Review
Product engineering of dispersed systems

https://doi.org/10.1016/S0924-2244(02)00245-5Get rights and content

Abstract

Product engineering is the design of products with desired properties using the methods of process engineering. To reduce the number of process parameters, necessary to obtain the desired properties, a characteristic feature of the respective product is helpful. For a dispersed system this characteristic feature is its complex structure on a micro-scale. This micro-structure is the link between the process and the properties of the final product. The principles of product engineering of dispersed systems are explained and demonstrated by means of different examples: Though there are limits to this concept, certain properties of dispersed systems can be obtained by determining and applying property and process functions.

Introduction

Dispersed systems, e.g. emulsions, foams, suspensions or powders, are commonly found in many branches of industries, ranging from chemical products to cosmetics, pharmaceuticals, food and innovative materials like metal and ceramic foams. Dispersions, in general, are systems with a characteristic structure on a micro-scale, which determines many of their physical properties and thus the quality and functionality of the product; their macroscopic appearance is often homogeneous, though. Stability, rheology, sensory and optical properties or mass transfer kinetics are only some of the properties, which are largely influenced by the micro-structure of a dispersed system. The correlation between a specific property and the micro-structure is called property function (Rumpf, 1967) (Fig. 1). The use of property functions only makes sense, if the main properties are clearly determined by the micro-structure. For dispersed systems this condition is usually fulfilled (Borho, Polke, Wintermantel, Schubert, & Sommer, 1991). Often, the micro-structure can be sufficiently described by a small number of characteristic parameters (e.g. mean values). In this case, properties are independent of the process conditions used to obtain these structural parameters. The structure is determined by the choice of ingredients as well as the preparation process. Changes in the recipe are often limited by functional demands of the final product or they are subject to legal restrictions. Knowledge about the, often cruical, influence of process parameters on structural characteristics is, therefore, indispensible. The desired micro-structure can be obtained by the choice of suitable process conditions, the relation between both is described by the process function (Borho et al., 1991, Polke, 1995). Thus, product engineering of dispersed systems means the design of products with desired properties, taking into account the methods of process or chemical engineering. The micro-structure of the system may be used as linking factor between the process and product properties.

Section snippets

Liquid dispersions: emulsions

Emulsions are dispersions of two or more insoluble liquids, e.g. water and oil, with the dispersed phase distributed in form of small droplets in the continuous phase. From a thermodynamic point of view such systems are unstable. As a consequence, energy input is required in the dispersion step, e.g. mechanical energy for droplet disruption. Afterwards, the dispersed state obtained has to be stabilized over the desired period of storage and usage of the respective product. Both dispersion and

Summary

The task of product engineering is to produce products of a certain quality, i.e. with specific properties. The tools to attain this target are the methods of process engineering. All properties are the result of certain physical, chemical or biological effects in the product, which are determined by the choice of ingredients and processing conditions. The understanding of these basic mechanisms is the key to a purposeful design of product properties. In case of dispersed systems, like

References (46)

  • F Bunge et al.

    Mechanischer Zellaufschluß in Rührwerkskugelmühlen

    Chem. Ing. Tech.

    (1993)
  • R.H Bunnell et al.

    Coloring Water-Base Foods with β-Carotene

    Food Technol.

    (1958)
  • Danner, T. (2001). Tropfenkoaleszenz in Emulsionen. Thesis, Universität Karlsruhe...
  • T Danner et al.

    Messen der stabilisierenden Eigenschaften von Emulgatoren in Emulsionen

    Lebensmittelverfahrens- und Verpackungstechnik

    (2000)
  • S Hogekamp

    Instantization of water soluble powdered foods by pre-agglomeration and solidifcation with condensing steam

    Product Eng. & Chem. Eng. Now

    (1999)
  • D Horn

    Preparation and characterization of microdisperse bioavailable carotenoid hydrosols

    Angew. Makromol. Chem.

    (1989)
  • Karbstein, H. (1994). Untersuchungen zum Herstellen und Stabilisieren von Öl-in-Wasser-Emulsionen. Thesis, Universität...
  • T Kawakatsu et al.

    Regular-sized cell creation in microchannel emulsification by visual microprocessing method

    Journal of the American Oil Chemists' Society

    (1997)
  • B Koglin et al.

    Kontinuierliches Emulgieren mit Rotor/Stator-Maschinen Einfluß der volumenbezogenen Dispergierleistung und der Verweilzeit auf die Emulsionsfeinheit

    Chem. Ing. Techn.

    (1981)
  • Kolk, J.H.H. (1974). Über die Vitamin-A-Wirksamkeit und Dotterpigmentierungsfähigkeit von drei Citranaxanthin-...
  • P Kyaw Hla et al.

    Wetting behaviour of instantized cocoa beverage powders

    Int. J. Food Sci. Technol.

    (1999)
  • Y.F Maa et al.

    Protein inhalation powders spray draying vs spray freeze drying

    Pharm. Res.

    (1999)
  • S.T Mayne

    Beta-carotene, carotenoids, and disease prevention in humans

    FASEB Journal

    (1996)
  • Cited by (0)

    View full text