On-line technologies for food process control

Martin Whitworth, Principle Scientist

Automated control of food processes enables greater process efficiency, more consistent product quality, and improved food quality and safety assurance. Harnessing these benefits requires reliable on‐line sensors capable of measuring relevant process conditions and product characteristics. A wide range of sensors are available, but many properties still rely on manual sampling and analysis.

Martin Whitworth discusses the progress of our research project into online process control in our latest video.

About Martin Whitworth

Martin has worked at Campden BRI and its predecessors since 1992. He has an MA and PhD in physics from Cambridge University, and an impressive number of food research publications from his time with us. He currently provides support and peer review for our research programme.

Martin specialises in physical characterisation of food products and ingredients including colour, structure and texture, with particular expertise in the application of imaging techniques and digital image analysis.

Martin has experience in cereal science and technology. He is a leading expert on bubble structure of doughs and baked products. He established our imaging laboratory, now part of our Food and Drink Microstructure team, which includes DigiEye colour imaging, hyperspectral NIR imaging and X-ray micro CT. He was the inventor of the C-Cell instrument for measurement of bread quality, and pioneered the use of X-ray tomography to study bread and cake structure during baking. He also carried out the initial research that led to the Branscan and Fluoroscan instruments for flour quality analysis.

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Online technologies provide food manufacturers with automated control of their processes, so that involves having some sort of sensor that can detect what the state of the process is or the condition of the product and the control system, and a means of actually taking action to keep the quality consistent. The benefit of this is a more automated process, consistent quality and consistent safety of product, and also the fact that you have records of that, you've got continuous monitoring, so you've got quality and safety assurance if something goes wrong. It also means you're alerted to it rapidly, you can respond to it and you minimise the amount of waste product that you produce.

This research project addresses the fact that, despite the benefits of being able to have online control, there are lots of properties of foods that we can't measure automatically and currently we have to take samples and take them to a lab or measure them at line. So, the purpose of the project is to identify what new sensors are available that perhaps could fill in a gap there and provide more consistent or complete online control. The types of technologies that we will be evaluating in the project include some of the things that are currently quite widespread in the food industry, so things like temperature sensors of which there are various types, pressure sensors, flow rate meters. We've written a review of those already that's available to members free of charge - you may be an expert in one particular type of technology but perhaps unaware of what other ones that exist.

We're looking at some newer technologies that are perhaps less familiar to the food industry. One of those that we've reviewed is electrical tomography and this is a non-contact or non-invasive system that uses electrodes mounted around, or even outside, a process vessel or a pipe and can measure the distribution of materials within based on their electrical conductivity or capacitance, so that helps you to tell, for example, whether a material is well mixed or whether particles are sedimenting out or floating to the top. It is very good at detecting bubbles, so one of the things we found is that it works quite nicely for monitoring the degree of aeration and could be used for online control of that. Another technology that we're planning to evaluate is a system for detecting foreign bodies in pumpable food materials, so liquids of a range of viscosities. Currently there are detectors such as x-ray or metal detectors that can detect some materials the technology. We're planning to look at claims to detect things like wood and plastic that are more difficult to detect with current technologies.

We very much welcome input from members on this, both letting me know if they have measurement needs - things that currently they have to take samples of and they can't measure automatically online, I'd love to know about that, also if there are technologies that they've become aware of and they think they might be relevant but they need information on what they are and how well they work, so suggestions for trials that we should be running of new technologies. I also welcome input in the trial that's coming up on the foreign body detection of offers of materials or suggestions for what products people would like us to be looking at - we plan to look at maybe four or five different categories of material,also what sort of foreign bodies we should be looking for in there. We've got a list in mind already but suggestions of things that members would like information on.

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