Non-invasive measurements of the dry solids content of whole potatoes using unilateral magnetic resonance: towards automation

Crisps or chips are considered a popular snack food around the world and at their most fundamental are potatoes which are sliced and then fried. It has been known for some time that during their production industrially, controlling the final oil content requires prior knowledge of the dry solids of the potatoes to modify the temperature and frying time to give the best product. The dry weight of a batch of potatoes is most commonly performed using a buoyancy measurement. In preliminary experiments, we have found evidence that such a measurement, whilst representative of the average dry solids, does not offer the most appropriate measurement since the variation within the batch is significant. We present an investigation into the properties of intact potatoes using magnetic resonance relaxation measurements and relate these to the dry solids content. This preliminary study will lay the groundwork for the development of an online process monitoring device based around a unilateral sensor to allow batch sorting of incoming potatoes.