Food structure and image analysis

Many foods and food materials have a non–uniform structure and composition. They may contain bubbles, emulsions, multiple components such as fruit pieces in yoghurt, structures such as marbling fat in meat, or gradients of fat, water or salt.

As well as measurements of average composition, aspects of the structure, appearance and distribution of components are also important. There are several techniques available to study these – and we are leaders in this field. Measurements can be used, for example to document appearance, to check that ingredients are uniformly dispersed or to study changes in colour or migration of components over shelf life.

Colour and appearance

The colour and appearance of food products are critical for customer acceptance. Colour meters and spectrophotometers provide accurate measurements for uniform products. For more complex products or to aid interpretation and communication of appearance, digital images are also used. Calibrated imaging systems using controlled imaging conditions and colour reference standards enable accurate colour reproduction to be achieved for digital and printed images. Images can be analysed to discriminate features such as lean meat and marbelling fat and to measure the colour of specific regions of interest.

Structure characterisation

X–ray micro–tomography is a powerful technique for characterising product structure, enabling the internal structure of samples to be scanned non–destructively in 3D at resolutions as small as 1 micrometre. The resulting images can be studied interactively on a computer screen without any destructive sample preparation and measurements can be made of properties such as bubble size distributions and internal product dimensions. Applications include characterisation of porous structures such as snacks, baked products and confectionery, and non–destructive investigation of problems such as leaks in plastic closures, or foreign bodies.

Optical and scanning electron microscopy methods are also useful for characterisation of product structure, particularly for high magnification work. These can be used in combination with techniques that provide further information on the structures imaged, including X–ray spectroscopy to identify elemental composition.

Compositional mapping

Imaging at non–visible wavelengths can provide information on product composition. A hyperspectral near infrared imaging system measures an NIR spectrum for each pixel in an image, enabling the distribution of compounds such as fat and moisture to be measured. Following calibration for a given product application, rapid quantitative measurements can then be made for test samples, including at–line measurements. Applications include mapping of moisture distributions, for example to study uniformity of baking processes, or to study moisture migration between product components during storage.

These techniques offer solutions for a diverse range of problems. Please get in touch to discuss your requirements.

Contact: Alix Cornish
+44(0)1386 842054
alix.cornish@campdenbri.co.uk