1-L-色氨酸-1-脱氧-D-果糖的合成及其热裂解

为探索以D-甘露糖与氨基酸的美拉德反应制备Amadori化合物的可行性问题,以D-甘露糖和L-色氨酸为原料合成了1-L-色氨酸-1-脱氧-D-果糖,利用IR、NMR和HR-MS对产物进行了结构表征,采用单因素试验和正交试验优化了合成工艺,利用在线裂解气相色谱/质谱联用（Py-GC/MS）法研究了产物的热裂解行为。结果表明:①最佳合成条件为:当L-色氨酸投料量为30 mmol时,反应温度65℃、反应时间6.0 h、物料比1:1（D-甘露糖与L-色氨酸的物质的量比）、催化剂用量0.5 mmol及溶剂用量80 mL,此条件下产率达到45.2%;②无论有氧或无氧条件下裂解,产物种类均随温度升高而增加,有氧条件裂解产物种类多于无氧条件;在600℃有氧条件下,1-L-色氨酸-1-脱氧-D-果糖裂解生成具有花香、烘烤香、坚果香、焦糖香等香韵的产物;③以D-甘露糖和L-色氨酸为原料合成1-L-色氨酸-1-脱氧-D-果糖的技术方法可行,产品收率较高。      

1-L-亮氨酸-1-脱氧-D-果糖和1-L-异亮氨酸-1-脱氧-D-果糖的热裂解分析

采用热重-差热法对1-L-亮氨酸-1-脱氧-D-果糖（Ⅰ）和1-L-异亮氨酸-1-脱氧-D-果糖（Ⅱ）的热失重和热裂解温度进行了研究,通过在线裂解GC-MS联用技术分别对（Ⅰ）和（Ⅱ）在350℃、450℃、550℃、650℃、750℃和850℃条件下的裂解产物进行了鉴定。研究结果表明2种Amadori化合物的的热失重曲线相似,（Ⅰ）的裂解温度为144.67℃,（Ⅱ）的裂解温度为164.26℃,600℃时（Ⅰ）和（Ⅱ）失重约80%;二者裂解产物主要为吡嗪类、吡啶类、吡咯类、喹啉类和呋喃类等杂环化合物,芳香族化合物以及醛类和酮类,其中以吡嗪类为主;裂解产物的数量随着裂解温度的升高而增多,（Ⅰ）的裂解产物数量与（Ⅱ）的裂解产物数量相当。对（Ⅰ）和（Ⅱ）的主要裂解产物形成途径进行了初步探讨,可为研究其在卷烟燃烧过程中的转化行为提供参考。      

1-L-谷氨酸-1-脱氧-D-果糖的热裂解分析研究

采用热重-微分热重技术研究了1-L-谷氨酸-1-脱氧-D-果糖的热失重和裂解温度,通过在线热裂解与气质联用技术分别分析研究了无氧和有氧条件下1-L-谷氨酸-1-脱氧-D-果糖在300℃、600℃、750℃和900℃四个温度的热裂解产物。研究结果表明1-L-谷氨酸-1-脱氧-D-果糖的裂解温度为161.3℃,在700℃时失重达到90.50%。无氧和有氧条件下裂解产物的种类和数量随着裂解温度升高而增多,有氧条件下裂解产物总数稍多于无氧条件,但品种有明显差异。 无氧裂解和有氧裂解产物主要为酮类、吡咯类、吡啶类、呋喃类、吡嗪类、吲哚类以及少量芳香族化合物。有氧热裂解产物的香韵分析结果表明1-L-谷氨酸-1-脱氧-D-果糖裂解产物具有烘烤香、坚果香、甜香、花香、奶香等香韵。      

水相体系中Amadori化合物的合成及检测方法研究

Amadori化合物(Amadori Compounds,ACs)是美拉德反应早期形成的稳定产物,普遍存在于热加工处理的蔬菜和水果等制品中,对产品品质有重要影响。在已经完成的8种ACs合成研究基础上,建立水相体系中合成1-脱氧-1-L-脯氨酸-D-果糖(Fru-Pro)、1-脱氧-1-L-丝氨酸-D-果糖(Fru-Ser)、1-脱氧-1-L-苏氨酸-D-果糖(Fru-Thr)和1-脱氧-1-L-甘氨酸-D-果糖(Fru-Gly)4种ACs组分,经超高效液相色谱-串联四级杆质谱(UPLC-MS/MS)、核磁共振(NMR)等手段表征后,确定其分别为Fru-Pro (C_(11)H_(19)NO_7,MW:277),Fru-Ser(C_9H_(17)NO_8,MW:267),Fru-Thr (C_(10)H_(19)NO_8,MW:281),Fru-Gly (C_8H_(15)NO_7,MW:237)。采用液质联用仪建立了同步测定全部12种ACs的方法,并对该方法进行了方法学验证,结果表明12种ACs在检测范围内线性关系良好,相关系数均大于0.99,对目标物的分离效果好,灵敏度高。最后对市场上13种果蔬干进行ACs含量的检测,结果显示该方法检测效果好,可以检测出产品中所含的ACs。     

1-L-苯丙氨酸-1-脱氧-D-果糖热解产物分析

采用热重-差热法测定了1-L-苯丙氨酸-l-脱氧-D-果糖(PDF)的热失重和热裂解温度,在线裂解GC/MS联用技术鉴定了PDF在350,450,550,650,750和850℃下的裂解产物.结果表明,PDF的初始裂解温度为145.91℃,二次裂解温度为170.70℃,500 ℃时裂解物失重约80%;裂解产物主要为芳烃类和杂环化合物类;裂解产物的数量随着裂解温度的升高而增多,尤其是芳香族化合物类.     

2-L-天冬氨酸-2-脱氧-D-葡萄糖的合成及热裂解分析

以D-果糖和L-天冬氨酸单钾盐为原料合成了2-L-天冬氨酸-2-脱氧-D-葡萄糖,利用傅里叶变换红外光谱、 1H核磁共振（nuclear magnetic resonance,NMR）、13C NMR和高分辨率质谱技术进行结构表征。应用热重-微商 热重和在线裂解气相色谱/质谱联用技术分别研究了2-L-天冬氨酸-2-脱氧-D-葡萄糖的热失重和热裂解行为。采用 1,1-二苯基-2-三硝基苯肼（1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除法和还原能力法对其体外抗氧化活性进 行测定。结果表明：合成产物为目标化合物;目标化合物的裂解温度为187.8 ℃,700 ℃时总失重达到91.26%;目 标化合物裂解产物的数量随温度的升高而增多,裂解产物包括杂环类、酮类、羧酸类、醛类、酚类、烯烃类、醇类 和芳烃类等化合物,裂解产物表现出烘焙香、甜香、焦甜香、可可香、花香和奶香等香韵;目标产物具有较强的 DPPH自由基清除能力和还原能力,是一种潜在的抗氧化剂。     

2-L-丙氨酸-2-脱氧-D-葡萄糖的合成、热裂解及保润性能研究

L-丙氨酸(Ala)和D-果糖(Fru)经缩合、脱水和重排反应合成了一种美拉德反应中间体2-L-丙氨酸-2-脱氧-D-葡萄糖(Ala-Glu);采用热重-微商热重(TG-DTG)和在线裂解气相色谱/质谱联用法(Py-GC/MS)对化合物热失重和热解行为进行研究;以烟丝干基含水率为指标,对化合物物理保润性能进行测试,并考察其对卷烟感官舒适度的影响。结果表明:产物为目标化合物;Ala-Glu初始裂解温度为178.9℃,800℃时总失重达到90%;裂解产物数量随温度的升高而增多,裂解产物主要为吡嗪类、吡啶类、吡咯类、呋喃类和吡喃酮类等化合物;Ala-Glu保湿性能优于丙二醇和甘油;AlaGlu具有使烟气圆润、柔和,减少刺激性和杂气,提升口感舒适性的作用。     

1-L-丙氨酸-1-脱氧-D-果糖的热裂解分析

采用热重/差热(TG-DTA)和在线裂解气相色谱/质谱联用(Py-GC/MS)分析技术对1-L-丙氨酸-1-脱氧-D-果糖(Ala-Fru)的热裂解进行了研究.TG-DTA分析结果显示,Ala-Fru的初始裂解温度为147.47℃,600℃时样品质量损失至原重的25%;在350℃,450℃,550℃,650℃,750℃和850℃这6个温度下的Py-GC/MS结果显示,裂解产物的种类和数量随裂解温度的升高而增多,其裂解产物主要为吡嗪类、吡啶类、吡咯类和呋喃类等杂环类化合物以及少量酮类化合物,这些物质是卷烟烟气中重要的香味成分.     

液质联用法同时测定烤烟型卷烟中的1-脱氧-1-L-脯氨酸-D-果糖和2-脱氧-2-L-脯氨酸-D-葡萄糖

1-脱氧-1-L-脯氨酸-D-果糖(Pro-Fru)和2-脱氧-2-L-脯氨酸-D-葡萄糖(Pro-Glu)是烤烟中重要的美拉德反应关键中间体(Amadori和Heyns化合物),对烟草香味和外观品质有重要影响。为实现烟草中这两种结构相似化合物的同时分析,建立了一种利用高效液相色谱-三重四极杆质谱(HPLC-MS/MS)测定烤烟型卷烟烟丝样品中Pro-Fru和Pro-Glu含量(质量分数)的方法。采用正离子多反应监测(MRM)模式,根据质谱碎裂机理分析选择各自的特征离子对(m/z)128/278和182/278作为定量离子进行分析,对10个烤烟型卷烟样品进行了测定。结果表明:方法加标回收率93.19%~101.46%,相对标准偏差(RSD)3.53%~8.54%,检测限0.12 ng/m L;10个烤烟型卷烟样品中Pro-Fru和Pro-Glu的含量分别为6.25~11.33和1.15~1.96 mg/g。该方法适用于烤烟型卷烟中Pro-Fru和Pro-Glu含量的同时、准确测定。     

两种Amadori衍生物的合成及其热降解产物研究

文章以D-果糖、L-苯丙氨酸和L-酪氨酸为原料合成两种Amadori衍生物:PDFD(二-O-异亚丙基-2,3:4,5-β-D-吡喃果糖基苯丙氨酸酯)和TDFD(二-O-异亚丙基-2,3:4,5-β-D-吡喃果糖基酪氨酸酯),用氢谱(1H NMR)、碳谱(13C NMR)以及高分辨质谱(HRMS)表征了物质的结构。采用热重(TG-DTG)、差示扫描量热法(DSC)、热裂解-气质(Py-GC/MS)联用技术研究了两种物质的热特性和热降解产物。结果表明,PDFD和TDFD最大质量损失率T_p值分别是273.3和340.5℃;两种物质均热降解产生大量的挥发性香味物质,如2-丁酮、苯甲醛、2-乙酰基呋喃、糠醛等,而且TDFD所需热降解温度较高且热降解产物含有酚类物质。对两种物质的热降解机理研究表明,保护糖环上的羟基在一定程度上可抑制吡喃糖环的降解,而氨基酸部分的降解几乎不受影响。该研究提供了一类基于Amadori化合物的香味前体物质,且为调控Amadori化合物热降解产物提供新思路。     

不同生态区域烤烟Amadori化合物含量与烟叶品质的关系分析

为明确不同生态区域烤烟中Amadori化合物含量(质量分数)差异,选取8个不同香型风格烤烟生态区249份烟叶样品,分析了不同生态区域Amadori化合物含量及其相关性,以及与化学品质指标间的关系.结果表明:①8个香型风格烤烟生态区不同部位烟叶Amadori化合物总量整体表现为:上部叶>中部叶>下部叶,基本服从正态分布,...     

赖氨酸Amadori和Heyns化合物热裂解产物对烟草风味的影响研究

  目的  比较赖氨酸Amadori和Heyns化合物的热解产物及对其烟草风味的影响。  方法  以赖氨酸和葡萄糖或果糖为原料,以偏重亚硫酸钠为催化剂、甲醇和冰醋酸为溶剂,分别合成赖氨酸的Amadori和Heyns化合物,采用在线热裂解-气相色谱/质谱联用技术(Py-GC/MS)对比了2种化合物的热解产物差异,并通过感官评吸实验比较了二者对卷烟风味的影响。  结果  （1）赖氨酸Amadori和Heyns化合物热解均能产生醛酮类、呋喃类、吡啶类、吡嗪类及吡咯类香味物质,同一类别产物的相对含量有较大差异。（2）赖氨酸Heyns化合物热解得到的风味成分数量更多。（3）赖氨酸Amadori化合物和Heyns化合物对卷烟的主要作用为增香、增浓和降低刺激,并使烟气更加流畅顺滑,赖氨酸Heyns化合物增加了卷烟白肋烟特征。  结论  赖氨酸Amadori化合物和Heyns化合物的热解产物不同,对卷烟风味的影响存在差异。      

造纸法再造烟叶氨基酸、Amadori化合物含量分析及工艺影响研究

氨基酸、Amadori化合物与造纸法再造烟叶感官品质密切相关,本文研究国内外代表性造纸法再造烟叶产品中氨基酸、Amadori化合物含量差异,并结合再造烟叶生产过程中氨基酸、Amadori化合物含量变化趋势分析,以指导国产造纸法再造烟叶工业控制。研究结果表明,国内外造纸法再造烟叶产品中氨基酸、Amadori化合物含量有较明显差异,国外产品中氨基酸含量最低,其总量分别仅为烟叶、国产产品均值的46.83%、73.52%,而Amadori化合物中Fru-Leu、Fru-Val、Fru-Ile、Fru-Tyr、Fru-Amb含量高于烟叶和国内产品。结合国产造纸法再造烟叶生产工艺分析,提取、净化过程中氨基酸、Amadori化合物分别损失66.32%、74.24%,但浓缩过程中氨基酸、Amadori化合物含量分别增加了48.05%、76.49%,原料中氨基酸、Amadori化合物产品转移率分别为51.87%、47.12%。因此国产造纸法再造烟叶产品氨基酸、Amadori化合物的调控应重点关注提取、浓缩过程控制。     

Studies on the formation of furosine and pyridosine during acid hydrolysis of different Amadori products of lysine

The behavior of different lysine Amadori compounds during acid hydrolysis was investigated in order to determine the molar yield of furosine and the other hydrolysis products. Based on this, the conversion factors for calculating the content of Amadori compound and lysine modification before hydrolysis can be derived. For that purpose, the peptide-bound Amadori compounds N^k-(1-deoxy-D-fructosyl)-, N^k-(1-deoxy-D-tagatosyl)-, N^k-(1-deoxy-D-lactulosyl)- and N^k-(1-deoxy-D-maltulosyl)hippuryllysine as well as free N^k-(1-deoxy-D-fructosyl)lysine were synthesized. For isolation of peptide-bound Amadori compounds, an optimized enzyme-enhanced reversed phase-high pressure liquid chromatography procedure was developed. Pyridosine and N^k-(carboxymethyl)hippuryllysine were synthesized as reference materials. After acid hydrolysis with 6 M hydrochloric acid the, molar yields of furosine were determined to be 32% for fructosyllysine, 34% for lactulosyl- and maltulosyllysine and 42% for tagatosyllysine. Hydrolysis with 8 M hydrochloric acid resulted in a higher yield of furosine for Amadori compounds containing a fructosyl-moiety, 46% for fructosyllysine, 50% for lactulosyllysine and 51% for maltulosyllysine. Compared with this, the molar yield for furosine was not affected by concentration of hydrochloric acid in the case of tagatosyllysine. Based on these conversion factors a reliable calculation of the amount of Amadori compound or lysine modification and with it the evaluation of the progress of the "early" Maillard reaction in foods and biological samples is possible via the quantification of lysine and furosine after acid hydrolysis.     

The Comparison of the Contents of Sugar,Amadori, and Heyns Compounds in Fresh and Black Garlic

Black garlic is produced through thermal processing and is used as a healthy food throughout the world. Compared with fresh garlic, there are obvious changes in the color, taste, and biological functions of black garlic. To analyze and explain these changes, the contents of water‐soluble sugars, fructan, and the key intermediate compounds (Heyns and Amadori) of the Maillard reaction in fresh raw garlic and black garlic were investigated, which were important to control and to evaluate the quality of black garlic. The results showed that the fructan contents in the black garlics were decreased by more than 84.6% compared with the fresh raw garlics, which translated into changes in the fructose and glucose contents. The water‐soluble sugar content was drastically increased by values ranging from 187.79% to 790.96%. Therefore, the taste of the black garlic became very sweet. The sucrose content in black garlic was almost equivalent to fresh garlic. The Amadori and Heyns compounds were analyzed by HPLC‐MS/MS in multiple reaction monitoring mode using the different characteristic fragment ions of Heyns and Amadori compounds. The total content of the 3 main Amadori and 3 Heyns compounds in black garlic ranged from 762.53 to 280.56 μg/g, which was 40 to 100‐fold higher than the values in fresh raw garlic. This result was significant proof that the Maillard reaction in black garlic mainly utilized fructose and glucose, with some amino acids.     

Chemistry of Amadori rearrangement products: Analysis,synthesis, kinetics,reactions, and spectroscopic properties

The chemistry of the key intermediate in the Maillard reaction, the Amadori rearrangement product, is reviewed covering the areas of synthesis, chromatographic analyses, chemical and spectroscopic methods of characterization, reactions, and kinetics. Synthetic strategies involving free and protected sugars are described in detail with specific synthetic procedures. GC‐ and HPLC‐based separations of Amadori products are discussed in relation to the type of columns employed and methods of detection. Applications of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy for structural elucidation of Amadori products are also reviewed. In addition, mass spectrometry of free, protected, and protein‐bound Amadori products under different ionization conditions are presented. The mechanism of acid/base catalyzed thermal degradation reactions of Amadori compounds, as well as their kinetics of formation, are critically evaluated.     

Metabolic transit of Amadori products.

In several studies, the absorption and urinary excretion of free and protein bound Amadori products were measured in rats and humans. Both, in vitro tests with everted intestinal sac preparations and in vivo experiments, showed that there is no active intestinal transport of these compounds but an absorption by diffusion. Trials with tissue slices have shown that there was an uptake into the cells of the liver, kidneys and muscles. Metabolism of Amadori products, if it exists in animals, tends to be very low. Micoorganisms in the large intestines decompose the Amadori products almost completely. The profile of urinary excretion of Amadori products after the ingestion of test meals showed a rapid elimination of the absorbed part, while the fecal output, although low because of the hind gut fermentation, persisted up to 3 days. Only 1-3% of the ingested amounts of protein bound Amadori products were recovered in the urine, which suggests a low absorption rate.     

Effect of digestive process on Maillard reaction indexes and antioxidant properties of breakfast cereals

Extrusion, drying and toasting are the most representative manufacturing processes suffered by breakfast cereals, conjugating thermal/moisture conditions that allow the Maillard reaction (MR) and caramelisation development, as well as the destruction of thermally labile antioxidant compounds. However, other compounds – like Amadori products and hydroxymethylfurfural (HMF) – are originated from the MR and caramelisation, showing different biological activities, as the antioxidant activity. But breakfast cereals are ingested and then affected by the digestive process, and so that the aim of this work was to analyse the effects of the digestion on the bioaccessibility of certain MR products (Amadori compound and HMF) and on the antioxidant activity of corn-based breakfast cereals, using a standardized in vitro gastrointestinal digestion. After digestion approx. 90% HMF remained soluble, but in some cases HMF distribution between soluble/insoluble fractions was higher than the initial HMF measured in the raw cereal, suggesting a release of initially bound Amadori products and its conversion to HMF during the digestion process. The Amadori compound was uniformly distributed between both fractions. The antioxidant activity of the soluble fraction was always higher than that from the raw cereal in any of the antioxidant method employed; therefore the digestion increased the solubility of the antioxidant compounds.     

Pyrolysis-GC Analysis as an Identification Method of Fats and Oils

Pyrolysis at 700°C for 10 set under N₂ gas and 360 mm Hg partial pressure of 18 fats and oils (including oils of the same type but from different sources or varieties), and subsequent GC analysis of the pyrolyzates, revealed differences in both the number and quantities of compounds produced. Statistical analysis of the data showed that all of these fats and oils were distinguishable from one another; moreover, varieties of the same lipid could also be differentiated. This technique requires only microgram quantities of the oil or fat to be analyzed, and the direct pyrolysis and GC analysis gives a “fingerprint” program that differentiates the lipid from others.