Mechanisms for sensing fat in food in the mouth: 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, USA., June 12, 2011

The brain areas that represent taste including the primary taste cortex and the orbitofrontal cortex also provide a representation of oral texture. Fat texture is represented by neurons independently of viscosity: some neurons respond to fat independently of viscosity, and other neurons encode viscosity. The neurons that respond to fat also respond to silicone and paraffin oil, indicating that the sensing is texture-specific not chemo-specific. This fat sensing is not related to free fatty acids such as linoleic acid, and a few other neurons that respond to free fatty acids typically do not respond to fat in the mouth. Complementary human functional neuroimaging studies show that the pleasantness of food texture is represented in the orbitofrontal cortex. These findings have implications for the design of foods that mimic the pleasant texture of fat in the mouth but have low energy content, and thus for the prevention and treatment of obesity.     

Viscosity drives texture perception of protein beverages more than hydrocolloid type

Hydrocolloids are added to alter rheological properties of beverages but have other properties that can contribute to overall taste and texture perception. In this study, tapioca starch and λ-carrageenan were used to determine how hydrocolloid type, viscosity level (4–6 mPa·s, 25–30 mPa·s, and 50–60 mPa·s at 50 s⁻¹), and complexity of the system (aqueous, skim milk, or whole milk) influence sensory taste and texture of fluids. All fluids were shear thinning; however, skim milk and whole milk solutions that contained carrageenan had much higher low shear viscosity and lower high shear viscosity than those with starch. There was a significant effect of viscosity level on sensory perception of consistency, creamy/oily, mouthcoating, and residual mouthcoating in aqueous, skim milk, and whole milk beverages, and a weak effect of hydrocolloid type. However, normalizing creamy/oily, paste, and mouthcoating against sensory consistency removed the effect of hydrocolloid type. Flavors (cream, cooked, cardboard, and melon/cardboard) were associated with the type of hydrocolloid and milk protein ingredient. Temporal dominance of sensations showed that samples exhibit similar temporal sensory profiles, although the addition of hydrocolloids enhanced dominance of creaminess even in samples without fat. Hydrocolloid type did not significantly influence mouthcoating or the persistence of astringency. Additionally, increasing viscosity from 3 to 74 mPa·s at 50 s⁻¹ did not suppress perceived sweet or salty taste. The results suggest that in fluid systems with viscosity levels typically found in beverages, textural properties are determined by viscosity and independent of the type of hydrocolloid.     

Thin Film Morphology and Tribology Study of Mayonnaise

The texture of food is considered related to its rheological behavior when confined within thin films between two shearing or squeezing surfaces. Such thin-film tribological properties may represent foods undergoing massive grinding and deformation during mastication. The thin-film tribological properties rather than the bulk rheological properties correlated with the composition (oil droplets, etc.) and texture of mayonnaise samples. Using the Surface Forces Apparatus (SFA) technique and optical interferometry using fringes of equal chromatic order, we characterized the thin-film morphology and measured tribological and other interfacial properties of mayonnaise emulsions. Results revealed new properties that help differentiate between full fat, light and fat free mayonnaises. This provides an important approach to determine properties of such foods in thin films which cannot be deduced from bulk properties.     

粳米与籼米组合对婴幼儿米粉食用品质的影响

研究了粳米和籼米不同搭配组合的基本理化指标、蒸煮特性、糊化特性和质构特性.结果表明,直链淀粉含量对食用品质具有重要影响.蒸煮特性上,直链淀粉含量越低,吸水率及膨胀体积越小,米汤pH、碘显色值和干物质含量越高,蒸煮及冲调性越好;糊化特性上,直链淀粉含量越低,峰值黏度和崩解值越高,回复值及衰减值越低,口感越好;质构特性上,...     

基于质地多面分析法对不同苹果品种果肉质构特性的分析

为了细致研究"华红"苹果贮藏期间果肉质地变化和不同苹果品种质构特性差异,本实验以套袋和未套袋"华红"苹果为试材,应用质地多面分析法定期测定贮藏期间果肉质地参数;以及以不同熟期"华红"、"华苹"、"寒富"、"红星"、"嘎拉"、"津轻"为试材,比较不同苹果品种果肉质地品质差异,同时分析各质地参数之间相关性。"华红"套袋和未套袋果肉质地参数在常温贮藏过程中变化趋势基本一致,且未套袋果肉的各项质地参数稍高于套袋的。硬度呈下降趋势,在黏附性、内聚性、弹性、咀嚼性、回复性方面,贮藏0 d的果实与48 d相比稍有升高。"华红"果肉贮藏期间质地参数变化相关性和6个苹果品种之间质地参数相关性有相似处,内聚性与弹性、回复性、咀嚼性都呈正相关,弹性与回复性、咀嚼性都呈较好地正相关,回复性与咀嚼性呈较好的正相关。不同的是,"华红"果肉硬度与黏附性、内聚性呈负相关,而不同品种之间果肉硬度与内聚性、弹性、回复性、咀嚼性呈高度正相关。不同品种之间各质地参数也进行了量化比较。综上说明本实验选用的P5探头测定的果肉内聚性、弹性、回复性、咀嚼性能反映"华红"果肉质地变化规律,适用于苹果果肉质地品质的客观评价。硬度、内聚性、弹性、回复性、咀嚼性质地参数中的一项或多项可以作为评价"华红"果肉质地和比较这6个苹果品种果肉质地差异性的重要参数。     

MECHANISMS UNDERLYING THE ROLE OF FRICTION IN ORAL TEXTURE

The role of friction in food texture sensations are reviewed with the focus on results from our own laboratory, concentrating on texture sensations that are affected by the lubricative properties (e.g., roughness and creaminess), by the viscosity (e.g., melting and thickness) and by the used thickeners (e.g., airiness and heterogeneity). A food's lubricative properties are affected by its fat content, fat droplet size, particle size and shape and thickener. Foods with lower fat contents, larger fat droplets, larger particles and specific thickeners exhibited higher friction while their creaminess and fattiness sensations, associated with good lubrication, are reduced. Roughness and dryness sensations, associated with poor lubrication, are increased. Taste and flavor compounds also affected these texture sensations, albeit via a different mechanism. Specific compounds can affect the lubricative properties of saliva resulting in friction‐related sensations, such as astringency. Astringent compounds interact with proline‐rich proteins in saliva, causing precipitation that may be sensed as discrete particles and/or increased roughness. Alternatively, the compounds may precipitate dead cells and other debris present in saliva. Astringent compounds may also directly affect the surface properties of the oral mucosa.     

Invited review: Sugar reduction in dairy products

Sugar overconsumption continues to increase worldwide and contributes to multiple health-related issues. Dairy foods represent a large market, grossing more than $125 billion per year worldwide. Consumer demands for healthier products are leading to a large push for sugar reduction in dairy foods. Sugar plays an important role in dairy foods, not only in flavor but also in texture, color, and viscosity. Replacing sugar can have negative effects, making substitution inherently difficult. Natural and artificial nonnutritive sweeteners exist for sugar reduction. Natural nonnutritive sweeteners are popular, particularly for label appeal, but many consumers still prefer the taste of artificial nonnutritive sweeteners. Sweet taste perception can also be affected by texture of the food matrix and the presence of fat. Other sugar reduction techniques include hydrolysis of lactose, ultrafiltration, and direct reduction. This review will address the role of sugar, alternative sweeteners, and sugar reduction in ice cream, yogurt, and flavored milk.     

ORAL PHYSIOLOGY AND TEXTURE PERCEPTION OF SEMISOLIDS

ABSTRACT

In the oral cavity, the food is subjected to several mechanical and chemical processes. It is fractured by the teeth, diluted and broken down by saliva, heated or cooled by the ambient temperature of the mouth, formed into a bolus and finally swallowed. Numerous receptors in the oral cavity and nose respond to the initially ingested food and monitor the changes during processing. This leads to central perceptions of taste, odor, irritation and texture of the food. Most sensations associated with food texture occur only when the food is manipulated, deformed or moved across the oral receptors. In addition, people assessing the same stimulus differ in their ratings of that stimulus and their oral physiological parameters also exhibit inter‐individual variations. This paper is based on the PhD thesis of one of the authors. It gives an overview of this study and includes related work of other authors. The aim of our research was to improve the understanding of oral texture perception, in particular to examine the role of oral physiological processes in oral texture perception of semisolids and to investigate whether individual differences in perception could be attributed to differences in oral physiology among subjects. The results of our study demonstrate that oral physiological parameters such as oral sensitivity, tongue movements, temperature and saliva composition are of importance for texture perception of semisolids. Many parameters of oral physiology correlate with various perceived texture attributes. This implies that intra‐individual differences in texture perception could be attributed to variations in oral physiology. Oral physiology thus plays a role in texture perception of semisolids and should be taken into account in future texture research.

PRACTICAL APPLICATIONS

By understanding the processes in the mouth while eating, a better understanding of the sensations and the perceptions of the food can be gained. Taking for each food the relevant physiological parameter into consideration when performing and designing rheological/instrumental measurements grants more natural conditions and better predictions of sensory perception. This could save time and money on time‐consuming and expensive sensory panels in the earlier steps of product development and renovation. Knowing how physiological processes highlight specific flavor/texture sensations may be useful for product development or quality control where one typically wants to focus on certain sensations and ignores others. In addition, a future application could be to tailor products for personalized nutrition, individual choices or clinical nutrition based on physiological groups.     

Effect of saliva on physical food properties in fat texture perception

Sensory properties of food drive our food choices and it is generally accepted that lipids greatly contribute to the sensory properties of many foods and consequently to eating pleasure. Many studies have investigated the mechanisms of the fat perception. Unfortunately they used a variety of methods and products, thereby making generalization very difficult. The mechanism of fat perception in oral cavity is combined of several processes. Lipid composition and its properties strongly influence food structure. During consumption food is exposed to a range of in-mouth processing steps. Oral sensation of fat texture changes with time, from a first bite to chewing, while mixing with saliva, up to swallowing and even after swallowing. The present work reviews many aspects of fat texture perception from physical chemistry to physiology. Understanding the underlying mechanisms of in-mouth lipid processing would provide new concepts to produce low-fat food products with full-fat perception.     

Texture is a sensory property

Realizing that texture is a sensory property gives proper orientation to facets of texture research. Following the breakthrough in the 1960s and 1970s in surfacing the multi-parameter nature of texture and in defining the general principles of texture acceptability, the field has essentially reverted to commodity work. This paper reviews briefly the state of knowledge and points out specific research areas that could constitute new significant breakthroughs. These include defining the components of complex textural characteristics, developing an understanding of the perceptual interplay among texture parameters and between textural and other (e.g. visual clues, taste) modalities, exploring the breakdown pathways in the mouth for various food categories, and repeating earlier studies on consumer attitudes and preferences in the context of 21st century cultures and lifestyles.     

我国地方绵羊品种与进口羊腿肉的营养质构差异分析

目的分析对比我国不同产区主要地方品种与进口羊腿肉的营养品质与质构差异。方法选取中东部农牧交错带肉羊优势区域主要产区:内蒙古锡林郭勒;西北肉羊优势区域的代表产区:新疆、甘肃和宁夏,以乌珠穆沁羊、滩羊、哈萨克羊3个地方品种为主,同时对比来自澳大利亚和新西兰的进口羊腿,品种分别为澳洲白与无角陶赛特羊。分析羊腿的蛋白、脂肪、脂肪酸及氨基酸、维生素、矿物质含量,以及质构参数。结果澳大利亚羊腿蛋白含量较高;甘肃肃北哈萨克羊脂肪酸组成最优;内蒙古锡林郭勒阿巴嘎旗乌珠穆沁羊的钙、磷、钾含量均较高。结论营养成分受品种、饲养方式、地理环境等综合影响:蛋白含量与品种有关,放牧会增加羊腿中不饱和脂肪酸的含量,地理环境与饲料共同影响羊腿的矿质元素含量特征;口感受饲养方式影响较大,放牧会导致羊肉硬度较高。     

Application of liquid and solid rheological technologies to the textural characterisation of semi-solid foods

Rotational rheometers and texture analysers are commonly used to test liquid and solid samples, respectively. This paper explores data provided by a texture analyser and a rheometer compared with that provided by a trained taste panel for semi-solid food.Associations are shown to exist for four different types of cream cheese with respect to the findings of a taste panel, rotational rheometry and texture profile analysis (TPA). Hardness, cohesiveness and adhesiveness are discussed for both taste panel and TPA. Good relationships were found between these techniques for hardness and adhesiveness, cohesiveness exhibited a less satisfactory correlation. In the case of the rheometer, yield stress, complex viscosity and viscoelastic moduli were measured. Yield stress was found to relate to hardness and adhesiveness, and complex viscosity and viscous modulus had relevance for cohesiveness. Elastic modulus, measured by the rheometer, and TPA elastic quality also correlated well. The relationships between textural measurements and microstructural engineering of the products have been discussed. The presence of vegetable gums, in particular addition of guar in instances where fat content is low can reduce the textural impact of the fat removal. The effects of high levels of calcium in spreadable products can be reduced by the addition of citric acid, which has been shown in the past to solubilise colloidal calcium phosphate.Combining instrumental techniques with a taste panel can increase the efficiency product quality assurance and design.     

Fatty versus creamy sensations for custard desserts,white sauces,and mayonnaises

Perceived fattiness and creaminess plus other texture and flavor attributes were assessed for a group of vanilla custard desserts, white sauces, and mayonnaises that differed widely in ingredients, fat content (0–72%), and consumption temperatures. In addition, the foods were measured instrumentally with regard to their lubricative properties, infra-red reflectance and turbidity of rinse water. Despite the variety in foods, fat content showed strong correlations with the instrumental measures, and perceived fattiness, and weaker but still significant correlations with creamy mouth and after-feel. Friction and infra-red reflectance demonstrated that properties of the surface of the oral food bolus are important for fat-related attributes via mechanisms such as lubrication. Turbidity of rinse water suggested that properties of the bulk of the food bolus are important as well. Creamy after-feel related less well to instrumental measures, fat content and other sensory attributes suggesting that the creaminess of oral coatings is not only affected by fat but also by other unknown properties.     

瑞士型苹果果粒酸奶的制备

研究了以复原奶、新鲜苹果果粒为主要原料，以嗜热链球菌和保加利亚乳杆菌为发酵剂，制备瑞士型苹果果粒酸奶的工艺。以0．15％（w／w）柠檬酸和0．045％（w／w）NaHSO，作为护色液，果粒沸水热烫1min以钝化多酚氧化酶和过氧化物酶，然后浸泡于含1％CaCl2溶液保脆，添加0．2％的苹果香精。     

低脂食品设计原理与研究现状

随着社会发展及科技水平的提高,人们逐渐意识到过度肥胖可能引发一系列健康问题,低脂肪含量的健康食品一度成为新的消费热点。但是单纯降低食品中的脂肪含量可能会破坏食品的口感、风味及营养属性,所以全球范围内相关领域的食品科学家致力于开发新型健康美味的低脂食品,本文主要介绍了低脂食品的设计原理及研究现状,希望能帮助读者了解该领域的发展前景并为新型低脂健康食品的研发提供思路。     

Influence of cultivar, fruit maturity and fruit anatomy on apple sauce particle size and texture

Particle size distribution, which largely determines the texture of finished apple sauce, was studied in relation to the fresh fruit properties of five apple cultivars. The different effect that continuing fruit storage has on particle size distribution of the sauce, depending on cultivar, is reported. Light microscopy supported the conclusion that the cell wall components affecting the separation of cells, and possibly re-aggregation in some instances, are mainly involved in these commercially important variations in texture. The possibility that vascular tissues in the fruit and starch granules in the cells may be other, lesser contributors to sauce texture is discussed. The study emphasizes the cultivar dependency of the properties reported.     

基于果形和穿刺测试的葡萄浆果质构特性分析

本文通过分析鲜食葡萄浆果单粒果重、形状和其穿刺质构特性,探究葡萄的质构特性和其商品性指标的相关性联系。以巨峰、茉莉莎、红宝石、白罗莎、意大利、红提、马奶、泽香、美人指、玫瑰香10个不同品种的葡萄为试材,分别进行穿刺测试。通过模拟牙齿咀嚼浆果受力过程,编辑力-位移穿刺分析方法,建立10个穿刺参数来表征浆果质构特性,分析各质构参数间的相关性。同时分析穿刺质构参数与商品性指标间的相关性。结果表明:浆果形变度分别和果皮刚度、跌落位移以及跌落脆性成显著负相关（p<0.05）,和穿刺果皮功成显著正相关（p<0.05）,和果肉匀质指数以及穿刺果肉功极显著负相关（p<0.01）。单果粒重分别和果皮硬度、果皮刚度、跌落硬度和果肉硬度成显著正相关（p<0.05）。浆果横径和跌落脆性成显著负相关（p<0.05）。浆果纵径和果皮刚度成显著正相关（p<0.05）。相关性分析结果表明,消费者可以根据某些葡萄品种的外观商品性状去选择质地适口的葡萄品种。也可以根据某些商品性指标去分析预测某个品种的耐贮运性。一些穿刺参数可以很好的体现整个葡萄浆果的质地特点。      

岱瞿族大黄鱼质构特性与感官评价的相关性分析

目的 分析养殖大黄鱼质构特性与感官评价的相关性。方法 选择温州不同海域的养殖大黄鱼样品进行肥满度、蛋白质、脂肪、水分、胶原蛋白测定,并进行感官评定和质构剖面分析(textureprofileanalysis,TPA);对结果进行因子和主成分分析,以及相关性分析;再以TPA指标为自变量、感官评价指标为因变量进行逐步回归分析,建立感官预测模型。结果 温州不同海域养殖大黄鱼,在肥满度、脂肪含量、蛋白质含量、质构测定中弹性与咀嚼性指标均存在显著性差异,感官评价指标也存在显著性差异。通过主成分分析得到TPA指标和感官评价指标各1个主成分,累计方差贡献率分别为72.86%和89.97%。相关性结果表明,感官评价结果与TPA测定结果之间存在显著的相关性(r=-0.933～0.808,P<0.05),并建立了色泽、滋味、肉纤维和质地与咀嚼性的预测模型和气味与弹性的预测模型。结论 本研究确定了温州地区养殖大黄鱼品质评价定量指标;大黄鱼感官评价指标受TPA指标中的弹性、咀嚼性影响;本研究的温州大黄鱼感官评价预测模型为大黄鱼品质评价标准体系的科学建立提供了依据。     

Understanding the oral processing of solid foods: Insights from food structure

Understanding the relationship between the structure of solid foods and their oral processing is paramount for enhancing features such as texture and taste and for improving health-related factors such as management of body weight or dysphagia. This paper discusses the main aspects of the oral processing of solid foods across different categories: (1) oral physiology related to chewing, (2) in-mouth food transformation, (3) texture perception, and (4) taste perception, and emphasis is placed on unveiling the underlying mechanisms of how food structure influences the oral processing of solid foods; this is exemplified by comparing the chewing behaviors for a number of representative solid foods. It highlights that modification of the texture/taste of food based on food structure design opens up the possibility for the development of food products that can be applied in the management of health.