油脂的风味及感知

油脂是一种重要的营养物质。随着我国经济水平的发展,居民越来越多地关注油脂的风味品质。油脂原料本身的差异以及加工制备过程中的脂肪氧化降解、热分解、美拉德反应等是影响油脂形成不同风味品质的主要因素。口腔加工中油脂及其制品经过味觉、嗅觉、三叉神经感觉等方面相互作用,在大脑特定区域形成风味的认知。目前有研究证明脂肪酸转位酶（CD36）、G蛋白偶联受体（GPCR）等受体参与到一个专门用于感知脂质的感官系统。因此,有人提出脂肪可能是第6种味道。复杂的多感官交互依赖于人类所有感官的反应,未来关于脂肪感知以及脂肪参与多感官交互方面还需要进一步研究。     

Genetic influences on oral fat perception and preference: Presented at the symposium "The Taste for Fat: New Discoveries on the Role of Fat in Sensory Perception, Metabolism, Sensory Pleasure and Beyond" held at the Institute of Food Technologists 2011 Annual Meeting, New Orleans, LA, June 12, 2011

Research suggests that dietary fat is perceived not only by texture, but also by taste. However, the receptors for chemosensory response to fat have not been identified. We report on 2 genes,TAS2R38 and CD36, that may play a role in fat perception and preference in humans. TAS2R38 is a taste receptor for bitter thiourea compounds, including 6-n-propylthiouracil (PROP) and phenylthiocarbamide (PTC). Nontasters of these compounds tend to be poor at discriminating fat in foods, even though they prefer higher fat versions of these foods. CD36, a fatty acid translocase expressed on multiple cell types including taste cells, plays a critical role in fat preferences in animals. In studies conducted in our laboratory with African-American adults, we identified a variant in the CD36 gene, rs1761667, that predicts oral responses to fat. Individuals who have the A/A genotype at this site tend to find Italian salad dressings creamier than those who have other genotypes at this site. In addition, A/A individuals report higher preferences for added fats, oils, and spreads (for example margarine). Assuming these data are confirmed in other populations, screening for CD36 genotype may provide helpful information to food companies for developing fat-modified products.     

Are Free Fatty Acids Effective Taste Stimuli in Humans?

The popularity of low- and reduced-fat foods has increased as consumers seek to decrease their energy consumption. Fat replacers may be used in fat-reduced products to maintain their sensory properties. However, these ingredients have been largely formulated to replicate nongustatory properties of fats to foods and have only achieved moderate success. There is increasing evidence that fats also activate the taste system and uniquely evoke responses that may influence product acceptance. Work supporting a taste component of fat has prompted questions about whether fat constitutes an additional "primary" or "basic" taste quality. This review briefly summarizes this evidence, focusing on human studies, when possible. Effective stimuli, possible receptors, and physiological changes due to oral fat exposure are discussed. Some studies suggest that there are fatty acid tasters and nontasters and if verified could have implications for targeted product development.     

A review of the associations between single nucleotide polymorphisms in taste receptors,eating behaviors,and health

Food preferences and dietary habits are heavily influenced by taste perception. There is growing interest in characterizing taste preferences based on genetic variation. Genetic differences in the ability to perceive key tastes may impact eating behavior and nutritional intake. Therefore, increased understanding of taste biology and genetics may lead to new personalized strategies, which may prevent or influence the trajectory of chronic disease risk. Recent advances show that single nucleotide polymorphisms (SNPs) in the CD36 fat taste receptor are linked to differences in fat perception, fat preference, and chronic-disease biomarkers. Genetic variation in the sweet taste receptor T1R2 has been shown to alter sweet taste preferences, eating behaviors, and risk of dental caries. Polymorphisms in the bitter taste receptor T2R38 have been shown to influence taste for brassica vegetables. Individuals that intensely taste the bitterness of brassica vegetables (“supertasters”) may avoid vegetable consumption and compensate by increasing their consumption of sweet and fatty foods, which may increase risk for chronic disease. Emerging evidence also suggests that the role of genetics in taste perception may be more impactful in children due to the lack of cultural influence compared to adults. This review examines the current knowledge of SNPs in taste receptors associated with fat, sweet, bitter, umami, and salt taste modalities and their contributions to food preferences, and chronic disease. Overall, these SNPs demonstrate the potential to influence food preferences and consequently health.     

Organoleptic Identification of Roasted Beef, Veal, Lamb and Pork as Affected by Fat

SUMMARY— A taste panel was used to study the identification of roasted beef, pork, lamb and veal by flavor alone and the effect of fat on identification. Only about one-third of the panel could identify correctly all four meats by memory of the flavors. There was an increase in the total number of correct identifications made by comparison of the unknown roasted meat samples with known standards but this was not significantly greater than the total correct responses by memory of the flavor alone. Beef and lamb, but not pork and veal, were identified significantly less often when lean ground roasts were tested than when normal ground roasts (containing fat) were used. Texture, color, mouth feel, and other factors may be important in the identification of meat. Beef, lamb and pork fat, as well as these fats after extraction with chloroform: methanol, were added to lean veal prior to roasting. Addition of beef fat did not increase recognition of veal as beef. Pork fat contained a factor increasing identification of veal as pork, but this factor was water-soluble and could be removed. Lamb fat contained a component, or a fat-soluble component, that significantly increased the identification of veal as lamb.     

Molecular Basis of Taste Sense: Involvement of GPCR Receptors

Taste perception is one of the senses crucial for many organisms. There are five basic tastes, i.e., sweet, bitter, salty, sour, and umami, and it is suggested that the taste of fat should be included in this list. This paper reviews the current state of knowledge about the involvement of G protein coupled receptors (GPCRs) in taste sensing and intracellular signaling. GPCR receptors are focal point of interest for pharmaceutical industry. However, their ability to interact with a variety of taste substances makes these receptors interesting target for food and nutrient companies.     

Fat and salt contents affect the in-mouth temporal sodium release and saltiness perception of chicken sausages

In cooked meats, sodium chloride is involved in taste, texture and flavour release. So a reduction in the salt content may have an impact on overall perception and acceptability. The aim of this study was to evaluate the influence of composition on sodium release and saltiness intensity in chicken sausages. The rheological properties of the sausages differed according to composition. Temporal sodium release and temporal saltiness intensity were evaluated by four selected subjects when eating sausages. At each time point, the effect of the salt level in sausages on sodium release was positive and highly significant. The effect of lipids on sodium release was negative. Concerning perception, the amount of salt used had a positive effect on saltiness intensity, and lipids seemed to exert a masking effect. Generally, clear relationships between salt levels, sodium release and saltiness intensity were found but the masking effect of lipids on saltiness intensity probably also involved texture or fat perception mechanisms.     

The Contribution of Modern Margarine and Fat Spreads to Dietary Fat Intake

The study of dietary fat consumption and its resultant effects on human health has been one of the most investigated topics in the field of human nutrition. Based on the results obtained from such studies, specific dietary recommendations on fat intake (both in terms of quantity and quality) have been established by health organizations around the globe. Among the various food industry sectors, the margarine manufacturers have also responded to these guidelines and now offer improved formulations with a desirable balance of fat contents and fat types. The main aim of this article is to provide an overview on how these modern margarines can contribute towards reaching the dietary guidelines relating to fat intake. In particular, the dietary recommendations with respect to the specific fatty acid types are comprehensively detailed along with an emphasis on the role of modern margarines in providing balanced fat types (more polyunsaturated fats, less saturated fats and a near‐complete absence of trans fats) in the daily diet.     

Lipid‐based fat substitutes

Fats and oils account for 38% of the total calories in the diet of Western populations, especially in the U.S. They provide the most concentrated source of energy, 9 kcal/g of a triacylglycerol molecule compared with 4 kcal/g provided by carbohydrate and protein. In response to consumer demands for low‐calorie or calorie‐free fats and their reluctance to give up the taste of fat, current research efforts have been directed toward the development of lipid‐like fat substitutes. These fat substitutes contain the fatty acids found in conventional fats and oils, with all the physical and organoleptic properties of fats, but provide few or no calories in the diet. Some of the fat substitutes are modified triacylglycerols (glycerol backbone) with reduced digestion and absorption; others are digestible and nondigestible carbohydrate fatty acid esters and polyesters, respectively. Sucrose polyester (Olestra^®), a sucrose molecule esterified with six to eight fatty acids, is the most studied of the lipid‐based fat substitutes containing a carbohydrate backbone. If approved by the FDA, sucrose polyester will find application in almost all fat‐containing foods. Specialty fats or fat substitutes targeted to certain individuals with special needs are being developed. Among these are the medium‐chain triacylglycerols and structured lipids (glycerol backbone), or “nutraceuticals” with reduced absorption and medical applications. Enzyme biotechnology is another tool available to lipid chemists to selectively modify, esterify, transform, transesterify, and interesterify fats and oils or synthesize new lipids such as structured lipids of food, nutritional, and medical importance. These designer fats may be the trend in the future to produce medical lipids that do not occur normally in nature. The different types of lipid‐based fat substitutes are reviewed with respect to their synthesis, analysis, metabolism, potential applications/uses, and the future of fat substitutes.     

Meat fats in nutrition

This article reviews the fat content and fatty acid composition of meats in the human diet and discusses nutritional facts related to meat, meat products and other meat-containing foods as sources of dietary fats. Meat is an increasingly important source of high-value animal protein worldwide. Meat fat comprises mostly monounsaturated and saturated fatty acids, with oleic (C18:1), palmitic (C16:0), and stearic acid (C18:0) being the most ubiquitous. Meat and meat products are considerable sources of cholesterol in the diet. In most industrialized countries, a high meat intake contributes to a higher than recommended total and saturated fat and cholesterol intake. Another concern is that meat may replace sources of other important nutrients in the diet. Therefore, the advice to consumers is to prefer lean meats and low-fat meat products and use meat in moderation only.     

The animal fat paradox and meat quality

The purpose of this paper is to address some of the paradoxical issues and perceptions regarding animal fats and the related effects on meat quality and consumer perceptions. Meat scientists have been studying carcass characteristics for many years and although the factors that influence the accumulation, distribution and composition of carcass fat in livestock have been extensively researched, the role, value and perceptions of animal fats in meat quality differ significantly in importance between producers, abattoirs, butchers, retailers and consumers. Fat and long-chain fatty acids, whether in adipose tissue or muscle, contribute to important aspects of meat quality and are central to the nutritional and sensory values of meat. In this review the nutritional value of fat, as well as the importance of fat in terms of carcass and meat quality will be highlighted. The 'quality' of meat depends greatly on the socio-demographic backgrounds of the consumer. The aim is to focus on the global importance of fat in the carcass to the producer, processor and consumer. There is currently no clear cut definition for fat quality because the acceptability and perceived quality of fat varies significantly in terms of quantity, colour, consistency and chemical composition in different species of livestock around the world. The association between animal fats and human health is critical and recommendations by health professionals range from excluding fats altogether to a moderate consumption of fats due to their essential role in the body. Recently the emphasis has shifted away from fat quantity to fat quality. Despite these recommendations and years of bad publicity in terms of the adverse affects of animal fats in human health, the livestock industry seems reluctant to shift its focus to fat quality rather than quantity. This approach may adversely affect future meat consumption by consumers who are becoming increasingly critical about the food they eat.     

Influence of defined milk products on the flavour of white coffee beverages using static headspace gas chromatography–mass spectrometry/olfactometry and sensory analysis

The influence of milk processing and ingredients on the sensory properties of white coffee beverages has, as yet, not been thoroughly investigated, so in this study analysed milk products processed in a defined manner were added to a standardized, fresh coffee beverage; the resulting odour, taste and retronasal odour perception were measured by intensity tests, and selected volatiles were analysed by static headspace gas chromatography/mass spectrometry. After adding pasteurized consumers’ milk, the effects of a different fat content (3.5 and 1.5%) and fat dispersion were studied. The milk with the lower fat content and with smaller fat globules, resulting from double homogenization (each 250/50 bar), induced a more intense coffee-related retronasal odour perception, whereas the milk-related impression was nearly the same. The addition of casein increased the creamy and milky retronasal odour perception and reduced the coffee-related taste and retronasal odour. These correlations may result in a custom-made development of milky coffee beverages controlled in their nasal and retronasal odour and taste by the defined processing of the milk component. With instrumental analysis it was observable that the effect of the addition of twice-homogenized, twice-pasteurized low-fat milk and of the addition of whole milk was similar. In both cases more volatiles were released from the beverage than with the addition of low-fat milk that was homogenized once. This is an unexpected result, because the whole milk has a higher fat content than the low-fat milk and therefore a greater retention of the flavour compounds was expected. Is it possible that the flavour compounds are not dissolved in fat and that interactions happen only with fat globule membrane constituents?     

Individual differences in oral tactile sensitivity and gustatory fatty acid sensitivity and their relationship with fungiform papillae density,mouth behaviour and texture perception of a food model varying in fat

Fat provides multimodal stimulation, particularly through mouthfeel and as a taste stimulant via free fatty acids. Individuals vary in perception of both mouthfeel and taste sensations from fat. Papillae number on the tongue can influence oral tactile and taste sensitivity. In addition, mouth behaviour (how foods are manipulated in the mouth during eating before swallowing) varies between individuals, and may influence mouthfeel perception. Limited research has explored the relationships between these factors.Fatty acid (FA) taste sensitivity was measured at two levels of oleic acid. Oral tactile sensitivity was measured using von Frey filaments. Fungiform papillae density (FPD) was measured on the tongue anterior. Mouth behaviour (MB) was measured by Graphic Jeltema/Beckley Mouth Behaviour (JBMB) classification tool. Mouthfeel perception (hardness, crunchiness, and greasiness) in a biscuit model was measured to examine the influence of FPD, tactile sensitivity and MB on mouthfeel perception.Higher FPD was significantly related to higher taste sensitivity to fatty acid and to higher oral tactile sensitivity. FPD and oral tactile sensitivity both significantly influenced mouthfeel perception of biscuits. The results demonstrate the need to characterise individual differences in oral sensory perception by more than one method, and suggest oral tactile sensitivity can be used as a marker of FPD. Further studies are required to understand the impact of MB on sensory perception. The BMI of participants in this study was negatively related to oral tactile sensitivity and the perception of greasiness.     

Olestra: A Solution to Food Fat?

Olestra is a sucrose polyester, the first fat substitute that replaces many of the uses of dietary fat such as in dough conditioning, in sprays, in filling ingredients, in flavors, as well as in frying. However, it is not absorbed in the human digestive system, and therefore, it does not provide any nutrition or energy. It has taste and cooking properties similar to the conventional fats and oils. FDA approved the use of olestra only in limited and specific foods with a listing of fat soluble vitamins (vitamins A, D, E, and K) in the ingredient statement of olestra-containing foods followed by an asterisk that is linked to the statement “Dietarily insignificant.” This article reviews the physiological, nutritional, health, and environmental effects of the human consumption of olestra.     

Olestra: A Solution to Food Fat?

Olestra is a sucrose polyester, the first fat substitute that replaces many of the uses of dietary fat such as in dough conditioning, in sprays, in filling ingredients, in flavors, as well as in frying. However, it is not absorbed in the human digestive system, and therefore, it does not provide any nutrition or energy. It has taste and cooking properties similar to the conventional fats and oils. FDA approved the use of olestra only in limited and specific foods with a listing of fat soluble vitamins (vitamins A, D, E, and K) in the ingredient statement of olestra-containing foods followed by an asterisk that is linked to the statement “Dietarily insignificant.” This article reviews the physiological, nutritional, health, and environmental effects of the human consumption of olestra.     

烤肉中脂类氧化及抗氧化研究

肉类食品中脂类的氧化会产生许多不利的影响,如使食品风味发生变化以及产生有害人体健康的物质等。本文综述了烤肉中脂类的氧化,分析了影响脂类氧化的因素,并总结了抗氧化的方法。     

食品脂肪味科学研究的文献计量分析

目的 对食品脂肪味研究进行文献计量分析,为有针对性地深入开展脂肪味的基础研究及其应用提供理论基础。方法 采用文献计量分析方法对脂肪味研究的主要研究现状、学术脉络和研究热点进行可视化分析。结果 脂肪味研究的发文量呈现逐步增长趋势,年引文次数增长迅速;中国的相关研究起步较晚,数量优势逐渐明显,国际合作频次占据优势,但有影响力的专家和机构偏少,国内相关研究报道很少;脂肪味研究不仅涉及食品风味和肉类食品,还涉及营养学、生理学、心理学、化学、医学、食品接触材料、口腔加工和食品物理学等多学科交叉领域;关键词的共现分析、聚类分析和突现分析等进一步揭示,脂肪味研究的热点领域包括脂肪味觉感知与敏感度分析、食品品质、健康、消费者喜好和脂肪酸;后续值得研究的难题包括脂肪味的健康效应、感知阈值、物质基础及其与受体相互作用。结论 我国与其他国家相比虽存在较大差距,但发挥的作用及国际合作趋势正在不断加强。后续我国可以从脂肪味是否是基本味觉的认识,脂肪味对健康的积极或消极影响规律,脂肪味的感知与喜好阈值,不同脂肪酸与脂肪味受体的相互作用方式等食品风味共性科学问题入手进行多学科交叉融合研究。     

Effects of CD36 Genotype on Oral Perception of Oleic Acid Supplemented Safflower Oil Emulsions in Two Ethnic Groups: A Preliminary Study

Previous studies demonstrate humans can detect fatty acids via specialized sensors on the tongue, such as the CD36 receptor. Genetic variation at the common single nucleotide polymorphism rs1761667 of CD36 has been shown to differentially impact the perception of fatty acids, but comparative data among different ethnic groups are lacking. In a small cohort of Caucasian and East Asian young adults, we investigated if: (1) participants could detect oleic acid (C18:1) added to safflower oil emulsions at a constant ratio of 3% (w/v); (2) supplementation of oleic acid to safflower oil emulsions enhanced perception of fattiness and creaminess; and (3) variation at rs1761667 influenced oleic acid detection and fat taste perception. In a 3‐alternate forced choice test, 62% of participants detected 2.9 ± 0.7 mM oleic acid (or 0.08% w/v) in a 2.8% safflower oil emulsion. Supplementation of oleic acid did not enhance fattiness and creaminess perception for the cohort as a whole, though East Asians carrying the GG genotype perceived more overall fattiness and creaminess than their AA genotype counterparts (P < 0.001). No differences were observed for the Caucasians. These preliminary findings indicate that free oleic acid can be detected in an oil‐in‐water emulsion at concentrations found in commercial oils, but it does not increase fattiness or creaminess perception. Additionally, variation at rs1761667 may have ethnic‐specific effects on fat taste perception.     

The influence of oral phenotypic markers and fat perception on fat intake during a breakfast buffet and in a 4-day food record

The ability to discriminate among foods with different fat contents has been associated with preference for high-fat foods and total fat intake. Consequently, oral phenotypic markers that influence fat perception may influence food selection and fat intake. The aim of this study was to investigate how the fungiform papilla (FP) count on the tongue tip, 6-n-propylthiouracil (PROP) bitterness, saliva flow, the increase in salivary flow via oil stimulation and the ability to perceive fat influence fat intake and food selection. A total of 107 subjects (80 female, 27 male) completed a 4-day self-administered food record before they rated the fat contents of different milk–cream mixtures and a high-fat emulsion. Of these subjects, 103 (76 female, 27 male) participated in an ad libitum breakfast buffet that was offered at the university cafeteria. The results show that the perception of the fat content of cream with 30.0% fat was associated with energy intake from fat and discretionary fats over 4 days and during the breakfast buffet. Subjects with lower FP counts ate relatively more high fat milk and spreads and as a consequence more fat during the breakfast buffet than subjects with high FP counts. The increase in salivary flow via oil stimulation was positively correlated with the reported intakes of discretionary and total fat over 4 days. These results support the hypothesis that FP count and the intensity perception of supra-threshold differences in fat content might play an important role in the selection of high-fat foods and fat intake.     

内蒙古锡盟地区传统肉制品的品质分析

研究结果表明,锡盟传统肉制品包括汽蒸类、烧烤类、油炸类、人工风干类、自然风干类、烘干类6大类;不同地区不同类型的传统肉制品均以体积小、水分质量分数18.6%～38.9%、蛋白质质量分数36.6%～54.8%、脂肪质量分数9.79%～13.9%、易携带,具有传统肉制品所特有的色泽和风味、呈现了良好的组织状态特点,自然风干类传统肉制品含水量低,口感较硬,不加任何添加剂,其他类型肉制品亚硝酸盐含量13～27mg/kg和食盐质量分数5.2%～7.9%;一些无包装产品或简单包装的产品存放过程细菌总数超标,霉菌和酵母菌开始生长,但大肠菌群数在标准范围内,未检测出致病菌金黄色葡萄球菌。