“口腔”摩擦学在食品质构感官研究中的应用

食品口腔加工是一个十分复杂的动态过程,包括食物摄入、咀嚼、唾液分泌、食团形成、吞咽等部分。食品在口腔中过程中的质构感官则更为复杂。传统的食品流变学常常只能描述咀嚼初期的感官性质,而不能描述口腔加工全过程的质构性质。近年来口腔摩擦被认为是口腔质构感官的重要机理,可以用来描述舌头与口腔上颚、舌头与食品之间相对运动和由此产生的触觉感官。本文阐述了口腔摩擦学的原理,介绍几种常用的摩擦测量装置(包括本实验室自主设计的摩擦简易装置)和它们各自的优缺点。通过"口腔"摩擦学用于食品质构感官研究的几个典型例子,阐述摩擦学技术在食品产品研发和质量评测中的应用前景。     

食品口腔加工过程中舌头的功能

饮食是一个复杂的食品口腔加工过程,包括食物的口腔处理、传送和感官评判等一系列的口腔和大脑行为,而人舌在这一系列的口腔加工过程中起着关键的作用。由于人舌生理结构的复杂性与口腔环境阻碍等原因,所以人们至今无法详细地探究人舌功能及其在食品口腔加工过程中的操作和控制机理,尤其是感知食品在口腔加工过程中的结构和感官的动态变化。本文从人舌生理结构出发,分析固体、软固体和流体食物在饮食过程中的舌体的功能与运动规律,阐释人舌在饮食吞咽过程中的物理作用(搅拌、移动、收缩挤压等)、化学传感(滋味)、物理传感(冷热、位置、质构、形态等)、吞咽(食团成形、食团推送)等作用,以便为建立新的更科学的食品品质体外评价技术提供理论依据。     

口腔摩擦学在食品口腔加工中的应用

口腔加工不仅是一个饮食过程，也是一个享乐过程。人们所感知的食物质地是一种多维的感官特征。目前仅通过流变学已无法表征这一复杂感官感知。摩擦学通过模拟食物在口腔内的加工过程和食物被舌头挤压至口腔表面时的润滑行为来客观表征食物在口腔加工中的感官属性。口腔摩擦学已成为表征食物口腔加工中润滑行为的重要工具。本文综述口腔摩擦学在食品加工和研发中的应用，重点阐述食物在口腔加工中的涩感、润滑感等感官感知及其润滑机制，旨在为未来食品设计提供参考。     

基于仿口腔平台的食品咀嚼效果评定方法研究

食品在口腔加工中的形变过程以及口腔加工能力与形成可吞咽食团的相互关系受到越来越广泛的关注,然而测试人员的食品口腔加工过程难以直接观察,咀嚼实验的相关数据难以获取;并且口腔加工能力不易重复量化,使得咀嚼效果难以评定。为解决这些问题,基于前期开发的仿口腔平台,以石蜡和花生作为试验样品,分别通过仿口腔平台和测试人员进行咀嚼实验,并将收集的食团进行咀嚼效果指数测定和比较。数据分析表明：体内和体外咀嚼实验与咀嚼次数间具有显著相关性,不同咀嚼次数下体内组和体外组的花生中值粒径d₅₀、石蜡咀嚼效果指数MEI存在显著性差异(P<0.05);且当咀嚼次数达到食团吞咽所需的次数时,体外实验得到的食团样品与测试者口腔中收集的样品咀嚼效果评定指标具有高度一致性。研究结果表明,基于模拟人类食品口腔加工并生成食团的仿口腔平台进行食品咀嚼实验来评定咀嚼效果,可有效替代实验人员,减少实验成本,增加实验可重复性。     

颗粒粒径和相互作用对凝胶颗粒团簇硬度的影响

食品质构是食品的物理和结构特性的感官响应,直接影响饮食的过程和感官愉悦。食品凝胶因其特殊和多变的软固体质构特性,常以破碎团簇的形式作为吞咽障碍患者的吞咽辅助食品。本研究以凝胶为对象,以硬度为主要质构指标,探索凝胶破碎后形成凝胶颗粒团簇的硬度与原凝胶强度、凝胶颗粒粒径、破碎凝胶颗粒之间相互作用的关系。结果表明,随凝胶颗粒粒径减小,凝胶颗粒团簇硬度呈快速线性下降趋势;随原凝胶强度和破碎凝胶颗粒之间相互作用力的增强,颗粒团簇硬度呈增大趋势。研究结果为凝胶类食品,尤其是吞咽辅助凝胶食品的开发和质量控制提供了理论支持和依据。     

口腔加工对于食品风味感知及其释放影响的研究进展

传统食品风味研究以材料学的方法与技术为基础,定量、定性地描述及分析食品风味物质多少以及变化,其忽略了口腔加工过程中食物风味释放及感知中"人"的因素。而食品口腔加工学的产生打破传统研究壁垒,以食品与人体相互作用为基础进行研究,探索食品在口腔加工过程中的结构及物理化学性质变化,揭示口腔的生理响应机制和感官心理结果。该文以食品口腔加工为切入点,详细介绍口腔加工对食品风味感知及释放影响的研究进展。     

模拟口腔加工对馒头体外淀粉消化特性的影响

为探究不同口腔加工方法对体外淀粉消化特性的影响,以青稞馒头和小麦馒头为实验材料,研究了5种模拟口腔加工方法(切块、切块加涡旋、切块加研磨、切块加涡旋并与人工唾液混合、切块加研磨并与人工唾液混合)对淀粉消化特性的影响,并以体内口腔加工为对照,以期优化馒头类产品的体外模拟淀粉消化方法。结果表明：体外模拟口腔加工后的食团粒径(155～350μm)和含水量(62%～64%)均高于体内口腔咀嚼(110～300μm、57%～59%);而模拟口腔加工的食团硬度(0.73～3.77 N)低于体内口腔咀嚼(2.44～4.39 N)。与未添加人工唾液组相比,添加人工唾液后得到的模拟口腔加工食团在物理特性和消化特性方面均更接近于体内口腔咀嚼。所有的体外方法中,切块加涡旋并与人工唾液混合的方法最能够模拟体内咀嚼,可作为馒头类制品体外模拟淀粉消化过程中的前处理方法。机械破坏的方式和水平以及固体颗粒与唾液混合的方式都会影响团块的形成,进而影响馒头的消化动力学。相关性分析结果显示,馒头类制品在消化后期的最终水解率与粒径呈显著负相关(r=-0.934 94,P<0.05)。考量各指标,切块加涡旋并与人工唾液混合...     

食品口腔加工研究的发展与展望

食品口腔加工是近年来兴起的食品科学与营养研究的新领域,它主要以食品与人体相互作用为基础,以多学科交叉的方法与手段来研究食品在口腔过程中的结构与物理化学性质变化,揭示口腔的生理响应机制和感官心理结果。它涉及食品物理学、口腔生理学、感官心理学和大脑神经科学等学科。本文以食品口腔加工概念的提出为切入点,详细介绍食品口腔加工研究的范畴和领域,重点讨论近十余年这一领域的主要研究进展,并对未来发展趋势进行预测和展望。     

不同质构特性西蓝花对口腔加工行为和米饭餐饱腹感的影响

为探究同样原料不同质构蔬菜对口腔加工行为、食物摄入和饱腹感的影响,以两种熟西蓝花为研究对象,分析健康受试者同时食用西蓝花与米饭或先食用西蓝花、后食用米饭时的口腔加工行为,并测定食物摄入量及餐后饱腹感相关指标。结果表明：与同时进食软西蓝花和米饭相比,先进食硬西蓝花、后进食米饭的处理可增加44%的咀嚼次数、34%的口腔感官暴露时间、57%的单位质量咀嚼次数,进食速率和米饭摄入量分别降低25%和20%,并有效抑制餐后饥饿感。结论：较硬西蓝花可通过促进口腔加工效应从而降低食物摄入并抑制餐后饥饿感,而这种效应在先进食西蓝花时表现得更为显著。     

不同结晶态脂肪比例对乳液奶油感感知的影响

通过调配无水乳脂肪的脂肪酸组成，构建含不同结晶态比例的乳脂肪模型和与牛奶脂肪含量和粒径匹配的乳液体系，进而模拟口腔加工，测定含不同结晶态脂肪比例乳液的口腔聚合性和摩擦学特性，并评价其奶油感。成功构建了含不同结晶态比例（10%～85%）的乳脂肪模型（F10～F85），所构建乳液（E10～E85）中脂肪球平均粒径为4 μm，在模拟口腔加工后，乳液粒径显著增大，其中E40样品增大程度最大。随着结晶态脂肪比例的增加，乳液口腔摩擦系数（μ20）先减小后增加，其中E40样品μ20最小，为（0.04±0.01）。描述性感官评价结果显示，随着结晶态脂肪比例的增加，乳液样品的整体奶油感先增大后减小，其中E40样品得分最高，为8.06±0.73。主成分分析结果显示，乳液的口腔光滑感和糊口感与整体奶油感相关性最强，其中E40样品与整体奶油感相关性最强。暂时性感官支配评价结果显示，口腔加工中后期，乳液在口腔感知中最显著的优势感官属性为口腔光滑感和糊口感，其中E40样品的口腔光滑感和糊口感优势率最高。本研究明确了结晶态脂肪比例对乳液奶油感感知的影响，为开发低脂但具备全脂口感的乳制品提供理论依据。     

Tribology and its growing use toward the study of food oral processing and sensory perception

Here we provide a comprehensive review of the knowledge base of soft tribology, the study of friction, lubrication, and wear on deformable surfaces, with consideration for its application toward oral tribology and food lubrication. Studies on “soft-tribology” have emerged to provide knowledge and tools to predict oral behavior and assess the performance of foods and beverages. We have shown that there is a comprehensive set of fundamental literature, mainly based on soft contacts in the Mini-traction machine with rolling ball on disk configuration, which provides a baseline for interpreting tribological data from complex food systems. Tribology-sensory relationships do currently exist. However, they are restricted to the specific formulations and tribological configuration utilized, and cannot usually be applied more broadly. With a careful and rigorous formulation/experimental design, we envisage tribological tools to provide insights into the sensory perception of foods in combination with other in vitro technique such as rheology, particle sizing or characterization of surface interactions. This can only occur with the use of well characterized tribopairs and equipment; a careful characterization of simpler model foods before considering complex food products; the incorporation of saliva in tribological studies; the removal of confounding factors from the sensory study and a global approach that considers all regimes of lubrication.     

In vitro oral simulation based on soft contact: The importance of viscoelastic response of the upper jaw substitutes

Real oral processing is the squeezing and shearing between two soft surfaces. The importance of soft palate surface cannot be ignored while focusing on tongue substitutes. Thus the effects of viscoelasticity, roughness of upper jaw substitutes, and fluid rheological properties on lubrication properties were explored by in vitro oral tribology experiments. Different palate substitutes significantly changed the friction curves of pure water, milk, and yogurt. The boundary friction coefficients of pure water and milk are higher under softer or smooth palate substitutes due to stronger viscoelastic responses of friction pairs. Their boundary friction coefficients are lowest at rigid upper jaw substitutes owing to smaller contact angles and deformation. However, the boundary friction coefficient of yogurt is lower owing to its high viscosity, low loss factor, and large particle size under soft friction pairs. In addition, it is highest at rigid palate friction pair because a smaller contact area reduces the entrainment of yogurt, resulting in poor lubricating performance.     

后鼻腔香气感知影响因素及其分析方法研究进展

后鼻腔香气感知是食品口腔加工过程中的一种重要感官体验,对消费者的食品感官享受、接受度以及行为学特征有重要影响。本文综述了遗传变异和饮食文化差异对香气认知和感知能力的影响;食品的基本性质和口腔加工生理参数对后鼻腔香气感知的影响;鼻气流和鼻腔生理结构对香气从口腔传递至后鼻腔的重要作用,并总结了后鼻腔香气检测和动态香气感官评价方法。后鼻腔香气感知与味觉、口腔触觉等多种感官存在跨模交互作用,明确后鼻腔香气感知机制对实现食品配方设计和口腔加工过程中风味感知的靶向调控有重要意义。     

Oral processing of hydrogels: Influence of food material properties versus individuals' eating capability

Food material properties play an important role in sensory perception and consumer acceptance of foods. However, the actual oral processing behavior may depend on both the material properties of the food that is being consumed and individuals' oral capabilities. This study aimed to examine the relationships between intrinsic (oral capabilities of healthy participants) and extrinsic (food material properties of a set of hydrogels) variables to the real oral processing behavior. Three κ-carrageenan hydrogels (κC), differing in fracture mechanics and oral tribology properties, were prepared: native κC, κC with added Na-alginate, and a κC matrix with added Ca-alginate beads of 300 μm. A composite score of eating capability (EC) was measured with non-invasive techniques (maximum bite force and tongue pressure) using a panel of 28 untrained consumers. The oral processing behaviors (number of chews, oral residence time, and chewing rate) were analyzed with the same participants using frame-by-frame video analysis. It was found that the EC scores did not correlate with any of the oral processing behaviors. The number of chews and oral residence time showed a strong correlation with the fracture force and friction force at orally relevant speeds (10–100 mm/s), whereas chewing rate did not vary with these properties. The results from this study indicate that oral processing in healthy adults seems mainly motivated by food material properties, and the chewing rate seems to relate more to individual differences and EC than to food properties. Insights from this study, using model hydrogels, have helped to promote knowledge on oral processing behavior in healthy individuals; could bridge the gap between consumer science, psychology, and food science; and may be of interest to product developers in designing foods with pleasant texture properties.     

The role of oral processing in dynamic sensory perception

Food oral processing is not only important for the ingestion and digestion of food, but also plays an important role in the perception of texture and flavor. This overall sensory perception is dynamic and occurs during all stages of oral processing. However, the relationships between oral operations and sensory perception are not yet fully understood. This article reviews recent progress and research findings on oral food processing, with a focus on the dynamic character of sensory perception of solid foods. The reviewed studies are discussed in terms of both physiology and food properties, and cover first bite, mastication, and swallowing. Little is known about the dynamics of texture and flavor perception during mastication and the importance on overall perception. Novel approaches use time intensity and temporal dominance techniques, and these will be valuable tools for future research on the dynamics of texture and flavor perception.     

FOOD TEXTURE AND ITS EFFECT ON INGESTION, MASTICATION AND SWALLOWING

The oral processing of most semisolid and solid foods can be summarized in terms of two opposing mechanical influences: forces that fracture food particles versus those that make them adhere to each other. During either the ingestion of food into the mouth or the early stages of mastication, the aim of processing solid food particles is usually to fracture them. However, later on towards swallowing, adhesion is desirable in order to try to form a sticky food bolus that could clear the mouth of isolated food fragments. Neither of these tendencies is actually a function of any particular force (or stress) or displacement (or strain) on food particles, but is instead controlled by energy. Food particles can adhere not only to each other but to the mouth's surfaces. This produces friction. While this is essential for the tongue to grip food particles and move them around the mouth, it also adds to the work that mouthparts must do during processing and may affect sensory perception of food quality. Successful processing of foods in the mouth requires a considerable amount of neural feedback from sensory receptors. We focus here on recent evidence about these sensory receptors with an attempt to reinterpret their role in terms of textural perception.     

Structural and mechanical characteristics of bread and their impact on oral processing: a review

Oral processing has become an important area of research in sensory and nutrition studies. Mastication process not only determines the dynamics of flavour release and texture perception but also affects the bioavailability of nutrients. Oral processing of bread is of particular interest because of the need to reduce its glycaemic potential while keeping its desired soft and aerated texture. Bread structure determines its mechanical strength and deformation behaviour which in turn decides people's texture perception and swallowing thresholds. The strong interconnection between food structure and its resistance to breakdown is the rationale behind designing bread to control bread digestion, starting from the oral phase. The present review summarises the characterisation and formation of bread structure, its interlink with bread mechanical behaviour and destruction during human oral processing. Future research should further elucidate the structure–mechanics–digestion interlink by implementing relevant mechanical analyses and micromechanical modelling.     

Food oral processing: Mechanisms and implications of food oral destruction

BackgroundFood oral processing is a simultaneous process of food destruction and sensory perception. How a food breaks down its structure inside the mouth and what mechanisms control this process are hugely important to our eating experience and sensory perception. A proper understanding of this process is urgently needed by the food industry for better design and manufacturing of quality tasty food.Scope and approachThis review article analyses research findings from literature and from author's own laboratory in order to identify main controlling mechanisms of food oral destruction. Appropriate experimental evidences are given wherever available to demonstrate the important implications of different destruction mechanisms to sensory perception.Key findings and conclusionsThree major controlling mechanisms of food oral destruction are identified: the mechanical size reduction, the colloidal destabilisation, and the enzymatic interactions. These mechanisms may be applicable to different food materials either independently or collectively. They could also be applicable through the whole eating process or just at a certain stage of an eating process.