预冷对黄冠梨贮藏品质和果皮褐变的影响

研究了贮前预冷对不套袋和套袋（外灰内黑、外黄内白双层纸袋）黄冠梨贮藏品质和果皮褐变的影响,结果表明：套袋黄冠梨果皮褐变明显重于不套袋果实,并以套外黄内白袋的果实褐变严重。预冷对黄冠梨可溶性固形物（TSS）没有显著影响,但加快硬度下降,在一定程度上延缓了可滴定酸含量下降,并减轻果皮褐变的发生率,特别是对减轻套外黄内白袋果褐变效果非常明显。相关分析表明,预冷主要通过影响不套袋果实果皮酚含量,套外灰内黑袋果实果皮POD活性和套外黄内白袋果实果皮PPO活性来调控果皮褐变的。     

贮藏温度对“保研-7号”红毛丹果皮褐变及果肉品质的影响

以海南"保研-7号"红毛丹为材料,研究不同贮藏温度(2、5、8、13、21℃)对红毛丹果皮褐变及贮藏品质的影响。结果表明,红毛丹在21℃贮藏第7天果皮褐变指数高达0.87,已无商品价值;5℃贮藏能较好地保持红毛丹果皮和果肉品质,显著抑制红毛丹果实呼吸作用及果皮褐变,保持红毛丹果皮和果毛颜色,14 d好果率达89%,较好地保持果实可溶性固形物含量(SSC),降低可滴定酸(TA)含量,保持较高的固酸比和VC含量,抑制细胞膜相对电导率升高。说明5℃为红毛丹果实贮藏适合的温度;8℃贮藏10 d内能够保持果皮和果肉新鲜品质;2℃贮藏7 d果皮颜色迅速褐变,果毛失水严重,出现明显冷害,同时SSC和VC损失增加,固酸比降低,果皮细胞相对电导率明显增加,红毛丹外观品质急剧降低。     

黄瓜果皮颜色的遗传规律与分子机理

黄瓜(Cucumis sativus L.)是重要蔬菜作物之一。黄瓜果皮颜色作为最直接的外观品质,具有重要的商品价值。黄瓜果皮颜色性状为数量性状,其遗传表达受到环境的影响。目前控制黄瓜果皮颜色的5个主要基因已被克隆。其中CsaARC5和CsYcf54控制黄瓜浅绿色果皮,w基因控制白色果皮,CsMYB36基因控制黄绿色果皮以及CsMYB60基因控制橙色果皮。它们均通过调控叶绿素以及类黄酮代谢途径来决定黄瓜果皮颜色。本综述总结了近年来黄瓜果皮颜色的遗传规律与分子机理的研究进展,为进一步完善黄瓜果皮颜色调控机制提供参考。     

鸭梨内在品质与低O_2高CO_2诱导组织褐变的关系初探

为研究鸭梨可溶性固形物(SSC)等内在品质对其组织褐变发生的影响,进而为鸭梨组织褐变采前防控技术提供理论依据,利用K-BA100R型无损水果糖度检测仪,按SSC高低对鸭梨进行分级,贮于0℃环境中,分别采用1%O2+10%CO2浓度的气体进行诱导褐变处理15 d和30 d,分析鸭梨果实采后品质与其组织褐变的关系。结果表明,诱导处理30 d,鸭梨果皮和果肉褐变指数与SSC分别呈极显著(R=0.999,R=0.992)正相关,与果实单果重呈显著(R=0.965,R=0.959)正相关,与可滴定酸(TA)含量呈显著负相关(R=-0.958,R=-0.966)。随着诱导时间的延长,果实组织褐变程度越重,TA和VC含量下降明显,且鸭梨果皮、果肉和果心组织的细胞膜透性增大。同时,在鸭梨果皮组织中,N、Ca和B元素的含量越高,则果皮无褐变或褐变程度较轻;在果肉和果心组织中,无褐变或褐变相对较轻的果实,其K和B元素含量较高;褐变程度较重的果实,其组织中的Ca含量较低。表明鸭梨果实的TA与VC含量及K、B、Ca等元素含量与其组织褐变关系密切,提高鸭梨果实的内在品质可在一定程度上减少褐变的发生,而SSC含量与高CO2伤害型黑心病的发生程度无明显规律。     

宣化马奶葡萄采后果实褐变机理的探究

以宣化马奶葡萄为试材,测定采后果实的褐变指数、5-羟甲基糠醛(5-HMF)、相对电导率及果皮硬度等指标,以明确马奶葡萄的褐变类型及易发生褐变的原因。结果表明:酶促褐变是马奶葡萄采后褐变的主要类型;马奶葡萄细胞膜透性的增大是酶和底物接触反应的关键;果皮硬度较小导致其极易受损,活性氧清除酶活性下降导致自由基的增加,促进了膜脂过氧化进程,加速了膜系统完整性的破坏,为酶和底物接触反应创造了条件;多酚氧化酶和过氧化物酶活性的升高也加快了马奶葡萄的褐变。     

园艺作物果实皮色遗传研究进展

果实皮色不仅是园艺作物最重要的外观品质之一,也是消费者进行选择时的最直观评价标准。随着育种目标目前向多样化和专用化方向进行转变,果实皮色的多样化也成为重要的育种目标之一。本文在论述园艺作物果皮颜色测定方法的基础上,对园艺作物果实皮色性状遗传规律等开展综述,并对园艺作物果皮颜色性状的紧密连锁的分子标记及QTL定位进展进行了归纳。研究认为,颜色性状的紧密连锁的分子标记及QTL定位大都分布在第2、第4和第5条染色体上,部分研究对控制果实皮色的相关基因进行了克隆,目前获得了Vvmyb A1、Pav MYB10、CCS基因,这些基因涉及控制果实皮色位点的基因家族。总的来说,果实皮色作为非常重要的农艺性状,对其开展相关的测定方法、遗传规律、分子标记和数量性状定位以及基因克隆等研究,将对园艺作物的皮色育种奠定非常重要的基础。     

浸钙、壳聚糖浸泡和温烫处理对台湾青枣果皮褐变的影响

为了探索抑制台湾青枣(Ziziphus mauritiana Lamk.)果皮褐变的绿色冷藏保鲜前处理技术及其抗活性氧损伤的生理机理,采用正交试验设计法,对台湾青枣果实经过浸钙、壳聚糖浸泡和温烫处理,探讨3因素处理后对冷藏台湾青枣果皮褐变的影响。结果表明：浸钙和温烫处理能抑制果皮褐变和降低果皮丙二醛(MDA)含量,而壳聚糖浸泡处理则加剧果皮褐变和提高果皮MDA含量;浸钙和温烫处理抑制果皮PPO活性,而壳聚糖浸泡处理则提高了果皮PPO活性;浸钙和温烫处理能提高果皮SOD和POD活性,壳聚糖浸泡处理则抑制了果皮SOD和POD活性;3因素处理对果皮CAT活性无抑制作用,在高峰期还呈现提高果皮CAT活性的效果。可见,浸钙和温烫处理能改善台湾青枣果实贮藏效果和减轻果皮活性氧损伤。     

1-MCP对南果梨冷藏防褐保鲜作用的初探

以南果梨为试材,在冷藏条件下,采用1-MCP处理技术对南果梨果实不同部位褐变底物及相关酶的变化规律进行研究。结果表明,1-MCP处理可显著地抑制果实呼吸强度,明显地抑制果实中酚类物质变化,抑制了果实中多酚氧化酶活性、脂氧合酶活性、丙二醛含量、果皮相对电导率上升,延缓果皮叶绿素含量、果皮褐变指数的变化进程。     

丰水梨果实采后生理生化变化的研究

研究了20℃、相对湿度80％～85％条件下丰水梨果实采后软化与褐变的生理生化变化规律。结果表明,丰水梨具有呼吸和乙烯跃变期,跃变期过后果肉硬度下降幅度较小．但果实风味急剧下降。跃变前期果肉快速软化是由乙烯和淀粉酶共同参与,之后果肉软化是由PG和纤维素酶共同作用的结果。果实不同部位褐变度、酚类物质、类黄酮及丙二醛含量均为果皮〉果心〉果肉．PPO活性依次为果心〉果皮〉果肉,果皮相对电导率低于果肉和果心。影响丰水梨贮藏品质的关键因素是果肉软化和风味劣变．而不是褐变。     

黄冠梨果皮褐斑病与Ca,Mg,K营养的关系

对不同果园黄冠梨果实分析表明,与正常果实相比,果皮发生褐斑的果实中Ca含量和Ca/Mg、Ca/K、Ca/(Mg K)比值较低,且果皮中的差别大于果肉。套袋显著降低果皮和果肉Ca含量及Ca/Mg与Ca/K比值,增加果皮的K含量,对果皮和果肉中Mg含量无显著影响。不同单果重果实比较,较小果实的果皮中含有较多的Ca含量及高的Ca/Mg、Ca/K和Ca/(Mg K)比值,发病程度轻,而特大果(>500 g)相反,中等果居中。这些说明,果皮中低的Ca含量以及Ca/Mg、Ca/K、Ca/(Mg K)比值可能是果皮发生褐变的重要原因。     

普通丝瓜果皮颜色性状的遗传研究

对普通丝瓜的果皮颜色性状进行遗传分析,旨在为果皮颜色控制基因的挖掘及外观品质改良提供理论依据。以绿果皮丝瓜材料YX014和白果皮高代自交系丝瓜材料LJ-01为亲本,配制成P₁、P₂、F₁、F₂、B₁、B₂等6个世代,通过目测的方法对6个世代单株的丝瓜果皮色性状观察和分级处理,应用植物数量性状主基因+多基因混合遗传模型对丝瓜果皮色性状进行遗传规律分析。结果表明,普通丝瓜果皮颜色的最佳遗传模型为B-1,即符合2对主基因控制并表现为加性-显性-上位性遗传模型。B₁、B₂和F₂分离世代的主基因遗传率较高,分别为96.4%、99.1%和99.4%。此外,2对主基因的加性效应分别为-2.50和0.00,显性效应分别为0.50和0.48,说明第一对主基因在加性效应中占主导地位,且为负向效应,2对主基因的显性效应近似相等。控制普通丝瓜果皮色的主效基因的遗传力较高,普通丝瓜果皮色遗传改良可以在早期分离世代时进行。     

不同梨果实褐变特异性分析

以黄金梨、大香水、新梨七号为试材,研究了贮藏后梨褐变不同部位酚类物质含量和种类、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性及可溶性蛋白的关系。结果表明,梨果实中的酚类物质以绿原酸为主,果实褐变与酚类物质含量和多酚氧化酶活性,特别是二者在果实中不同部位的分布特性有关。黄金梨果心与其他部位比较具有较高的酚类物质含量和PPO活性。由果皮至果心CAT活性依次降低,而果皮中POD活性极大地高于其他部位。SOD的活性与褐变的直接关系不明显。     

广东鲜食橄榄果实质构特性比较

为比较分析广东省主要鲜食橄榄果实质构特性的差异,探讨鲜食橄榄果实质地评价的量化参数,验证感官评价质地的有效性。采用质构刺穿试验法对7个优质鲜食橄榄品种果肉质构参数和2种水肥管理方式不同成熟期的‘香甜榄’果实品质进行测定和比较分析。结果表明,不同品种之间果肉的各质构参数变异系数为12.57%~23.95%,差异性显著,与感官评价一致;果皮强度与果皮脆性和果皮韧性均呈显著正相关,果皮破裂深度与果肉硬度呈显著负相关。采用本次试验栽培管理方式可以提高橄榄完熟果实可溶性固形物6%、可滴定酸3.5%、单宁54.9%、果皮强度12.7%、果皮脆性23.5%,降低粗纤维10%、果皮韧性13.7%。果实质地品质参数主成分分析表明,果皮强度、果实硬度和纤维指数可作为质地参数量化区分不同品种间的差别,并明确果皮强度、果实硬度分别小于2300、1600 g和纤维指数大于10,为鲜食橄榄果肉质地品质较好的数值范围。研究初步建立了利用质构刺穿试验法量化评价鲜食橄榄果实质地品质的方法。     

Postharvest physiology and browning of longkong (Aglaia dookkoo Griff.) fruit under ambient conditions

Longkong (Aglaia dookkoo Griff.) fruit rapidly loses its yellow skin color and turns brown after harvest. We aimed to elucidate the postharvest physiology and browning mechanism of longkong fruit stored at a 70–85% RH and at room temperature (25 °C). The respiration rate slightly decreased with progressive fruit browning, while ethylene production was dramatically increased. Preliminary experiments showed that ethylene treatment markedly increased peel browning, suggesting that this is induced by ethylene. The peel L-value continuously decreased during storage, in relation to the severity of peel browning. The peel surface morphological data indicated that the ultrastructure of longkong peel collapsed after harvest, especially around brown areas. The total phenolic content of peel tissue rapidly increased, concomitant with rapid increases in phenylalanine ammonia lyase (PAL) activity and browning score on day 2. Tissue from the lower part of the fruit had higher total phenolic contents, as well as polyphenol oxidase (PPO) and PAL activities, compared to the top and middle parts of the fruit; however, peroxidase (POD) activity slightly changed during storage, possibly independent of phenol oxidation. The browning of longkong peel was not associated with changes in soluble solids contents, titratable acidity or ascorbic acid levels.     

橘小实蝇对桃果实的产卵选择

为评估橘小实蝇对桃果的危害风险,以'大久保'、'川中岛'、'中蟠11'、'岱妃'、'中华寿桃'等品种及'莱山蜜'未成熟、近成熟、成熟的果实为材料,探究橘小实蝇在不同品种及3个成熟度果实上的产卵量,测定不同桃果果实生理指标,分析果实品质与橘小实蝇产卵量的相关性;并选取在生产中较为常用的果袋,测定其对橘小实蝇产卵的阻隔效果...     

Use of chlorine dioxide fumigation to alleviate enzymatic browning of harvested ‘Daw’ longan pericarp during storage under ambient conditions

Pericarp browning reduces both the shelf-life and market value of harvested longan fruit stored at room temperature. Our study investigated the efficiency of chlorine dioxide (ClO₂) fumigation at reducing pericarp browning of longan (Dimocarpus longan Lour.) cv. Daw. Fresh longan fruit were fumigated with 0 (control), 2.5, 5, 10 and 25 mg/L ClO₂ for 10 min, before being packed in cardboard boxes, and stored at 25 ± 1 °C, RH 82 ± 5% for 7 days. Fruit treated with ClO₂ had a lower browning index, but higher hue angle (true color), L* (lightness) and b* (yellowness) values than non-treated fruit. The 10 and 25 mg/L ClO₂ treatments were the most effective at extending shelf-life from 1 to 5 days, compared with the control, by reducing pericarp browning, the activities of polyphenol oxidase (PPO) and peroxidase (POD), disease development and by maintaining the highest total phenolic content. However, quality acceptance of fruit treated with 10 mg/L ClO₂ was higher than fruits treated with 25 mg/L, as determined by odor and flavor. Consequently, ClO₂ fumigation at a concentration of 10 mg/L was considered to be the most effective treatment to reduce pericarp browning of longan, whilst maintaining fruit quality.     

云南不同烟区片烟醇化过程色度及主要化学成分变化特征研究

研究云南不同烟区片烟醇化过程中外观颜色以及内在化学物质变化差异,为云南烟区醇化片烟的使用提供理论依据。取云南3个产区片烟进行醇化,对比分析其在醇化过程中的颜色以及内在化学物质变化差异。不同产区片烟在醇化过程中色差值L、b与总糖、总氮、烟碱呈现逐渐下降趋势,云南文山片烟色差值L、色差值b、总糖、总氮下降幅度大于云南保山与云南大理;还原糖与质体色素降解产物先上升后下降,云南大理峰值出现时间晚于云南保山与云南文山;色度值R、苯丙氨酸降解产物、西柏烷类降解产物、棕色化产物逐渐上升,不同产区变化幅度表现为云南文山>云南保山>云南大理。云南文山片烟在醇化过程中,片烟的外观颜色与内在化学物质变化幅度更大,达到最佳醇化期所需时间少于云南大理与云南保山。     

The role of active oxygen metabolism in hydrogen peroxide-induced pericarp browning of harvested longan fruit

Effects of hydrogen peroxide (H₂O₂), as exogenous reactive oxygen, on browning and active oxygen metabolism in pericarp of harvested ‘Fuyan’ longan fruit were investigated. The results showed that as compared with the control fruit, there was a higher browning index in pericarp of H₂O₂-treated fruit. The fruit treated with H₂O₂ resulted in increased rate of superoxide anion (O₂⁻) production, reduced activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), decreased amounts of ascorbic acid (AsA), glutathione (GSH) and carotenoid, and increased malondialdehyde (MDA) content. These results indicated that H₂O₂-induced browning in pericarp of harvested longan fruit might be due to a reducing capacity of active oxygen scavenging and an increase of accumulation of O₂⁻, which might stimulate membrane lipid peroxidation, disrupt cellular membrane structure, and cause the loss of cellular compartmentalization, in turn, resulting in the contact of polyphenol oxidase (PPO) and peroxidase (POD) with phenolic substrates and subsequently oxidation phenolics to form brown polymers.     

The effects of nitric oxide and nitrous oxide on enzymatic browning in longkong (Aglaia dookkoo Griff.)

The effect of nitric oxide and nitrous oxide on pericarp browning of longkong fruit was studied. The fruit was either dipped for 5 min in 0.25 mM sodium nitroprusside (SNP), a nitric oxide donor, or continually exposed to 90% nitrous oxide (N₂O) vapour for 3 h and was compared to the untreated fruit (control). The fruits were then stored at 13 °C and RH of 90 ± 5%. The fruit treated for 3 h with nitrous oxide vapour had delayed pericarp browning with higher phenolic compounds. However, these fruit showed lower levels of phenylalanine ammonia lyase, polyphenol oxidase and peroxidase than the control fruit and those treated with 0.25 mM SNP. Therefore, we conclude that nitrous oxide delays browning and reduces the activities of browning enzymes in longkong pericarp.     

Effects of a phospholipase D inhibitor on postharvest enzymatic browning and oxidative stress of litchi fruit

Membrane lipid degradation catalyzed by phospholipase D (PLD) results in postharvest browning and senescence of litchi fruit. The effects of n-butanol, a specific PLD inhibitor, on enzymatic browning and oxidative stress during storage of litchi fruit at room temperature were evaluated. n-Butanol-treated fruit had a lower browning index and disease index than untreated fruit. n-Butanol treatment also decreased PLD activity. As a result, the decompartmentalization of litchi polyphenoloxidase and substrates was reduced. The conversion of substrates (−)-epicatechin and procyanidin A₂ into quinones was slowed down and enzymatic browning of litchi pericarp tissues was lower after 6 d storage. Additionally, n-butanol-treated fruit possessed significantly lower malondialdehyde contents than untreated fruit after 4 d storage. Analysis of antioxidative enzyme activities showed that n-butanol treatment inhibited oxidative stress mainly by maintaining high catalase activity in litchi pericarp tissues. Consequently, senescence of litchi fruit during storage was moderated.