Characterisation tools measures up for food science

Researchers have developed a variety of improved and novel colloidal delivery systems for food and pharmaceutical applications

Armed with a Zetasizer Nano, a Mastersizer 2000 particle size analyser, and a Kinexus rheometer, Professor David Julian McClements and his team of researchers at the Department of Food Science, University of Massachusetts (UMass), Amherst, USA, have developed a recipe for success in the development of foods.

This trio of characterisation tools from Malvern Instruments has enabled the UMass team to develop a variety of improved and novel colloidal delivery systems for food and pharmaceutical applications, including microemulsions, nanoemulsions, multilayered emulsions, solid lipid nanoparticles, and hydrogel particles.

Professor McClements said: "We use all three Malvern systems in our studies. They work well and are easy to use so students like them and use them for multiple applications. In fact, the Zetasizer is used so often, I recently bought a second instrument."

"Many of our studies employ 'layer-by-layer' deposition to create novel functional materials. We make a particle and coat it with sequential layers of positive and negative polymers.

"The Malvern Zetasizer, which has both dynamic light scattering (DLS) and particle electrophoresis modules, enables us to measure particle size and charge and therefore understand the electrical interactions used to build shells around individual particles.

He continued: "Mastersizer laser diffraction is essential for measuring the dimensions of food grade nanoparticles and microparticles. We also use the Mastersizer for determining hydrocolloid stability and droplet growth through flocculation, coalescence and Ostwald ripening."

Enviromental stresses

In addition to the development of novel food and health-promoting compounds, several members of the department focus on investigating the impact of environmental stresses such as pH, ionic strength and temperature, and production stresses such as mixing, thermal treatment and homogenisation, on the formation of colloid systems.

This type of study combines particle size characterisation with rheometry to optimise production, product quality, and functionality.

For example, the team recently used the Kinexus dynamic shear rheometer in development of reduced-calorie products with desirable textural properties based on electrostatic heteroaggregation of oppositely charged particles and polymers.

As part of a wider scope in food research, the UMass Department of Food Science employs the basic principles and instrumental techniques of the physical and chemical sciences to improve our understanding of complex food systems.

Meanwhile, Malvern Instruments' new Mastersizer 3000 laser diffraction particle size analyser made its Analytica debut in Munich, Germany, earlier this year. This state-of-the-art, small footprint instrument is designed for smart particle sizing, delivering precise, high-resolution wet and dry sample measurement from 10nm to 3.5mm.

New sample dispersion units provide a solution for every application, including the dry dispersion of fragile particles, while simple intuitive software drives user-defined measurements and simplifies method development.

Particle shape

Meanwhile, Malvern's Morphologi G3 particle characterisation system was also be on show. Understanding particle shape can have a significant impact upon the performance and process handling of many particulate materials.

The Morphologi G3 image analysis system delivers both particle size and shape information, providing a wide range of morphological parameters for even greater detail in the analysis of particulate materials.

Analysing coffee beans

Renowned globally for the quality of its coffee makers, manufacturer De'Longhi has transformed QC processes for grinders at its manufacturing facility in Mignagola di Carbonera, using the Insitec on-line particle size analyser from Malvern Instruments.

The Malvern applications team worked closely with engineers at De'Longhi to develop a fully automated solution that supports the target of achieving 100 per cent testing, of every element, of each 'bean to cup' coffee maker. Grinder set-up is assessed on the assembly line by analysing the particle size of freshly ground coffee beans.

The Insitec solution is easy to use, extremely reliable and robust, and testing is complete in just a few seconds. Three systems are now in continuous operation on three parallel assembly lines.

Commenting on the innovative solution, De'Longhi said: "Because we wanted to test every single grinder that comes off the assembly line, measurement speed was critically important to us. Insitec quantifies grinder performance in real-time. The interface we've developed then guides the assembly line worker as to any corrective action required to ensure that this performance meets our defined specification. The results are tagged to the specific grinder so we have an audit trail for every single coffee maker that leaves the site."

'Bean to cup' coffee makers, as the name suggests, incorporate an integral grinder, whose performance has a defining influence on the taste of the finished cup of coffee. At De'Longhi, grinder set-up is assessed, on the assembly line, by analyzing the particle size of freshly ground coffee beans. While the essential basis of the solution is particle size distribution data, the system has been engineered to provide operatives with simple pass/fail information.

Out-of-specification performance is rectified by turning a gear wheel in either direction to move the grinding surfaces closer or further apart, the Insitec interface providing direct instructions as to what action to take.

The Insitec is a laser diffraction particle size analyzer for in- or on-line use. Measuring up to four complete size distributions every second it provides real-time data that effectively tracks even the most rapidly changing processes.

Malvern Instruments is based in Malvern, UK.

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