食品中鲜味物质研究进展

鲜味作为五大基本味觉之一,对食品滋味具有重要贡献。食品中的鲜味物质(包括鲜味肽、有机酸、氨基酸、核苷酸以及复合鲜味剂等)以其营养、安全等特点,近年来逐渐成为食品鲜味科学领域以及鲜味调味品方面的研究热点,为相关食品风味的改善提供了理论参考及研究方向。本研究介绍了鲜味物质的发展过程,并对鲜味及鲜味物质的研究现状进行了综述。同时对鲜味物质的种类进行概述,并对食品中主要的鲜味物质检测方法研究进展进行总结,最后对食品中鲜味物质的发展进行展望,以便于为食品中仪器检测鲜味物质相关研究提供参考和依据。     

食品中鲜味的来源及其评价方法

鲜味作为5 种基本滋味之一,对食品滋味和品质有着重要的贡献,近年来被人们广泛关注。本文以鲜味为中心展开,介绍了食品中的鲜味物质,包括呈味游离氨基酸、核苷酸以及鲜味寡肽;归纳了几种鲜味评价方法,包括化学分析、人工感官分析以及智能感官分析;阐述了物理和生物方面的鲜味获取方法,并从对鲜味影响较大的食材和加工方式两个方面进行综述,还对未来鲜味的研究方向进行了展望,以期为食品中鲜味的相关研究提供参考。     

Novel Umami Ingredients: Umami Peptides and Their Taste

Umami substances are very important for food seasoning and healthy eating. In addition to monosodium glutamate and some nucleotides, recent investigations have revealed that several peptides also exhibit umami taste. In recent years, 52 peptides have been reported to show umami taste, including 24 dipeptides, 16 tripeptides, 5 octapeptides, 2 pentapeptides, 2 hexapeptides, 1 tetrapeptide, 1 heptapeptide, and 1 undecapeptide. Twenty of these peptides have been examined for the present of umami taste. In this review, we have listed these umami peptides based on their category, source, taste, and threshold concentration. The evidence for peptides showing umami taste, the umami taste receptors on the human tongue, and the peptides whose umami taste is controversial are also discussed.     

不同鲜味物质对干腌马鲛鱼鲜味的贡献与比较分析

以8?种市售干腌马鲛鱼为研究对象,通过比较不同产品中鲜味物质成分和含量差异,并结合其滋味强度值和味精当量的分析计算,以确定对干腌马鲛鱼鲜味贡献最大的物质。结果表明：干腌马鲛鱼具有突出的咸、鲜味和浓厚味感,而其鲜味主要是由谷氨酸、鲜味肽等鲜味物质和乳酸等增鲜物质赋予。在其鲜味物质中,谷氨酸的滋味强度值大于1（除3、5、7号样品）,显示出它对干腌马鲛鱼鲜味的突出贡献,超滤组分的感官分析和肽分子质量分布测定结果表明,分子质量小于1?000?Da的小分子肽对样品的鲜味具有重要贡献。此外,长时间的风干可能会促进乳酸和鲜味肽的生成,但随着水分的流失,其苦味和咸味也增高;而辅料蔗糖和白酒的添加将抑制乳酸的产生,且蔗糖能在一定程度上促进谷氨酸的生成。值得强调的是,8?种样品的核苷酸均已降解为肌苷（inosine,HxR）和次黄嘌呤（hypoxanthine,Hx）等苦味物质,且长时间的风干可能会促进HxR和Hx的积累。     

食品中呈鲜味物质研究进展

鲜味作为五大基本味之一,对于食品整体味道及人们对食品的评价至关重要。本文以鲜味为中心,从宏观角度介绍了富含鲜味的几种食物及影响其鲜味呈现的因素,总结了较新的几种鲜味提取方法,从微观角度综述了富含鲜味的几种氨基酸、核苷酸、肽、有机酸以及有机碱。简述了两种基本的鲜味受体蛋白——味型代谢性谷氨酸受体和味觉受体异源二聚体,并从鲜味感知和鲜味的协同增效作用两方面重点分析了鲜味的呈味机理。总结了当前常用的鲜味测定分析方法:感官评价法、高效液相色谱法、毛细管电泳法,以及比较新颖的生物和化学传感器法,为今后食品中鲜味物质的挖掘、感知、检测等研究提供参考。     

MEASUREMENT OF THE RELATIVE TASTE INTENSITY OF SOME L-α-AMINO ACIDS AND 5'-NUCLEOTIDES

SUMMARY— Intensity of glutamate-like and/or inosinate-like taste (umami in Japanese) of various flavor amino acids and flavor nucleotides was studied using sensory analysis and always found proportional to that of monosodium glutamate (MSG) and disodium 5'-inosinate (IMP), respectively. By application of this fact to a previously obtained equation expressing the relationship between the taste intensity of MSG-IMP mixture and that of MSG alone, the intensity of umami of the mixture of any flavor amino acids and nucleotides could be expressed as an elementary equation: y = u +γ uv, where u and v are the concentrations of amino acids and nucleotides in terms of the concentrations of MSG and IMP, respectively, in the mixture; y is the equivalent concentration of MSG alone; and γ is a positive constant. Interrelationships within each group of substances were additive.     

Umami: a universal taste

The identification and acceptance of umami as a basic taste together with the recent advances in umami research are reviewed, beginning with fish sauces in ancient Greece and Rome and concluding with an examination of the data leading to the realization that umami is indeed a basic taste. The contribution of umami to the flavor of a variety of foods, the role of glutamate and 5′-ribonucleotides in triggering the perception of umami as well as the role of glutamate, the dominant umami compound, in human metabolism are also reviewed.     

Umami: a universal taste

The identification and acceptance of umami as a basic taste together with the recent advances in umami research are reviewed, beginning with fish sauces in ancient Greece and Rome and concluding with an examination of the data leading to the realization that umami is indeed a basic taste. The contribution of umami to the flavor of a variety of foods, the role of glutamate and 5'-ribonucleotides in triggering the perception of umami as well as the role of glutamate, the dominant umami compound, in human metabolism are also reviewed.     

鲜味物质及其在水产调味品中的应用

阐述了氨基酸和核苷酸等一些鲜味物质的结构，产生鲜味的机理，列举了部分天然食品中鲜味物质的含量，介绍鲜味物质的呈味特性，生产现状及其应用情况。阐述了氨基酸和核苷酸之间的显著的相乘作用。详细的介绍了水产品中鲜味物质的研究，包括水产品中鲜味物质的种类，水产品中的味与鲜味的关系，鉴定水产品中特征风味成分的方法，为水产品鲜味调味品的开发利用提供了科学依据。     

“厚味”γ-谷氨酰-缬氨酸增味作用差异性机制

γ-谷氨酰-缬氨酸（γ-Glu-Val）具有多变的呈味特性,在水溶液中呈现涩味,可以增强基本味觉物质的味感强度,赋予奶酪、鸡汤、酱油等食物厚味味感。目前对于γ-Glu-Val呈味特性的机理研究甚少,尤其是鲜见它对于味觉增强效果的差异性机制的研究。本实验利用感官实验和分子模拟对γ-Glu-Val增味作用的差异性机制进行研究。感官实验结果显示,γ-Glu-Val对于基本味感（鲜味、甜味、咸味和酸味）均有一定的提升作用,而对于鲜味的提升效果最为明显。分子模拟实验的结果表明,γ-Glu-Val对基本味感受体（T1R1、T1R2和T1R3）均有一定的亲和力,其中对于鲜味受体T1R1的亲和力最强、结合自由能最高,与此相反,γ-Glu-Val对甜味受体T1R2的亲和力最弱、结合自由能最低,暗示其增鲜作用强于增甜作用。分子动力学结果显示,在味精存在的前提下,γ-Glu-Val可通过氢键和疏水键与鲜味受体T1R1上的氨基酸残基（Phe-274、Ser-275、Ser-300、Trp-303、Ala-147、Ala-170）相互作用,激活鲜味受体,以实现其增鲜作用。本实验解析了γ-Glu-Val增味作用差异性分子机制,为进一步验证其呈味机理提供理论支撑;同时为小分子物质的增味作用研究提供了思路。     

Umami Taste Components and Their Sources in Asian Foods

Umami, the fifth basic taste, is the inimitable taste of Asian foods. Several traditional and locally prepared foods and condiments of Asia are rich in umami. In this part of world, umami is found in fermented animal-based products such as fermented and dried seafood, and plant-based products from beans and grains, dry and fresh mushrooms, and tea. In Southeast Asia, the most preferred seasonings containing umami are fish and seafood sauces, and also soybean sauces. In the East Asian region, soybean sauces are the main source of umami substance in the routine cooking. In Japan, the material used to obtain umami in dashi, the stock added to almost every Japanese soups and boiled dishes, is konbu or dried bonito. This review introduces foods and seasonings containing naturally high amount of umami substances of both animal and plant sources from different countries in Asia.     

食品鲜味研究热点：争议与功能

鲜味作为5 种基本滋味之一，是蛋白质或/和L-氨基酸等含氮营养素摄入的信号，具有调味和生理功能调控双重角色，带给人愉悦的味觉体验和心理享受。鲜味科学的发展已逾百年，民众对鲜味的科学认知如鲜味（肽）味感以及鲜味成分的安全性等方面仍存争议。本文归纳了鲜味与鲜味肽的味感描述、鲜味代表物质谷氨酸钠（味精）的安全性以及鲜味的功能等研究热点，概述了鲜味的广义和狭义定义、鲜味肽的呈味多元性及其影响因素，梳理了鲜味安全性评价与调节食欲等方面的作用，为食品鲜味科学研究提供参考。     

海产鲜味物质及海产品特征滋味的研究进展

素有"海鲜"之称的海产品,以其味道鲜美而备受人们的喜爱。迄今为止,人类所发现的氨基酸、核苷酸、有机酸三类鲜味物质在海产品中都广泛存在,这是海产品鲜味形成的共同物质基础。然而,不同的海产品又呈现出各具特色的特征滋味,这主要归因于各鲜味物质的不同比例以及多种呈味物质的存在。总结了主要海产鲜味物质的研究概况,综述了贝、鱼、虾、蟹等典型海产品特征滋味及其构成的研究进展。并在此基础上预测了今后海产鲜味物质的研究与开发趋势。     

食品中鲜味物质及鲜味肽的研究进展

鲜味是食品五大基本味觉之一,也是深受人们喜爱的美味之一。"天然、营养、安全"的鲜味物质(包括氨基酸类、核苷酸类、有机酸类、鲜味肽等)的开发是近年来食品鲜味科学的研究热点和鲜味调味品研发的重点方向。本文概述了食品中鲜味及鲜味物质的研究现状,并重点介绍了鲜味肽的来源(水产品等)、特点、构效关系、呈鲜机制以及制备和鉴定方法等方面的研究新进展,以期为鲜味调味品的开发,鲜味肽的研究利用及呈鲜机制的研究等提供依据和参考。     

Molecular insights into human taste perception and umami tastants: A review

Understanding taste is key for optimizing the palatability of seaweeds and other non-animal-based foods rich in protein. The lingual papillae in the mouth hold taste buds with taste receptors for the five gustatory taste qualities. Each taste bud contains three distinct cell types, of which Type II cells carry various G protein-coupled receptors that can detect sweet, bitter, or umami tastants, while type III cells detect sour, and likely salty stimuli. Upon ligand binding, receptor-linked intracellular heterotrimeric G proteins initiate a cascade of downstream events which activate the afferent nerve fibers for taste perception in the brain. The taste of amino acids depends on the hydrophobicity, size, charge, isoelectric point, chirality of the alpha carbon, and the functional groups on their side chains. The principal umami ingredient monosodium l -glutamate, broadly known as MSG, loses umami taste upon acetylation, esterification, or methylation, but is able to form flat configurations that bind well to the umami taste receptor. Ribonucleotides such as guanosine monophosphate and inosine monophosphate strongly enhance umami taste when l -glutamate is present. Ribonucleotides bind to the outer section of the venus flytrap domain of the receptor dimer and stabilize the closed conformation. Concentrations of glutamate, aspartate, arginate, and other compounds in food products may enhance saltiness and overall flavor. Umami ingredients may help to reduce the consumption of salts and fats in the general population and increase food consumption in the elderly.     

不同生长阶段下中华绒螯蟹滋味成分差异研究

本文比较了8月份到12月份下中华绒螯蟹雄蟹滋味物质间的差异。通过用电子舌区分不同月份下中华绒螯蟹三个可食部位(体肉、性腺、肝胰腺)的滋味轮廓,并测定其游离氨基酸和呈味核苷酸含量,计算TAV值、EUC值,结果表明电子舌能较好区分不同月份下各可食部位滋味轮廓间的差异,11月份、12月份的滋味轮廓与8月份、9月份相比差异较大;三个可食部位中呈甜味氨基酸含量与性腺中呈鲜味氨基酸含量均在11月份达到最高;蟹肉中呈味核苷酸总量最高,且波动较大,11月份以后呈鲜味核苷酸和呈甜味核苷酸含量显著增高,而性腺和肝胰腺中呈味核苷酸含量波动较小;不同阶段下中华绒螯蟹各可食部位的Glu、Ala、Arg和Lys的TAV值均大于1,对蟹的整体滋味贡献较大;性腺中的EUC值显著高于其他部位,并且在9月份、12月份达到最高。综上,雄蟹在11月份滋味最佳。     

Suppression of Umami Aftertaste by Polysaccharides in Soy Sauce

Umami is one of 5 basic tastes that make foods savory and palatable. The umami aftertaste is a long‐lasting taste sensation that is important for Japanese broth (dashi) utilized for various Japanese foods. Soy sauce is usually added when making dashi‐based dishes; however, different soy sauces produce distinct effects on the umami aftertaste. In this study, we attempted to identify the substances that cause the suppression of the umami aftertaste in soy sauce by combining sensory analysis, size fractionation, chemical analysis, and enzymatic treatment. The suppressive substance was revealed to be polysaccharides with molecular weights between 44900 and 49700. The results of acid hydrolysis and enzymatic treatment suggested that the polysaccharides were cellulose. These results indicate that a type of water‐soluble cellulose derived from soybean, wheat, or microorganisms has a suppressive effect on the umami aftertaste of soy sauce. Future studies should focus on developing a strategy that regulates the amount of these polysaccharides generated during soy sauce production, to maintain or enhance the umami aftertaste.     

鱼露中Gly-Pro和Val-Hyp呈味特性研究

本文采用感官评价和电子舌技术相结合的方式,对鱼露中分离鉴定后进行固相合成的两种肽Gly-Pro和Val-Hyp的单体呈味和二肽与谷氨酸钠、氯化钠相互作用的呈味特性进行研究。结果表明,在单体呈味分析中,Gly-Pro具有鲜味和浓厚感,Val-Hyp具有鲜味且鲜味较持久和轻微浓厚感;在相互作用分析中,Gly-Pro降低了谷氨酸钠的鲜味,Val-Hyp对谷氨酸钠呈味无明显影响。Val-Hyp与氯化钠有显著协同作用,且溶液整体有厚味,而Gly-Pro与氯化钠没有协同作用,反而抑制咸味,但口感丰富。由此可得,鱼露中Gly-Pro和Val-Hyp的呈鲜特性的研究结果表明了其对鱼露鲜美味感具有一定贡献。     

利用1H NMR分析小龙虾的特征性滋味组成

为深入研究小龙虾的非挥发性滋味活性物质,利用1H核磁共振（nuclear magnetic resonance,NMR）对小龙虾中游离氨基酸、核苷酸、有机酸、可溶性糖和生物碱等滋味成分进行定性定量分析,并采用味道强度值（taste activity value,TAV）分析其味觉活性成分,以及通过味精当量（equivalent umami concentration,EUC）评价鲜味。结果表明,使用1HNMR共检测到小龙虾中33种滋味化合物,其中精氨酸、组氨酸、谷氨酸、丙氨酸、赖氨酸、甘氨酸、5’-单磷酸腺苷二钠、5’-单磷酸肌苷二钠、琥珀酸和乳酸的TAV大于1,它们对小龙虾的滋味有重要影响。EUC值以谷氨酸钠质量计,发现小龙虾样品的EUC值为9.1 g/100 g,说明小龙虾具有非常强烈的鲜味。