葫芦巴胶改善吞咽障碍者饮水安全性的流变学研究

参照美国吞咽障碍膳食标准,以样品的η50黏度为分类依据,将葫芦巴胶制备成黏度分别为180cP(花蜜型)、1000cP(蜂蜜型)和2500cP(布丁型)的增稠流体,对其流变学性质进行研究,并评价葫芦巴胶用于改善吞咽障碍者的饮水安全性。结果表明,溶解温度是葫芦巴胶流变性质能否满足改善饮水安全性要求的关键。80℃制备的葫芦巴胶具有与黄原胶、结冷胶相似的流变学性质:明显的剪切变稀行为且对增稠级别的依赖程度较小;具有G′>G″和tanδ<1的弱凝胶弹性性质;在高增稠级别,相较于黄原胶和结冷胶,其具有更好的流动性。     

增稠组件在老年吞咽功能障碍患者中的使用

随着我国特殊消费者人群数量的不断增加,市场对增稠组件类产品的需求也在迅速增长。如何对这类产品进行科学有效的规范和管理,引导企业研究开发出满足特殊人群特定营养需求的个性化产品,不仅是生产企业和消费者十分关注的问题,也是监管部门十分紧迫的任务。本文阐述了老年吞咽功能障碍的流行病学、吞咽困难评估方法、增稠组件类产品在老年吞咽功能障碍患者中的使用、增稠流体黏稠程度影响因素、食物质构等级的分类标准和评价方法,提出生产企业依据食物的质构特性,以及不同质构特性产品与不同吞咽困难严重程度患者之间的对应关系,研究设计符合或匹配于目标人群饮食能力的产品,有望成为增稠组件类产品未来的研究方向。     

黄原胶对流质配方食品流变特性的影响

为了探究黄原胶添加对流质配方食品性质的影响,采用物性学方法进行测定表征。将不同配比的黄原胶添加到流质配方食品中,测定其pH、渗透压、流变等特性的变化。结果表明:经黄原胶调控的流质配方食品为假塑性流体,具有更好的增稠效果和食用安全性。pH、渗透压结果表明其相关食用品性安全。黄原胶的添加使流质配方的表观黏度增大并具有剪切稀化现象;加入黄原胶提高了其贮能模量、损耗模量,降低了损耗角正切值tanδ,增强了体系的稳定性,但当黄原胶浓度高于2.5%时,配方增稠效果、稳定性趋于稳定,无显著性变化。此次试验为该流质配方产品市场化提供了物性安全稳定依据,并为开发相关研究提供了配方参数和理论指导。     

多糖的增稠、胶凝及乳化特性研究进展

多糖是可再生的天然大分子物质,具有显著的增稠、胶凝、乳化等特性,在食品工业中常作为添加剂应用。然而,多糖种类繁杂、结构差异大、流变特性多样,长期以来国内有关多糖流变学特性的报道相对有限。本文从多糖水溶性高分子的本质特征出发,综述了食品多糖增稠、胶凝、乳化特性及其凝胶化影响因素的基本原理,同时介绍了非凝胶多糖和表面活性多糖分子聚集的原理,旨在为多糖在食品工业中的进一步应用提供理论指导。     

天然抗氧化功能细菌胞外多糖的流变性研究

对一株葡糖杆菌胞外多糖的增稠性、触变性等流变学特性进行了初步的研究,结果表明,该胞外多糖具有良好的增稠性,呈现高度的假塑性,并且有广泛的耐盐性和耐酸碱性,可与黄原胶等食品胶协同增稠,在食品添加剂领域具有良好的应用潜力。     

羧甲基淀粉钠与凝胶性多糖的应用及发展

分别介绍了羧甲基淀粉钠和魔芋胶、海藻酸钠与卡拉胶等三种凝胶性多糖的结构性质及其在食品等工业中的应用.羧甲基淀粉具有好的分散力和结合力、吸湿性、乳化性,稳定性好,透明度好等特点.作为食品的乳化剂、稳定剂及增稠剂,使组织细腻且可口性好,可显著提高食品品质及风味.海藻酸钠在水中具有良好的溶解特性、凝胶特性、生物相容性、成膜性、稳定性和螯合性,用作食品添加剂、澄清剂和增稠剂.魔芋胶具有良好的成膜性和凝胶性,具有流变性、增稠性、增效性、黏结性、吸水性、成膜性、衍生性等性质.卡拉胶具有形成亲水胶体、凝胶、增稠、乳化、成膜、稳定分散等特性,在食品工业中的作用主要表现在具有凝胶、增稠和蛋白反应性三个方面.同时对羧甲基淀粉钠和一种凝胶性多糖共混的一些研究作了简要阐述,并根据各自的特性展望了它们的发展方向.     

增稠触变剂对中性墨水流变性能的影响

通过对国外中性墨水样品流变特性进行分析,对比研究黄原胶和缔合型丙烯酸酯增稠触变剂对中性墨水流变性能的影响,分析不同增稠剂对中性墨水应力触变环面积、黏度触变环面积以及屈服应力与屈服黏度的影响,结果表明：黄原胶增稠触变剂具有较大屈服应力与屈服黏度,良好的增稠效果,受体系氢键影响较大;缔合型丙烯酸酯乳液增稠剂具有较小的屈服应力和较大的屈服黏度,良好的增黏效果,受体系离子浓度影响较大。     

多相剪切增稠液的流变性能

为研究多相剪切增稠液(STFs)的流变行为,以气相二氧化硅(SiO_2)、碳化硅(SiC)为分散相,聚乙二醇(PEG200)为分散介质制备多相剪切增稠液。利用旋转流变仪测试不同质量分数SiC的剪切增稠液的流变性能,分析多相剪切增稠液的稳态以及动态流变行为规律。结果表明:SiC颗粒的加入会使得STFs体系的黏度增加。稳态流变情况下,STFs随着剪切速率的增加呈现先变稀再增稠的现象;随SiC含量的增加,临界剪切速率减小,增稠周期缩短,增稠比增大。动态流变情况下,分散体系中耗能模量(G″)都大于储能模量(G′),以耗能为主;体系主要表现为黏性,模量随着SiC含量的增加有所提高。     

涂布滑石粉流变性的改进

影响颜料泥浆流变特性的重要因素包括粒径分布和粒子形态，高形态比和窄粒径分布的颜料呈现出剪切增稠的流变特性。     

蒸制温度对老年蔬菜类易食食品质构特性的影响

目的:研究蒸制温度对增稠后的老年蔬菜类易食食品质构特性的影响,确定增稠老年蔬菜类易食食品的最佳蒸制温度。方法:利用质构仪和冷冻离心机分别对增稠后的老年蔬菜类易食食品进行质构测试和持水力测试,分析比较不同蒸制温度条件下增稠食品的质构、硬度均一性和持水力。结果:90℃蒸制温度时样品硬度、硬度均一性和持水力均相对较低;100℃蒸制温度时样品硬度、硬度均一性和持水力均较好;110℃蒸制温度与100℃蒸制温度相比,样品硬度、硬度均一性和持水力差异不大;120℃蒸制温度时样品的硬度开始降低。结论:增稠蔬菜类易食食品最佳的蒸制温度温度为100℃。     

Food polysaccharides and roles of rheology and tribology in rational design of thickened liquids for oropharyngeal dysphagia: A review

In today's market environment, an aging society is recognized as one of the megatrends in the world. The demographic change in the world population age structure has driven a huge demand in healthcare products as well as services that include the technological innovation for the health and wellness of the elderly. Dysphagia or swallowing difficulty is a common problem in the elderly as many changes in swallowing function come with aging. The presence of a strong relationship between swallowing ability, nutritional status, and health outcomes in the elderly leads to the importance of dysphagia management in the population group. Modification of solid food and/or liquid is a mainstay of compensatory intervention for dysphagia patients. In this regard, texture-modified foods are generally provided to reduce risks associated with choking, while thickened liquids are recommended for mitigating risks associated with aspiration. In this review, we discuss thickened liquids and other issues including the importance of their rheological and tribological properties for oropharyngeal dysphagia management in the elderly. The review focuses on both commercial thickeners that are either based on modified starch or xanthan gum and other potential polysaccharide alternatives, which have been documented in the literature in order to help researchers develop or improve the characteristic properties of thickened liquids required for safe swallowing. Furthermore, some research gaps and future perspectives, particularly from the nutrition aspect related to the interaction between thickeners and other food ingredients, are suggested as such interaction may considerably control the rate of nutrient absorption and release within our body.     

Texture and texture assessment of thickened fluids and texture‐modified food for dysphagia management

Thickened fluids and texture‐modified foods are commonly used in the medical management of individuals who suffer from swallowing difficulty (known as dysphagia). However, how to reliably assess texture properties of such food systems is still a big challenge both to industry and to academic researchers. This article aims to identify key physical parameters that are important for objective assessment of such properties by reviewing the significance of rheological or textural properties of thickened fluids and texture‐modified foods for swallowing. Literature reviews have identified that dominating textural properties in relation to swallowing could be very different for thickened fluids and for texture‐modified foods. Important parameters of thickened fluids are generally related with the flow of the bolus in the pharyngeal stage, while important parameters of texture‐modified foods are generally related with the bolus preparation in the oral stage as well as the bolus flow in the pharyngeal stage. This review helps to identify key textural parameters of thickened fluids and texture‐modified foods in relation to eating and swallowing and to develop objective measuring techniques for quality control of thickened fluids and texture‐modified foods for dysphagia management.     

Rheological,tribological and sensory attributes of texture-modified foods for dysphagia patients and the elderly: A review

Texture-modified foods (TMFs) and thickened fluids have been used as a therapeutic strategy in the management of food intake in the elderly and people with dysphagia. Despite recent advances in describing rheological features of TMFs for dysphagia management, there is still paucity of research regarding the sensory attributes, therapeutic thickness levels and swallowing safety of these foods. Additionally, the relationship between mechanical and structural properties of TMFs throughout the oral processing is not yet fully understood. The present review discusses several properties of food boluses that are important during oral processing to allow for safe swallowing. Dynamic changes that occur during oral processing of TMFs will be reviewed. The use of hydrocolloids to improve the cohesiveness of TMFs and how this impacts the sensory properties of TMFs will be also discussed. Additionally, this review will suggest potential new research directions to improve textural and sensory properties of TMFs.     

Rheology of liquid foods under shear flow conditions: Recently used models

Proper modeling of flow or viscosity curves as a function of shear rate is a useful tool in any engineering activity. The rheology of foods depends on the composition, processing to which they have been subjected and the state of dispersion in which they are found. Liquid foods are complex biosystems, that show non-Newtonian behavior under flow conditions. This review presents models used in recent decades to describe the experimental rheological behavior of various liquid foods, ranging from Newtonian fluids to the most complex. Some non-Newtonian parameters such as those of the Ostwald-de Waele, Bingham, Herschel–Bulkley, Casson, Cross, and Carreau models are summarized. Examples of thixotropic behavior described by the Weltman and Abu-Jdayil models are also presented. In each model, explanations based on the composition and dispersion state of the food are made. This is useful in innovative processing technologies and for scientists new to the field of food rheology. An attempt is made to exemplify and group the expected behavior for most fluid foods, including some for a dysphagia diet, depending on their composition or the dispersed system formed, which will be useful for professionals who wish to compare reported rheological parameters with those obtained experimentally.     

RHEOLOGY OF LIQUID FOODS - A REVIEW1

Liquid foods are classified and their properties discussed under various types of rheological behavior: Newtonian, pseudoplastic, shear thickening, thixotropic, and viscoelastic. Rheological data on selected liquid foods are summarized in either tabular form or in the form of equations. Wherever possible the influence of temperature, constituents, and structure on the rheological behavior is detailed. Because many foods are suspensions, the measurement of flow properties of suspensions and factors influencing their rheological behavior are also covered. Finally, the relationship between the flow behavior and the sensory evaluation of mouth feel and viscosity is discussed.     

Obtaining the Shear Stress Shear Rate Relationship and Yield Stress of Liquid Foods from Parallel Disk Data

ABSTRACT: In this article, Tikhonov regularization is used to process the steady-shear data generated in the parallel disk geometry by a commercial viscometer for a number of liquid foods. This way of processing parallel disk data has the advantage of being independent of any rheological model. The resulting shear stress versus shear rate relationships cover the maximum range of shear rates consistent with the experimental data. It will also be shown that if the liquid food being tested has a yield stress, Tikhonov regularization will automatically obtain an estimate of this stress. For each of the liquid foods investigated, the resulting rheological properties are used to back-calculate the torque and rotational speed data points and compare with the original experimental data.     

现代分析技术在低热量冰淇淋研究中的应用

食品的低热量化是当今世界食品发展的主要趋势之一，因此低热量冰淇淋逐渐成为国际冷饮市场的消费热点。本文综述了现代分析技术(高效液相色谱、质构仪、扫描电子显微镜等)在低热量冰淇淋研究中的应用，涉及到低热量冰淇淋功效成分的检测、质构分析、流变学特性等方面的研究。     

Effect of shear thinning on aspiration – Toward making solutions for judging the risk of aspiration

Polysaccharide solutions containing a contrast medium were prepared so that their viscosity at 50 s⁻¹, which was reported as a shear rate in the oral cavity, is the same but different at other shear rates. Preparation procedure of such solutions based on heat treatment using widely used polysaccharides in foods is described, and the rheological properties of these solutions are discussed in relation with flow behaviours in the swallowing process. Videofluorographic observation was performed for healthy persons and patients and compared with rheological characteristics of these solutions to understand the mechanism of aspiration. It was shown that the degree of aspiration depended on the degree of shear thinning of polysaccharide solutions. This study showed the possibility to find what kind of fluid induces the aspiration and to reduce the risk of aspiration in dysphagic patients by controlling the food rheology.     

Advances in Ultraviolet Light Technology for Non-thermal Processing of Liquid Foods

A negative, public reaction is growing over the addition of chemical preservatives to liquid foods and beverages to extend their shelf life and to protect against foodborne pathogens. As a physical method, ultraviolet light (UV) irradiation has a positive consumer image and is of interest to the food industry as a low cost non-thermal method of preservation. Recent advances in the science and engineering of UV light irradiation have demonstrated that this technology holds considerable promise as an alternative to traditional thermal pasteurization for liquid foods and ingredients, fresh juices, soft drinks, and beverages. However, its use for treating foods is still limited due to low UV transmittance of liquid foods. The goal of this review is to provide a summary of the basic principles of UV light generation and propagation with emphasis on its applications for liquid food processing. The review includes information on critical product and process factors that affect UV light inactivation and consequently the delivery of a required scheduled process in liquids foods; measuring and modeling of UV inactivation, and the important effects of UV light on overall quality and nutritional value of liquid foods. The commercially available UV light sources and UV reactor designs that were used for liquid foods treatment are reviewed. The research priorities and challenges that need to be addressed for the successful development of UV technology for liquid foods treatment are discussed.