Exopeptidases and their application to reduce bitterness in food: a review

When exopeptidases catalyze hydrolysis of peptide bonds, the product(s) may have a less bitter taste, and the free amino acids or small peptides formed may function in food as pleasant-tasting flavor compounds or as flavor precursors. There are several classes of exopeptidase based on specificity for hydrolysis of synthetic substrates. Exopeptidases in food-stuff may be of natural origin or may be extrinsic, that is, produced by microorganisms or parasites. Exopeptidases used to modify foods are also becoming increasingly available in the industrial enzyme market. Exopeptidases contribute to a variety of quality changes in postharvest fruit, meats, and food fermentations. Foodstuff impacted by these enzymes during processing include cocoa, beer, aged and cured meat products, koji, fish sauce, ripened cheeses, and protein hydrolysates. An important role of exopeptidases in food is the hydrolysis of hydrophobic, bitter peptides. The relationship between peptide structure and sensory transduction/receptor models is discussed. Research on the use of exopeptidases to reduce bitterness is reviewed.     

Invited review: Sensory analysis of dairy foods

Sensory quality is the ultimate measure of product quality and success. Sensory analysis comprises a variety of powerful and sensitive tools to measure human responses to foods and other products. Selection of the appropriate test, test conditions, and data analysis result in reproducible, powerful, and relevant results. Appropriate application of these tests enables specific product and consumer insights and interpretation of volatile compound analyses to flavor perception. Trained-panel results differ from dairy judging and grading and one objective of this review is to clearly address and demonstrate the differences. Information on available sensory tests, when and how to use them, and the powerful results that can be obtained is presented.     

炸制过程中糖醋脆皮鱼风味物质的变化

目的:为糖醋脆皮鱼的产业化生产提供理论依据。方法:利用电子鼻、电子舌、气相离子迁移谱图(GC-IMS)、氨基酸自动分析仪,结合主成分分析(PCA)、聚类分析(CA)和相关性分析,分别从香气化合物和滋味化合物变化进行评价。结果:在炸制过程中,糖醋脆皮鱼的香气响应强度呈先增加后减小的趋势,滋味响应强度呈增大的趋势。糖醋脆皮鱼中共检出香气化合物46种,其中醛类7种,酮类5种,醇类10种,酯类9种,烯烃类4种,杂环类7种,其他化合物4种;A样品(定型炸制1.5 min)相对含量最高的是醇类,B样品(定型炸制3.0 min)相对含量最高的是醛类和酮类。糖醋脆皮鱼中共检出游离氨基酸21种,其所含的谷氨酸、丙氨酸、精氨酸等对样本的鲜味、甜味、苦味均有较大贡献,其中C样品(熟制1 min)的鲜味、甜味均表现突出。由相关性分析可见,醇类化合物与大部分电子鼻传感器呈显著性正相关(P<0.05),鲜味氨基酸和电子舌传感器AHS、PKS、CTS和NMS呈显著性正相关(P<0.05),醛类化合物与甜味氨基酸和苦味氨基酸呈显著性负相关(P<0.05)。结论:糖醋脆皮鱼的大部分香气化合物在炸制过程...     

Beef flavor: a review from chemistry to consumer

This paper briefly reviews research that describes the sensation, generation and consumer acceptance of beef flavor. Humans sense the five basic tastes in their taste buds, and receptors in the nasal and sinus cavities sense aromas. Additionally, trigeminal senses such as metallic and astringent are sensed in the oral and nasal cavities and can have an effect on the flavor of beef. Flavors are generated from a complex interaction of tastes, tactile senses and aromas taken collectively throughout the tongue, nasal, sinus and oral cavities. Cooking beef generates compounds that contribute to these senses and result in beef flavor, and the factors that are involved in the cookery process determine the amount and type of these compounds and therefore the flavor generated. A low‐heat, slow cooking method generates primarily lipid degradation products, while high‐heat, fast cookery generates more Maillard reaction products. The science of consumer acceptance, cluster analyses and drawing relationships among all flavor determinants is a relatively new discipline in beef flavor. Consumers rate beef that has lipid degradation products generated from a low degree of doneness and Maillard flavor products from fast, hot cookery the highest in overall liking, and current research has shown that strong relationships exist between beef flavor and consumer acceptability, even more so than juiciness or tenderness. © 2015 Society of Chemical Industry     

The role of conching in chocolate flavor development: A review

Chocolate is an indulgent product whose consumption is mostly motivated by its alluring sensory properties. Among them, flavor stands as the key driver for consumer preference and purchase intention. Flavor is a complex multimodal perception whose discrimination depends mostly on the retronasal aromas associated with the presence of odor-active compounds in the matrix. The development of chocolate flavor relies on several factors, ranging from intrinsic properties of raw materials to formulation and processing conditions. As the last step of liquid chocolate manufacture, conching develops proper fluidity/texture and finetunes flavor, by means of intensive mixing and continuous heating of chocolate mass for several hours. Time and temperature are the main parameters determining the extent of conching effects upon flavor, despite factors such as ventilation, energy input onto chocolate mass, and configuration of conching machine being also relevant to some of the physicochemical mechanisms involved in flavor modification. Overall, conching impacts chocolate flavor by either changing the concentration of key odor-active compounds or modifying their distribution throughout the matrix, affecting their binding to other components and, ultimately, their rate of release during ingestion. The present review aims to gather evidence on the physicochemical transformations promoted by conching responsible for flavor enhancement and overall sensory quality of chocolates.     

Sensory and Physicochemical Studies of Thermally Micronized Chickpea (Cicer arietinum) and Green Lentil (Lens culinaris) Flours as Binders in Low‐Fat Beef Burgers

Pulses are known to be nutritious foods but are susceptible to oxidation due to the reaction of lipoxygenase (LOX) with linolenic and linoleic acids which can lead to off flavors caused by the formation of volatile organic compounds (VOCs). Infrared micronization at 130 and 150 °C was investigated as a heat treatment to determine its effect on LOX activity and VOCs of chickpea and green lentil flour. The pulse flours were added to low‐fat beef burgers at 6% and measured for consumer acceptability and physicochemical properties. Micronization at 130 °C significantly decreased LOX activity for both flours. The lentil flour micronized at 150 °C showed a further significant decrease in LOX activity similar to that of the chickpea flour at 150 °C. The lowering of VOCs was accomplished more successfully with micronization at 130 °C for chickpea flour while micronization at 150 °C for the green lentil flour was more effective. Micronization minimally affected the characteristic fatty acid content in each flour but significantly increased omega‐3 and n‐6 fatty acids at 150 °C in burgers with lentil and chickpea flours, respectively. Burgers with green lentil flour micronized at 130 and 150 °C, and chickpea flour micronized at 150 °C were positively associated with acceptability. Micronization did not affect the shear force and cooking losses of the burgers made with both flours. Formulation of low‐fat beef burgers containing 6% micronized gluten‐free binder made from lentil and chickpea flour is possible based on favorable results for physicochemical properties and consumer acceptability.     

苹果酸-乳酸发酵对威代尔冰酒香气的影响

以酒精发酵与苹果酸-乳酸发酵同时进行的威代尔冰酒为实验组,以单一酒精发酵的冰酒为对照,采用液相色谱（LC）、顶空固相微萃取（HS-SPME）和气相色谱-质谱联用（GC-MS）技术,对有机酸含量和挥发性香气成分进行定性定量检测,同时进行感官评定,探究苹果酸-乳酸发酵对威代尔冰酒香气的影响。结果表明,苹果酸-乳酸发酵能使冰酒中苹果酸含量降低26%,乳酸含量增加50%,显著提高冰酒中脂肪酸乙酯类（34.71%）和萜类香气物质含量（15.2%）（P＜0.05）,显著降低戊醇等高级醇类含量（12.19%）（P＜0.05）,提高冰酒的花香、果香、焦糖香,显著降低化学味。感官分析结果表明,苹果酸-乳酸发酵能增加冰酒中的果香、花香,降低冰酒酸度,提高糖酸平衡感,从而提高其整体接受度。     

不同脂肪酶酶解奶油制备奶味香基的研究

选用Hansen calf lipase、Amano lipase A6、Lipozyme RM IM 3种脂肪酶对无水奶油进行适度酶解制备奶味香基。采用气相色谱分析了酶解奶油中游离脂肪酸组成,结合顶空固相微萃取-气相色谱质谱联用技术对酶解奶油中的挥发性风味成分进行研究,并通过感官评价对酶解奶油进行风味剖面分析并对烘焙产品偏好性评定。结果表明:3种脂肪酶选择性酶解产生中短链脂肪酸的能力均较强,其中动物来源的Hansen calf lipase对中短链脂肪酸的选择性酶解能力最高,酶解奶油中短链脂肪酸相对含量为42.9%,且该酶解奶油和烘焙产品具有令人愉悦的奶味和干酪味;3种酶解奶油中的挥发性风味成分主要为脂肪酸、醛类、酮类、内酯类物质。     

五味调与营养平衡及其信号传导

“五味调”是中国餐和烹饪的基本理论和原则。一直以来,很多人认为中国餐虽然讲究色、香、味,但是不讲究营养,而有关味觉和嗅觉受体与相应的配体相互作用研究表明,味觉和嗅觉所传感的正是机体所需要的营养成分,并构成营养体内平衡的分子结构识别机制和生理调节与代谢基础,五味调和在机体生命活动和营养体内平衡中具有重要作用。味觉和嗅觉受体以G蛋白偶联受体超家族为主体,构成机体对营养物质的结构与功能、定量与定性的传感系统。该传感系统不仅分布在舌和鼻咽部的味蕾处,而且遍布整个消化道系统,以及神经信号传导系统,在外周系统和大脑之间构建起通讯联系和“编码系统”。大量研究表明,在漫长的进化中,人和动物已经形成了一个从看到食物开始,一直到食入、咀嚼、消化、吸收、排泄等各个关键环节的时序控制及其复杂的信号级联激活和传递系统。机体通过味觉和嗅觉系统从饮食的形态、质构到分子结构与功能等进行严格的识别和筛选,系统地控制各种营养成分的消化和吸收,并同时以严格的时序性信号传递与级联,从神经信号的快速传递到神经和体液混合传递,再到体液传递相互配合,构成食品营养与安全的交响乐式的信号传递与控制过程,决定了机体的营养吸收、防御、体内平衡、生理活动、代谢与健康。本文在综述这些进展的基础上提出：五味调和是健康饮食的基础,通过味觉和嗅觉受体及其与配体的相互作用的研究,不仅可以为嗅觉和味觉测定开辟新的方法和途径,而且为调味品的研究和健康饮食,控制现代文明病的发生和发展提供科学依据。     

Flavor Comparison of Natural Cheeses Manufactured in Different Countries

Abstract: The objective of this study was to determine the main flavor components of different natural aged cheese types from various countries and determine whether a unique sensory characteristic exists within specific countries for European cheeses. The flavor of 152 cheeses from Estonia, France, Italy, Germany, Holland, Austria, England, Greece, Ireland, Spain, Switzerland, Sweden, Belgium, and Denmark were described during 4 independent studies. The sensory data from these studies were combined. The cheeses were sorted according to milk type and texture, and flavor characteristics of these groups were described. The main flavor characteristics of the cheeses tested were salty, sweet, sour, astringent, biting, pungent, sharp, nutty, musty/earthy, dairy fat, buttery, and dairy sweet. The cluster analysis divided the cheeses into 4 clusters: clusters 1 and 2 were sour, dairy sour, salty, astringent, biting, and varied in buttery (cluster 1) and sharp notes (cluster 2). Cluster 1 and 2 were mainly composed of French cheeses, while clusters 3 and 4 represented cheeses from various countries. Cluster 3 and 4 were sweet, with cooked milk and nutty characteristics and varied from buttery (cluster 3) to sharp notes (cluster 4). Cheeses from some countries, for example, France and Estonia, generally exhibited common sensory characteristics within the specific country, but cheeses from some other countries, such as Italy, varied widely, and seemed to have no common sensory theme. Most regional cheese standards are not specific about flavor profiles and these results suggest it may be possible to start a further characterization of cheeses in some countries. Practical Application: This research shows the main flavor characteristics of certain types of cheeses manufactured in various countries. The information may be useful to cheese manufacturers, product developers, food scientists, cheese connoisseurs, and government officials to better understand the flavor classification of cheeses from various countries.     

市售豉香型白酒品质及风味感官分析

目的 探究市售豉香型白酒品质特性,通过理化指标与感官风味评价的总体分析,构建其之间的相互关系。方法 以12种市售豉香型白酒为研究对象,采用高效液相色谱法(highperformanceliquid chromatography, HPLC)结合风味感官评价方法,通过有机酸含量、酒精度、总酸、总酯、酸酯总量、pH及风味感官特性等指标综合分析市售豉香型白酒的品质。结果 12种市售豉香型白酒中均检测出乳酸和乙酸2种有机酸,并未检测出草酸和柠檬酸;相比于浓香、清香等白酒,豉香型白酒中苹果酸和酒石酸含量较低; 12种市售豉香型白酒属于平均为29.8%vol的低度酒,总酸和总酯含量平均分别为0.54 g/L和0.53 g/L; 92%的样品酸酯总量不小于8mmol/L,符合一级豉香型白酒的要求;样品的pH都在3.06～4.53内;市售豉香型白酒在水果香、蜜香、米香等风味强度上无显著性差异,而在醇香和脂肪味上具有显著差异。结论 豉香型白酒相关理化指标所代表的风味物质对其风味感官具有一定贡献,研究结果为豉香型白酒理化指标与风味感官存在相互关系,理化指标测定结果对豉香型白酒风味感官评价具有导向作用。     

酸辣芥末凤爪的加工工艺研究

试验以凤爪为研究对象,通过添加不同比例的芥末提取物、芥末粉,采用感官评定法,测定不同添加量对凤爪风味的影响。试验结果表明:当凤爪基本配方确定时,添加比例(芥末提取物添加量为1%、芥末粉添加量为6%),辣味适中,外观,适口性最佳。     

榨菜的风味化学及其风味形成的探讨

对榨菜风味形成中的各种关键物质进行了介绍,简述了榨菜腌制发酵的原理,阐述了榨菜风味形成的原理。     

啤酒有机酸类物质研究进展

有机酸类物质是啤酒中一类重要的化合物，其组成和含量不仅影响啤酒的风味，而且与酵母的活力也有较密切的联系。文中参照国内外研究资料，从有机酸对啤酒风味的影响以及有机酸的代谢与酵母活力之间的联系阐述有机酸类物质对于提高啤酒质量的重要性。     

淡水鱼鱼肉风味物质及其影响因素研究进展

随着生活水平的提高和水产品养殖及其加工工业的发展,人们对鱼肉的风味越来越重视。鱼肉中的呈味核苷酸、呈味氨基酸以及挥发性成分等的含量直接影响鱼肉的风味。本文系统阐述贮藏和加工温度、饲料成分、宰杀与加工方式等对淡水鱼鱼肉风味物质的影响,旨在为从鱼类养殖、鱼肉贮藏和加工等方面改善和增强淡水鱼鱼肉风味提供思路。