HS-SPME-GC-MS法分析3种块菌子囊果主要挥发性成分

本研究采用顶空-固相微萃取结合气相色谱-质谱联用技术(HS-SPME-GC-MS)比较分析了假喜马拉雅块菌Tuber pseudohimalayense、中华夏块菌T. sinoaestivum和印度块菌T. indicum子囊果主要挥发性有机化合物(volatile organic compounds,VOCs)组成与含量。结果表明,在3种块菌子囊果中共鉴定到173种VOCs,其中假喜马拉雅块菌、中华夏块菌和印度块菌子囊果中分别检测到79、63和71种挥发性成分,3种块菌子囊果中共有成分11种,其中1-辛烯-3-醇是含量最高的共有化合物(39.52%、38.98%和8.46%)。利用挥发性成分对3种块菌种类进行判别分析,结果表明2-丁酮、庚醛、苯乙烯、1-辛烯-3-醇和环十四烷能100.0%地将3种块菌样品按照种类正确分类。本研究初步确定了3种块菌子囊果VOCs组成和含量的差异,并探究了用VOCs相对含量区分3种块菌种类的可行性,为我国块菌质量评价,尤其是加工的块菌商品的鉴别提供了重要的理论依据。     

金菠萝品种果实香气成分和特征香气研究

采用固相微萃取-气相色谱质谱联用法研究了金菠萝品种果实不同部位果肉、中柱和果皮的香气成分,并利用香气值确定了不同部位的特征香气。结果表明:各部位香气组成不同,果肉和中柱部位以酯类为主,果皮部位以萜烯类为主。己酸乙酯和己酸甲酯是果肉和中柱部位含量较高的成分,(Z)-β-罗勒烯是果皮部位含量最高的成分。4-甲氧基-2,5-二甲基-3(2H)呋喃酮和癸醛是果皮香气贡献较大的成分,而2-甲基丁酸乙酯、4-甲氧基-2,5-二甲基-3(2H)呋喃酮和己酸乙酯是果肉和中柱香气贡献较大的成分。金菠萝品种果肉和中柱的香气值与果皮差异较大,且香气值主要集中于果肉。     

枇杷品种香甜和解放钟及两者杂交子代优系果实香气成分分析

采用顶空固相微萃取和气质联用技术,分析测定了果实无明显香味的枇杷品种解放钟和香味明显的品种香甜及其正反交子代中香味明显的优系香钟11号和钟香25号的果肉香气成分。结果表明,4个枇杷品种(系)共检测出11类91种香气成分,其中萜类物质D-柠檬烯相对含量最高(62.59%~68.32%),其次是醛类物质(12.53%~18.15%);亲本香甜香气成分种类最多(62种)、解放钟最少(44种),子代香钟11号、钟香25号介于双亲之间,香甜与2个子代共有成分为38种和36种,解放钟与2个子代共有成分为27种和26种,子代香气成分更多遗传自香甜;主要特征香气成分有D-柠檬烯、(E)-2-已烯醛、正辛醛、正己醛、乙酸苏合香酯、2-甲基丁酸甲酯、庚酸烯丙酯、2-甲基丁酸乙酯等;并讨论了解放钟果肉香味不明显可能的原因。     

中国福建铁观音茶、色种茶、武夷水仙茶和武夷奇种茶的香气成分研究

本文首次报道著名的中国福建乌龙茶:铁观音茶、色种茶、武夷水仙茶和武夷奇种茶的香气成分。上述茶样香气浓缩物,用 GC-MS 和 SCOT 玻璃毛细管柱气相色谱标样叠加法及红外光谱,鉴定出70种香气成分。从中找出了12种典型特征香气成分:苯乙醇、反-芳樟醇氧化物(吡喃型)、顺-芳樟醇氧化物(呋喃型)、3,7-二甲基-1,5,7-辛三烯-3-醇、苯甲醇、反-芳樟醇氧化物(呋喃型)、香叶醇、吲哚、顺-茉莉酮、茉莉酮内酯、橙花叔醇和茉莉酮酸甲酯。从而初步剖析了由不同茶树品种、不同地区以及加工风格差异所形成的香气变化规律。     

木瓜果实贮藏期间香气成分的变化研究

采用同步蒸馏萃取(SDE)法提取不同贮藏期木瓜果实的香气成分,通过GC-MS进行分析,结果表明:木瓜果实成熟后随着贮藏期延长,香气成分总体呈现出醇类、酮类、醛类相对含量下降,酯类、烯烃及萜烯类上升趋势。贮藏初期果实的主要香气成分包括4-甲基-5-(1,3-二戊烯基)-四氢呋喃-2-酮、二氢-β-紫罗兰醇、(Z)-3-己烯醇等。当8℃贮藏40 d时,香气物质主要以萜烯类、酯类和醇类为主,相对含量分别为21.07%、18.73%和16.34%。当贮藏90 d时脂肪酸乙酯类相对含量明显增加,达到34.86%,其中3-壬烯酸乙酯相对含量最高(21.67%),成为构成木瓜香气的关键物质。α-金合欢烯相对含量在整个贮藏期间不断上升,由贮藏初期的3.63%上升到贮藏40 d时的19.00%,当贮藏90 d时达到35.22%。     

海南红厚壳花香气成分采集和TCT-GC-MS分析

用鲜花循环式动态顶空技术采集红厚壳鲜花的香气成分,TCT-GC-MS联用技术分析鉴定。4-羟基-2-丁酮,双烯酮,1、2-环氧-2-甲基丁烷,1、2-环氧-3-甲基丁烷,2-乙基戊烷,3-己醇,甲基环戊烷,2-丁醇等24个成分被检测出,占总离子流出峰面积的90.28%。并对结果进行了分析讨论。     

植物菌根块菌分子鉴定及菌丝培养基优化的研究

块菌属(Tuber)是由真菌感染其适宜植物根系形成,部分块菌如法国黑孢块菌(T. melanosporum)和中国印度块菌(T. indicum)等为珍稀药食两用菌,具有很高的经济价值。对块菌的过度挖掘造成野生块菌资源匮乏,块菌人工栽培技术则是实现块菌产业可持续性发展的重要基础。目前国内外人工栽培主要采用块菌子实体匀浆制成的子囊孢子悬浮液,与人工种植苗木根系共生。利用块菌菌丝替代子实体孢子悬浮液进行接种,具有减少对块菌子实体的依赖性和生产成本、保护林下块菌野生资源、促进块菌人工繁育进程的积极意义,但需要成熟高效的菌丝培养技术。该研究从云南、陕西等地林下采取块菌样品,在ITS分子鉴定并纯化得到纯种菌丝的基础上,以菌丝直径为指标,经单因素实验和4因素3水平正交实验L9(34),筛选得出最适宜的菌丝生长培养基。结果表明:(1)形态和ITS分子鉴定得到的13份块菌样品分属印度块菌(T. indicum)和假凹陷块菌(T. pseudoexcavatum)两种。(2)纯化的印度块菌菌丝培养基的最佳碳源为马铃薯浸出液,最佳氮源为酵母膏,VB1对印度块菌菌丝生长并无显著性促进作用。(3)最佳的碳源、氮源、无机盐组合为马铃薯浸出液150 g·L~(-1)、酵母膏3 g·L~(-1)、MgSO_42 g·L~(-1)、KH2PO42 g·L~(-1)。25℃,自然pH下培养8 d菌丝直径可达49.44 mm。     

藤茶中香气组成的气相色谱测定

本文用GC和GC/MS系统测定了藤茶中的香气组成。鉴定出28种香气成分,占香精油总量的64％。藤茶中的香气主要成分为反-2-已烯醛、乙酸顺-3-己烯酯、三甲基吡嗪、苯乙醛、α-萜品醇、水杨酸甲酯、香叶醇、β-紫罗酮、顺-茉莉酮、雪松醇、6,10,14-三甲基-2-十五烷酮等。并考察了藤茶中键合态香气成分向游离态转化的潜力。     

挥发性香气物质和乙烯生产在"湖景蜜露"桃果实发育过程中的变化

以"湖景蜜露"水蜜桃(Prunus persica L.)为试材,检测了果实从未成熟到成熟发育过程中乙烯生成、呼吸速率及挥发性香气性物质的变化;同时对果实大小、果皮色泽、果肉硬度、可溶性固形物、可滴定酸进行了测定;对与果实乙烯产生密切相关的1-氨基环丙烷-1-羧酸(ACC)含量、ACC合成酶活性、ACC氧化酶活性也进行了测定.结果表明,随果实成熟度的增加,果实大小、果皮L*值、可溶性固形物含量增加,而果实硬度、果皮h°值、可滴定酸含量减少.在未成熟的果实中,C6的醛类(反式-2-己烯醛)和醇类(顺式-3-己烯醇)是主要的成分;乙烯生成量很低;呼吸速率较高.到跃变阶段C6～C12的内酯类物质明显增加,尤其是γ和δ-内酯类成为果实主要的香气挥发性物质.推测果实乙烯、呼吸作用等基本的生理变化可能调节着内酯类物质的生成.在乙烯跃变上升时果肉中ACC氧化酶的活性下降,ACC含量和ACC合成酶活力的变化与乙烯生成量变化的趋势一致.根据以上结果可以认为桃果实主要的香气挥发性物质的形成与乙烯、呼吸跃变的开始密切相关.香气物质形成速率动态变化可能是桃果实发育过程中成熟度的另一个生理学指标.     

顶空固相微萃取法分析毛药山茶花香气成分

采用顶空固相微萃取法提取了毛药山茶鲜花的香气成分,通过气相色谱-质谱联用技术(GC-MS)对香气成分进行了分析。共检测到50种香气成分,鉴定出19种,占总香气含量的71.72%。毛药山茶花香气成分主要为芳香族化合物、倍半萜、烷烃、烯烃和脂肪酸酯,其中倍半萜在总香气中的比例最高,为46.31%,其次为烷烃,为19.79%。     

Evaluation of aroma active compounds in <Emphasis Type="Italic">Tuber</Emphasis> fruiting bodies by gas chromatography–olfactometry in combination with aroma reconstitution and omission test

The aroma active compounds of three Tuber fruiting bodies (i.e., Tuber himalayense, Tuber indicum, and Tuber sinense) were firstly systematically evaluated by instrumental gas chromatography–olfactometry combining with quantitative analysis, aroma reconstitution, and omission tests. Twelve aroma active compounds were characterized by aroma extract dilution analysis, and 3-(methylthio) propanal, 3-methylbutanal, and 1-octen-3-ol with the highest flavor dilution (FD) factor (i.e., 1,024–2,048) were suggested as key contributors to the aroma. Odor activity value (OAV) was employed to determine the relative contribution of each compound to the aroma, and the compound with the highest FD factor also had the highest OAV (i.e., 10,234–242,951). Then, the synthetic blends of odorants (aroma reconstitution) were prepared with OAV larger than 15, and their aromas were very similar to the originals. Omission tests were carried out to verify the significance of 3-(methylthio) propanal, 1-octen-3-ol, and 3-methylbutanal as key compounds in the aroma of tested Tuber fruiting bodies.     

Discrimination of truffle fruiting body versus mycelial aromas by stir bar sorptive extraction

Stir bar sorptive extraction (SBSE) was applied in head space mode (HS), coupled with GC/MS, to compare the aroma profile of three truffle species. A total of 119 volatile organic compounds (VOCs) were identified from the fruiting bodies, of which 70 were not yet described in truffles and 60 in fungi. VOCs profile showed a high intra- and inter-specific variability, with alcohols and sulfur compounds dominating the HS of Tuber borchii and, alcohols, aldehydes and aromatic compounds the HS of T. melanosporum and T. indicum. Despite these variations, eight VOCs markers could be identified allowing the discrimination of the three species. Additionally, T. borchii and T. melanosporum both distinguished themselves from T. indicum due to higher aroma content and larger variety of sulfur containing compounds. Mycelial VOCs production was also investigated under two cultural conditions and led to the identification of eight VOCs. On one side, seven of them were also detected in the fruiting body, confirming their mycelial origin. On the other side, the total absence of some class of compounds (i.e. sulfur) in the mycelium raises questions about their origins in the fruiting bodies and confirms deep metabolic changes between the reproductive (fruiting body) and vegetative (mycelium) stages.     

Truffle volatiles inhibit growth and induce an oxidative burst in Arabidopsis thaliana

The function of fungal volatiles in fungal-plant interactions is poorly understood. The aim here was to address this lack of knowledge, focusing on truffles, ectomycorrhizal fungi that are highly appreciated for their aroma. The effect of volatiles released by truffles was tested on Arabidopsis thaliana in a closed chamber bioassay. The volatiles produced by Tuber melanosporum, Tuber indicum and Tuber borchii fruiting bodies inhibited A. thaliana in terms of root length and cotyledon leaf size, and in some cases induced a bleaching of the seedlings, thus indicating toxicity. Ten synthetic volatiles were tested in a similar way. The strongest inhibitory effect was observed with C(8) molecules such as 1-octen-3-ol, an alcohol with a typical 'fungal smell'. Two of these C(8) compounds were further tested to investigate their mechanism of action. 1-Octen-3-ol and trans-2-octenal induced an oxidative burst (hydrogen peroxide, H(2)O(2)) in the A. thaliana leaves as well as a strong increase in the activities of three reactive oxygen species (ROS)-scavenging enzymes. These results demonstrate that fungal volatiles inhibit the development of A. thaliana and modify its oxidative metabolism. Even though limited to laboratory observations, these results indicate the presence of a hitherto unknown function of fungal volatiles as molecules that mediate fungal-plant interactions.     

Intraspecific genotypic variability determines concentrations of key truffle volatiles

? Aroma variability in truffles has been attributed to maturation (Tuber borchii), linked to environmental factors (Tuber magnatum), but the involvement of genetic factors has been ignored. We investigated aroma variability in Tuber uncinatum, a species with wide distribution. Our aim was to assess aroma variability at different spatial scales (i.e. trees, countries) and to quantify how aroma was affected by genotype, fruiting body maturity, and geographical origin. ? A volatile fingerprinting method was used to analyze the aroma of 223 T. uncinatum fruiting bodies from seven European countries. Maturity was estimated from spore melanization. Genotypic fingerprinting was performed by amplified fragment length polymorphism (AFLP). ? Discriminant analysis revealed that, regardless of the geographical origin of the truffles, most of the aroma variability was caused by eight-carbon-containing volatiles (C8-VOCs). In an orchard of T. uncinatum, truffles producing different concentrations of C8-VOCs clustered around distinct host trees. This clustering was not associated with maturity, but was associated with fungal genotype. ? These results indicate that the variation in C8-VOCs in truffles is most likely under genetic control. They exemplify that understanding the factors behind aroma variability requires a holistic approach. Furthermore, they also raise new questions regarding the ecological role of 1-octen-3-ol in truffles.     

PCR primers specific for the genus Tuber reveal the presence of several truffle species in a truffle-ground

Truffles are hypogeous Ascomycete fungi belonging to the genus Tuber and forming fruiting bodies highly prized for their taste and aroma. The identification of the genus Tuber and its species is important to investigate their ecology and avoid fraud in the food market. As genus-specific primers are not available, the aims of this work were (1) to assess the usefulness of the β-tubulin gene as a DNA barcoding region for designing Tuber genus-specific primers, (2) to test the primers on a range of fruiting bodies, representing a large part of truffle biodiversity and (3) to check their ecological usefulness, applying them to truffle-ground soil. The new primers designed on the β-tubulin gene were specific to the Tuber genus in nested PCR. When applied to DNA from soils, they gave a positive signal for 23 of 32 soils. Phylogenetic analysis confirmed that the bands corresponded to Tuber and that at least five Tuber species were present in the truffle-ground. β-tubulin was found to be a good barcoding region for designing Tuber genus-specific primers, detecting a high Tuber diversity in a natural environment. These primers will be useful for understanding truffle ecology and for practical needs in plantation management.     

国产松露乙醚提取物的GC-MS分析

采用气相色谱-质谱(GC-MS)法分析我国云南产黑松露(Tuber indicum)乙醚提取物的化学成分.从中鉴定了56个化合物,占提取物总含量的87.37％,化合物组成特征:以脂肪酸类化合物为主,占59.98％,其中含亚油酸达26.51％;醇、酯、醛和烃类化合物分别占7.96％、2.79％、2.44％和13.12％,另外还含有少量的苯衍生物,占1.08％.     

Olfactory orientation of the truffle beetle, Leiodes cinnamomea

Although the truffle beetle, Leiodes cinnamomea, inflicts substantial damage to the ripe stage of fruiting bodies of the economically important black truffle (Tuber melanosporum), it is not attracted by ripe truffle odours. Rather, male beetles are attracted to infested truffles only in the presence of female beetles, suggesting that the former employ a pheromone to locate truffles over short distances. In contrast, female beetles show no attraction to infested or uninfested truffles, suggesting that they employ other cues, possibly linked to odours emitted by truffles prior to the ripe stage. We hypothesize that the chemical composition of truffle volatiles changes over the life of the truffle fruiting body, being attractive to insects early on and to mammals just prior to decomposition.     

贮藏保鲜中SO2伤害对红提葡萄香气组分的影响

采用固相微萃取技术及气相-质谱联用技术对不同SO2漂白伤害程度的红提果实进行香气成分的提取与鉴定,以探讨SO2漂白伤害对贮藏葡萄果实中香气组分的影响.结果表明,果实经漂白伤害后其具有芳香气味的气体所占比重明显下降,主要成分醇类化合物下降最多,而具有刺激难闻气味的酸类化合物所占比重明显上升;此外,4-萜烯醇、正己醇、月桂醇、松油醇、芳樟醇、橙花醇、乙酸萜烯酯及青叶醛等具有葡萄特征性香味的化合物在香气中所占比例明显下降或消失,而异辛醇、1-辛烯-3-醇、壬酸、辛酸、正癸酸、乙酸、己酸、2,6-二叔丁基对甲酚及2-丁基-5-(2-甲基丙基)-噻吩等具有臭味或刺激性气味的化合物出现或所占比重上升.说明,SO2伤害对红提果实香气的影响主要表现为香味化合物所占比重的减少或消失及异味化合物的产生.     

CARBONYL COMPOUNDS PRODUCED BY CERATOCYSTIS FAGACEARUM

Ceratocystis fagacearum produces both in nature and in laboratory culture a characteristic fruity aroma. It is assumed that the odor may serve as an attractant for insects which are vectors for the disease as well as important agents in the fertilization mechanism. A number of carbonyl compounds were identified from liquid cultures of C. fagacearum and included: acetaldehyde, furfuraldehyde, acetone, 2-hexenal and 2-methylbutanal. The 2,4-dinitrophenylhydrazones of the compounds were identified by means of thin-layer chromatography, melting-point determination, gas chromatography and infrared spectroscopy.