武定鸡肉中鲜味肽分离鉴定及呈味特性

利用超滤分级、凝胶过滤色谱法和反相-高效液相色谱法对武定鸡肉中鲜味肽进行分离纯化,结合感官评价追踪鲜味最强烈的组分,以纳升高效液相色谱-串联质谱联用技术与固相合成法对鲜味肽进行鉴定和合成,进一步分析鲜味肽的序列来源及其呈味特征。结果表明：从武定鸡肉中分离鉴定出8 条多肽,分子质量范围为365.20～1 735.92 Da,其中LDF、FVT和DLAGRDLTDYLMKIL这3 条肽段具有明显的鲜味活性,阈值在0.062～0.250 mg/mL之间,是武定鸡肉鲜味的关键组分。     

大孔吸附树脂对鲜味肽分离效果及影响因素的研究

从6种极性不同的大孔吸附树脂(NKA-Ⅱ,D3520,X-5,D101,AB-8,DA201)中筛选出一种对鲜味肽吸附性能强、解吸率高、产品鲜味佳的大孔吸附树脂NKA-Ⅱ.研究了粗肽液浓度、乙醇浓度、吸附时间等条件对大孔吸附树脂的吸附性能和解吸率的变化规律,并采用先静态吸附再动态解吸分离得到鲜味肽.通过感官评价,分析了鲜味肽呈味阈值和鲜味肽与其它鲜味剂的协同效应.研究结果表明,NKA-Ⅱ树脂为快速平衡型树脂,粗肽液浓度为20mg/mL,吸附效果最佳,洗脱剂乙醇浓度为75%,解吸率最高.鲜味肽呈味阈值为0.125mg/mL,鲜味肽与谷氨酸钠MSG的协同效果最显著,增效系数为14.3%.     

酱油中鲜味二肽的分离鉴定及其呈味特性研究

为了明确酱油中鲜味肽的结构序列,本文对酱油中鲜味肽进行分离鉴定,并系统地研究了其呈味特性。酱油经超滤膜(膜通量:5 ku、3 ku和1 ku)分离获得4个组分(F1,F2,F3和F4),通过感官评定筛选出鲜味最强的组分F4(1 ku)。该组分通过Sephadex G-15凝胶层析色谱继续分离得到8个组分(P1、P2、P3、P4、P5、P6、P7和P8),经感官评定筛选出鲜味最强的组分P2。采用超高压液相色谱串联质谱技术对P2组分进行多肽结构鉴定,通过手动De novo测序得到4条新的鲜味肽,其序列分别是Asn-Pro(230.1135 u)、Ala-His(227.1026 u)、Gly-Pro(173.0929 u)和Gly-Leu(189.1230 u)。然后采用固相合成技术合成四条肽并通过感官评定和电子舌分析,结果表明四条肽均具有明显的鲜味或鲜味增强作用。进一步研究发现,酱油的鲜味不仅来自于谷氨酸和天冬氨酸等鲜味氨基酸,小分子肽类也是构成酱油鲜味的重要成分之一。     

大孔吸附树脂对鲜味肽分离效果及影响因素的研究

从6种极性不同的大孔吸附树脂（NKA-Ⅱ,D3520,X-5,D101,AB-8,DA201）中筛选出一种对鲜味肽吸附性能强、解吸率高、产品鲜味佳的大孔吸附树脂NKA-Ⅱ。研究了粗肽液浓度、乙醇浓度、吸附时间等条件对大孔吸附树脂的吸附性能和解吸率的变化规律,并采用先静态吸附再动态解吸分离得到鲜味肽。通过感官评价,分析了鲜味肽呈味阈值和鲜味肽与其它鲜味剂的协同效应。研究结果表明,NKA-Ⅱ树脂为快速平衡型树脂,粗肽液浓度为20mg/mL,吸附效果最佳,洗脱剂乙醇浓度为75%,解吸率最高。鲜味肽呈味阈值为0.125mg/mL,鲜味肽与谷氨酸钠MSG的协同效果最显著,增效系数为14.3%。      

养殖暗纹东方鲀中7 种醇提鲜味肽的鉴定及其呈鲜特性

为进一步发掘鲜味肽并探索其构效关系,以60%乙醇溶液作为提取剂,采用超滤纳滤、凝胶色谱层析并结合人工感官评价,从养殖暗纹东方鲀肌肉中分离纯化多肽馏分,进一步利用纳升液相四极杆轨道阱质谱鉴定多肽的分子质量及氨基酸组成。将初步鉴定肽进行固相合成,结合人工感官及电子舌技术验证其呈味特性,并采用分子对接探讨多肽结构与鲜味的关系。结果表明：7 条新鉴定的鲜味肽NWDDMEK、KTGLSPDQF、KTDLNFENL、ASLDGEFKG、ALASLDGEFKG、ALTSLDGEFKG和RLGSSEVEQVQ,其分子质量范围为922.3～1 230.6 Da,鲜味阈值范围为0.38～1.04 mmol/L。鲜味肽序列上的谷氨酸（Glu）、天冬氨酸（Asp）和赖氨酸（Lys）及鲜味受体上的N69、S276、R151、R277、A302、T149和N150等氨基酸残基对多肽的呈鲜特性有重要的意义。本研究可为后期进一步探明肽的呈鲜规律提供参考。     

不同结构改性与美拉德反应前后鲜味二肽(Asn-Pro和Ala-His)呈味特性的对比分析

本文为了探讨不同结构改性(氨基酸顺序改变、增加鲜味氨基酸、串联肽)与美拉德反应对鲜味二肽(Asn-Pro和Ala-His)鲜味与增鲜效果的影响,利用电子舌分析了Asn-Pro和Ala-His及其结构改性后获得的新肽和美拉德反应产物的呈味特性,评价了Asn-Pro和Ala-His结构改性前后以及美拉德反应对味精(MSG)...     

葵花籽肽ALEPIER呈鲜机制及其鲜味稳定性

为评估葵花籽肽ALEPIER作为鲜味剂的实际应用价值,通过TS-5000Z智能味觉分析系统(电子舌)测定了葵花籽肽ALEPIER的呈鲜能力并利用分子对接技术探究其呈鲜机制,并与味精(谷氨酸钠,MSG)进行对比,探讨加工条件(pH、温度)和常见食品辅料(氯化钠、蔗糖、柠檬酸)对葵花籽肽ALEPIER鲜味的影响,考察其鲜味稳定性。另外,探讨了葵花籽肽ALEPIER对MSG鲜味的增强作用。结果表明：葵花籽肽ALEPIER的鲜味值和鲜回味值分别为4.09和1.02,均高于MSG的(3.27和0.84);分子对接结果显示葵花籽肽ALEPIER中的谷氨酸、精氨酸、亮氨酸和丙氨酸与鲜味受体T1R1/T1R3上的His71、Asp147、Ser148、Thr149、Ala170、Ser172、Tyr220、Ser276、Glu301和Ser385等氨基酸残基的结合是葵花籽肽呈鲜的关键机制;在pH 4.0～8.0范围内,葵花籽肽ALEPIER鲜味值随着pH的上升而显著上升;在20～121℃范围内,葵花籽肽ALEPIER的鲜味值不随温度的变化而改变;氯化钠可提升葵花籽肽ALEPIER的鲜味值;蔗糖对葵花籽...     

热加工暗纹东方鲀肌肉中呈味肽分离鉴定及呈味特性研究

为明确养殖暗纹东方鲀煮制时关键呈味肽的结构序列,本文对热加工暗纹东方鲀肌肉中呈味肽进行分离鉴定并对其呈味特性进行研究。热加工暗纹东方鲀肌肉水提物经超滤(3 ku)、纳滤(200 u)及Sephadex G-15凝胶过滤色谱分离得到4个多肽组分(F1、F2、F3和F4),感官评价结合电子舌分析筛选出滋味特性最强组分F2。利用半制备RP-HPLC对F2组分进一步分离得到3个组分(F2-1、F2-2和F2-3),电子舌评价F2-1组分鲜味较强。对组分F2-1中呈味肽的氨基酸序列采用基质辅助激光解析电离飞行时间质谱(MALDI-TOF/TOF MS/MS)进行测定,得到了两种新的呈味五肽和六肽结构:Cys-Ala-Leu-Thr-Pro(CA,503.9253 u)及Arg-Pro-Leu-Gly-Asn-Cys(RP,659.7747 u),2条肽链中均含有的亲水性Cys残基,可能是造成肽具有浓厚感和鲜味的关键。两个肽段经固相合成后测定其呈味特性,肽段RP具有较强鲜味,且肽段RP还与氯化钠和谷氨酸钠具有滋味协同作用,可增强鲜味强度。     

大球盖菇风味肽高效制备及其ACE抑制活性

以基料呈味特性和肽产量为指标，通过响应面工艺优化，获得大球盖菇风味肽高效制备酶解工艺，即酶解时间51.62 min，碱性蛋白酶加酶量0.99%(酶活力200 000 U/g)，酶解温度42.03 ℃，底物质量浓度48.45 g/L。在传统酶解最优制备工艺基础上，采用同步超声辅助定向酶解技术制备大球盖菇富肽风味基料，平板超声辅助酶解30 min时，基料中肽含量(469.21 mg/g干重)可达到传统酶解最优条件下的产肽量，基料制备时间显著缩短；辅助酶解40 min时的产肽量(492.87 mg/g干重)较传统酶解产肽量提升了6.5%。同步超声定向酶解制备的富肽基料，在咸味和鲜味呈味特性上，分别较传统酶解基料提升了1.1~1.8倍和1.1~1.3倍。所有制备工艺得到的富肽基料均具有较优的血管紧张素转化酶(ACE)抑制活性，半抑制浓度(IC50)分别为0.071，0.074，0.122 mg/mL和0.123 mg/mL。通过对大球盖菇风味肽氨基酸序列分析发现，肽链中存在天冬氨酸(D)、缬氨酸(V)、谷氨酸(E)、亮氨酸(L)、甘氨酸(G)、精氨酸(R)、脯氨酸(P)、丙氨酸(A)的氨基酸组合肽段DD、VV、EL、VG、VE、RP、RA、RV、VR时，多肽呈现咸鲜味呈味特性。上述氨基酸组合占比较高，可能是基料呈咸鲜味的主要原因。计算机模拟分子对接技术对大球盖菇风味肽体外抑制ACE活性的预测结果显示，风味肽可与ACE活性口袋氨基酸残基形成氢键，推测这是风味肽发挥ACE抑制作用的主要原因。本研究结果为大球盖菇风味富肽基料的高效制备及开发应用提供理论依据，为制备减盐增鲜调味品、降血压功能食品或食品添加剂提供参考。     

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。     

草菇鲜味肽的分离鉴定及呈味特性分析

通过超滤、凝胶过滤色谱结合电子舌与感官引导对草菇水提物进行初步分离纯化，得到鲜味最佳组分F1，利用反相高效液相色谱结合主成分分析从F1中分离出更接近草菇原始滋味的组分F1-a，进一步采用超高效液相色谱-四极杆飞行时间质谱从F1-a中鉴定出鲜味肽；并将所鉴定的鲜味肽合成后通过感官评价与电子舌分析对其呈味特性进行研究。结果表明：草菇水提物中含有4 种鲜味肽，分别为Asp-Asp-Cys-Pro-Asp-Lys、Leu-Val-Asp-Lys-Pro-Arg、Gln-Ala-Asp-Lys-Arg-Lys、Asp-Thr-Phe-Asn-Asp-Lys，鲜味阈值分别为0.10、0.33、0.42、0.17 mg/mL；草菇中4 种鲜味肽的呈味特性是氨基酸通过肽键形成特定的结构引起，其中鲜味肽Asp-Asp-Cys-Pro-Asp-Lys对味精溶液的增鲜效果最佳，且最佳添加量为20 mg/mL。     

Analysis of binary taste-taste interactions of MSG,lactic acid,and NaCl by temporal dominance of sensations

Temporal dominance of sensations (TDS) is a relatively novel sensory evaluation technique that measures the temporal evolution of sensory perception. The sensory properties of food or drink products have been described by TDS; however, basic sensory data on TDS are still lacking. We analyzed TDS data for solutions of three basic tastes (umami, salty, and sour) and their binary combinations. The duration of TDS for the main taste of each type of solution (monosodium glutamate [MSG] for umami, sodium chloride [NaCl] for saltiness, and lactic acid for sourness) increased in a concentration-dependent manner. In addition, the duration of the umami taste of MSG was longer than that of MSG/inosine 5′-monophosphate solution with an umami taste of equivalent intensity. The duration of NaCl saltiness was increased by coexistence with MSG and decreased by coexistence with lactic acid. On the other hand, the duration of the umami taste of MSG was suppressed by coexistence with NaCl but not lactic acid, while the duration of the sour taste of lactic acid was suppressed by MSG but not NaCl. These findings provide novel insight into the temporal sequence of basic taste perception during food consumption.     

Evaluation of Peptide Contribution to the Intense Umami Taste of Japanese Soy Sauces

ABSTRACT: Koikuchi and tamari shoyu are 2 types of traditional Japanese soy sauce whose low-molecular-weight fractions (less than 500 Da) are known to have the most intense umami taste. Given that peptides were also abundant in some umami fractions of both shoyu, further investigation was conducted to evaluate the precise contribution of peptides to the soy sauce tastes. To locate and isolate peptide fractions, separation procedures using Sephadex G-25 SF, Sephadex G-10, and reversed-phase high-performance liquid chromatography (RP-HPLC) linked to sensory evaluation (by taste dilution analysis), as well as amino acid analysis were performed. Peptides having glutamyl residue were present in most peptide fractions. However, they all revealed negligible contributions to the intense umami taste of the soy sauces. On the other hand, free Glu, in the presence of sodium salt, as well as free Asp and several sweet-taste eliciting free amino acids were considered to be the main contributors to the umami taste of the soy sauces. This study of Japanese soy sauces gives a clear explanation of the frequently questioned peptide contribution to the taste of savory food product.     

Umami Taste Enhancement of MSG/NaCl Mixtures by Subthreshold L-α-Aromatic Amino Acids

l ‐Phenylalanine (l ‐Phe) and l ‐tyrosine (l ‐Tyr) are L‐α‐aromatic amino acids that have recently been discovered to be important components of the savory fractions of soy sauce in addition to l ‐glutamate. Their effects are evaluated on the umami or savory taste of monosodium L‐glutamate (MSG), with or without sodium chloride (NaCl). Because l ‐Phe at subthreshold concentration (1.0 mM) significantly enhances an umami taste of a MSG/NaCl mixture (P= 0.000), combinations of 4 subthreshold concentrations (0, 0.5, 1.5, and 5.0 mM) of l ‐Phe with a weakly suprathreshold MSG (4.0 mM) and NaCl (80 mM) mixture were then rated for salty and umami intensities relative to those of standard solutions. L‐Phe was found to significantly enhance the umami tastes of the MSG/NaCl mixtures when it was added in a concentration range of 0.5 to 5.0 mM (P= 0.000). However, neither the umami taste of MSG alone nor the salty taste of NaCl alone was intensified. In a further experiment, l ‐Tyr at the 3 subthreshold concentrations (0, 0.5, and 1.5 mM) studied was shown to have the same activity as L‐Phe. The phenomenon of umami or savory enhancement by subthreshold aromatic amino acids in the soy sauce system has been established.     

广西北部湾3 种贝类中主要呈味物质的测定及呈味作用评价

测定广西北部湾牡蛎(Crassostrea rivularis)、文蛤(Meretrix meretrix)和波纹巴非蛤(Paphia undulata) 3种贝类中的呈味核苷酸(AMP、GMP、IMP)、糖原等非挥发性呈味物质的含量,并采用味道强度值和等价鲜味值(或味精当量)评价这些非挥发性呈味物质的呈味作用鲜味强度。结果表明：牡蛎、文蛤和波纹巴非蛤的味精当量分别为3.2、1.9、2.7g MSG/100g,对应的味精当量的味道强度值分别是106.7、63.3、90,均远大于1,是其呈强烈鲜味的主要原因。     

白腐乳中呈味肽的分离与鉴定

目的:从白腐乳中寻找呈味肽,分析其氨基酸序列,人工合成肽样品,研究其滋味特性。方法:白腐乳提取液经过超滤、Sephedex G-15葡萄糖凝胶过滤层析,分离出3个呈味组分,通过感官评价筛选出呈鲜效果最优的组分,采用反相高效液相色谱对其进一步分离纯化,选择峰面积最大的组分,使用基质辅助激光解析电离-飞行时间质谱结合De Novo软件分析呈味肽的氨基酸序列,人工合成肽样品,对合成肽样品的呈味特性进行分析。结果:在白腐乳中发现并确定序列的肽链3条,其氨基酸序列分别为:Asp-Phe-Lys-Arg-Glu-Pro、Asp-Arg-Glu-Lys-Phe-AspGlu、Asp-Glu-Asp-Phe-Lys-Arg-Glu-Pro。其中肽Asp-Phe-Lys-Arg-Glu-Pro具有鲜味,肽Asp-Glu-Asp-Phe-Lys-ArgGlu-Pro兼具鲜味与酸味,肽Asp-Arg-Glu-Lys-Phe-Asp-Glu虽无明显特征滋味,但在味精溶液中则体现出较强的增鲜效果。结论:腐乳的鲜味不仅仅来自于谷氨酸等氨基酸成分,还与小分子肽类的呈鲜作用有关。     

“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。     

风干武昌鱼中鲜味肽的分离纯化及二级结构分析

采用电子舌测定鲜味,超纳滤、反相高效液相色谱从风干武昌鱼中分离纯化出纯度均一的鲜味肽,基质辅助激光解析电离-飞行时间质谱仪、氨基酸自动分析仪、傅里叶变换红外光谱测定鲜味肽的分子质量、氨基酸组成和二级结构,探讨鲜味肽结构与风味的关系。结果显示：从风干武昌鱼中纯化得到了一种鲜味较强的肽P2a-2,其分子质量为1 304.59 Da。P2a-2的鲜味氨基酸谷氨酸（21.97%）、甘氨酸（10.67%）和丙氨酸（9.51%）比例较高,且助味氨基酸组氨酸的比例最高（27.54%）,β-转角为主要的二级结构（90.16%）,推断P2a-2呈现较佳鲜味与其高含量的鲜味氨基酸和β-转角相关。     

Isolation and identification of two novel umami and umami-enhancing peptides from peanut hydrolysate by consecutive chromatography and MALDI-TOF/TOF MS

Peanut hydrolysate produced by crude protease extract from Aspergillus oryzae HN 3.042 was found to elicit intense umami and umami-enhancing effect. Taste profiles, amino acid and organic acid composition of peanut hydrolysate and its separation fractions by ultrafiltration were evaluated. The results revealed that peanut hydrolysate was mainly low molecular weight compounds. Fractions of 1-3 kDa and below 1 kDa prominently contributed to the umami taste and umami-enhancing effect of the peanut hydrolysate. The two fractions were further purified, using gel filtration chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC), in combination with sensory evaluation, to obtain a umami peptide and umami-enhancing peptide. The active peptides were identified as Ser-Ser-Arg-Asn-Glu-Gln-Ser-Arg (SSRNEQSR, 963.9 Da) and Glu-Gly-Ser-Glu-Ala-Pro-Asp-Gly-Ser-Ser-Arg (EGSEAPDGSSR, 1091.1 Da), by MALDI-TOF/TOF MS, respectively.