Study of taste-active compounds in the water-soluble extract of mature Cheddar cheese

The chemical composition of the water-soluble extracts of mature Cheddar cheese were identified, with the emphasis on understanding the interplay of compounds contributing to the savoury taste in Cheddar. The ultra-filtered water-soluble extracts of two mature Cheddar cheeses were fractionated by gel permeation chromatography (GPC). By sensory evaluation, two taste-active GPC fractions were identified from each cheese. On the basis of chemical profiling of these fractions, aqueous model tastant mixtures were prepared and sensory omission tests carried out. Glutamic acid, organic acids and mineral salts were the main tastants, whereas the other amino acids had a limited impact on taste. The characteristic umami taste was explained by a synergistic effect of glutamic acid and salts. Matching umami taste intensities were obtained from different concentrations of glutamic acid and salts. Unmasking of a bitter or sweet taste from mixtures of sub-threshold concentrations of amino acids without glutamic acids was also observed.     

酵母抽提物对原酿黄豆酱呈味物质的影响研究

通过自动电位滴定、高效凝胶过滤色谱等方法研究了1%添加量的3款纯品型和3款5'肌苷酸二钠＋5'鸟苷酸二钠（I+G）型酵母抽提物（YE）对原酿黄豆酱中游离氨基酸、5'-呈味核苷酸、小分子肽等呈味物质和感官评价的影响。结果表明,1%添加量的纯品型酵母抽提物YE3、I+G型YE4以及I+G型YE5分别能明显提升原酿黄豆酱的丙氨酸、谷氨酸、5'-呈味核苷酸等鲜味物质的含量,提升效果分别为90%、27%、63倍;纯品型YE2可使分子质量为400～1 000 Da的小分子肽提升64%,并在口感上对应的体现出提鲜、淡咸、抑苦、增厚和协调整体口感等应用效果,应用效果较好的是3款I+G型酵母抽提物。     

蒸制鲟鱼肉特征性滋味组分的鉴定

为明确传统热加工鲟鱼肉特征性滋味组分,对蒸制鲟鱼肉中游离氨基酸、核苷酸、有机酸、甜菜碱及无机离子等滋味组分进行定量分析,并结合滋味活性值、滋味组分减缺、添加及重组实验探究蒸制鲟鱼肉的关键味觉化合物。结果表明：蒸制16 min鲟鱼肉的关键味觉化合物为甘氨酸、谷氨酸、丙氨酸、5’-一磷酸腺苷、5’-一磷酸肌苷、乳酸、琥珀酸、K＋、Na＋和Cl－;将10 种关键味觉化合物按其天然含量溶解在超纯水中制备简化重组液,简化重组液能够较为完整地复制完全重组液的味道,但与天然提取液相比,在鲜味上仍有所欠缺。     

甜面酱的鲜味成分分析

采用国标方法分别对7种市售甜面酱样品的水分、粗脂肪、总氮和粗蛋白的含量进行了测定,利用氨基酸自动分析仪、高效液相色谱仪分别对甜面酱中的游离氨基酸及核苷酸含量进行了测定,利用凝胶色谱柱对甜面酱中小分子肽的分子量分布进行了测定,同时分析计算了甜面酱的水解度、平均肽链长度和氨基酸味道强度值,及其对呈味的贡献。研究结果表明:7种市售甜面酱的水分、粗脂肪、总氮和粗蛋白等平均含量分别为51.42%,1.84%,1.284%和7.32%;甜面酱中游离氨基酸总含量为1.55~2.78 g/100 g,含量相对较高的为脯氨酸、谷氨酸、亮氨酸、天门冬氨酸,其中谷氨酸的味道强度值(TAV值)最高(7.00~25.67),对鲜味具有重要的贡献;甜面酱中的核苷酸主要为次黄嘌呤(3.19~4.87 mg/100 g),但其TAV值均小于0.5,对甜面酱的滋味没有直接影响;甜面酱中小分子肽的含量为0.55~3.31 g/100 g,平均肽链长度为2~4,分子量主要分布于221~445 u之间,且对鲜味具有一定的贡献。     

Taste and flavor of artisan and industrial Manchego cheese as influenced by the water-soluble extract compounds

The correlation between chemical and sensory analysis of the water-soluble extract compounds with molecular weight less than 1,000 Da (WSE < 1,000 Da) from Manchego cheese at different stages of ripening, as well as the influence of the pasteurization processes, has been studied. Free amino acids, peptides and volatile compounds were more abundant in raw milk cheeses WSE < 1,000 Da. Further fractionation of the WSE < 1,000 Da was carried on by gel permeation chromatography and amino acids, peptides, ions and volatiles were determined in the fractions. The same fractions were also subjected to organoleptic evaluation. Volatile compounds were related to the aroma and small peptides and amino acids to the taste. Volatile compounds were mainly alcohols and ketones. Fresh and floral notes were detected in the 4-month-old cheeses, which evolved into more intense and complex flavors in the 8-month-old cheeses. Peptides detected in the fractions were mainly hydrophilic. Umami taste was predominant in most of the fractions and it could be related to the presence of glutamic and aspartic acids in these fractions. Salty taste was perceived with high intensity in the fractions with a high content of salts. Bitter taste was mainly detected in the last eluting fractions and it was attributed to the Tyr, Phe and Trp residues found in these fractions. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

基于多元统计学解析我国四大烧鸡菜肴制品滋味物质图谱

以我国典型民族菜肴四大烧鸡为研究对象,系统分析其游离氨基酸和5’-核苷酸滋味物质,并计算其味精当量值和滋味活度值（taste activity value,TAV）,结合主成分分析（principal component analysis,PCA）、偏最小二乘判别分析（partial least squares discrimination analysis,PLS-DA）和聚类分析（hierarchical cluster analysis,HCA）等多元统计分析方法,解析我国四大烧鸡菜肴的滋味图谱。结果表明：我国四大烧鸡菜肴中游离氨基酸含量差异较大,其中沟帮子熏鸡菜肴中总氨基酸含量最高,为363.66～396.96 mg/100 g;通过TAV分析发现,谷氨酸对沟帮子熏鸡菜肴呈鲜味特征有显著贡献,肌苷酸对道口烧鸡菜肴呈鲜味特征有显著贡献;电子舌结果表明,我国四大烧鸡菜肴滋味存在差异;通过PCA、PLS-DA和HCA均可直观对我国四大烧鸡菜肴进行有效区分,不同烧鸡的鲜美滋味并不是由单一氨基酸和游离核苷酸决定的,鲜味、甜味和苦味氨基酸间的平衡以及与核苷酸的协同作用,导致我国四大烧鸡菜肴...     

Identification of Small Peptides Generated in Spanish Dry-cured Ham

ABSTRACT: A water‐soluble extract of dry‐cured ham was fractionated by gel filtration chromatography. Collected fractions (below 1200 Da) were sensory‐analyzed and subjected to amino acid analysis with and without previous acid hydrolysis, in order to determine the amino acid and peptide distribution. Those fractions with the highest peptide amount were further separated by reverse‐phase and cation‐exchange high‐performance liquid chromatography in order to isolate the peptides and sequence them. The results demonstrated the presence of small peptides, mainly dipeptides. The combination of these peptides and free amino acids may contribute to the characteristic taste in the savory fractions of dry‐cured ham.     

北海沙蟹特征滋味成分的分析

为研究沙蟹中的非挥发性滋味物质,采用氨基酸自动分析仪、高效液相色谱仪和电感耦合等离子体发射光谱仪检测沙蟹的游离氨基酸、5’-呈味核苷酸、有机酸以及无机离子等呈味物质的含量,并采用味道强度值（taste activity value,TAV）确定其中主要的呈味物质及贡献,最后通过味精当量（equivalent umami concentration,EUC）分析鲜味氨基酸和呈味核苷酸之间的协同作用,并对其鲜味进行评价。结果表明,精氨酸、组氨酸、甘氨酸、丙氨酸、谷氨酸、5’-单磷酸肌苷二钠、5’-单磷酸鸟苷二钠和Na＋的TAV大于1,是沙蟹滋味的主要贡献者。EUC值以谷氨酸钠质量计,结果表明沙蟹样品的EUC值为6.4?g/100?g,说明沙蟹具有强烈的鲜味特点。     

基于游离氨基酸、挥发性组分和感官评价的2 种酸化技术加工乳饼的滋味特征差异分析

为明确传统酸水乳饼和发酵型乳饼的特征呈味物质,利用氨基酸分析仪和气相色谱仪分别对传统酸水乳饼和发酵型乳饼中的特征呈味物质（游离氨基酸、游离脂肪酸）进行测定,采用滋味活度值（taste activity value,TAV）判定特征呈味物质,同时进行感官评价;并且结合游离氨基酸和挥发性成分分析特征呈味物质与感官属性之间的相关性。结果表明,谷氨酸、组氨酸和癸酸、月桂酸、肉豆蔻酸、油酸、亚油酸的TAV大于1,对乳饼的滋味有着重要贡献。在感官和呈味物质组成方面,2 种工艺加工的乳饼明显区分开。发酵型乳饼的总体滋味强度高于传统酸水乳饼（P＜0.05）,感官属性以酸味、甜味、苦味和鲜味为主,而传统酸水乳饼伴有不愉悦的异味。偏最小二乘法对特征呈味物质与感官属性之间的相关性分析表明,感官属性与游离氨基酸相关性高,传统酸水乳饼的咸味与精氨酸,异味与甘氨酸、癸酸和棕榈烯酸呈显著正相关（P＜0.05）;发酵型乳饼的酸味与硬脂酸和亚油酸,甜味与天冬氨酸、苏氨酸、丝氨酸、谷氨酸、丙氨酸以及亚油酸,苦味与缬氨酸、蛋氨酸、异亮氨酸、亮氨酸、酪氨酸以及肉豆蔻酸,鲜味与天冬氨酸、谷氨酸、丙氨酸均呈显著正相关（P＜0.05）。发酵酸化技术促进蛋白质和脂肪的分解,改善乳饼的滋味。     

Amino acid pattern of the Egyptian apricot fruits (Hamawy)

Apricot fruits were subjected to acid hydrolysis and the amino acids were separated and quantitatively determined by paper chromatography. The analysis revealed the presence of 19 amino acids, predominantly glutamic acid, aspartic acid, histidine, arginine and tyrosine. The results also demonstrated that the concentrations of cystine, methionine and hydroxyproline were relatively small.     

南美白对虾虾头自溶产物主要呈味成分分析

以南美白对虾虾头为原料,制备风味良好的自溶产物。采用高效液相色谱法、原子吸收光谱等方法分析其主要的呈味物质。结果表明：游离氨基酸含量丰富,总量达9300mg/L,其中天门冬氨酸、谷氨酸、甘氨酸、丙氨酸4 种呈鲜味氨基酸的总含量达2130mg/L,占总游离氨基酸的22.9%;核苷酸及其关联化合物中,与鲜味有着密切联系的肌苷酸(IMP)含量为6.12mg/L;无机质离子Na+、K+、Cl －含量分别达663.7、182.1、417.2mg/L;甜菜碱、乳酸和琥珀酸含量分别达2400、15.27、13.32mg/L。这些成分都影响着南美白对虾虾头自溶产物的鲜味、甜味及整体的滋味。     

Taste of Water-Soluble Extracts Obtained from Over-Fermented Tempe

Over-fermented tempe, known as tempe semangit, is popular in Indonesian culture, especially in Java, as an umami seasoning in traditional foods. The objective of this study was to characterize taste-active compounds in water soluble extracts of over-fermented tempe. Over-fermented tempe was prepared from fresh tempe in which the fermentation was prolonged (0 to 96 h). Free amino acids in the water soluble extract were analyzed and characterized for their taste activity values. Water soluble extracts contained umami and bitter tasting free amino acids at relatively high concentrations. Their umami and bitter taste activity values were higher than the taste threshold concentration. Water soluble extract from 72 h over-fermentation had a higher umami taste activity value than bitter taste activity, exhibiting the highest umami taste dilution factor. The high-performance liquid chromatography profile of water soluble extract fractions obtained using Sephadex G-25 gel filtration chromatography demonstrated that fractions having higher umami taste intensity had more hydrophilic components than hydrophobic components.     

CHANGES IN NITROGEN FRACTIONS AND FREE AMINO ACIDS DURING RIPENING OF SPANISH DRIED BEEF "CECINA"

The changes in nitrogen fractions (total nonprotein nitrogen -NPN-, amino acid nitrogen, peptide nitrogen and volatile basic nitrogen) and free amino acids during the ripening of "cecina" (a Spanish dried beef product) were tracked. The amount of total NPN, amino acid nitrogen and volatile basic nitrogen increased during processing, while peptide nitrogen decreased in the last stage. An increase was observed in all amino acids except taurine. In the final product, the most abundant free amino acids were leucine-isoleucine mixture, lysine and proline-methionine mixture. Taking into account the concentrations of the most abundant amino acids detected in cecina and the taste thresholds described for L-amino acids in water, it appears that several amino acids i.e. lysine, alanine, valine and glutamic acid, could contribute to the flavor of this meat product.     

红曲菌发酵对低盐半干鲩鱼的提味增鲜作用

为探究红曲菌发酵对低盐半干鲩鱼的增鲜作用,在传统低盐半干鲩鱼工艺上引入红曲菌发酵技术,以普通低盐半干鱼组和添加灭活红曲菌发酵剂的低盐半干鱼组（添加灭活发酵剂组）作为对照,通过水可溶性氮、三氯乙酸可溶性氮两指标分析蛋白的降解程度,游离氨基酸和5’-核苷酸含量计算滋味活性值和味精当量。结果表明：红曲菌发酵后的半干鱼产品滋味更加鲜美醇厚,色泽红润诱人;产品中蛋白质大量降解,水可溶性氮、三氯乙酸可溶性氮含量显著增加;红曲菌发酵半干鱼样品的味精当量达到7.34?g/100?g,是红曲菌未发酵半干鱼样品的4.38?倍;总游离氨基酸,特别是谷氨酸和天冬氨酸等鲜味氨基酸的含量明显增加,5’-鸟苷酸和5’-肌苷酸等呈鲜核苷酸含量也明显提高;并且5’-鸟苷酸与谷氨酸的滋味活性值均大于1,表明红曲菌发酵对低盐半干鱼具有明显提味增鲜作用,其中5’-鸟苷酸与谷氨酸是影响产品鲜味的2 个主要成分。     

Non-volatile taste active compounds in the meat of Chinese mitten crab (Eriocheir sinensis)

The non-volatile taste active compounds, including soluble sugars, succinic acid, free amino acids and flavour 5′-nucleotides in the meat of Chinese mitten crab (Eriocheir sinensis) were analyzed, and their taste impacts were evaluated by taste active values (TAVs) and equivalent umami concentration (EUC) methods. The total free amino acid content of crab meat was 20.9 mg/g. Arginine, glycine and alanine were the major free amino acids, accounting for more than 70% of the total free amino acids. 5′-Adenosine monophosphate (AMP) was the main flavour 5′-nucleotide (75.3 mg/100 g), followed by 5′-inosine monophosphate (IMP) (34.4 mg/100 g) and 5′-guanosine monophosphate (GMP) (2.3 mg/100 g). Arginine, glycine, alanine, glutamic acid, IMP and AMP were of high TAV (greater than one), and they had strong taste impacts on the crab meat flavour. Glycine and alanine contributed to the major sweet taste, while glutamic acid, IMP and AMP contributed to the strong umami taste. As the TAVs of soluble sugar, succinic acid and bitter free amino acids were lower than one, thus those compounds are likely to have insignificant impact on the taste of the crab meat. The EUC was 4.2 g MSG/100 g crab meat, which meant that the umami taste of the crab meat was very intense.     

鸡汤及鸡肉酶解液中游离氨基酸及呈味特性的对比分析

为对比分析酶解液与鸡汤中游离氨基酸的组成及含量,采用氨基酸自动分析仪分析检测鸡汤及鸡肉酶解液中的游离氨基酸,并用电子舌分析两者滋味轮廓。结果表明,酶解液中的游离氨基酸总含量相对鸡汤显著增加,两者呈味氨基酸占总游离氨基酸（total free amino acids,TFAA）的比例相近。鸡汤中味道强度值最大的为组氨酸,其次为谷氨酸,酶解液中味道强度值较大的除谷氨酸为呈鲜味的氨基酸外,其余均为呈苦味氨基酸。鸡汤中呈鲜味和甜味氨基酸占TFAA比例之和与呈苦味氨基酸相近,而酶解液中呈苦味氨基酸占TFAA比例多达72.60%,可见鸡汤整体滋味以鲜甜为主,而酶解液整体滋味以苦味为主。电子舌主成分分析结果表明鸡汤与酶解液滋味有显著差异。     

响应面法优化郫县豆瓣游离氨基酸的提取工艺及呈味特性分析

本文优化了郫县豆瓣中游离氨基酸提取工艺并对其呈味特性进行研究。以游离氨基酸提取量作为指标,在单因素实验的基础上,采用响应面试验优化游离氨基酸提取工艺,并通过氨基酸自动分析仪测定6种郫县豆瓣中氨基酸含量。采用味道强度值(Taste activity value,TAV)确定主要呈味物质及贡献,并利用滋味感官评价对郫县豆瓣进行呈味评定。结果表明,最佳提取工艺参数:液料比27:1(mL/g),超声温度35℃,超声时间30 min,氨基酸提取量18.51 mg/g。6种郫县豆瓣样品中呈鲜酸味氨基酸(谷氨酸(Glu)、天冬氨酸(Asp)、天冬酰胺(Asn))含量最高,总量平均达6.380 mg/g;其次为甜鲜味氨基酸(苏氨酸(Thr)、丝氨酸(Ser)、甘氨酸(Gly)、丙氨酸(Ala)、脯氨酸(Pro)),总量平均达5.540 mg/g,呈苦味和苦甜味氨基酸含量最低,6种样品呈鲜味氨基酸总量平均达11.920 mg/g。丙氨酸、谷氨酸、天冬氨酸、赖氨酸、组氨酸、精氨酸和缬氨酸TAV大于1,是郫县豆瓣呈味主要贡献者。滋味感官评价结果显示6种郫县豆瓣鲜、咸口感最为突出。通过响应面优化郫县豆瓣游离氨基酸的最佳提取条件,该工艺方便可行;6种郫县豆瓣中游离氨基酸组成和含量存在一定差异,其中谷氨酸鲜味贡献作用最大。     

不同加工方式对羊肚菌水提液鲜味及抗氧化性能的影响

本文研究了热加工（70、90 ℃）和非热加工（室温、超声、均质和超高压）对不同粒径羊肚菌水提液鲜味成分及抗氧化性能的影响,为羊肚菌的精深加工提供参考。采用高效液相色谱和氨基酸分析仪分别检测了提取液中5’-核苷酸（5’-CMP、5’-UMP、5’-XMP、5’-GMP、5’-IMP和5’-AMP）和游离氨基酸（17种）的含量,并计算、对比各加工条件下羊肚菌的等鲜度（EUC）。通过三种抗氧化法（DPPH、FRAP和ABTS）综合评价各提取液的抗氧化性能。结果表明,除室温处理外,其它处理下,超微粉碎（P2或P3,菌粉粒径分别为35.52和6.28 μm）不同程度地提升羊肚菌水提液中5’-核苷酸含量,但降低了提取液中呈鲜味氨基酸和总游离氨基酸（FAA）含量,使得菌粉的EUC值从106.58 g MSG/100 g~493.97 g MSG/100 g降低至74.70 g MSG/100 g~364.35 g MSG/100 g。相比室温处理,其它处理均能提高羊肚菌水提液的EUC值,但热处理降低了提取液的抗氧化性能,非热处理中HHP（超高压处理）能够取得最优的EUC值和理想的抗氧化效果,其中,未经超微粉碎的菌粉经HHP处理后具有最高EUC值和抗氧化能力,适用于羊肚菌水提液的精深加工。     

烧鸡加工过程中滋味成分变化的研究

采用高效液相色谱和氨基酸自动分析仪研究了烧鸡加工过程中滋味成分的变化。实验结果表明,烧鸡成品中的主要游离氨基酸是谷氨酸、天门冬氨酸、赖氨酸、亮氨酸和精氨酸,烧鸡成品中谷氨酸和天门冬氨酸等鲜味氨基酸的含量分别是其阈值的162倍和95倍,风味核苷酸5＇-IMP的含量高于其阈值6倍多,风味核苷酸和鲜味氨基酸是构成烧鸡滋味的重要成分;油炸工艺对烧鸡游离氨基酸、核苷酸等滋味成分作用不显著;煮制工艺是形成烧鸡美味的重要过程。     

Study of agricultural by-products. Extractability and amino acid composition of grape (Vitis vinifera) skin proteins from cv palomino

Extractability in various solvents of grape skin proteins from cv Palomino, the most abundant and characteristic grape in the sherry zone, was studied. The greatest extractability was obtained in NaOH solutions. Amino acid analysis of the various protein extracts showed that the most abundant amino acid was glutamic acid and the limiting ones were tryptophan and the sulphur-containing amino acids, methionine and cystine.