糜状食品物料微结构图象特征的小波分析

由于糜状食品物料微观结构和流变特性密切相关 ,所以正确地识别和提取糜状食品微结构图象的特征 ,是建立流变特性计算模型的关键步骤 .本文基于多分辨率分析方法 ,对不同微观结构的糜状食品图象进行小波变换 ,研究了图象多尺度特征 .同时对变换后的小波系数进行统计分析 ,探讨了不同微结构图象小波变换系数统计量的区别及变化特点 ,并通过计算矩阵特征值 ,对建立流变特性计算模型的统计参数进行降维处理 .     

糜状食品物料微结构与流变特性的相关性研究

以猪肉糜这个最具代表性的糜状食品物料为研究对象,利用显微图像处理系统和非线性科学工具分析、模拟微结构的模式形态特征,采用偏最小二乘法探讨微结构与流变特性之间的相关关系,并建立其定量描述模型。     

食品流变特性研究的进展

概述了近几年来国内外有关食品流变特性的研究及其进展情况 ,介绍了国内外对研究流变学而开发的测量仪器的现状 ,以及对固态、液态等食品物料流变特性的研究情况。     

温度、浓度对證清莴苣汁粘度的影响

近年来,国内杂志相继报道了有关食品如果汁、蜂蜜、乳制品等物料的流变特性的研究,但有关蔬菜汁流变特性的研究报道还很少。粘度是流变特性中较重要的指标之一,本文试图对莴苣汁粘度与温度及浓度关系的研究,为我国的蔬菜汁加工以及有关设备的设计提供理论依据。     

植物基纳米纤维素在食品3D打印中的应用

3D打印技术通过逐层添加物料的方式实现特定结构物体的快速成型,可根据需求实现对原料组成和成品空间结构的个性化定制,在食品领域具有广阔发展潜力。大多数食品原料不具备可打印性,这制约了用于3D打印的食品原料的来源和种类,限制了3D打印技术在食品行业的应用规模。植物基纳米纤维素来源广泛,具有优异的机械性能和流变特性,能够增强物料的可打印性,是3D打印的理想原料。明确植物基纳米纤维素的功能特点,制备的3D打印墨水特性以及在食品3D打印中应用现状,对充分利用新兴加工技术和新食品原料尤为重要。本文重点介绍植物基纳米纤维素结构特点及与3D打印相适应的功能特性,包括高机械强度,易表面改性,适于打印的流变特性以及较好的生物安全性。在分析凝胶和乳液两种形式的植物基纳米纤维素打印墨水特性和用途的基础上,总结其在食品添加剂、食品包装材料、食品新鲜度指示器、功能物质载体等相关食品领域的应用现状,并展望未来制备新兴功能食品和智能食品包装的前景,以期为相关技术发展提供参考。     

食品增稠剂流变学研究综述

文章综述了食品流变学研究的目的,增稠剂的相对分子质量、结构、增稠剂溶液浓度、pH值、温度、外界切变力等对增稠剂流变特性的影响和增稠剂间的增效作用以及增稠剂在改善食品流变特性中的应用,即加入少量的增稠剂就能对食品粘度产生惊人的影响,使其获得良好的流变特性。     

酸奶流变特性研究与进展

食品流变学是研究在力的作用下物质变形的科学。通过对食品物质流变特性的测定,可以控制产品的质量,鉴别成品的优劣,并且可以为工艺及设备的设计提供有关数据。可以认为食品流变特性的检测是目前生产过程中必不可少的检测手段之一。本文主要论述酸奶流变特性的测定方法及目前研究进展情况。1 工艺过程对流变特性影响根据最近文献研究表明:在酸奶生产过程中各阶段对其组织结构和流变特性都起了显著性影响。这些生产过程可分为如下:(1)鲜奶的准备与热处理;(2)保温;(3)冷处理过程。1.1 热处理过程对其流变特性影响鲜奶是不能直接酝酿而成酸奶的。首先应将鲜奶进行预处理并加热和加入某些添加剂进行混合制作,根据Dannenberg和Kessler(1988)的研究     

双螺杆食品挤压蒸煮研究的进展

本文综述了双螺杆食品挤压蒸煮研究的进展,包括大豆蛋白的挤压组织化机理、流变性能、挤出理论、挤出机头和食品挤出试验的系统分析模型,主要是针对大豆蛋白质物料。     

吞咽障碍者增稠流体食品流变学研究进展

吞咽障碍已经成为当今社会面临的一项严重的健康问题。增稠流体能够有效降低吞咽障碍病人吸入性肺炎 的风险,在吞咽障碍病人的治疗和护理过程中应用广泛。增稠流体的生产和使用与其流变特性密切相关,因而流变 学成为了吞咽障碍食品领域一个十分重要的研究方向。本文根据近期国际上在该方向的最新研究成果,详细介绍了 利用流变特性评判增稠流体黏稠程度的原则以及测量方法,深入分析了各种因素对于增稠流体流变特性的影响,并 对影像学造影剂、增稠流体食品流变特性的差异和匹配、口腔对于流变特性变化的分辨能力等问题进行了探讨。目 的是为我国增稠流体食品研究提供理论指导和技术参考。     

花生豆腐加工过程中凝胶质构形成研究进展

花生豆腐是一种新型花生蛋白凝胶制品,其凝胶质构形成与工艺技术、加工条件和原料特性等密切相关。本文重点论述典型加工工艺对豆腐质构的影响,加工过程中花生乳功能特性如热特性、流变特性变化以及豆腐凝胶微结构变化,指出花生豆腐研究中存在的问题,展望未来的发展趋势,旨在为花生豆腐加工提供理论支撑和技术指导。     

食品流变性能测试技术研究进展

本文综述了测试食品流变性能的传统改进方法,介绍了近年来国内外食品流变性能测试方法和新仪器的研究情况。     

Emulsion gels: The structuring of soft solids with protein-stabilized oil droplets

Many food products can be categorized as emulsion gels. This is especially the case for protein-based oil-in-water emulsions which can be converted into soft-solid-like materials by common food processing operations such as heating, acidification, and enzyme action. This review article outlines how the rheological and structural properties of protein-stabilized emulsion gels are influenced by the dispersed oil volume fraction, the oil–water interfacial composition, and the colloidal interactions of the constituent emulsion droplets. For model systems of variable oil content and containing different food proteins, some general trends of rheological behaviour at small and large deformations are identified. Experimental rigidity data are considered in relation to: (i) material science theories of the reinforcement of solid materials by active and inactive filler particles, and (ii) Brownian dynamics simulations of aggregated particle networks containing bonded and non-bonded particles. Influences of interfacial composition and particle–matrix interactions on microstructure and rheology are explained with particular reference to the role of small-molecule surfactants. Compositional and structural factors affecting the large-deformation rheology and fracture properties are described. Finally, the practical relevance of the model system studies to the behaviour of real food products is critically assessed.     

Evaluation of the effect of Gleditsia amorphoides gum on the properties of rennet-induced milk protein gels

The study and characterisation of food gels obtained from phase-separated systems has gained interest since a wide variety of gel structures and textures can be developed. In this study, the phase and rheological behaviour of milk protein/espina corona gum (MP/ECG) mixtures were evaluated. These mixtures presented a segregative phase separation and a rheological behaviour proportional to the ECG concentration. Microstructural analysis, textural parameters and water-holding capacity of gels obtained from MP/ECG mixed systems using rennet as gelling agent were determined. At high ECG concentrations (≥0.05%, w/v), the gel microstructure changed from a coarse strand to a bicontinous microstructure. Such microstructural changes affected the textural parameters, firmness and break point, and the water-holding capacity of the gels. The results obtained in this work could be explained by the interplay between the segregative interaction of the biopolymers and the rennet-induced gelation rate.     

COMPLETE RHEOLOGICAL CHARACTERIZATION OF TIME-DEPENDENT FOOD PRODUCTS

Rheological data are presented for three mayonnaise samples. The material shows pseudoplastic behaviour, and also exhibits a yield stress and time-dependent characteristics. Mayonnaise data are used to demonstrate how the time-dependent behaviour of a food product can be completely characterized using a simplified kinetic and rheological model.     

不同打印条件的鱼糜3D打印成型效果分析

为了实现以鱼糜为原料,打印出的产品在形貌、强度、色泽等方面满足要求。本文研究了填充密度、分层高度、打印速度以及喷嘴孔径对鱼糜凝胶3D打印成型效果的影响。通过切片软件改变模型的打印参数,比较打印成型样品的打印精度、凝胶强度、白度以及流变学特性。结果表明,当填充密度为60%以上,成型样品具有较高的凝胶强度,内部填充连续,没有明显的断条现象发生;当分层高度过高或者过低时,都会导致打印精度降低,0.8mm的分层高度具有较好的打印效果;打印速度越快,耗时越少,成型样品的白度越好,但是过快容易导致样品坍塌;鱼糜浆料从过小的喷嘴孔径中挤出易发生断线,打印不完整。综合表明,当填充密度大于60%,分层高度、打印速度和喷嘴孔径分别为0.8 mm、35 mm/s和1.2 mm时,鱼糜浆料体系的3D打印能够打印出品质较好、精度较高的成型样品。本研究对鱼糜浆料在食品3D打印领域的发展具有积极的指导意义,同时也将为在食品3D打印领域开发新的食品应用提供参考。     

Microwave heating effect on rheology and microstructure of white sauces

The microstructure and rheological properties of white sauces formulated with different starches were analyzed after being microwave-heated for different times. Significant differences (P < 0.05) in rheological parameters analyzed-storage modulus (G'), loss modulus (G″), and loss tangent (tanδ)-were obtained for sauces made with different starches. Microwave reheating did not affect G' and G″ values until water evaporation became significant. In addition, tanδ values did not change significantly (P < 0.05) even during long reheating times showing that sauce viscoelastic properties did not change after microwave irradiation. However, microstructure assessed by confocal laser scanning microscopy showed changes in fat globule and protein. These microstructural changes did not seem to have a significant effect on rheological measurements since starch and ι-carrageenan are mainly responsible for the viscoelastic behavior of the sauces. Practical Application: The development of products appropriate to microwave heating is constantly rising in food industry. It is necessary to understand the behavior of the ingredients and the final product to microwave heating in order to choose those ingredients which will develop the best performance. Starches are common ingredients in industrial sauces, and rheological and microstructural techniques have shown their usefulness in characterization of starch-based systems.     

THE EFFECT OF TEMPERATURE ON THE RHEOLOGY OF BUTTER, A SPREADABLE BLEND AND SPREADS

The texture of lipid-based food materials is an important topic for investigation. In this study, the rheological properties of five edible fats were determined. A puncture test was performed to investigate the rheological properties of the food materials at 5C and at 19C using a texture analyzer. The force-displacement measurements were converted to stress–strain by assuming incompressibility of edible fat food materials in a linear viscoelastic region (LVR). Young's modulus of each edible fat was calculated using stress–stain curves in a LVR. Shear elastic moduli of edible fats in a LVR were obtained using a rheometer. Further to that the effect of temperature on storage modulus and loss modulus and creep test were obtained using a rheometer. The tests showed good correlation between Young's modulus and shear elastic modulus for each material. The mechanical properties correlated well with the structural properties of each of the materials.

PRACTICAL APPLICATIONS

The texture of butter, blends and spreads is determined by temperature, rheological properties, processing conditions and the composition of the material. Our research investigated the effect of temperature on the rheological properties of these foods. The results may be used to model the relationship between the microstructure and mechanical properties of the fat crystal network.     

USE OF RHEOLOGICAL TERMS AND CORRELATION OF COMPATIBLE MEASUREMENTS IN FOOD TEXTURE RESEARCH1

The importance of maintaining the purity of rheological terms and using them only when measurements and definitions are in accordance with the accepted rheological definitions is pointed out. It is shown that if rheological terms and methods of measurements and analyses are used correctly, they can be employed in food texture studies even though conditions upon which the theory is based are not fully met. It is proposed that the term “modulus of elasticity” be replaced by the term “modulus of deformabtiity” which considers both recoverable and unrecoverable deformations that often take place when a food sample is subjected to even very small strains. It is also submitted that mechanical properties reflecting the behavior of the material under small strains do not necessarily correlate significantly with mechanical properties which reflect the yielding and fracturing or failure of the material. Published data are examined to test the validity of this hypothesis. In general, correlations between well-defined failure type instrumental tests and panel tests are good, whereas correlations between small-strain instrumental tests and panel tests are poor.     

Wheat Dough Microstructure: The Relation Between Visual Structure and Mechanical Behavior

The microstructure of food matrixes, and specifically that of wheat-flour dough, determines mechanical behavior. Consequently, the analysis of such microstructure is both necessary and useful for understanding the physico-chemical and mechanical alterations during the production of cereal-based products such as breads. Confocal laser scanning microscopy (CLSM) is an established tool for the investigation of these matrix properties due to its methodical advantages such as easy preparation and handling, and the high depth resolution due to the optical sectioning of probes. This review focuses on the microstructure of wheat-flour dough from a mechanical and visual point of view. It provides an overview of the dependencies between the visibly detectable microstructural elements achieved by CLSM and the physical determined rheological properties. Current findings in this field, especially on numerical microstructure features, are described and discussed, and possibilities for enhancing the analytical methodology are presented.