5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine – an aroma-active compound formed in course of the Likens–Nickerson extraction

 5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine (thialdine) is an aroma-active compound that has been isolated from different species of meat. In this study we have investigated the formation of thialdine using the simultaneous distillation–extraction according to Likens–Nickerson for the extraction of aroma compounds. Three isomers of thialdine were identified in the aroma extract of cooked and dried hen meat. It was shown that these compounds are not genuine substances from the sample examined, but that they are artefacts formed during sample preparation. Received: 30 October 1996     

5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine – an aroma-active compound formed in course of the Likens–Nickerson extraction

 5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine (thialdine) is an aroma-active compound that has been isolated from different species of meat. In this study we have investigated the formation of thialdine using the simultaneous distillation–extraction according to Likens–Nickerson for the extraction of aroma compounds. Three isomers of thialdine were identified in the aroma extract of cooked and dried hen meat. It was shown that these compounds are not genuine substances from the sample examined, but that they are artefacts formed during sample preparation. Received: 30 October 1996     

金华火腿重要香味化合物的分离鉴定及其生成机理初探

用同时蒸馏-提取器(SDE,simultaneousdistillationextractor)提取金华火腿中的挥发性香味物质,用Vigreux柱将其浓缩,浓缩物用气相色谱-质谱联用仪(GC-MS)进行分离鉴别。结果表明,重要的肉香味化合物(E,E)-2,4-癸二烯醛、2-乙基呋喃以及2-戊基呋喃被鉴定出;且本实验分离出的化合物中有多种是在以前对金华火腿的研究报告中未见的:如3-甲基-2-(2-羰丙基)-呋喃、甲基戊基二硫、2-辛烯-1-醇(Z)-2-庚烯醛等。     

非发酵臭豆腐挥发性风味物质的研究

通过同时蒸馏萃取(SDE)得到非发酵臭豆腐的挥发性风味物质,并通过气相色谱-质谱联用仪(GC-MS)进行分析,共有49种化合物被检出。从含量上看,酸类、醇类、醛类、酯类是主要的种类。从化合物的香气活性值可知,3-甲基丁醛、(E,E)-2,4-癸二烯醛、二甲基二硫醚、4-甲基苯酚、丁酸乙酯、1-辛烯-3-醇、壬醛是非发酵臭豆腐挥发性风味成分的重要部分。并且,果味、脂肪味、卷心菜味、药味、泥土味等是非发酵臭豆腐的特征风味。     

Extraction of Cookie Aroma Compounds from Aqueous and Dough Model System

Two extraction methods, simultaneous distillation-extraction and direct extraction by solvents, were compared to analyze aroma compounds added to cookies using a model system. The optimum extraction was obtained after 1 hr of simultaneous distillation-extraction, but some compounds such as vanillin, γ-butyrolactone, maltol, and 4-(4-hydroxyphenyl)-2-butanone were not easily distilled. However, these compounds were extracted well by direct extraction using polar or apolar solvents. These two methods are complementary and can be well adapted to cookie aroma analysis.     

北京鸭/樱桃谷鸭肉汤中香味物质的比较

北京鸭 /樱桃谷鸭分别经同时蒸馏提取 ,香气提取物用Vigreux柱浓缩后 ,用气 质联用仪对其进行分析。结果表明 ,重要的鸭肉味香味化合物 (E ,E) 2 ,4 癸二烯醛、二 ( 2 甲基丙基 )二硫 ,以及 2 戊基呋喃均从文中试验的 2种鸭肉中分离鉴定出 ;北京鸭含有樱桃谷鸭所没有的重要香味化合物如 3 甲基 2 ( 2 羰丙基 ) 呋喃、1 0 十一烷烯醛、(E) 2 癸烯 1 醇等。     

中华绒螯蟹蟹肉和蟹黄中挥发性风味物质组成

采用同时蒸馏萃取技术(SDE)方法提取中华绒螯蟹中的挥发性风味成分,利用气相色谱-质谱联用技术(GS-MS)对提取的中华绒螯蟹蟹肉和蟹黄中挥发性风味成分进行分离鉴定。结果表明：在中华绒螯蟹中共检测到97种挥发性化合物。其中,蟹肉和蟹黄中含有的挥发性化合物的数量分别为60种和67种,仅有30种挥发性化合物被检测到同时存在于蟹黄和蟹肉中;中华绒螯蟹蟹黄和蟹肉中的挥发性成分在组成上的差别主要体现为在醇类、芳香类、烷烃类和含硫类化合物的组成上,这可能是导致中华绒螯蟹蟹黄和蟹肉香气差异的主要原因;除了组成上的差异,蟹黄中检测到的挥发性化合物的含量普遍高于蟹肉中检测到的化合物的含量。     

Volatile flavour profile of goat meat extracted by three widely used techniques

Three procedures for the isolation of volatiles from grilled goat meat were compared: dynamic headspace entrainment on Tenax TA, simultaneous steam distillation-extraction, and solid-phase microextraction. Headspace entrainment on Tenax TA extracted the highest number of Maillard-derived volatile compounds. Two hundred and three volatile components were identified; 159 are reported for the first time in goat meat. Most of the volatiles detected (155) were lipid oxidation products, such as hydrocarbons, aldehydes, alcohols, ketones, carboxylic acids and esters. Forty-eight Maillard-derived compounds were identified, comprising pyrazines, pyrroles, thiophenes, furanthiol derivatives, alkyl and alicyclic sulphides, pyridines, and thiazoles. Some reported character impact compounds of cooked meat, e.g., 12-methyltridecanal, (E,E)-2,4-decadienal, methional, and dimethyl trisulphide were identified in the volatile profile of goat meat, together with a series of C₂ to C₅ alkylformylcyclopentenes, which have been reported in cooked chicken, pork, beef and lamb, as being important for the characteristic flavour impression of different animal species.     

Alkaline hydrolysis of the cyclic nitramine explosives RDX,HMX, and CL-20: new insights into degradation pathways obtained by the observation of novel intermediates

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, I) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) hydrolyze at pH > 10 to form end products including NO2-, HCHO, HCOOH, NH3, and N2O, but little information is available on intermediates, apart from the tentatively identified pentahydro-3,5-dinitro-1,3,5-triazacyclohex-1-ene (II). Despite suggestions that RDX and HMX contaminated groundwater could be economically treated via alkaline hydrolysis, the optimization of such a process requires more detailed knowledge of intermediates and degradation pathways. In this study, we hydrolyzed the monocyclic nitramines RDX, MNX (hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine), and HMX in aqueous solution (pH 10-12.3) and found that nitramine removal was accompanied by formation of 1 molar equiv of nitrite and the accumulation of the key ring cleavage product 4-nitro-2,4-diazabutanal (4-NDAB, O2NNHCH2NHCHO). Most of the remaining C and N content of RDX, MNX, and HMX was found in HCHO, N2O, HCOOH, and NH3. Consequently, we selected RDX as a model compound and hydrolyzed it in aqueous acetonitrile solutions (pH 12.3) in the presence and absence of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) to explore other early intermediates in more detail. We observed a transient LC-MS peak with a [M-H] at 192 Da that was tentatively identified as 4,6-dinitro-2,4,6-triaza-hexanal (O2NNHCH2NNO2CH2NHCHO, III) considered as the hydrolyzed product of II. In addition, we detected another novel intermediate with a [M-H] at 148 Da that was tentatively identified as a hydrolyzed product of III, namely, 5-hydroxy-4-nitro-2,4-diaza-pentanal (HOCH2NNO2CH2NHCHO, IV). Both III and IV can act as precursors to 4-NDAB. In the case of the polycyclic nitramine 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), denitration (two NO2-) also led to the formation of HCOOH, NH3, and N2O, but neither HCHO nor 4-NDAB were detected. The results provide strong evidence that initial denitration of cyclic nitramines in water is sufficient to cause ring cleavage followed by spontaneous decomposition to form the final products.     

Volatile constituents of cooked bullfrog (Rana catesbeiana) legs

Volatile extracts obtained from pressure-cooked bullfrog legs by simultaneous steam distillation and solvent extraction were analyzed by gas chromatography–mass spectrometry. Although the raw bullfrog legs used in this study contained 0.6% fat only, the extracts were dominated (qualitatively and quantitatively) by lipid oxidation volatiles such as alkanals, alkenals, alkadienals, alkanols and alkenols. Few Maillard volatiles were found, amongst them 2-acetylthiazole, the only sulfur-containing compound found in the extract. This profile of volatiles may be explained by the high proportion of phospholipids and low concentration of sulfur amino acid cystine in raw bullfrog meat, as previously reported by other researchers. Odour activity values (OAV) of volatiles were also estimated and major OAV compounds were: (E,E)-2,4-decadienal, (E,Z)-2,4-decadienal, (E,Z)-2,6-nonadienal, 1-octanol, and (E)-2-nonenal. Some of these potent unsaturated aliphatic aldehydes have also been associated with chicken flavour. This may contribute to flavour resemblances between bullfrog and chicken meat.     

Volatile Compounds in Processed Duck Fillet

Volatile components of smoked and dry-cured, smoked, brined or raw duck fillets were fractionated by simultaneous distillation-extraction before GUMS. Volatile compounds (62) identified were phenols, alcohols, ethers, aldehydes, ketones, hydrocarbons, acids, esters, terpenes and N-and S-compounds. Some compounds (34) were related to the smoke process. Most of these flavor compounds had been identified in smoked meat products and 7 are reported for the first time. The formation of aldehydes and alcohols mainly results from oxidative decomposition of membrane polyunsaturated fatty acids.     

MMSE-GC-MS/GC-O法鉴定熟制阳澄湖大闸蟹关键嗅感物质

本文采用新型材料-MonoTrap作为固相萃取整体捕集剂,提取阳澄湖大闸蟹的挥发性成分。利用气相色谱-质谱联用仪(GC-MS)对雄性、雌性阳澄湖大闸蟹四个部位(体肉、钳肉、足肉和性腺)中的挥发性成分进行了分离鉴定,共得到9大类76种挥发性物质。同时,采用气相色谱-嗅闻技术(GC-O)并运用直接强度法对挥发物进行分析,共嗅闻到17种气味特征,其中体肉气味特征强度最弱,性腺最强。青草味是四个部位中最显著的气味特征,而性腺气味特征较其他部位不同的是具有较强的油脂味和烤肉味。在76种挥发性物质中,筛选出56种具有气味特征的嗅感物质(Odor Compound,OC),其中三甲胺、(Z)-4-庚烯醛、2,5-二甲基吡嗪、(E,E)-3,5-辛烯-2-酮和(Z)-4-癸烯醛在各可食部位中均存在,对阳澄湖大闸蟹的典型风味贡献显著。     

5,6-二氢-1,3,5-二噻嗪类食用香料研究进展

5,6-二氢-2,4,6-三取代基-1,3,5-二噻嗪是一类重要的含硫含氮杂环香料化合物,目前从食品中鉴定出的已经有70种左右。由于这类香料化合物具有典型的烤香、肉香、坚果香、蔬菜香等香气特征,有的已经被我国及世界上多个国家批准用来调配食用香精,用于食品加香,如2,4,6-三甲基-5,6-二氢-4H-1,3,5-二噻嗪、2(4)-异丁基-4(2),6-二甲基-5,6-二氢-4H-1,3,5-二噻嗪、2,4-二甲基-4H-吡咯[2,1-d]-1,3,5-二噻嗪等。本文对67种5,6-二氢-2,4,6-三取代基-1,3,5-二噻嗪类香料化合物的天然存在和香气特征进行了归纳;由于在食品基质中这类化合物的形成与多种因素有关,如梅拉德反应、脂肪的氧化、Strecker降解、pH、温度等,因此有必要对其在食品热加工过程中的形成机理进行研究和总结;考虑到1,3,5-二噻嗪类化合物在香料工业中的潜在价值,本文也对文献报道的该类化合物的合成方法进行了概括。     

兔肉挥发性风味成分提取效果的比较

为比较不同提取技术对兔肉挥发性风味物质的提取效果,明确兔肉特征风味物质。采用同时蒸馏萃取（simultaneous distillation extraction,SDE）、固相微萃取（solid phase micro extraction,SPME）和超临界二氧化碳流体萃取（supercritical carbon dioxide fluid extraction,SFE）3 种常用方式,提取兔肉风味物质,定量加入2,4,6-三甲基吡啶,通过气相色谱-质谱法进行定性和定量研究,比较提取率差异,确定兔肉主体风味成分。结果显示：SDE法提取到包括烃、醇、醛、酸、酯、酮、醚和杂环共8 类75 种化合物;SPME法提取到烃、醛、酮和酯共4 类41 种化合物;SFE法提取到烃、醇、醛、酯和杂环共5 类38 种化合物。提取物质种类：SDE＞SFE＞SPME,提取物质量：SFE＞SDE＞SPME,提取量：SPME＞SFE＞SDE。通过气味活度值法,确定己酸、己醛、辛醛、壬醛、2,4-癸二烯醛和1-辛烯-3醇为兔肉主体风味物质。     

黑猪肉关键香气物质分析鉴定

对豫南黑猪后腿肉进行研究,测定肉的主要脂肪酸为油酸（42.89%）、棕榈酸（21.62%）、二十碳烯酸（8.78%）、硬脂酸（7.73%）、棕榈油酸（5.93%）、豆蔻酸（5.84%）、亚油酸（5.51%）;主要氨基酸为谷氨酸（13.70%）和天冬氨酸（8.19%）。采用同时蒸馏萃取处理,DB-WAX极性柱和DB-5弱极性柱气相色谱-质谱联用分析、稀释法DB-5弱极性柱气相色谱-嗅闻分析。基于保留指数和质谱库检索,气相色谱-质谱联用分析鉴定出98种化合物,主要为十六碳醛、十八碳醛、壬醛、1-己醇、十七碳醛。基于保留指数、气相色谱-质谱结果、气味特征、标准品比对,气相色谱-嗅闻分析鉴定出26种香气活性化合物,其中关键香气化合物（log2FD≥5）为2-甲基-3-呋喃硫醇、3-甲硫基丙醛?γ-癸内酯、（E）-2-癸烯醛、1-辛烯-3-醇、（E,E）-2,4-癸二烯醛、壬醛、（E）-2-壬烯醛、3-羟基-2-丁酮、己醛、甲硫醇、糠硫醇、二甲基三硫、2-乙酰基-1-吡咯啉、（E）-2-己烯醛、（E）-2-庚烯醛、苯乙醛、戊醛。研究结果对于全面了解猪肉风味构成及研制肉味香精具有参考性。     

Determination of 2,4,6-tri-tert-butylphenol and related compounds in foods

An analytical method has been developed for the determination of 2,4,6-tri-tert-butylphenol (TTBP) in foods. TTBP was determined by GC/MS (SIM) after extraction from food samples using a steam distillation technique. The developed method was able to determine simultaneously 2,4-di-tert-butylphenol (2,4-DTBP), 2,6-di-tert-butylphenol (2,6-DTBP), 3,5-di-tert-butylphenol (3,5-DTBP) and 2,4-di-tert-pentylphenol (2,4-DTPP). The method was applied to analyze the residues of the 5 phenolic compounds in 101 food samples purchased from markets. TTBP was found in some samples of meat, liver and fish (muscle) at the levels of trace (tr)-0.50 ng/g, tr and tr-1.83 ng/g, respectively. 2,4-DTBP was found in some samples of vegetables, meat, liver, fish (muscle) and fish (viscera) at the levels of 1.4-10.6 ng/g, 2.7-26.4 ng/g, tr-34.2 ng/g, tr-21.6 ng/g and tr, respectively. 2,6-DTBP was found in some samples of fish (muscle) and fish (viscera) at the levels of tr-3.9 ng/g and tr, respectively. 3,5-DTBP and 2,4-DTPP were not found in any of the analyzed samples.     

臭豆腐中挥发性香成分提取与分析

为分析臭豆腐中的挥发性成分,采用固相微萃取和同时蒸馏萃取的方法对北京产老才臣臭豆腐中的挥发性成分进行提取,提取物经气相色谱-质谱联用仪分析,结合对比标准品保留时间和计算分离出的成分的保留指数。结果共鉴定出43种成分,其中,醇类15种、酸类3种、酯类8种、酮类3种、醛类2种、酚类1种、硫醚类4种、杂环类5种、芳香烃类2种,采用面积归一化法确定相对含量;两种方法中都鉴定出的挥发性成分有17种,主要为醇类、酯类、含硫化合物和杂环类;对臭豆腐香气特征贡献较大的有吲哚、二甲基二硫、二甲基三硫、二甲基四硫、2,3,5-三硫杂己烷、苯酚等。     

郫县豆瓣特征香气物质的研究鉴定

以三种一级传统郫县豆瓣为研究对象,通过同时蒸馏萃取法（SDE）提取豆瓣中的挥发性化合物,再通过气质联用技术（GC-MS）对其进行定性定量分析,进一步采用气相色谱-嗅觉测量法（GC-O）及香气活性值法（OAV值）对郫县豆瓣中的特征香气物质进行鉴定。结果发现,在三种郫县豆瓣中共检测出112种挥发性物质,其中糠醛、异戊醛、3-甲硫基丙醛、芳樟醇、苯乙醇、4-乙基-2-甲氧基苯酚、十六酸乙酯对郫县豆瓣的贡献最大（OAV值＞1）,初步确定此七种香气化合物为一级传统郫县豆瓣中的特征香气物质。     

鲜黄芪和干黄芪挥发性化学成分比较分析

采用同时蒸馏-萃取法提取,用气相-色谱质谱联用法结合计算机谱图检索,对鲜黄芪和干黄芪挥发性化学成分进行分析鉴定。结果表明：鲜黄芪和干黄芪挥发性成分的得率分别为0.64%、0.43%,鲜黄芪和干黄芪共鉴定出挥发性成分76种;二者的共有成分为正己醇、(E)-2-己烯-1-醇、正己醛、己-2-烯醛等11个化合物;鲜黄芪中鉴定出43种挥发性成分,主成分是正己醇、邻二甲苯、(E)-2-己烯-1-醇、(E)-2-己烯醛、正己醛;干黄芪中鉴定出44种香气成分,主成分是正己醛、正己醇、己-2-烯醛。干黄芪挥发性成分与新鲜黄芪挥发性成分相比较组成和相对含量存在着较大差异。     

56—THE WRINKLING BEHAVIOUR OF WOOL FABRICS: THE EFFECT OF THE STRUCTURE OF FORMALDEHYDE CONDENSATION POLYMERS ON THE STABILIZATION OF ANNEALED WOOL

An investigation is reported of the use of formaldehyde condensation polymers of aromatic amines, heterocyclic amines, and phenols to stabilize the improved wrinkle-recovery of annealed wool. These polymers were formed in situ during the annealing process.

The most effective polymer networks were those obtained from the reaction of formaldehyde with multifunctional compounds such as (i) 2,4,6-triaminopyrimidine, (ii) 2,6-diaminopyridine, (iii) 3,5-diamino-1,2,4-triazole, (iv) 1,3,5-trihydroxybenzene, (v) 1,3-dihydroxybenzene, and (vi) 2,4,6-triamino-s-triazine.