The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

Eric Dickinson - One of the best experts on this subject based on the ideXlab platform.

  • Food Colloids, Biopolymers and Materials - Food Colloids, biopolymers, and materials
    Special Publications, 2020
    Co-Authors: Eric Dickinson, T. Van. Vliet
    Abstract:

    Aggregation and Gelation Emulsions, Foams and Interfaces Biopolymer Interactions Subject Index.

  • On the road to understanding and control of creaminess perception in Food Colloids
    Food Hydrocolloids, 2018
    Co-Authors: Eric Dickinson
    Abstract:

    Creaminess is recognized to be a complex sensory attribute. Consumers generally describe it as a pleasant desirable property that is closely related to other positive attributes such as thickness, smoothness, mouth-coating and dairy flavour. Such knowledge has been derived from various sensory studies involving a broad range of Food products such as yoghurt, custard and ice cream, as well as from experiments involving model emulsion-based systems. In the case of well-defined oil-in-water emulsions and emulsion gels, understanding of the underlying mechanistic basis of creaminess perception has been enhanced by fundamental studies of the interactions of emulsion droplets with saliva and the stability of oil droplets at oral surfaces. In terms of the physical parameters influencing creaminess perception, there is an increasing recognition of the importance of tribological factors (lubrication) as well as bulk rheology (viscosity). In developing reduced-fat products with a creamy mouthfeel, the Food technologist has a range of formulation strategies available — the enhancement of oil droplet aggregation, the fabrication of double emulsions, the incorporation of microbubbles, and the use of functional ingredients such as microparticulated protein and hydrocolloid thickening agents.

  • Colloids in Food ingredients structure and stability
    Annual Review of Food Science and Technology - (new in 2010), 2015
    Co-Authors: Eric Dickinson
    Abstract:

    This article reviews progress in the field of Food Colloids with particular emphasis on advances in novel functional ingredients and nanoscale structuring. Specific aspects of ingredient development described here are the stabilization of bubbles and foams by the protein hydrophobin, the emulsifying characteristics of Maillard-type protein–polysaccharide conjugates, the structural and functional properties of protein fibrils, and the Pickering stabilization of dispersed droplets by Food-grade nanoparticles and microparticles. Building on advances in the nanoscience of biological materials, the application of structural design principles to the fabrication of edible Colloids is leading to progress in the fabrication of functional dispersed systems—multilayer interfaces, multiple emulsions, and gel-like emulsions. The associated physicochemical insight is contributing to our mechanistic understanding of oral processing and textural perception of Food systems and to the development of colloid-based strategie...

  • Structuring of colloidal particles at interfaces and the relationship to Food emulsion and foam stability.
    Journal of Colloid and Interface Science, 2014
    Co-Authors: Eric Dickinson
    Abstract:

    Abstract We consider the influence of spherical colloidal particles on the structure and stabilization of dispersions, emulsions and foams. Emphasis is placed on developments in the use of the methods of liquid state theory and computer simulation to understand short-range structuring of concentrated colloidal dispersions and ordering of particle layers near surfaces and within liquid films. Experimental information on the structuring of surfactant micelles and caseinate particles in thin liquid films is described, including an assessment of the effect of particle polydispersity on depletion interactions and kinetic structural stabilization. We specifically discuss the relevance of some of these structural concepts to the stability of Food Colloids.

  • Bridging Flocculation in Emulsions Made with a Mixture of Protein + Polysaccharide
    Food Polymers Gels and Colloids, 2014
    Co-Authors: Eric Dickinson, Vanda B. Galazka
    Abstract:

    Publisher Summary Proteins and polysaccharides have a major role in controlling the stability and rheology of Food Colloids. In any emulsion, the principal role of the protein is as an emulsifier and stabilizer of emulsion droplets against aggregation and coalescence. High molecular weight polysaccharides are generally added as gelling agents or thickeners to modify the rheological behavior of the aqueous phase, thereby retarding or inhibiting the processes leading to instability, such as creaming, flocculation, and coalescence. During the preparation of oil-in-water emulsions, colloidal particles may become aggregated by macromolecular bridging, which is generally due to there being insufficient emulsifier to completely cover a newly created surface. Emulsion formation by a binary mixture of hydroColloids is affected by competition between the components for adsorption at the oil-water interface. Recently, it has been reported that, for high volume fraction oil-in-water emulsions (55 wt% n-tetradecane) made with mixed protein systems (caseinate + gelatin or whey protein + gelatin), it was not possible to produce stable emulsions with certain emulsifier concentrations and compositions. Furthermore, light microscopy revealed that these emulsions were flocculated and that the degree of flocculation was dependent on emulsifier composition. This chapter presents a paper that reports on the behavior of the caseinate + gum arabic system. This behavior turns out to be qualitatively similar to that of the caseinate + gelatin system, which suggests that bridging flocculation is caused by partial displacement of polysaccharide from the interface by the more surface-active caseinate component during homogenization.

Malcolm J.w. Povey - One of the best experts on this subject based on the ideXlab platform.

  • Applications of ultrasonics in Food science - novel control of fat crystallization and structuring
    Current Opinion in Colloid and Interface Science, 2017
    Co-Authors: Malcolm J.w. Povey
    Abstract:

    Abstract Low power ( − 2 ) ultrasound spectroscopy has been used for many years for the characterisation of Food Colloids with respect to particle size distribution, adiabatic compressibility, particle solvation and dissolution, crystal nucleation and solid content. Whilst high power (> 1 kW m − 2 ) ultrasound methods are well-known to impact on fat crystallization and structuring, they have many drawbacks, causing off-flavours through product oxidation and a metallic taste probably associated with sonotrode wear. Furthermore, process development with power ultrasound is hit and miss, applications being largely empirical and poorly understood. We have recently shown that well-controlled crystal nucleation can be obtained using low power, quasi-continuous ultrasound and acoustical pressure fields, opening up a new field of application in Food processing for ultrasonics.

  • nucleation in Food Colloids
    Journal of Chemical Physics, 2016
    Co-Authors: Malcolm J.w. Povey
    Abstract:

    Nucleation in Food Colloids has been studied in detail using ultrasound spectroscopy. Our data show that classical nucleation theory (CNT) remains a sound basis from which to understand nucleation in Food Colloids and analogous model systems using n-alkanes. Various interpretations and modifications of CNT are discussed with regard to their relevance to Food Colloids. Much of the evidence presented is based on the ultrasound velocity spectrometry measurements which has many advantages for the study of nucleating systems compared to light scattering and NMR due to its sensitivity at low solid contents and its ability to measure true solid contents in the nucleation and early crystal growth stages. Ultrasound attenuation spectroscopy also responds to critical fluctuations in the induction region. We show, however, that a periodic pressure fluctuation such as a quasi-continuous (as opposed to a pulse comprising only a few pressure cycles) ultrasound field can alter the nucleation process, even at very low acoustic intensity. Thus care must be taken when using ultrasound techniques that the measurements do not alter the studied processes. Quasi-continuous ultrasound fields may enhance or suppress nucleation and the criteria to determine such effects are derived. The conclusions of this paper are relevant to colloidal systems in Foods, pharmaceuticals, agro-chemicals, cosmetics, and personal products.

  • Crystal nucleation in Food Colloids
    Food Hydrocolloids, 2014
    Co-Authors: Malcolm J.w. Povey
    Abstract:

    Crystal nucleation in Food Colloids is considered in the light of recent developments in classical nucleation theory (CNT); it is shown that CNT remains a sound basis upon which to understand nucleation in Colloids and in particular nucleation in lipids such as triacylglycerols. Computation of the energy barrier to nucleation for a studied triacylglycerol system (Cocoa butter oil-in-water emulsion) indicates that whilst homogeneous nucleation is unlikely at higher surface energies the addition of surfactant, lowering the interfacial energy may have a dramatic impact on surface nucleation rates. Data is included supporting this contention. The impact of reducing the size of colloidal particles to the point where the interfacial region occupies a significant proportion of the total volume of the dispersed phase is discussed and it is suggested that in these circumstances undercooling may fall significantly in comparison with the undercooling measured in micrometre emulsions.

Harjinder Singh - One of the best experts on this subject based on the ideXlab platform.

  • Chapter 12 – Interactions and Functionality of Milk Proteins in Food Emulsions
    Milk Proteins, 2020
    Co-Authors: Harjinder Singh
    Abstract:

    Because of their high nutritional quality and versatile functional properties, milk proteins are widely used as ingredients in many manufactured Food Colloids, e.g., dairy desserts, nutritional beverages, ice cream, yogurt, spreads, confectionery, and baked goods. Milk proteins perform a wide range of key functions in prepared Foods, including emulsification, thickening, gelling, and foaming. An important functionality of milk proteins in Food Colloids is their ability to facilitate the formation and stabilization of oil droplets in emulsions. The ability of milk protein products to adsorb at the oil–water interface and to stabilize emulsions is influenced by the structures, flexibility, and aggregation state of the constituent proteins. This chapter deals mainly with the properties and functionalities of Food emulsions formed with a range of milk protein products and how they are influenced by different environmental and processing conditions. Of particular importance are the effects of pH, calcium ions, and protein content and the influences of thermal and high-pressure processing. The chapter focuses on the structure and composition of adsorbed protein layers, competition between proteins, and the creaming and flocculation behaviors of emulsion droplets. Recent work on the influence of the emulsion structure, in particular of the adsorbed layers, on lipid oxidation and lipid digestion behavior is also reviewed briefly.

  • Aspects of milk-protein-stabilised emulsions
    Food Hydrocolloids, 2011
    Co-Authors: Harjinder Singh
    Abstract:

    Abstract Milk proteins are widely used as ingredients in prepared Foods, in which they perform a wide range of key functions, including emulsification, thickening, gelling and foaming. An important functionality of milk proteins in Food Colloids is their ability to facilitate the formation and stabilisation of oil droplets in emulsions. The ability of milk proteins to adsorb at the oil–water interface and to stabilise emulsions has been exploited by the Food industry in the manufacture of nutritional products, specialised medical Foods, dietary formulations, cream liqueurs and dairy desserts. This article provides an overview of the properties and functionalities of Food emulsions formed with milk proteins, focusing on the structure and composition of adsorbed protein layers, competition between proteins and the physical and chemical stability of emulsion droplets. Of particular importance is the understanding of the behaviour of milk-protein-based emulsions under the conditions relevant to digestion in the human gastrointestinal tract. Recent relevant research in this area is reviewed and discussed.

  • Aspects of milk-protein-stabilised emulsions
    Food Hydrocolloids, 2011
    Co-Authors: Harjinder Singh
    Abstract:

    Milk proteins are widely used as ingredients in prepared Foods, in which they perform a wide range of key functions, including emulsification, thickening, gelling and foaming. An important functionality of milk proteins in Food Colloids is their ability to facilitate the formation and stabilisation of oil droplets in emulsions. The ability of milk proteins to adsorb at the oil-water interface and to stabilise emulsions has been exploited by the Food industry in the manufacture of nutritional products, specialised medical Foods, dietary formulations, cream liqueurs and dairy desserts. This article provides an overview of the properties and functionalities of Food emulsions formed with milk proteins, focusing on the structure and composition of adsorbed protein layers, competition between proteins and the physical and chemical stability of emulsion droplets. Of particular importance is the understanding of the behaviour of milk-protein-based emulsions under the conditions relevant to digestion in the human gastrointestinal tract. Recent relevant research in this area is reviewed and discussed. © 2011 Elsevier Ltd.

  • Interactions and Functionality of Milk Proteins in Food Emulsions
    Milk Proteins, 2009
    Co-Authors: Harjinder Singh, Aiqian Ye
    Abstract:

    Abstract Because of their high nutritional quality and versatile functional properties, milk proteins are widely used as ingredients in many manufactured Food Colloids, e.g., dairy desserts, nutritional beverages, ice cream, yogurt, spreads, confectionery, and baked goods. Milk proteins perform a wide range of key functions in prepared Foods, including emulsification, thickening, gelling, and foaming. An important functionality of milk proteins in Food Colloids is their ability to facilitate the formation and stabilization of oil droplets in emulsions. The ability of milk protein products to adsorb at the oil–water interface and to stabilize emulsions is influenced by the structures, flexibility, and aggregation state of the constituent proteins. This chapter deals mainly with the properties and functionalities of Food emulsions formed with a range of milk protein products and how they are influenced by different environmental and processing conditions. Of particular importance are the effects of pH, calcium ions, and protein content and the influences of thermal and high-pressure processing. The chapter focuses on the structure and composition of adsorbed protein layers, competition between proteins, and the creaming and flocculation behaviors of emulsion droplets. Recent work on the influence of the emulsion structure, in particular of the adsorbed layers, on lipid oxidation and lipid digestion behavior is also reviewed briefly.

V. Kiosseoglou - One of the best experts on this subject based on the ideXlab platform.

  • Egg yolk protein gels and emulsions
    Current Opinion in Colloid and Interface Science, 2003
    Co-Authors: V. Kiosseoglou
    Abstract:

    Abstract Egg yolk remains a key ingredient of a number of Food products. Yet, its main functional properties, e.g. emulsifying ability and gel structure formation, upon heating, have not attracted the attention of too many researchers specializing in the area of Food Colloids. It is not surprising then that there have been only very few major advances in the field over the period of the last few years. These are discussed in the present review and include recent research findings on competitive adsorption between yolk protein constituents at emulsion oil–water interfaces, and also on the relationship between yolk particle supermolecular structure disorganization and the rheological properties of yolk-based emulsions and gel-network structures.

  • Egg yolk protein gels and emulsions
    Current Opinion in Colloid and Interface Science, 2003
    Co-Authors: V. Kiosseoglou
    Abstract:

    Egg yolk remains a key ingredient of a number of Food products. Yet, its main functional properties, e.g. emulsifying ability and gel structure formation, upon heating, have not attracted the attention of too many researchers specializing in the area of Food Colloids. It is not surprising then that there have been only very few major advances in the field over the period of the last few years. These are discussed in the present review and include recent research findings on competitive adsorption between yolk protein constituents at emulsion oil-water interfaces, and also on the relationship between yolk particle supermolecular structure disorganization and the Theological properties of yolk-based emulsions and gel-network structures. © 2003 Elsevier Ltd. All rights reserved.

Vitaly Buckin - One of the best experts on this subject based on the ideXlab platform.

  • High-frequency shear and volume viscoelastic moduli of casein particle gel
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2001
    Co-Authors: Cormac Smyth, Evgeny Kudryashov, Vitaly Buckin
    Abstract:

    Abstract Protein particle gels, which consist of a continuous three-dimensional network of flocculated particles, such as casein micelles, are the main constituents of many biological and Food Colloids. These gels have an extremely short region of linear elastic behaviour and small fracture strain, thus creating complications for their rheological analysis. In the present paper we describe the application of low amplitude ultrasonic measurements for the monitoring of casein particle gel formation in a suspension of casein particles (a process similar to the formation of gel network in yoghurt). Combination of high-resolution longitudinal and shear wave measurements allowed us to make a complete analysis of the shear and volume viscoelasticity of casein particle gels in the frequency range 5–25 MHz. Both shear moduli, the storage ( G ′ Gel ∼30 kPa, at 7 MHz) and the loss moduli ( G ″ Gel ∼100 kPa, at 7 MHz) of the gel in the megahertz frequency range are several orders higher than those determined previously by dynamic rheology at low frequency (0.1 Hz), indicating different contributions of the gel network to the changes in the viscoelastic parameters at low and high frequencies. The volume storage ( K ′ Gel ∼75 kPa, at 7 MHz) and loss ( K ″ Gel ∼15 kPa, at 7 MHz) moduli of the casein particle gel are of the same order as the shear modili of the gel. The contribution of the gel to the volume storage modulus of the whole suspension of casein particles is very small, about 0.001%. This indicates the importance of high-resolution ultrasonic measurements for analysis of these systems.

  • High‐resolution longitudinal and shear wave spectroscopy for analysis of complex Colloids
    Journal of the Acoustical Society of America, 2000
    Co-Authors: Cormac Smyth, Evgeny Kudryashov, Vitaly Buckin
    Abstract:

    In the present paper we describe the applications of the high‐resolution ultrasonic longitudinal and shear wave resonator techniques for Food and bio‐Colloids. Our longitudinal wave technique allows us to measure the velocity and attenuation of ultrasonic waves with a resolution of 0.0001% for ultrasonic velocity and 0.1% for the ultrasonic attenuation in small volumes (0.1 to 1 ml) in the frequency range 4–20 MHz. The shear wave technique provides information on viscoelastic parameters of liquids and gels in the frequency range 4–25 MHz. Both techniques allow continuous, temperature ramp and automatic titration measurements for analysis of various processes in complex Colloids. Examples of the application of both techniques for studying heat‐induced milk coagulation, phase transitions in milk fats, acid milk gelation, and the detection of Food pathogens are described. Combination of both techniques shows a high sensitivity to various processes, e.g., pregelation and gelation, in Food Colloids and provide...

  • ultrasonic high resolution longitudinal and shear wave measurements in Food Colloids monitoring of gelation processes and detection of pathogens
    Progress in colloid and polymer science, 2000
    Co-Authors: Evgeny Kudryashov, Cormac Smyth, G Duffy, Vitaly Buckin
    Abstract:

    In the present paper we describe the applications of the ul- trasonic high-resolution longitudinal and shear wave measurements for Food and bio-Colloids. In the first example, both ultrasonic methods were used for the monitoring of the acidified milk gelation induced by glucono-d-lactone (formation of gel network in yoghurt). Ultrasonic measurements demonstrated a high sensitivity to pre-gelation and gela- tion processes during the formation of acid milk gels. The hydration of colloidal calcium phosphate released into serum and the swelling of casein in micelles at pH 5.6-5.0 are sug- gested as the main contributors to the ultrasonic velocity and attenua- tion changes during the pre-gelation. The increase in shear loss modulus of acidified milk at pH 5.0-4.85 can be explained by the aggregation of the casein micelles into clusters. Subsequent reformation of these clusters into a gel network at pH 4.85-4.6 is observed as a sharp rise in the storage moduli of acid milk gels and an increase in the ultrasonic velocity. The second example is the application of the ultrasonic shear wave measurements for the detection of Salmonella in liquids. The anti- gen-antibody binding monitored by impedance measurements of a quartz crystal at 5, 15 and 25 MHz results in both the decrease in reso- nant frequency and an increase in the imaginary part of the quartz impedance. The analysis of the data indicates that the bacteria cells on the sensor surface do not exhibit pure mass-load behaviour, and the viscoelastic properties of the inter- facial layer must be taken into account for quantitative analysis. Overall, our ultrasonic measure- ments demonstrate their high po- tential as non-destructive methods of analysis of complex Foods and bio-Colloids.

  • High-resolution ultrasonic resonator measurements for analysis of liquids
    1999
    Co-Authors: Vitaly Buckin, Cormac Smyth
    Abstract:

    This paper describes the basic principles and the key components of the resonator technique for high-resolution ultrasonic measurements in liquids and illustrates its application to the analysis of Food Colloids. In this technique the ultrasonic parameters of liquids are obtained through the measurements of resonance characteristics of acoustic resonators. Modern advances in electronics and in the construction of ultrasonic resonators combined with the scientific background of interpretation of ultrasonic characteristics obtained in the last decade make high-resolution ultrasonic measurements a powerful tool in different kinds of analysis of Food Colloids in research and industry.