Food: Reliable particle sizing for streamlined quality control using the Mastersizer 3000+

When you’re producing chocolate, dairy products, ground coffee, flour or other foodstuffs, it’s vital to understand the sizes of the particles present during quality control of the manufactured foods. But you need a particle-sizing system you can rely on to generate quality data over the long-term. And that’s where Mastersizer 3000+ has the edge over other instruments, helping you to streamline quality control in every aspect of food particle size analysis.

Particle sizing using laser diffraction

Understanding and monitoring particle size is a vital aspect in the production of coffee, chocolate, dairy products, flavors, colors and numerous dry goods such as flour. The variety of these products is reflected in the variety of reasons for carrying out size analysis, which include:

• Monitoring raw material quality
• Minimizing the energy cost of grinding and homogenization
• Eliminating powder handling issues
• Monitoring homogenization and emulsion-breaking
• Ensuring that the sensory characteristics of the final product meet consumer expectation

Laser diffraction is widely regarded as the ‘gold standard’ technique for particle sizing, and over the last 30 years, Mastersizer instruments have developed a loyal following amongst food manufacturers, who value their reliability, reproducibility, versatility and ease of use.

Following on from this long record of success (and our decades of technical knowledge and experience), in March 2024 we introduced the Mastersizer 3000+, with three added software features to enhance your particle-sizing capabilities and inform your critical decision-making:

• Size Sure for improved confidence in routine measurements and method development
• Data Quality Guidance for helping you to make independent decisions on real-world samples
• SOP Architect for standardized, streamlined method development for wet samples.

Combine this with existing modules like Smart Manager for optimizing uptime and usage, and you have a system that remains the very best you’ll find for obtaining particle size distributions (PSDs) in the food sector.

To demonstrate what we mean, we’ll explain below how Mastersizer 3000+ can help you tackle some commonly encountered challenges in the analysis of particle size in foods.

Challenge 1: Being able to handle any sample you’re given

Analyzing the particle size of foods requires a system that can easily adapt to a range of sample types, particle sizes and sample volumes – and Mastersizer 3000+ has you covered on all these aspects.

To start with, the Mastersizer 3000+ caters for every particle size you’ll encounter in the food sector, with its wide dynamic range of 10 nm to 3500 μm allowing characterization of everything from fine emulsion droplets to larger flocculated or coalesced particles. Sieving, in contrast, although working reasonably well for larger particles, suffers from being slow, low-resolution and labor-intensive (with cleaning of finer sieves being a particular problem).

Mastersizer 3000+ also offers easy-to-use options for different sample types (Figure 1). Our Aero accessories for dry dispersions ensure rapid, reproducible powder dispersions. Meanwhile, our Hydro accessories for wet dispersions provide excellent results with both water and oil-based dispersants and also form part of our Chocosizer kit for reliably dispersing chocolate, cocoa and milk solids. And of course, switching between any of them is quick, easy and convenient.

Coverage of sample volumes is also strong with the Mastersizer 3000+ accessories, with good reproducibility obtained for both large amounts (e.g. up to 130 mL of dry samples such as ground coffee with our dry powder disperser) and small amounts (e.g. down to 0.01 g). 

Figure 1: The adaptability of the Mastersizer to different particle types and distribution scales: (A) PSDs of whole, semi-skimmed and skimmed milks, showing contributions from different particle types; (B) PSDs for chocolate samples of differing quality and mouthfeel; (C) PSDs for coffees obtained using different grinding conditions.

Challenge 2: Reliably detecting coarse particles

We’ve probably all experienced it – what we think is an outlier in the particle size distribution, which turns out to be nothing more than a one-off contaminant or a few bubbles in the dispersant (Figure 2). Fortunately, Mastersizer 3000+ can now help you troubleshoot such issues, thanks to its Size Sure software module.

Figure 2: In this analysis of a flavor emulsion, you need to know whether the small amounts of large particles present (arrowed) are transient or real (and hence a sign of instability) – and that’s where Size Sure can help.

Size Sure uses machine-learning algorithms to separate steady-state data (i.e. the true sample) from such transient-state data. It then generates two PSDs, allowing you to check the size distributions in each set, and understand the nature of any transients present before deciding whether to proceed or not. Importantly, the data is not discarded (or even filtered) – it’s all there to view, and you can re-combine it if you need to. In the example above, Size Sure would be able to show that the large particles seen are in the steady state, and not transient, so it could point to an unstable formulation.

Therefore, using Mastersizer 3000+ for routine QC will help you to understand any potential quality issues that the particle-sizing process is highlighting, enabling you to take the most appropriate action straight away.

Challenge 3: Achieving consistency across multiple instruments

If you’re a larger manufacturer, then you’ll likely have encountered the challenge of achieving instrument-to-instrument consistency in particle size measurements, whether it’s between buildings or sites. So it’s good to know that Mastersizer 3000+ meets the highest standards of reproducibility (Figure 3), giving you confidence that you’re seeing a genuine difference between samples and not an artifact.

Figure 3: Overlay of measurements of coarse and fine grades of dry coffee powder (n = 15 for both), using the Aero S disperser with the Mastersizer. The data indicates a measurement repeatability of 3% for Dv50 and 5% for Dv10 and Dv90. Furthermore, no adhesion of the finer coffee to the sample flow path was observed, facilitating rapid sample turnaround. 

Another source of variation can arise from those using the equipment. Over the years, Mastersizer systems have become well-known for their easy-to-learn user interface, which shortens the learning curve for new users. Learning how to run a laser diffraction method has now been made even easier with the intelligent feedback offered through our Data Quality Guidance software module.

Data Quality Guidance uses machine-learning algorithms founded on our many years of experience to identify when there might be a measurement issue – such as residual sample from a previous measurement – and suggests a course of action to resolve it (Figure 4). As a result, you’ll be able to spot problems as soon as they occur, and take swift and targeted action to avoid wasting time.

The software makes it simple to compare results between sites, and even see the differences in methods, so any deviation in raw materials or procedures can be easily spotted and resolved.

Figure 4: A typical panel from Data Quality Guidance, showing an instance where an oily residue from a previous sample was adhering to the wall of the dispersion accessory.

Challenge 4: Developing robust methods for wet samples

Have you ever encountered a problem that you thought was down to the instrument, when it actually turned out to be a flaw in the standard operating procedure (SOP)? In our time helping customers with their enquiries, this actually happens quite a bit. But now we’ve got something to help you avoid those awkward situations, in the shape of the SOP Architect software module.

SOP Architect helps you with the complexities of method development for wet samples, by guiding you through the sequence of steps, and offering advice along the way (Figure 5). As a result, if you’re new to laser diffraction you’ll be able to proceed independently and with confidence, while if you’re more experienced, you should find it a useful reminder of best-practice. And ultimately, the entire process benefits because you’re generating robust methods that will give you results you can trust, whatever the sample.

Methods generated using SOP Architect use Malvern Panalytical’s ‘.sop’ file type, meaning that they run on SOP Player, and can be edited using SOP Editor. As a result, the three modules form part of a complete ecosystem for SOPs that is easily transferred between labs, wherever they’re based.

Figure 5: Example screenshot of SOP Architect during measurement acquisition, showing the various pieces of information about the sample being generated.

Conclusion

When it comes to quality control in the food industry, every minute you waste in preparing samples or troubleshooting unexpected results has an impact on production efficiency. So, with its unparalleled versatility, robustness and reliability, together with its handy software tools helping you along with way, Mastersizer 3000+ will help you streamline sample prep and ensure that your critical decisions are right first time.

As well as instrument performance, just as important for our customers is the worldwide support you get from Malvern Panalytical, giving you expert advice when you need it, and helping keep your manufacturing processes running 24/7.

Thousands of companies and research institutes across the world already rely on Mastersizer for their laser diffraction measurements – and with the added benefits of the Mastersizer 3000+, making your next instrument decision just became even easier.