Laser diffraction and light scattering techniques for the analysis of food matrices

The food industry has evolved over the last 30 years to a technological level where color, texture, fragility, smell, particle size, and many other previously unquantifiable properties can be measured reliably, and optimized to provide products that satisfy customer expectations of quality, freshness and taste. The product quality is now highly dependent upon the effective use of analytical technology and particularly the measurement of particle sizes. In fact, several food products and ingredients are supplied in the form of powders, pellets, pastes and/or emulsions. Particle size distribution is important because it can affect taste, appearance, texture, reliability, functionality and/or the stability of the final product. Across the food industry, the key technologies for measuring particle size, due to their reliability, accuracy and ease of use, are laser diffraction and dynamic light scattering (DLS). These procedures allow performing particle sizes and size distribution from measurements of the angular intensity of scattered laser light, produced as the light passes through a dispersed sample. Furthermore, the wide variety of particulate ingredients handled in food production implies a demand for particle sizing instrumentation and techniques that is both versatile and easy to use. The laser diffraction and DLS technologies represent easier measurements to get reliable and accurate results quickly in different food products. Focusing on particle size and size distribution, this paper discusses how such technology is shaping up to meet the industry’s needs and reviews the main applications of laser diffraction and DLS in different food products.