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1.
在可持续性发展和降低生产成本的驱使下,食品香料工业近年来,特别是2014年,在利用生物技术生产香原料方面取得了显著的进展,并通过生物技术开发了许多重要的香料化合物。本文对食品香料工业利用酶和发酵技术开发氨基酸衍生的风味增强剂谷氨酸钠和γ-谷氨酰-缬氨酰-甘氨酸,广藿香醇,香兰素,香紫苏醇,β-檀香醇等香料化合物进行了介绍。 相似文献
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香精香料是食品添加剂中的一个重要组成部分,由人工调配混合而成,其中含有2种或2种以上的香料,一般由天然提取香料、化学试剂、合成香料、甜味剂等多种成分构成[1]。随着香精香料使用范围的不断扩大,人们对香精香料质量控制等问题的关注度越来越高[2]。目前,为加强食品添加剂的规范生产经营,国家标准GB2760-2014《食品安全国家标准食品添加剂使用标准》对一些易滥用食品添加剂进行了严格的限量规定[3]。 相似文献
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《理化检验(化学分册)》2016,(11)
试验制得400℃,500℃,600℃,800℃等4个温度下的烟草干馏香料,以薄荷醇(IS1)和苯甲酸丙酯(IS2)为双内标物,进行气相色谱-质谱(GC-MS)定性定量分析。干馏香料中的化学成分随着温度的上升大致呈下降趋势,特别是干馏香料中杂环类与醛酮类等主要香味物质,干馏香料中占主导地位的烟碱成分,其含量也随着干馏温度的上升有规律地下降。在400℃温度条件下制备的干馏香料可以达到传统卷烟的效果。 相似文献
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提出了顶空-气相色谱-离子迁移谱法快速测定化妆品中丙烯酸乙酯、苧烯、反式-2-庚烯醛、芳樟醇、柠檬醛等5种香料含量的方法。取化妆品样品或用水稀释后的化妆品样品,在80℃下孵化20 min,顶空进样,在正离子模式,迁移管线性电压400 V·cm-1,迁移管温度45℃,迁移气流量150 mL·min-1的条件下测定样品中丙烯酸乙酯、苧烯、反式-2-庚烯醛、芳樟醇、柠檬醛等5种香料的含量。结果表明,5种香料标准曲线的线性范围为0.1~5.0 mg·L-1,检出限(3S/N)为0.02~0.05 mg·L-1。方法用于分析8批化妆品,检出苧烯和芳樟醇两种香料,检出量为0.005~352μg·g-1,与常规气相色谱-串联质谱法检测结果进行对比,相对偏差为-8.6%~10%。 相似文献
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应用在线热裂解/气相色谱-质谱(PY/GC-MS)研究了紫苏葶、β-紫罗兰酮、香紫苏内酯、异丁香酚、苯甲醛、2-乙酰基吡嗪、2-乙酰基噻唑、3-乙酰基吡啶、山楂酊、树兰净油在氦气氛围中分别于300、600、800℃下的裂解产物,通过对裂解产物中芳香烃类化合物的分析,讨论了裂解温度和香料组分化学结构对芳香族物质产生量的影响,并以有机结构理论总结了香料成分的结构与高温裂解产生芳烃物质含量的关系。研究结果表明:β-紫罗兰酮、香紫苏内酯、异丁香酚、树兰净油等在800℃时均裂解生成芳香烃类化合物(苯系物、茚系物和萘系物),其中裂解物中芳香烃类物质含量最高者为β-紫罗兰酮,达到16.290%,树兰净油为5.376%;而2-乙酰基吡嗪、2-乙酰基噻唑、3-乙酰基吡啶的裂解产物中未检测到上述芳香烃类物质,香料成分的结构是高温裂解产生芳烃物质的重要因素;随着裂解温度的升高,裂解产物中芳香烃类化合物的含量呈上升趋势;其中2-乙酰基吡嗪、2-乙酰基噻唑和3-乙酰基吡啶适宜用作卷烟香料。 相似文献
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呋喃类杂环化合物几乎存在于所有食品中[1]。目前已从不同食品中鉴定出200余种呋喃类化合物,通过剖析和模拟天然食品中香气成分的组成和结构,已研究开发出100余种呋喃类杂环香料[2],许多α呋喃酯类化合物已成为重要的合成香料新品种[3]。本文通过高分辨核磁共振方法研究了... 相似文献
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开发了两步亲和色谱法:肝素-琼脂糖凝胶、Ni-琼脂糖凝胶色谱纯化人血浆中硒蛋白-P的方法,并采用氢化物发生-原子荧光分光光度法(HG-AFS)检测,成功搭建了硒蛋白-P的纯化检测平台。确定了亲和色谱纯化的最佳梯度洗脱条件,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)定性检测,得到了一定纯度的硒蛋白-P,其回收率达43.2%。HG-AFS方法的线性相关系数为0.999 1,检出限为0.09μg/L,日内精密度(RSD)为0.12%,日间精密度(RSD)为0.27%,加标回收率为95%~104%。该亲和色谱纯化方法简单易控、回收率高,HG-AFS检测灵敏度高,结果准确可靠。 相似文献
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This paper describes an expedient and straightforward total synthesis of the two pyrrothine natural products holomycin (7 steps, 11% overall) and xenorhabdin I (7 steps, 11% overall) and analogs thereof via a common late-stage intermediate. The pathway proceeds via the pyrrothine hydrochloride intermediate (6 steps, 17% overall) which also gave access to very fast synthesis of analogs as demonstrated by the synthesis of , and (7 steps, 11-12% overall). 相似文献
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以5步反应从邻碘苯甲酸乙酯合成了9,10-二氢-9,9,10,10-双(γ-丁内酯)菲,减少了3步反应,总产率提高7%.又由邻碘苯甲酰氯与乙烷-1,1,2-三羧酸三乙酯缩合,继以消除两个乙酯基合成Dallacker双内酯,反应减少一步,产率则增高13%.还研究了联苯-2,2-二甲酰氯分别与乙烷-1,1,2-三羧酸三乙酯和氰基琥珀酸二乙酯的缩合,均能得到良好的产率. 相似文献
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Lena Freimuth Prof. Dr. Jens Christoffers 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8214-8221
The fluorescent diaminoterephthalate scaffold was equipped by amidation with three types of reactive functions: thiols for metal‐surface binding, alkynes for click reactions, and maleimides for ligation with proteins. Starting from a succinyl succinate derivative with two orthogonally cleavable ester functions, three monoamides (38–57 % yield over three steps) and two bisamides (19 and 25 % yield over five steps) were prepared. Although alkyne and thiol derivatized compounds showed reasonable luminescence behavior (Φ≈1–4 %), the fluorescence was quenched by the maleimide moiety. It was turned on (10‐ to 20‐fold increase of fluorescence quantum yield) by conjugate addition of thiols. 相似文献
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E. Milaré J. R. Turquetti G. R. Souza A. V. Benedetti F. L. Fertonani 《Journal of Thermal Analysis and Calorimetry》2006,86(2):403-410
Thermogravimetry (TG), cyclic
voltammetry (CV) and other analytical techniques were used to study the reactions
of mercury with Pt–30% Ir alloy. The results allowed to suggest that
an electrodeposited mercury film interacts with the substrate and when subjected
to heat or electrochemical removal at least four mass loss steps or five peaks
appeared during the mercury desorption process. The first two steps were attributed
to Hg(0) removal probably from the bulk and from the adsorbed monolayer which
wets the electrode surface. These two processes are responsible for peaks
D and F in the cyclic voltammograms. The last two peaks (G, H) in CV were
ascribed to the intermetallic compound decomposition. In TG curves, the last
two steps were attributed to the PtHg4 (third step),
and PtHg2 decomposition followed by Hg removal from
the subsurface. The PtHg2 was formed by an eutectoide
reaction: PtHg→PtHg2+Hg(Pt–Ir). The Hg diffused
to the subsurface was not detectable by cyclic voltammetry. 相似文献
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[reaction: see text] The total synthesis of (+)-sparteine was accomplished from 2,5-norbornadione in 15 steps and 15.7% overall yield. The key steps were two ring-expansion reactions, one involving an intramolecular Schmidt reaction and one using a novel variant of the photo-Beckmann rearrangement. 相似文献
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(S,R,R,S,R,S)-4,6,8,10,16,18-Hexamethyldocosane (1) was synthesized in 11% yield in 11 steps in the longest linear sequence from > or =98% pure (S)-beta-citronellal and 6 additional steps for the preparation of 11 in 23% yield from propene. Five of the six asymmetric carbon centers were generated catalytically and stereoselectively by the ZACA reaction (5 times), one lipase-catalyzed acetylation, and two chromatographic operations. 相似文献
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用一种新的简便方法对Verbenachalcone进行全合成, 针对目标物的结构特征, 将其切为2个合成片段, 即化合物4和6, 然后再将2个片段连接. 从对羟基苯甲醛(2)开始经过溴代、乙酰化、Ullmann反应、甲氧甲基化、羟醛缩合、脱保护和催化加氢等7步反应完成了标题化合物的全合成, 总收率为39.1%, 合成的关键步骤是3-溴-4-羟基苯甲醛(3)和香兰素进行的Ullmann反应. 关键中间体与最终产物的化学结构经1H NMR, 13C NMR和ESI-MS等表征确认. 相似文献
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W. P. C. de Klerk W. Colpa P. J. van Ekeren 《Journal of Thermal Analysis and Calorimetry》2006,85(1):203-207
The ageing
characteristics of pyrotechnic compositions are influenced not only by temperature,
but also by surrounding effects as humidity and vibrations. In this paper
the thermal stability of the pyrotechnic system magnesium–sodium nitrate
will be investigated.
In an inert helium atmosphere two steps
of mass loss, which were not completely separated from each other, were observed
in the temperature range from 65 to 265°C: a mass loss of about 15% between
65 and 160°C and about 34% between 160 and 265°C. It is assumed that
these two steps are caused by different processes. The separation between
the two steps was not or hardly detectable for measurements that were performed
in a nitrogen atmosphere. Using MS and FTIR (mass spectrometry/Fourier transform
infrared spectroscopy) the evolved gases were analysed. Only above about 170°C
evolving gases were detected (which means that during the first step no gases
were detectable). The detected gas mainly consists of CO2,
CO and N2O, with smaller amounts of NO2,
NO and possibly HCN. A third step of mass loss (8–9%) was observed above
314°C. The process which caused this step of mass loss is considered not
to contribute significantly to the ageing of the material at much lower temperatures
of maximum 80°C, which is of interest in view of the use of the materials. 相似文献
20.
Patrick Zimdars Dr. Yuzhou Wang Prof. Dr. Peter Metz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(29):7968-7973
A concise enantioselective total synthesis of the neoclerodane diterpene (−)-salvinorin A is reported. The stereogenic center at C-12 was installed by catalytic asymmetric propargylation with excellent enantioselectivity, and the remaining six stereogenic centers were set up highly diastereoselectively under substrate control. As for our previous synthesis of racemic salvinorin A, two intramolecular Diels-Alder reactions were applied to generate the tricyclic core. A chemoselective Mitsunobu inversion of a syn 1,2-diol allowed for further streamlining of the original reaction sequence by two steps. Overall, (−)-salvinorin A was synthesized in only 16 steps starting from 3-furaldehyde with 1.4 % total yield. Furthermore, an alternative intramolecular Diels-Alder strategy employing a 2-bromo-1,3-diene moiety was investigated. 相似文献