二肽甜味剂结构的研究进展

以aspartame为代表的二肽甜味剂在甜味剂市场上占有重要的地位，研究二肽甜味剂的结构与甜味变化的关系有助于开发和评价新的二肽甜味剂。二肽甜味剂对N-端的结构有严格的要求，C-端却是经常可以变化的。为进一步揭示二肽甜味剂的结构，本论文分析了一系列aspartame的衍生物。研究表明，苯丙氨酸上的疏水基团X当改变其结构大小时，甜度的变化不大。而肽键对于维持甜味是必需的，用酯键取代肽键导致甜味消失，氨基上的氢键对于维持甜味来说也是必需的，当它被甲基取代时甜味也消失了。     

胶基糖的甜味剂

胶基糖是以天然树胶为胶姆基制成的糖果．因树胶具有很强的弹性及韧性，故极具咀嚼性，如口香糖和泡泡糖。胶基糖在咀嚼过程中始终保持较强的粘性和柔软的弹性，具有清洁口腔、爽心治神的作用。但有些胶基糖在咀嚼时，甜味持续时间短且在咀嚼后期产生苦味，严重地影响了胶基糖的口感。究其原因主要是胶基糖的甜味剂使用不当。以α－L-天冬氨酰-L-苯丙氨酸甲酯（简称AP）为代表的H盼甜味剂具有类似砂糖的圆润甜味，属低热量甜味剂，甜度高且甜味稳定，持续时间长，可作为胶基据的甜味剂。但二肽甜味剂对热、水分和胶基糖的填充剂碳酸钙等因…     

氨基酸和肽在食品中的呈味作用

本文综述了在食品中有呈味作用的氨基酸和肽。天然氨基酸大多具有甜味或苦味,MSG有强烈的鲜味,阿斯巴甜、阿力甜、索马钳和莫奈林是强力甜味剂。鲜味二肽、咸味二肽、苦味肽、美味肽等也出现了潜在的商业价值。     

二肽衍生物甜味活性构象的研究进展

论述二肽衍生物呈现甜味所需要的构象,以及不同构象排列对甜度的影响。通过对X射线衍射以及NMR、计算机模拟等方法分析到的不同衍生物构象进行对比。发现AH、B、X基团呈“L”构型的二肽衍生物能呈现甜味,而疏水基团X指向-z轴结构的二肽衍生物呈现苦味,而其他构型的二肽衍生物呈现无味。此外,在Tinte-Nofre多结合位点模型中,D区域的基团的存在以及空间填充性对二肽衍生物甜度的增强程度有影响,D区域中芳烷基基团的交互作用对二肽甜味剂甜度的提高有很大帮助。二肽衍生物的甜度与其构象密切相关。     

蛋白糖—佣于饮料食品的最佳甜味剂

一、蛋白糖简介“蛋白糖”这个名词刚刚诞生五年,对于很多人来说可能还比较陌生。它是由构成天然蛋白质的最小单位氨基酸所组成的一种二肽类新型甜味剂,其学名为天门冬氨酰苯丙氨酸甲酯,即由天门冬氨酸和苯丙氨酸构成。1966年,美国塞尔(G.D.Searle)公司的研究人员在合成促胃液分泌激素时,偶然发现其中间体天门冬氨酰苯丙氨酸甲酯(Asp—Phe—Ome)具有约150—200倍蔗糖的甜味。由此,开始了天门冬氨酰二肽甜味剂的研究开发工     

肽类甜味剂的结构与甜味的关系

本文通过对氨基酸的结构与甜味的分析，并以Ａｓｐａｒｔａｍｅ为例，讨论了肽异构体Ｎ—端氨基酸，Ｃ—端氨基酸的结构对甜味的影响，对肽类甜味剂与甜味的关系进行小结，并提出了合成甜味剂的最新进展。     

新型甜味剂N-（对氯苯甲基）-阿斯巴甜的制备研究

为制备新型高倍二肽甜味剂,从甜味机理出发,通过钯碳催化和阿斯巴甜分子选择性催化加氢反应方法,以对氯苯甲醛为原料,研究制备新型高倍甜味剂N-(对氯苯甲基)-阿斯巴甜.结果表明,所得产物由于在阿斯巴甜分子上引入了疏水基团"Cl",甜度大大提高,约为蔗糖的1 500倍.     

阿斯巴甜及其在21世纪食品工业中的发展潜力

甜味是人类最喜爱的基本味之一,甜味剂特别是高品质的强力甜味剂,在现代食品工业朝着口味清淡化、低热量化、低糖化发展过程中发挥着重要作用。在世界食品添加剂总市场中,甜味剂约占20%,位居首位。现代食品工业对强力甜味剂的理想化要求必须同时具备以下4点:(1)绝对的安全性。(2)良好的甜味特性,没有不良的口感与后味。(3)适当的溶解度与稳定性,以便于应用在食品工业上。(4)等甜度下的价格要低于蔗糖。在目前已开发的各种甜味剂中,Ａｓｐａｒｔａｍｅ是一种比较接近于上述4种理想化要求的强力甜味剂。Ａｓｐａｒｔａｍｅ是一种二肽类甜味剂,…     

食品中的甜味与天然甜味剂

天然甜味剂存在于自然界中的动植物中,它分为两大类:一类是糖及其衍生物糖醇;另一类是天然含氮化合物甜味剂。 一、糖与糖醇的比甜度 糖都有甜味,但有甜味的不一定都是糖。糖按结构差别分为蔗糖、葡萄糖等。对于糖,我们评定其甜味是糖与糖醇的比甜度。蔗糖是测量甜味     

天然及合成甜味剂的最新进展

<正> 甜味剂的使用可以追溯到史前时期蜂蜜的发现。科学研究已经表明,人类对甜味的需求是先天的,而不是后天对环境要求的一种客观反应。 甜味剂发展概况 五、六十年代以前的近一个世纪,糖精是人们所能应用的唯一的高甜度甜味剂。五、六十年代之后,甜蜜素、二肽甜味剂以及Acesulfamek等在美国、欧洲及日本等国相继     

Structure-taste relationship of some sweet-tasting dipeptide esters.

The sweetness of dipeptide esters, structurally related to L-aspartyl-L-phenylalanine methyl ester (Aspartame), depends among other things on molecular size. This paper describes a method for predicting whether a dipeptide ester is sweet or not with the aid of atomic models. The method is based on the determination of the size, length and shape of the side chain (R) of the amino-acid ester attached to L-aspartic acid. We measured the side chains of 28 dipeptide esters, 13 of which were synthesized and evaluated for sweetness in our laboratory. Data of the other esters were taken from the literature. Twentyone dipeptide esters were sweet; the size and length of the side chains could be correlated with the degree of sweetness. An ester is sweet provided the length of the side chain (R) is between 4.8 and 8.8 A, and its size greater than or equal to 29 A; as for shape of R in sweet esters, there were two maxima in space filling at about 2 and 4 A or about 3 and 5 A from the asymmetric carbon atom.     

The Stereochemistry of Sweetness

Conformational analogies between sugars, deoxy sugars, substituted sugars, glycosides and cyclitols are examined in relation to current hydrogen bond theories of sweetness. Although the sensory properties of saporous molecules are probably multifunctional in origin, hydrophilic and lipophilic substituents vary in their effects. The former depend on configuration, whereas the latter may either enhance sweetness by strengthening binding to the taste bud protein, or cause re-alignment of the molecule, eliciting a bitter response.     

Sensory Quality of Selected Sweeteners: Unbaked and Baked Flour Doughs

Sucrose, fructose, aspartame, acesulfame K, sodium saccharin, and calcium cyclamate were studied in unbaked and baked shortbreadtype cookies. Sweeteners were evaluated for initial, maximum, and residual sweetness intensity and nonsweet aftertaste for effects of lemon and vanilla flavor on sweetness character. Type of sweetener influenced sweetness quality in unbaked and baked cookies. Intensities and sweetness profiles for the six sweeteners differed between unbaked and baked cookies, particularly for aspartame. Sweetness of sucrose and saccharin were perceived similarly in baked cookies, but they differed in quality and intensity of nonsweet aftertaste. Flavor did not affect initial, maximum, or residual sweetness but nonsweet aftertaste was less intense in lemon and plain unbaked cookies than in vanilla-flavored unbaked cookies.     

具有甜味抑制作用的2-(4-甲氧基苯氧基)丙酸衍生物的构效关系

2-(4-甲氧基苯氧基)丙酸（2-(4-methoxyphenoxy) propionic acid,HPMP）是一种应用广泛的高效甜味抑制剂,但其构效关系尚不清晰。本实验旨在研究HPMP苯环对位疏水基团的变化对甜味抑制效果的影响,为探索新型甜味抑制化合物提供理论依据,以期改善高能食品、运动食品、传统高糖食品的食用品质。本实验合成HPMP及其4 种衍生物,构建甜味抑制效果的电子舌评价方法,考察HPMP及其衍生物对蔗糖、果糖、木糖醇、山梨糖醇甜度的影响。结果表明,电子舌能够反映HPMP的甜味抑制规律,其结果与感官评价结果具有良好的相关性,可作为甜味抑制效果的评价工具。HPMP及其衍生物对4 种甜味剂都有一定的甜味抑制作用。当不同的烷氧基修饰对位时,电子舌甜度抑制率随取代基体积的增大逐渐降低,甲基、氯原子等较小的疏水性基团修饰的衍生物在甜味抑制方面与HPMP效果相当,推测对位疏水取代基的空间体积大小是影响甜味抑制效果的关键因素。     

High pressure induced hydrolysis at C-terminus of peptide derivatives yielding bioactive peptides

If the cyclization of a peptide is associated with a volume reduction, pressure should displace the reaction equilibrium in the direction of a lower volume. Here, results in model solutions are considered, showing a pressure-accelerated transformation of linear dipeptides with reactive C-terminals. The theorised cyclization of dipeptides after hydrolysis of the C-terminal amide H–Leu–Gly–NH₂ or methyl ester groups H–Leu–Gly–OMe and H–Leu–Gly–OtBu was found to be significantly accelerated during application of combined pressure/temperature treatments up to 600–800 MPa and 60–80 °C. Yields were dependent on the nature of the reactive site. Products of those reactions were identified as H–Leu–Gly–OH and cyclo(Leu–Gly), which is a bioactive dipeptide. The dipeptide amide yielded only trace concentrations of the amino acid H–Leu–OH and the linear dipeptide. Steric hindrance prevented a pressure induced cyclisation of a dipeptide with tert-butyl ester at the C-terminus, and only the linear peptide H–Leu–Gly–OH was formed.     

基于细胞水平的甜度定量测定方法及其在卷烟中的应用

  目的  建立一种体外细胞的甜度定量测定方法并应用于卷烟甜感评价,以弥补感官质量评吸存在的不足。  方法  通过构建小分子标签的重组甜味素受体细胞系,利用PTI钙离子成像技术检测钙离子的响应,建立甜度定量测定方法,应用于特色香料及烟气甜度测定。  结果  特色香料相对甜度值与烟气甜度值呈正相关,其中百香果提取物能获得较好烟气甜感与口腔甜感。  结论  此方法可用于以增加甜感为目的的卷烟烟用香精香料评价及烟气甜感评价。      

计算机辅助的蛋白质降血压活性评估方法

目的 借助虚拟水解与分子对接软件, 建立蛋白质降血压活性评估函数。方法 采用Autodock软件将胃肠道蛋白酶水解可能产生的二、三肽与血管紧张素I转化酶(angiotensin I-converting enzyme, ACE)进行分子对接, 根据对接能量值对短肽的ACE抑制活性进行预测, 并对肽的结构特征进行了详细地分析和统计。基于肽段与ACE结合的能量值建立可评估食品蛋白质降血压活性(G值)的打分函数, 并对22条已知氨基酸序列的可口革囊星虫(Phascolosoma esculenta)蛋白质的降血压活性进行评估。结果 对于二、三肽, 由带电荷的氨基酸、芳香族氨基酸和脯氨酸组成的肽段更易与ACE结合, 此外, 酸性氨基酸(带负电荷)所组成的肽段也易与ACE结合。采用打分函数对22条可口革囊星虫蛋白质的降血压活性进行评估, 其中19条蛋白质具有较好的降血压活性。结论 可口革囊星虫是一种良好的降血压肽来源, 计算机辅助的基于对接能量值的ACE抑制活性预测以及打分函数建立对生物活性肽的研究具有重要的参考价值。     

The Stereochemical Basis of Bitterness in Sugar Analogues

Bitterness of sugars and their derivatives appears to be the result of polar as well as hydrophobic molecular features. It is multifunctional and the ring oxygen atom, the anomeric oxygen atom and the C-2 hydroxyl group (and possibly the C-6 hydroxyl group), all of which constitute the most polar and highly reactive “end” of the sugar molecule, together interact to elicit bitterness. The configuration of the substituents on C-1 and possibly on C-2 is critical in determining bitterness in many sugars an indeed β-glycosides and β-linked disaccharides are more likely to be bitter than α-linked anomers. Unlike sweetness, no distinct interorbital distances can yet be established for bitterness. However, current hydrogen bond theories of sweetness seem suffice to explain bitterness in most types of sugar analogue. “Polarisation” of bitter/sweet molecules on taste receptors are also discussed and evidence obtained suggests that at least some of the sweet and bitter receptor sites might be extremely close to one another, and probably within 3–4 Å.     

The effect of frequency of consumption of artificial sweeteners on sweetness liking by women

ABSTRACT:  Research into sweetness perception and preference thus far has demonstrated that sweetness preference is related not to the total sugar consumed by an individual but the amount of refined sugar ingested. Research has yet to be conducted, however, to determine whether a diet high in artificial sweeteners contributes to sweetness liking and preference with the same result as a diet high in sugar. The purpose of this research was to determine if such a relationship exists with regard to diets high in artificially sweetened beverages. Seventy-one female participants were recruited and screened for sweetener consumption in beverages. Sixty-four of these individuals were selected for sensory testing. All participants evaluated orange juice samples (ranging from 0% added sucrose to 20% added sucrose) for liking of sweetness using a 9-point hedonic scale. Based on screening survey data, participants were categorized according to sweetener consumption group (artificial sweetener consumers and natural sweetener consumers) and by overall sweetened beverage intake (low or high, regardless of sweetener type normally consumed). Sensory data were analyzed to compare sweetness liking in each of these groups. Significant differences in liking were observed, with individuals in the high sweetened beverage intake group preferring sweeter orange juice than those in the low-intake group. Categorization by sweetener type resulted in no significant differences between the groups, indicating that regardless of the type of sweetener consumed in a beverage, liking of sweetness will be influenced in the same manner.