40 FOOD & DRINK TECHNOLOGY
Shape and size matter when analysing food particles
still one of the methods used by researchers at Campden BRI, there is an increasing awareness and acceptance that particle shape also has a significant bearing on food products’ characteristics.
Te shape of particles not only affects the mouth-feel and taste of food but also affects how certain products behave during processing. Te bulk density, compressability and flow-ability of raw materials are highly dependent on particle shape as well as size. For example, how a powdered ingredient, such as flour, flows or how much water is absorbed during the processing of a dough or a batter, can have an impact on processing. Tis could potentially lead to interruptions in production or technical issues with equipment.
Analytical instrumentation Proper particle characterisation and analysis requires accurate and reliable analytical instrumentation. Te challenge for food manufacturers is to select the best techniques and the optimum technology available to accurately determine particle shape and size.
Fig. 1. There are a range of practical applications in the food and beverage industry for the accurate analysis of particle shape and size.
It is vital that food manufacturers have a greater understanding of the influence of both particle shape and size on ingredient properties. Helen Metcalfe reports.
Il est essentiel que les fabricants de produits alimentaires comprennent mieux l’influence aussi bien de la forme que de la taille des particules sur les propriétés des ingrédients. Compte-rendu d’Helen Metcalfe.
Lebensmittelhersteller brauchen ein besseres Verständnis der Auswirkungen von Partikelform und -größe auf die Eigenschaften der Zutaten. Helen Metcalfe berichtet.
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any food products and their ingredients exist in particulate form ranging
from powders to emulsions, suspensions and pellets. Te shape and size distribution of particles can have an important impact on many aspects of food including: taste, texture, appearance, stability, processability and functionality of the final product.
Until relatively recently, the food industry primarily focused on traditional sieving, as the most common technique for particle sizing. While sieving is still widely used to determine particle size in the food industry today and indeed,
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Tere are issues with some methods of measurement, such as laser diffraction, which measures the angular variation in intensity of light scattered as a laser beam passes through a dispersed particulate sample.
While laser diffraction can determine the size of particles ranging in size from hundreds of nanometres up to several millimetres in size, it assumes all particles are spherical in shape, which is not always the case. Terefore, with this technique, it is impossible to accurately determine the size of irregularly-shaped particles.
Campden BRI, as part of its latest installation of £1.4m worth of analytical and processing equipment, has recently installed a brand new, leading-edge particle analyser that can accurately measure the shape and size distribution of particles
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