兔肉腥味物质的提取和鉴定

1　引　　言兔肉中有特殊腥味物质存在 ,而且该腥味在加工中不易去除。其对兔肉的实用价值产生不利影响。目前国内外未见引起兔肉腥味的物质的有关报道。本研究通过对兔肉中腥味成分进行提取、收集 ,了解其在体内存在形式。经气 质联谱鉴定分析 ,初步确定了引起腥味的物质成分。2　实验部分2 1　材料与试剂　根据有关研究表明 ,全兔中以腹部肌肉组织的腥味最重。所以选择其为提取原料。所用试剂均为国产分析纯试剂。2 2　腥味物质提取　采用ＮｉｔｒｏｇｅｎＰｕｒｇｅ ａｎｄ Ｔｒａｐ(ＮＴＰ)技术。经改进。加入十二烷基硫酸钠 (ＳＤＳ)…     

中华猕猴桃果实香气成分的GC-MS分析

采用溶液萃取法，提取“早鲜”猕猴桃果实中的香气成分，经气相色谱－质谱联机分析，鉴定出45个香气组分，占总峰面积的95．9％，其相对含量，以棕榈酸，辛酸，油酸，3－羟基丁酸乙酯，（Z，Z）－9，12－十八二烯酸，1，2，4－三羟基－（对）－萜烷，（E）－2－己烯醛，1，2－苯二甲酸双（2－甲氧基乙基）酯，硬脂酸，2－己烯醛等为主。     

辣椒油化学成分的气相色谱-质谱分析

采用溶液进样和顶空固相微萃取进样，GC－MS分离鉴定，总离子流色谱的峰面积归一化法定量分析了辣椒油的化学成分；在溶液进样方法中，鉴定的主要成分相对含量依次为辣椒碱（37.0％）、亚麻酸乙酯（26.3%)、棕榈酸（10.9%)、二氢辣椒碱（10.1%)、邻苯二甲酸二乙基己基酯（1.2%)和硬脂酸（1.1%)等；在顶空固相微萃取方法中，鉴定的成分主要为易挥发的头香成分，依次为顺－2，4α,5,6,9,9α-六氢-3,5,5，9－四甲基－1H－苯并环庚烯（22.9%)、2，4α，5，6，7，8，9，9α－八氢－3，5，5－三乙基－1H苯并环庚烯（9.2%)、正十五烷（6.7%)、艾蒿脑（5.9%)、正戊酸己酯（5.2%)、正十六烷（3.3%)、麝香内酯（3.3%)、正十七烷（2.4%)及5，6，7，7α－四氢－4，4，7α－三甲基－2（4H)-苯并呋喃酮（2.2%)等。     

5，12－二苯基－7，14─二甲基－1，4，8，11－四氮杂环十四烷－N－乙酸及其Cu（Ⅱ）、Ni（Ⅱ）配合物的合成与表征

５，１２－二苯基－７，１４─二甲基－１，４，８，１１－四氮杂环十四烷－Ｎ－乙酸及其Ｃｕ（Ⅱ）、Ｎｉ（Ⅱ）配合物的合成与表征张悠金，贺群，谢复新，许志强，倪诗圣（合肥经济技术学院加工工艺系合肥２３００５２）（安徽大学化学系合肥）关键词四氮杂环十四烷－Ｎ...     

噻唑烷类配体的手性结构及其在催化苯乙酮不对称硅氢化？…

用分级结晶或柱层析方法对２－（２－吡啶基）－４－羧甲基－１，３－噻唑烷及２－甲基－２（２－吡啶基）－４－羧甲基－１，３－噻唑烷两种手性配体进行提纯，分别考察了其与」Ｒｈ（ＣＯＤ）Ｃｌ「２制备的在位催化剂催化苯乙酮的不对称硅氢化反应，发现只有噻唑烷环上的Ｃ４位手性中心对催化反应结果有影响，其Ｃ２位手性中心在Ｒｈ（Ｉ）催化下发生了快速差向异构化反应。     

一种香豆素化合物的结构鉴定

一种香豆素化合物的结构鉴定陈望忠焦克芳（北京军事医学科学院毒物药物研究所，北京１００８５０）关键词２，１５－十六烷二酮３－乙酰基－６－乙氧羰基－５－羟基－４，７－二甲基香豆素ＮＭＲ中图分类号Ｏ６５６．２２麝香酮是麝香中的主要成分之一，Ｓｔｏｌ［１］采...     

B_nX_n~（0，2－）（X＝H，Cl；n＝4，6，8，9，10，12）稳定性的从头计算研究

用双ζ型收缩高斯基对全卤代硼烷Ｂ_ｎＸ_ｎ~（０，２－）及相应硼烷Ｂ_ｎＸ_ｎ~（０，２－）（ｎ＝４，６，８，９，１０，１２）进行了从头计算。讨论中性卤代硼烷稳定存在的原因及Ｂ_ｎＣｌ_ｎ与Ｂ_ｎＸ_ｎ~（０，２－）稳定性随ｎ变化的不同趋势，并通过对Ｂ_４Ｘ_ｎ~（０，２－）结构规则的计算与分析，提出骨架成键轨道未填满电子是Ｂ_４Ｘ_ｎ~（０，２－）不稳定及迄今尚未发现中性Ｂ_ｎＨ_ｎ存在的重要原因。     

铜(Ⅱ)-5-取代邻菲啰啉-二氧四胺大环三元体系的稳定性研究

用pH法在25±0.1℃、I＝0．lmol·dm－3KNO3条件下研究了钢（Ⅱ）与13－（2’-羟基-3’、5’-取代苄基）－1，4，8，11-四氮杂环十四烷-12，14-二酮所形成的二元配合物的稳定性以及铜（Ⅱ）－5-取代-1，10-邻菲啉与13－（2’-羟基-3’，5’-取代苄基）－1，4，8，11-四氮杂环十四烷-12，14-二酮所形成的三元配合物的稳定性，并探讨了大环配体的取代基效应及二元、三元配合物的结构．     

天然产物(±)-Litsenolide C_2的立体选择性合成

含3一烷叉基一4，5一二氢一4一羟基一5一甲基一2－（3H）一吠哺酮（简称AHF）结构的天然产物广泛存在于律科植物中［‘j，该类化合物往往具有高细胞毒性和抗肿瘤等生物活性［’－’1．Litseno－lideC是1972年Ishii等［‘j首次从樟科植物中分离得到的一种AHF，其结构为3一十四烷叉基一4，5一二氢一个羟基一5一甲基一2－（3H）一块哺酮，根据其烷又基构型不同又可分为：（3Z，4a，sp）－LitsenolideC；和（3E，4a，sg）－LitsenolideC。（1）．目前大多数合成LitsenolideC的方法立体选择性较差［’－’j，反应产物多为两种异构体的混…     

双臂套索冠醚PVC膜碘离子选择电极

研究了两种新型双臂套索冠醚1，10－二（5－氯－8－羟基喹啉－7－亚甲基）－1，10－二氮杂－4，7，16－三氧杂－13，19－二硫杂环二十一烷（Ⅰ）和1，13－二（5－甲基－8－羟基喹啉－7－亚甲基）－1，13－二氮杂－4，7，10－三氧杂－16，19－二硫杂环二十一烷（Ⅱ）为载体的PVC膜电极的响应行为；实验结果表明，两电极均显示阴离子响 应，其中对碘离子具有优良的能斯特电位响应性能，线性范围为10^－5－10^-1mol/L，斜率分别为－59．1mV/pcI-和－57．6mV/pcI-；电极具有读数稳定，重复性好，PH值范围宽等优点；将该电极用于药品中碘含量的测定，其结果与药典法一致。     

Characteristic aroma compounds from different pineapple parts

Characteristic aroma volatile compounds from different parts of cayenne pineapple were analyzed by headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS). The main volatile compounds were esters, terpenes, ketones and aldehydes. The number and content of aroma compounds detected in pulp were higher than those found in core. In pulp, the characteristic aroma compounds were ethyl 2-methylbutanoate, ethyl hexanoate, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF), decanal, ethyl 3-(methylthio)propionate, ethyl butanoate, and ethyl (E)-3-hexenoate; while in core the main compounds were ethyl 2-methylbutanoate, ethyl hexanoate and DMHF. The highest odor units were found to correspond to ethyl 2-methylbutanoate, followed by ethyl hexanoate and DMHF. The odor units found for pulp were higher than those for core.     

Optimization of Jinhua Ham Classification Method Based on Volatile Flavor Substances and Determination of Key Odor Biomarkers

Jinhua ham is a traditional cured meat food in China. For a long time, its grade has mainly been evaluated by the human nose through the three-sticks method, which is highly subjective and is not conducive to establishing evaluation standards through odor markers. In this paper, we analyzed the well-graded Grade I–III hams provided by Jinzi Ham Co., Ltd. (Jinhua, China). Firstly, we used different extraction fibers, extraction temperatures, and extraction time to determine the optimal conditions for headspace solid-phase microextraction (HS-SPME). Then, the aroma components of Jinhua ham were analyzed by headspace solid-phase microextraction combined with gas chromatography–mass spectrometry (GC–MS), and OAV was calculated to screen the key aroma volatiles of three kinds of Jinhua ham. It was found that a total of 56 components were detected in the three types of ham. Among them, there are 21 kinds of key aroma volatiles. Aldehydes, alcohols, and acids are the three main components of Jinhua ham, and the content of aldehydes gradually decreases from Grade I to Grade III ham. The content of acids gradually increased, and we speculated that the increase in acid content was caused by the proliferation of microorganisms in Grade III ham. The key flavor volatiles in Grade I hams was hexanal and 2-methylbutanal. Grade I hams had a strong meat aroma, pleasant fatty, and roasted aroma without any off-flavors. In Grade II ham, the characteristic volatiles (E,E)-2,4-decadienal and ethyl isovalerate were detected. These two volatiles contribute greatly to the flavor of Grade II ham, which makes the flavor of Grade II ham have a special fruity aroma. They also may be prone to sourness and affect the flavor of the ham. Volatiles with low threshold values, such as pyrazines, furans, and sulfur-containing compounds, were relatively high in Grade III hams. This may also contribute to the poorer flavor quality of Grade III hams. This experiment provided a reliable test method and evaluation basis for the rating of Jinhua ham. These results have positive implications for the establishment of odor markers-based grading criteria.     

Research on Very Volatile Organic Compounds and Odors from Veneered Medium Density Fiberboard Coated with Water-Based Lacquers

Very volatile organic compounds (VVOCs) are a group of important odor pollutants affecting indoor air quality that have been shown to be harmful to human health. A 15 L environmental chamber, combined with multi-bed tube was used to collect gases. Fifteen very volatile organic compounds (VVOCs), including 12 odor compounds, were identified from veneered medium density fiberboard coated with water-based lacquer (WB-MDF) using gas chromatography–mass spectrometry/olfactometry (GC-MS/O). The total very volatile organic compound (TVVOC) and total odor intensity (TOI) showed a decreasing trend over time, reaching equilibrium on day 28. TVVOC showed an overall slow-fast-slow emission profile, from day 3 to day 7, with a maximum decay rate of 29.7%. TOI showed the greatest rate of decline from day 1 to day 3, at approximately 12%. Alkane and alcohol VVOCs were the more abundant compounds, accounting for at least 60% and even up to 80% of the total. The major odor impression was fruity, with a highest odor rating of 6.6, followed by sweet, with an odor rating of 6.1. Although the odor impression changed from sweet to fruity over time, it seemed pleasant overall. The odor contributors were mainly alkanes, alcohols, esters, and ethers, which had relatively high odor intensities. The main odor-contributing substances were dichloromethane, ethanol, ethyl acetate, 2-methylacrylic acid methyl ester, and tetrahydrofuran. When WB-MDF is used for furniture or other decorative materials, it is strongly recommended that it be stored under ventilation for at least 28 days and the adoption of substitute solvents of lacquers, modified adhesives, and low-odor wood raw materials is recommended. These possible initiatives would contribute to the aim of building an environmentally friendly indoor environment.     

Biodiversity of volatile organic compounds from five French ferns

Five French ferns belonging to different families were investigated for volatile organic compounds (VOC) by GC-MS using organic solvent extraction. Fifty-five VOC biosynthesized from the shikimic, lipidic and terpenic pathways including monoterpenes, sesquiterpenes and carotenoid-type compounds were identified. The main volatile compound of Adiantum capillus-veneris L. (Pteridaceae) was (E)-2-decenal with a plastic or "stink bug" odor. The volatile profiles of Athyrium filix-femina (L.) Roth (Woodsiaceae) and Blechnum spicant (L.) Roth (Blechnaceae) showed similarities, with small amounts of isoprenoids and the same main volatile compounds, i.e., 2-phenylethanal (odor of lilac and hyacinth) and 1-octen-3-ol (mushroom-like odor). The main volatile compound of Dryopteris filix-mas (L.) Schott (Dryopteridaceae) was (E)-nerolidol with a woody or fresh bark note. Polyketides, as acylfilicinic acids, were mainly identified in this fern. Oreopteris limbosperma (Bellardi ex. All.) J. Holub (Thelypteridaceae), well-known for its lemon smell, contained the highest biodiversity of VOC. Eighty percent of the volatiles was issued from the terpenic pathway. The main volatiles were (E)-nerolidol, alpha-terpineol, beta-caryophyllene and other minor monoterpenes (for example, linalool, pinenes, limonene, and gamma-terpinen-7-al). It was also the fern with the highest number of carotenoid-type derivatives, which were identified in large amounts. Our results were of great interest underlying new industrial valorisation for ferns based on their broad spectrum of volatiles.     

Combining different analytical approaches to identify odor formation mechanisms in polyethylene and polypropylene

In a previous study, we identified carbonyls as highly odor-active compounds in both unprocessed and processed polypropylene (PP) with higher intensities after processing, indicating a temperature-driven forming mechanism. In the presented work, we studied whether (a) these carbonyls are the major odor drivers to the overall odor of polyolefins, (b) their formation is taking place already at moderate temperatures well below the typical processing temperatures, (c) conventional antioxidants in polyolefins can prevent or reduce their formation, and (d) whether reducing the amount of oxygen present can decrease the overall odor. One polyethylene (PE) and one PP were selected, and both stabilized and unstabilized polymer powder samples were exposed to conditions differing in oxygen concentration and aging time. The changes in the volatile fraction as well as the formation of odor-active compounds were monitored using a multidisciplinary approach by combining analytical methods based on gas chromatography (GC), multivariate data analysis, and sensory methods (GC–olfactometry and a sensory panel). Both investigated materials (PE and PP) showed similar degradation products (aldehydes, ketones, carboxylic acids, alcohols, and lactones) which increased dramatically with increasing aging time and the lack of stabilization. Oxidation products, mainly carbonyl compounds, were responsible for the odor of the investigated materials. The main odor drivers were unsaturated ketones and aldehydes with a chain length between six and nine C-atoms. Interestingly, similar odor patterns were found for both stabilized and unstabilized samples, indicating that similar formation processes take place independent of the stabilization.     

The Difference of Volatile Compounds in Female and Male Buds of Herpetospermum pedunculosum Based on HS-SPME-GC-MS and Multivariate Statistical Analysis

Herpetospermum pedunculosum (Ser.) C. B. Clarke (Family Cucurbitaceae) is a dioecious plant and has been used as a traditional Tibetan medicine for the treatment of hepatobiliary diseases. The component, content, and difference in volatile compounds in the female and male buds of H. pedunculosum were explored by using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) technology and multivariate statistical analysis. The results showed that isoamyl alcohol was the main compound in both female and male buds and its content in males was higher than that in females; 18 compounds were identified in female buds including 6 unique compounds such as (E)-4-hexenol and isoamyl acetate, and 32 compounds were identified in male buds, including 20 unique compounds such as (Z)-3-methylbutyraldehyde oxime and benzyl alcohol. (Z)-3-methylbutyraldehyde oxime and (E)-3-methylbutyraldehyde oxime were found in male buds, which only occurred in night-flowering plants. In total, 9 differential volatile compounds between female and male buds were screened out, including isoamyl alcohol, (Z)-3-methylbutanal oxime, and 1-nitropentane based on multivariate statistical analysis such as principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA). This is the first time to report the volatile components of H. pedunculosum, which not only find characteristic difference between female and male buds, but also point out the correlation between volatile compounds, floral odor, and plant physiology. This study enriches the basic theory of dioecious plants and has guiding significance for the production and development of H. pedunculosum germplasm resources.     

Volatile compounds and odor preferences of ground beef added with garlic and red wine,and irradiated with charcoal pack

Irradiation is the most efficient non-thermal technology for improving hygienic quality and extending the shelf-life of food products. One of the adverse effects of food irradiation, however, is off-flavor production, which significantly affects the sensory preferences for certain foods. In this study, garlic (5%, w/w) and red wine (1:1, w/w) were added to ground beef to increase the radiation sensitivity of pathogens and improve meat odor/flavor. Samples were irradiated at 0 or 5 kGy in the presence of charcoal pack. SPME-GC–MS analysis was performed to measure the changes in the volatile compounds and sensory characteristics of the samples. The amount of total volatile compounds produced from ground beef was greater when the sample was irradiated. When garlic and red wine were added to the ground beef, the amount of volatile compounds significantly increased, and the amount of volatile compounds increased even further after irradiation. However, when the samples were irradiated with charcoal pack, the amount of volatile compounds decreased significantly. Sensory evaluation indicated that charcoal pack significantly increased the odor preferences for both irradiated and non-irradiated ground beef added with garlic. These results indicated that addition of charcoal pack to ground beef could reduce off-odor problems induced by irradiation, and this effect was consistent even when certain additives such as garlic and red wine were added.     

Structure-odor relationships of α-santalol derivatives with modified side chains

(Z)-α-Santalol, which has a unique woody odor, is a main constituent of sandalwood essential oil. We investigated the structure-odor relationship of (Z)-α-santalol and its derivatives, focusing on the relationship between the structure of the side chain and the odor of the compounds. Various α-santalol derivatives (aldehydes, formates, and acetates) were synthesized from (Z)- and (E)-α-santalol, which were prepared from (+)-3-bromocamphor through modifications of a reported synthetic route. The Z- and E-isomers of α-santalols have different double-bond configurations in the side chain. Analogues with saturated side chains were also prepared from the corresponding α-santalols, and the odors of the all the prepared compounds were evaluated. We found that the odors of the Z-isomers (woody) were similar to those of the corresponding saturated compounds, but clearly different from the odors of the corresponding E-isomers (odorless, fresh, or fatty). These results indicate that the relative configuration of the side chain with respect to the santalane frame plays an important role in the odor of α-santalol. E-configuration in the side chain eliminates the woody odor character of α-santalol and its examined derivatives, whereas the Z-configuration or saturation of the carbon side chain does not.     

A Narrative Review of the Current Knowledge on Fruit Active Aroma Using Gas Chromatography-Olfactometry (GC-O) Analysis

Fruit aroma, a mixture of chemical compounds with odor, is a strong attractant derived from a complex mixture of different amounts and intensities (threshold) of chemical compounds found in fruits. The odor-producing compounds of fruit aroma are derived from carbohydrates, lipids, phenolic compounds, and mono- and sesquiterpenes, among others. The identification of compounds responsible for fruit aroma is usually conducted using gas chromatography coupled with olfactometry (GC-O). This technique separates the chemical compounds from the aroma of foods using a chromatographic column and divides the resultant outflow between the physical detector and a testing outlet (sniffing port). Trained judges describe the perceived odor in terms of the intensity of the odor zones perceived according to their training method. Moreover, the use of GC-O coupled with a mass detector (GC-MS-O) allows for the retrieval of chemical information such as identification and quantification of compounds, which can be correlated to sensory information. This review aimed to demonstrate the application of GC-MS-O in the identification of precursor compounds in fruit aroma, considering important factors for the application, main results, and most recent advances in this field.     

The Maillard Reaction as Source of Meat Flavor Compounds in Dry Cured Meat Model Systems under Mild Temperature Conditions

Flavor is amongst the major personal satisfaction indicators for meat products. The aroma of dry cured meat products is generated under specific conditions such as long ripening periods and mild temperatures. In these conditions, the contribution of Maillard reactions to the generation of the dry cured flavor is unknown. The main purpose of this study was to examine mild curing conditions such as temperature, pH and a_w for the generation of volatile compounds responsible for the cured meat aroma in model systems simulating dry fermented sausages. The different conditions were tested in model systems resembling dry fermented sausages at different stages of production. Three conditions of model system, labeled initial (I), 1st drying (1D) and 2nd drying (2D) and containing different concentrations of amino acid and curing additives, as well as different pH and a_w values, were incubated at different temperatures. Changes in the profile of the volatile compounds were investigated by solid phase microextraction and gas chromatography mass spectrometry (SPME-GS-MS) as well as the amino acid content. Seventeen volatile compounds were identified and quantified in the model systems. A significant production of branched chain volatile compounds, sulfur, furans, pyrazines and heterocyclic volatile compounds were detected in the model systems. At the drying stages, temperature was the main factor affecting volatile production, followed by amino acid concentration and a_w. This research demonstrates that at the mild curing conditions used to produce dry cured meat product volatile compounds are generated via the Maillard reaction from free amino acids. Moreover, in these conditions a_w plays an important role promoting formation of flavor compounds.