椪柑浮皮时挥发性成分变化及萜烯类物质合成基因表达特征

以椪柑果实为材料,运用气相色谱-质谱和RNA-Seq技术分析在浮皮时,果皮挥发性物质的变化规律以及萜烯类物质合成途径基因的表达特征。结果表明：从椪柑果皮中鉴定到53?种挥发性物质,其中萜烯类化合物的相对含量为96%。浮皮发生时,果皮挥发性物质的组分并没有改变,但有32?种组分的含量发生了变化;挥发性物质总量在浮皮时降低为正常果实的82%,萜烯类化合物降为正常果实的81.4%。鉴定到12?个萜烯类化合物合成途径的关键基因,大部分在浮皮时表达量降低。本研究首次阐明椪柑果皮挥发性物质组分及含量在浮皮时的变化特征,并且这种含量的降低与萜烯类物质合成途径基因的下调密切相关。     

贮藏温度对耐贮性不同的柑橘品种果皮蜡质含量及其化学组成的影响

为探究果皮蜡质与柑橘果实耐贮性的关系，以广东西江流域著名特产柑橘‘贡柑’（耐贮性较强）、‘砂糖橘’（耐贮性差）果实为试材，采收后装入塑料薄膜保鲜袋中分别在自然室温（（14.2±2.8）℃）和冷库温度（（6.5±0.5）℃）下贮藏90 d，定期检测果实质量损失率、腐烂率、果皮表面结构和蜡质含量及化学组成。结果表明，在不同温度下贮藏，两种柑橘质量损失率和腐烂率显著增加（P＜0.05），表面结构发生改变，果皮蜡质总含量及主要组分（长链脂肪醛、长链脂肪酸、长链脂肪烃、长链脂肪伯醇）含量均显著降低（P＜0.05），冷藏相对于室温贮藏会抑制这些变化，起到关键的保鲜作用。质量损失率、腐烂率均与果皮蜡质总含量及4 类主要组分含量均呈极显著负相关（P＜0.01）；贮藏过程中果皮蜡质不同组分含量的降低幅度存在差异，其中耐贮性较强的‘贡柑’长链脂肪酸含量降幅最大、长链脂肪伯醇含量降幅最小，耐贮性差的‘砂糖橘’长链脂肪伯醇含量降幅最大、长链脂肪酸含量降幅最小；小分子质量的支链烷烃、烯烃和烯醛对贮藏温度的响应更敏感。说明两种柑橘果实的耐贮性与果皮蜡质含量和组分有密切关系。     

脱落酸处理对苹果成熟、乙烯合成及其信号转导基因表达的影响

为研究脱落酸（abscisic acid,ABA）对苹果果实采后成熟、乙烯合成及其信号转导基因表达的影响,本实验以‘Granny Smith’苹果果实为实验材料,将其进行外源ABA处理后置于20 ℃贮藏（以无菌水处理为对照）,测定贮藏过程中的硬度、可滴定酸质量分数、纤维素酶活力、果胶甲酯酶活力、叶绿素含量、内源ABA含量、乙烯产生速率及乙烯生物合成基因（ACO1、ACO2、ACS1、ACS3）、苹果乙烯信号转导基因（ERS1、ERS2、ETR2、ERF3、ERF4、ERF5）的表达量。结果表明,与对照组相比,ABA处理能降低苹果果实贮藏过程中的硬度和可滴定酸质量分数,提高果实中的纤维素酶和果胶甲酯酶活性,促进叶绿素a、叶绿素b和总叶绿素含量降低。定量聚合酶链式反应分析结果表明,与对照组相比,ABA处理能够显著提高苹果乙烯生物合成基因的表达量（P＜0.05）。同时,参与苹果乙烯信号转导的ERS2、ETR2和ERF3、ERF4、ERF5表达量随着果实采后成熟明显增加,并且ABA处理组果实中的表达量总体显著高于对照组（P＜0.05）。综上,外源ABA处理能够促进苹果内源ABA的合成,提高苹果乙烯生物合基因和信号转导基因的表达,促进苹果内源乙烯合成和乙烯信号的转导,加快苹果果实的采后成熟进程。     

6个白葡萄品种类黄酮物质差异分析

该研究利用高效液相色谱（HPLC）技术分析了6个白葡萄品种‘霞多丽’、‘小芒森’、‘贵人香’、‘雷司令’、‘长相思’和‘维欧尼’果皮和种子中类黄酮物质的组成和含量。结果表明,‘长相思’果皮含有较多的黄酮醇（10.61 mg/kg）,显著高于‘贵人香’、‘霞多丽’和‘维欧尼’（P＜0.05）。此外,异鼠李素仅在‘小芒森’和‘长相思’中检测到,芦丁和山奈酚仅在‘贵人香’和‘雷司令’中检测到。‘维欧尼’果皮的黄烷醇含量较高（2.74 g/kg）,‘小芒森’葡萄籽中的黄烷醇含量较高（11.15 g/kg）,均显著高于其他品种（P＜0.05）。基于类黄酮物质含量的主成分分析结果表明,类黄酮类化合物的组成和含量与白葡萄品种密切相关,可以将供试的白葡萄品种区分开。     

苯并噻二唑处理对柑橘果实采后病害控制效果及机制分析

以‘丰脐’柑橘果实为试材,研究了不同浓度苯并噻二唑（benzothiadiazole,BTH）和青霉菌 （Penicillium italicum）、绿霉菌（Penicillium digitatum）、炭疽菌（Colletotrichum gloeosporides）同孔、异孔接 种对柑橘果实青霉病、绿霉病、炭疽病的控制效果,筛选出针对这3 种病害控制效果最适宜的BTH浓度,在此浓 度下考察打孔和浸泡处理对果实果皮内源水杨酸含量和抗病性相关酶活力的影响。实验结果表明：0.25、0.50、 1.00 mmol/L 3 种浓度的BTH与P. italicum、P. digitatum、C. gloeosporioides同孔或异孔接种均可以降低果实青霉病、 绿霉病、炭疽病的病斑直径,其中,0.50 mmol/L的BTH效果最好;在病害发病率方面,3 种浓度的BTH处理均在果 实发病初期有效果,后期效果不显著,相比之下,0.50 mmol/L的BTH效果较好。最适浓度下,通过对果实果皮内源 水杨酸含量和抗病性相关酶活力的研究发现,BTH损伤接种能增加果皮内源水杨酸的含量,BTH浸泡处理对果皮内源 游离态水杨酸含量无显著影响,但能促进果皮内源结合态水杨酸含量的积累;BTH损伤接种和浸泡处理均能增加柑橘 果皮β-1,3葡聚糖酶、几丁质酶、苯丙氨酸解氨酶、过氧化物酶和多酚氧化酶的活力。由此推测,BTH处理诱导柑橘果 实提高了其采后抗病性。     

普通橄榄和清橄榄果实游离氨基酸差异成分与谷氨酰胺代谢

基于高效液相色谱-串联质谱法结合多元统计分析技术测定普通橄榄‘长营’和清橄榄‘清榄1号’果实游离氨基酸的差异成分并对其代谢进行分析,为研究氨基酸在普通橄榄和清橄榄风味贡献上的差异提供依据。通过主成分分析、偏最小二乘投影判别分析和显著性分析确定差异成分,并进行对象之间的相关性分析。结果表明：普通橄榄‘长营’和清橄榄‘清榄1号’果实中游离氨基酸成分存在差异,差异氨基酸为呈甜味的丝氨酸（Ser）、谷氨酰胺（Gln）和呈鲜味的谷氨酸（Glu）,且三者均以‘清榄1号’含量居高,使‘清榄1号’Ser、Gln和Glu对风味的贡献大于‘长营’,与其鲜食品质一致,其中2?个品种平均含量排名为Glu＞Gln＞Ser,差异倍数排名为Ser＞Gln＞Glu,综合2?个指标以Gln为重要氨基酸;‘长营’Gln含量与天冬酰胺合成酶（asparagine synthetase,AS）呈显著（P＜0.05）负相关（r=－0.792）,与可溶性糖呈显著（P＜0.05）负相关（r=－0.711）,与蔗糖和还原糖相关性不显著（P＞0.05）,‘清榄1号’Gln含量与AS活性相关性不显著（P＞0.05）,与蔗糖呈极显著（P＜0.01）正相关（r=0.953）,与可溶性糖呈显著（P＜0.05）正相关（r=0.791）,与还原糖呈显著（P＜0.05）负相关（r=－0.780）,2?种橄榄Gln含量与其代谢酶和糖类的相关性存在差异;综上揭示了游离氨基酸对普通橄榄和清橄榄风味贡献存在差异,特别是Gln对2?类橄榄的影响且其可能通过调控AS活性和糖代谢来实现对其含量的调控进而影响果实风味。     

不同品种薄皮甜瓜成熟期果实质地品质分析及综合评价

以10 个品种薄皮甜瓜为研究对象,采用质构仪与常规理化分析测定了8 个质构指标、6 个质地相关的化学指标,通过相关性分析、因子分析、系统聚类分析,建立一套综合评价薄皮甜瓜果实质地品质的方法,以期为深入探究决定其质地特性的关键因子和优良质地品种选育提供理论依据。相关性分析表明,质构剖面分析（texture profile analysis,TPA）硬度与胶着性、咀嚼性和穿刺硬度均呈极显著正相关（P＜0.01）,黏附力与黏附性呈极显著正相关（P＜0.01）,内聚性与胶着性、咀嚼性均呈显著正相关（P＜0.05）,胶着性与咀嚼性呈极显著正相关（P＜0.01）,穿刺硬度与胶着性和咀嚼性均呈极显著正相关（P＜0.01）;原果胶含量和含水量与TPA硬度、穿刺硬度、咀嚼性和胶着性呈不同程度显著负相关（P＜0.05）,水溶性果胶含量与穿刺硬度呈显著负相关（P＜0.05）,淀粉含量与黏附力和黏附性呈显著正相关（P＜0.05）,纤维素含量与内聚性呈显著负相关（P＜0.05）。经因子分析并基于特征值大于1的原则,提取了3 个主因子,累计方差贡献率为89.40%,根据各主因子代表性指标,依次命名为梗硬因子F1、黏绵因子F2和内聚因子F3,方差贡献率分别为52.76%、25.73%和10.91%,因子分析综合得分模型显示,‘玉美人’和‘彩虹七号’质地品质较优,‘红皮面’和‘香沙蜜’较差,其余品种居中。系统聚类分析将10 个品种薄皮甜瓜果实的质地特性分为5 类,第I类包括‘千玉’、‘白糖罐’、‘特甜蜜宝’,呈脆硬质地;第II类包括‘红到边’、‘羊角蜜’,呈酥脆质地;第III类包括‘花蕾王’、‘彩虹七号’、‘玉美人’,呈梗硬质地;第IV类为‘香沙蜜’,呈沙软质地;第V类为‘红皮面’,呈黏绵质地。     

‘红富士’苹果气调贮藏期间果皮色泽变化及花青苷合成相关基因相对表达量的差异比较

研究采收时苹果果皮颜色对气调贮藏期间果皮色泽及花青苷合成相关基因相对表达量的影响,为苹果贮藏保鲜提供理论依据。以2种不同色泽的‘红富士’苹果为试材,采用色差仪、紫外分光光度计和荧光定量聚合酶链式反应法分别测定贮藏期间果皮色值、花青苷、叶绿素含量及花青苷相关合成基因的相对表达量变化。贮藏过程中,花青苷含量出现波动变化,其中着色好的苹果果皮中花青苷含量下降幅度为51.36%~69.51%,而着色差的苹果花青苷含量下降幅度为74.45%~95.30%;着色好的叶绿素含量下降显著高于着色差的苹果。采收时着色好的苹果果皮中花青苷合成相关基因除LDOX外,相对表达量均显著高于着色差的苹果;随着贮藏时间的延长,2种不同色泽的苹果果皮中花青苷合成相关基因的相对表达量均显著降低;但在贮藏后期着色差的苹果果皮中CHI、F3H、DFR、ANR相对表达量显著高于着色好的苹果。随着贮藏时间的延长,花青苷合成相关基因的相对表达量显著降低,导致花青苷合成速率下降,花青苷降解,果实发生果皮褪色现象。采收时着色差的‘红富士’苹果在气调贮藏期间比着色好的苹果更容易发生果皮褪色现象。     

α-松油醇对指状青霉抑霉唑抗性菌株Pdw03的抑制作用

本研究探讨了α-松油醇对指状青霉抑霉唑抗性菌株Pdw03的抑制作用及其抑菌机理。体外实验结果表明α-松油醇抑制Pdw03生长的最小抑菌浓度（minimal inhibitory concentration,MIC）和最小杀菌浓度（minimal fungicidal concentration,MFC）均为4.00 μL/mL;体内实验研究发现MFC和5 MFC α-松油醇可明显降低接种Pdw03椪柑果实的绿霉病发病率和发病直径;碘化丙啶（propidium iodide,PI）染色实验发现,经1/2 MIC α-松油醇处理后,Pdw03的细胞膜完整性降低,麦角固醇含量显著降低（P＜0.05）,麦角固醇合成相关基因ERG9表达量显著下调（P＜0.05）。综上,α-松油醇通过抑制ERG9基因的表达影响菌株Pdw03的生长,可作为采后柑橘病害防治的有效替代品。     

欧亚种‘丹娜’葡萄不同砧穗组合果实香气物质的差异比较

利用气相色谱-质谱联用技术，连续两年（2016和2017年）研究了‘1103P’、‘140R’、‘101-14’、‘3309C’、‘SO4’和‘贝达’6 种砧木嫁接对‘丹娜’（Vitis vinifera L. cv. ‘Tannat’）葡萄果实香气物质积累的影响。结果表明：2016年，不同砧木对果实香气影响更加显著，其中‘1103P’可以显著提高‘丹娜’葡萄果实C6/C9类物质的总含量，游离态的己醇、(Z)-3-己烯醇、(E)-2-己烯醛和正己醛是其特征性的C6/C9化合物；‘140R’有利于‘丹娜’葡萄果实酯类物质的合成；而‘3309C’则降低了‘丹娜’葡萄果实酯类、C6/C9类和挥发性酚类香气物质的含量。‘贝达’和‘SO4’在两个年份中均提高了‘丹娜’葡萄果实萜烯类物质的含量；‘SO4’还可以显著提高‘丹娜’葡萄果实C13-降异戊二烯类物质的含量，其特征性C13-降异戊二烯类化合物为游离态(E)-β-大马士酮和(Z)-β-大马士酮。本研究可以为实际生产中‘丹娜’葡萄嫁接砧木的选择与应用提供一定的参考。     

外源脱落酸对发芽玉米籽粒中类胡萝卜素合成的影响

为研究脱落酸（abscisic acid,ABA）及抑制剂钨酸钠（Na2WoO4）处理对发芽玉米中类胡萝卜素合成的影响,以‘苏玉29’黄色玉米为材料,将其进行不同质量浓度外源ABA浸泡处理后进行发芽,测定发芽玉米中可溶性蛋白、游离氨基酸、脯氨酸、VC、总酚、抗氧化酶活性、抗氧化能力、类胡萝卜素含量及类胡萝卜素合成基因表达量。结果表明,与对照组相比,ABA处理能提高发芽玉米中可溶性蛋白、游离氨基酸、脯氨酸、VC、总酚的含量和内源ABA含量;5 mg/L ABA条件下,类胡萝卜素含量达到最高,叶黄素和玉米黄质分别较对照组提高了27.6%和20.1%,而Na2WoO4会抑制内源ABA的合成,同时降低类胡萝卜素含量。实时聚合酶链式反应结果表明,ABA处理能够显著提高发芽玉米类胡萝卜素合成基因的表达量。同时,发芽玉米籽粒中抗氧化酶活性及抗氧化能力明显增强。综上,外源ABA处理能够促进发芽玉米内源ABA合成,提高发芽玉米类胡萝卜素合成基因的表达,促进发芽玉米中类胡萝卜素的合成,增强发芽玉米抗氧化能力,提高发芽玉米籽粒的营养品质。     

Abscisic Acid in the Response of ‘Fortune’ Mandarins to Chilling. Effect of Maturity and High-Temperature Conditioning

The possible role of abscisic acid (ABA) and peel colour in chilling tolerance of ‘Fortune’ mandarins has been examined. Fruit stored at 2·5°C, but not at 12°C, showed pitting damage. The degree of damage changed considerably during development and maturity from November until May. Green fruit were more tolerant to chilling injury (CI). After colour break, chilling susceptibility increased from the beginning of December until January and February (the coolest season during the growing period) and declined towards May. This trend did not parallel changes in fruit colour index or free and bound ABA levels, which increased from November until May. At the time of chloroplast transformation to chromoplast a noticeable shift in free but not in bound ABA occurred. During storage, free ABA levels increased in fruits stored at 12°C, but not at 2·5°C. Changes in ABA with storage temperature depended on the stage of maturity of the fruits, but not on their susceptibility to CI. It has also been shown that there was no relationship between ABA content following exposure to 37°C and chilling tolerance. At all stages of maturity, the susceptibility of the fruits to CI and the free ABA levels of the flavedo decreased after conditioning the fruits for 3 days at 37°C. After storage at 2·5°C, the ABA levels of the conditioned fruit were similar or even lower than those of non-conditioned fruit. Treatment of fruit for 3 days with 10 μl litre^-1 ethylene increased free ABA about four times, whereas bound ABA remained nearly constant. This treatment enhanced cold-induced peel damage after prolonged storage. Thus, the ethylene-induced changes in free ABA appear not to be related to the induced changes in chilling susceptibility. The results obtained indicated, therefore, that free and bound ABA appear not to be involved on the adaptative mechanism developed in ‘Fortune’ mandarins to cope with chilling stress. © 1997 SCI.     

MAJOR CAROTENOIDS IN JUICES OF PONKAN MANDARIN AND LIUCHENG ORANGE

The identification and quantitation of major carotenoids in juices of Ponkan mandarin and Liucheng orange and their changes during harvesting were studied. Neoxanthin, violaxanthin, lutein, β-cryptoxanthin, α-carotene and β-carotene are the major carotenoids for Ponkan mandarin. During the harvesting period, the contents of violaxanthin, β-cryptoxanthin and β-carotene increase significantly. For Liucheng orange, neoxanthin, violaxanthin, lutein, antheraxanthin, β-cryptoxanthin, α-carotene and β-carotene are the major carotenoids. Among them, neoxanthin, violaxanthin, lutein, antheraxanthin and β-cryptoxanthin increase significantly during the harvesting period. The β-cryptoxanthin and β-carotene are the major contributors to the color of Ponkan mandarin juice while neoxanthin, violaxanthin, lutein and antheraxanthin are the major ones for the color of Liucheng orange juice.     

Carotenoid composition and vitamin A value of the brasilian fruit Cyphomandra betacea

The carotenoid pigments of the fruit of the Tree Tomato Cyphomandra betacea were identified and quantified. β-carotene, β-cryptoxanthin, ζ-carotene, 5,6-monoepoxy-β-carotene, lutein and zeaxanthin were detected in both the pulp and the peel. The quantitative patterns of the pulp and the peel were similar, with cryptoxanthin and β-carotene predominating. The high average vitamin A value (2475 IU/100 g edible portion) is due to the principal carotenoids that have provitamin A activity.     

Storage Stability of Carotenoids in Orange Oil

Citrus essential oils are used as flavoring agents in foods and beverages. Recently a premium price was paid for oils with a high carotenoid content because they were also used as natural coloring agents. Commercially manufactured samples of ‘Pineapple’ oils were concentrated 5, 10, and 25-fold, stored for 12 moat –18, 4, 26, and 32°C and sampled periodically. The carotenoid content was measured spectrophotometrically with β-carotene as a standard. From an initial value of 7.2 mg of β-carotene/100g of oil, it decreased 6.6, 18.4, and 24.6% upon concentrating 5, 10, and 25-fold, respectively. The 25-fold sample lost 6% of its β-carotene at –18°C and 90% at 32°C during 12 mo of storage. There was a highly significant fit of the time, temperature and concentration data to a second order model.     

Increases of 2-Furanmethanol and Maltol in Korean Red Ginseng during Explosive Puffing Process

ABSTRACT: The explosive puffing process may provide characteristic physicochemical properties in red ginseng. The effects of explosive puffing on the changes of volatiles in red ginseng were investigated using headspace-solid phase microextraction (HS-SPME)-gas chromatograph (GC) with a mass selective detector (MS). Formation of porous structures and smaller pieces were clearly observed on the surface of puffed red ginseng by scanning electron microscopy. Total volatiles in puffed red ginseng increased by 87% compared to those in red ginseng. Hexanal, Δ-selinene, and β-panasinsene were major volatiles in red ginseng, whereas aristolene, β-panasinsene, and calarene were main volatiles in puffed red ginseng. Puffing process decreased volatiles from lipid oxidation including aldehydes, ketones, and 2-pentylfuran and increased terpenoids in red ginseng. Selective ion monitoring (SIM) mode for GC/MS results showed that 2-furanmethanol and maltol were present at the concentrations of 0.20% and 0.24%, respectively, in red ginseng and 5.86% and 3.99%, respectively, in puffed red ginseng. The explosive puffing process increased 2-furanmethanol and maltol in puffed red ginseng significantly (P < 0.05) with the changes of microstructures.     

Relationship between Hunter Color Values and β-Carotene Contents in White-Fleshed African Sweetpotatoes (Ipomoea batatas Lam)

White-fleshed sweetpotatoes (Ipomoea batatas (L) Lam) are a major food crop in Uganda. This study was done to evaluate carotenoid content in sweetpotatoes and to relate the color of the sweetpotatoes to the β-carotene present. A Hunter Color Tristimulus Meter was used to determine the color and the β-carotene was determined by reverse-phase HPLC. Regression analysis was carried out on the color values L, a, b, b/a and tan^-1 b/a to determine which color value could be used to express the content of β-carotene in white-fleshed sweetpotatoes. The ‘b’ color value appeared to be the best estimation for correlation at 0·74 in this study for raw roots and 0·09 for purée. The ‘a’ value was 0·39 for raw roots and 0·16 for purée, L was -0·74 for raw roots and -0·45 for purée. © 1997 SCI.     

Carotenoid content and expression of phytoene synthase and phytoene desaturase genes in bitter melon (Momordica charantia)

Momordica charantia, a tropical plant, produces a fruit that has a β-carotene concentration five times higher than that of carrot. To elucidate the molecular basis of β-carotene accumulation in M. charantia, the gene expression levels of phytoene synthase (McPSY) and phytoene desaturase (McPDS) were determined. These levels were particularly high in the flowers of M. charantia. During fruit maturation, the expression levels of McPSY and McPDS decreased during the mid-stages but increased in the fully mature fruit. In addition, carotenoids accumulated as the peel changed from green to orange. Thus, McPSY and McPDS expression correlated with carotenoid accumulation during fruit maturation. Principal component analysis (PCA) also was used to evaluate the differences among the profiles of seven carotenoids identified in the fruit at several maturation stages. Riper fruits had higher carotenoid concentrations than less ripe fruits.