Using rheology to characterize flow and viscoelastic. Rheological studies become particularly useful when predictive relationships for rheological properties of foods can be developed which start from the molecular architecture of the constituent. In the past few years, however, these forms also have been explored for the systemic delivery of various drugs. Mathematical relationships, derived from simple force balances, provide a fundamentalview of rheological testing. Abstract samples of lard and shortening have been examined by five rheological techniques. Fluid mechanics is the foundation of food rheology and the correlation of stress and strain can be used to describe rheological properties of food systems in different models. Requirements for specific types of topical semi solid dosage forms creams definition creams are homogeneous, semi solid preparations consisting of opaque emulsion systems. Semisolid dosage forms usually are intended for localized drug delivery. Measurement of rheological properties foods are diverse and complex materials which exhibit a wide range of different rheological properties, e. Yield stresses usually are caused by structural networks extending throughout an entire system. Nov 07, 2016 extrusion testing has several applications within the food and other industries, for texture assessment.
Rheological properties are important to the design of flow processes, quality control, storage and processing stability measurements, predicting texture, and learning about molecular and conformational changes in food materials davis, 1973. Theoretical concepts as well as practical applications are described in order to show the influence of the rheological properties on the physicochemical and biological characteristics of formulations containing nanosystems. Recently, a number of more sophisticated instruments, based on dynamic rheological measurements, have been developed to characterize the rheological properties of solids, plastics, and viscoelastic materials harwalker and ma 1990, wunderlich 1990, whorlow 1992. Solid foodstuffs viscoelasticity and its role in quality control, journal of texture studies on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Texture analysis extrusion testing of semisolids and. The rheology of pharmaceutical and cosmetic semisolids. Furthermore, yield stresses are connected to certain food properties. Rheology is important in a number of different areas of food science. Unfortunately familiarity sometimes also leads the notion that foods relate. The rheology of pharmaceutical and cosmetic semisolids cannon. Thermal properties were primarily dependent on the moisture content of the. Rheograms are constructed by plotting shear stress o as a function of the shear rate j tixier et al.
Mechanical properties of solids hookes law extension shear. Com 3 eating quality, usage properties such as ease of cutting, spreading and melting characteristic as well as handling and packaging characteristics. Pdf microstructure analysis and rheological behavior of. In this chapter, rheological properties of foods are discussed, concentrating on the principles of flow behavior and deformation of food systems. Simultaneous effects of total solids content, milk base, heat. Microstructure and rheological properties of az91 and elektron 21 magnesium alloys in semi solid state were studied. During the past few decades the science of fluids and semi fluids rheology has been improved significantly therefore food professionals need to appreciate the fundamental principles and suitable measurements of rheological properties of food as well as the impact of structure and composition on it. Determination of the rheological properties of mayonnaise karastojanov stefan 1, dragoslav kocevski 2 1. Svensson department of thematic studies, water and environmental studies, linkoping university, sweden 1. Thermophysical and rheological properties of mango pulp were evaluated at different temperatures 20, 40, 60, and 80 c and total soluble solids concentrations 15, 20, 32, and 40 brix. It is the instrument of choice for simple viscosity determination as well as for complex rheological investigations from low viscous liquids to stiff pastes and semi solids. Rheological and textural properties of various food. The cup was filled to the scribed line with the test sample and placed on the platform of the instrument.
Two major rheological analysis methods are available for the characterisation of creamspastes and semi solids, such as controlled stress rheology rheometrics sr500 to predict properties such as shelf lifeease of application and stability sedimentation rate performed over a variety of test temperatures and controlled strain rate rheology rheometrics ares, rdaii. This revised third edition of rheology of fluid, semisolid, and solid foods includes the following important additions. The principles of viscosity and texture measurement methods and the devices used in these methods are explained in detail. Rheological properties semisolids do not flow at low shear stresses but undergo reversible deformation like elastic solids. Rheology in pharmaceutical formulationsa perspective longdom. For semi solids, no compendial methods are available, but the. Pdf rheological characterization of semisolid metals. Contour plots of each response were depicted, based on the equation given by the statisticalfitted models. Sigworth gks engineering and graphic service, 321 tioga street. As for any structured product, the rheological properties of chocolate are closely related to its microstructure which is imparted by choice of ingredients and. Rheology studies the flow and deformation of matter and is an important tool to characterize fundamental material properties of food systems. Rheological behavior of semisolid formulations containing.
May, 2011 the rheological properties of chocolate in its molten state short referred to as chocolate in the following are important to the eating quality and processing of chocolate. The present study attempted to characterize the rheological properties of different sizes of gnps at. Differential scanning calorimetry revealed significant differences in melting. Rheology of fluid, semisolid, and solid foods principles.
Rheological properties of chocolate new food magazine. Results from numerous fields, particularly polymer rheology, are used to address the flow behavior of food. Rheological properties of metal alloys in the semisolid. This haake viscotester iq rheometer sets new standards in modularity, ease of use and intelligent user guidance. The present study was undertaken to obtain a quantitative evaluation of the rheological properties of representative bases. For fluids a flow curve or rheogram is used to describe rheological properties. Measurement of rheological properties food emulsions. Professor at faculty of agriculture science and food, skopje, macedonia stefan. The rheological properties of gnps have not been previously documented. The goal of rheological experiments is to quantify dynamic viscoelasticity over as wide a range of time and deformation scales as possible, and ultimately to relate these viscoelastic properties to material structure.
Some invitro methods are particularly useful for early studies and screening purposes. If you continue browsing the site, you agree to the use of cookies on this website. When a characteristic shear stress, called the yield value or yield stress, is exceeded, they flow like liquids. Many of the textural properties that human beings perceive when they consume foods are largely rheological in nature, e. The rheological properties of different gnps lipids in. Topical semisolid dosage forms world health organization. A yield stress can improve the stability of dispersed systems by preventing sedimentation or as an example simply keeping a ketchup from sinking in too much into french fries instead of forming a nice thick layer on top of the fries. For transdermal patches, the paddleoverdisc method described in the united states pharmacopeia and the european pharmacopoeia is a reliable test to determine the invitro dissolution rate. The platform was raised so that the surface of the test sample was level with the. Rheological properties of solids part 1 jeyam subbiah. The rheological properties of a number of solid, thin, ductile, foods, such as edible films and fruit skins can be determined in extension. A section on microstructure discussion of the quantitative characterization of nanometerscale milk protein fibrils in terms of persistence and contour. Role of additives in enhancing the rheological properties of. Gel formulations with suitable rheological and mucoadhesive properties increase the contact time at the site of absorption.
Consequently, a variety of different instruments have been developed for characterizing their rheological properties. Therefore, the product behaviour must be monitored at the time of application. The optimum area for the ointment base properties, were. Rheological properties of semisolids viscosity of the semisolid dosage forms may directly influence the diffusion rate of the drug. These properties may be of importance in anaerobic digestion for the dimensioning of e. Therefore, rheological measurements, an important route to revealing the flow and deformation behaviors of materials, cannot only improve efficiency in processing but can also help formulators and end users find pharmaceutical and cosmetic products that are opti. Experimental study on the rheological properties of polymer. This method is suitable for viscous liquids or semisolids, where the products rheological properties affect the flow. Food rheology covers a wide range of fluids and semi solid materials from dilute juices, through gels and emulsions to solid cheese and breads. Viscositydefined as a materials resistance to flow deformation and is a function of shear rate or stress, with time and temperature dependence viscoelasticity is a property of a material that exhibits both viscous and elastic character. Microstructure and rheological properties of az91 and elektron 21 magnesium alloys in semisolid state were studied. Articles a rheological study of some pharmaceutical semisolids. Rheological properties of semi solids pdf download. Rheological properties are determined by measuring force and deformation as a function of time.
Food rheology encyclopedia of life support systems. Also, nonviscous properties and transient conditions are discussed since they are especially relevant for the industrial semisolid processing. These rheological properties are associated with important characteristics, such as physicochemical stability, drug delivery properties and applicability of each. Introduction the biogas process has long been a part of our biotechnical solutions for the handling of sewage sludge and waste. Food is familiar to all and everybody can relate to the texture or consistency and thus get a feel for its rheological properties. The appli cation and acceptance of pharmaceuticals and cosmetics are also dependent on the flow properties of the final product. Rheological properties are determined in relation to the stress applied on a material and the subsequent deformation as a function of time. An overview of both their solution properties dilute to semi dilute and gel properties is described. Rheological properties of metal alloys in the semi solid state. In terms of food, rheology is the study of the deformation and flow of the raw materials, the intermediate products, and the final products of the food industry bourne, 2002. This chapter presents an overview of the rheological properties of semisolids before and after the incorporation of nanostructures. Recent developments in rheological instruments hold out a definite scope for generating valuable informations on the basic rheological parameters of these products. Their consistency and rheological properties depend on the type of emulsion, either waterinoil wo or oilinwater ow, and on the nature of the solids in the internal. The rheological characterization of foods provides important information.
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