity. Hence it can be concluded that chitosan has the potential to control brown rot, preserve valuable attributes and prolong the shelf life of postharvest peaches, presumably because of its antifungal property and inhibition of the ripening and senescence process of postharvest peaches. © 2000 Society of Chemical Industry     

基于iTRAQ技术研究采后1-甲基环丙烯和乙烯利处理对茭白线粒体蛋白质组变化的影响

为探讨茭白采后衰老的分子机制,应用同位素标记相对与绝对定量蛋白质组学技术研究了茭白常温贮藏期间线粒体蛋白质表达谱的变化及1-甲基环丙烯（1-methyleyelopropene,1-MCP）和乙烯利（ethylene,ET）处理对茭白线粒体蛋白质组变化的影响。结果表明：共鉴定到肽段数大于等于2的可信蛋白1 908 个,与贮藏0 d相比,对照（CK）组、ET和1-MCP处理组茭白贮藏3 d和6 d后,共有315 个蛋白表达量变化倍数在2.0 倍以上且重复组数据统计学差异显著（P＜0.05）。生物信息学分析显示代谢途径、次生代谢产物生物合成、氨基酸生物合成与代谢、核苷酸代谢、含碱基小分子代谢途径等可能与茭白采后衰老有关,三羧酸循环、氧化磷酸化、磷酸戊糖途径、C5支链二元酸代谢及氨基酸代谢途径可能在茭白采后衰老中发挥重要作用。这些差异表达蛋白的生物学功能分析表明,茭白采后碳水化合物水解加速,磷酸戊糖途径加强而糖酵解途径和氧化磷酸化减弱,导致能量合成减少,同时形成氧化胁迫,这可能激活Ca2＋/MAPKs、细胞色素c和茉莉酸等信号途径,造成初级代谢紊乱和次级代谢产物（如木质素）积累,从而促进细胞凋亡或细胞坏死,最终加速衰老。     

Reduction of energy usage in postharvest horticulture through management of ethylene

Cool chain management is the preferred technology to extend the postharvest life of horticultural produce, but with rising energy costs and community pressure to reduce greenhouse gas emissions, there is a need to use less energy‐intensive technologies. Minimising the level of ethylene around horticultural produce inhibits ripening and senescence and therefore has the potential to reduce the use of refrigeration. The long‐distance transport of bananas within Australia and from Central America to Europe is used as a case study to show that the need for refrigeration could be reduced if the appropriate concentrations of ethylene were maintained around fruit during transit. Data are also presented to show a similar benefit of ethylene control with green beans, as well as another study showing that apples treated with the ethylene action inhibitor 1‐methylcyclopropene could be stored at a higher temperature without loss of quality to the consumer. The range of technologies available to manage ethylene levels is discussed. © 2014 Society of Chemical Industry     

采后黄金百香果失水规律及其与品质劣变的关系

采后失水是百香果果实在贮运流通和销售环节最显著的品质劣变特征之一,严重影响其商品价值。本文利用低场核磁共振技术（Low Field Nuclear Magnetic Resonance,LF-NMR）研究采后黄金百香果果实在贮藏过程中的失水过程,并解析失水规律与品质劣变的关系。LF-NMR结果显示,黄金百香果在贮藏过程中,果浆和果皮的质子密度大幅下降,与外观严重失水表现一致;此外,果实失水以自由水为主,其含量下降了14.98%,结合水在贮藏后期显著减少,失水程度与果实采后成熟和衰老进程有关。进一步研究表明,黄金百香果采后成熟期有两个呼吸高峰,此时失水及其引起的失重较小,果皮叶绿素减少和类胡萝卜素增加促进了亮度和色调升高,果浆可溶性固形物保持在较高含量,可滴定酸含量和果实硬度均下降,果实正常完成后熟,极少出现腐烂;而在果实衰老期,呼吸速率下降,失水和失重加剧,果皮类胡萝卜素的迅速减少降低了表面亮度和色泽,果浆可溶性固形物和可滴定酸含量以及果实硬度下降,腐烂率迅速升高。因此认为,黄金百香果完熟后严重失水,不仅造成果实失重、失鲜,还可加剧其生理代谢以及细胞和组织结构变化,降低果实耐贮性,加快品质劣变。本研究可为百香果采后失水劣变机制和相应保鲜控制技术研究提供参考,并为果蔬采后水分状态的无损检测提供借鉴。     

豇豆采后保鲜技术的研究进展

豇豆在我国各地广泛种植,属于消费量较高的豆类蔬菜。其营养丰富,富含蛋白质、碳水化合物、维生素和矿物质元素,经济价值较高。但是,豇豆属于季节性蔬菜,销售具有季节性和区域性的限制,又因果荚组织幼嫩、呼吸强度很高,采后极易产生成熟衰老、锈斑化、冷害等问题,导致品质降低、营养成分流失、腐烂变质,严重影响食用价值。保鲜技术的应用可以对豇豆采后的营养品质、感官品质、酶活性等起到一定的作用,达到保持豇豆良好品质风味、延长货架期的目的。因此,该研究从物理保鲜技术、化学保鲜技术两个方面对豇豆的采后保鲜研究进行了总结,旨在为豇豆采后贮藏保鲜技术研究提供理论参考,缓解局部产量过剩、供过于求的局面,改变豇豆采后保鲜的现状。     

Tools to maintain postharvest fruit and vegetable quality through the inhibition of ethylene action: a review

Ethylene is a plant hormone controlling a wide range of physiological processes in plants. During postharvest storage of fruit and vegetables ethylene can induce negative effects including senescence, over-ripening, accelerated quality loss, increased fruit pathogen susceptibility, and physiological disorders, among others. Apart from the endogenous ethylene production by plant tissues, external sources of ethylene (e.g. engine exhausts, pollutants, plant, and fungi metabolism) occur along the food chain, in packages, storage chambers, during transportation, and in domestic refrigerators. Thus, it is a great goal in postharvest to avoid ethylene action. This review focuses on tools which may be used to inhibit ethylene biosynthesis/action or to remove ethylene surrounding commodities in order to avoid its detrimental effects on fruit and vegetable quality. As inhibitors of ethylene biosynthesis and action, good results have been found with polyamines and 1-methylcyclopropene (1-MCP) in terms of maintenance of fruit and vegetable quality and extension of postharvest shelf-life. As ethylene scavengers, the best results can be achieved by adsorbers combined with catalysts, either chemical or biological (biofilters).     

水杨酸用于水果采后贮藏保鲜的研究进展

综述近年来使用水杨酸减少水果腐烂、延缓采后果实成熟衰老、保持果实品质、增强果实抗冷害性能和诱导采后果实对病原菌的抗性等方面的研究进展,并展望水杨酸用于水果采后贮藏保鲜的趋势和研究方向.     

二氧化碳处理对不结球白菜采后品质及过氧化氢清除系统的影响

不结球白菜采后贮藏过程中品质易发生变化。贮藏过程中采用二氧化碳气体（CO2）处理可以延缓采后不结球白菜的衰老进程。减少重要营养物质维生素C（Vc）、可溶性蛋白和叶绿素的损失;CO2处理可抑制过氧化氢清除酶系统中的过氧化氢酶（CAT）、抗坏血酸过氧化氢酶（APx）和过氧化物酶（POD）活力的升高。50％和100％的CO2处理都可延缓采后不结球白菜贮藏过程中品质的下降,而前者的处理效果要优于后者。在室温下（25℃）CO2处理对品质的保持效果较明显．4℃下CO2处理的效果并不明显;在CO2处理的条件下,不同温度处理对品质的改变也不明显,因此不结球白菜采后短期保存可单独采取CO2处理或低温贮藏的方法。     

1-甲基环丙烯在抑制果实衰老软化方面的应用

1-甲基环丙烯是一种乙烯作用抑制剂,可以延缓果实采后衰老与软化,提高果实的贮藏品质和货架寿命。概括了1-甲基环丙烯抑制果实衰老软化的作用效果及常见果品1-MCP处理的最佳温度、时间,展望了1-MCP在果实贮藏保鲜上的应用现状及前景。     

1-MCP应用于芒果贮藏保鲜的研究进展

呼吸跃变型水果芒果对乙烯非常敏感。1-MCP是一种有效的乙烯作用抑制剂,它能抑制乙烯所诱导的与果实后熟相关的一系列生理生化反应,进而延缓采后呼吸跃变型果实的衰老进程,保持果实的贮藏品质。综述了1-MCP的作用机理及1-MCP对采后芒果的呼吸速率、乙烯产量、果实品质及生理病害等生理生化指标的研究现状,同时介绍了1-MCP结构类似物以及1-MCP结合其他保鲜方法的应用情况,并对1-MCP应用前景进行了展望,以期为1-MCP在芒果贮藏保鲜中的应用和研究提供参考。