Customer: Charles Clifford, Zeinab Al-Rekabi & Suzanne L. Davies, National Physical Laboratory, UK
Highlighted publication: Nanomechanical properties of potato flakes using atomic force microscopy, Charles Clifford et al. (2021) Journal of Food Engineering 307 110646
Instrument: Asylum Cypher S
Probes: SCOUT 350 RAl
Imaging modes: Tapping, Contact
Keywords: Food Industry, AFM, Atomic Force Microscopy, AFM Probes, Microscopy, Quality Assessment, Quality, Quantitative, Manufacturing, Characterisation
Potato flakes are a key base ingredient in many processed foods and snacks, and offer a longer-life alternative to raw potatoes. Flakes are industrially manufactured through a carefully controlled process where raw potatoes are selected by their suitability based on size, variety, reducing sugar, starch, and water content.
The quality of potato flakes can cause problems in the manufacturing process, for example in the production of crisps. Large blisters can form on the surface of the chip post-frying, causing issues during production and on final product quality.
The National Physics Laboratory (NPL) was tasked with identifying whether AFM screening of potato flakes at the point of selection could distinguish between flakes that would perform well right the way through to the finished product. This is something current quality checks are unable to do conclusively.
In the study, NPL used an Asylum Research Cypher S AFM and NuNano SCOUT 350 RAl probes to investigate the nanomechanical properties of four different types of low-leach potato flake samples provided by two suppliers from the initial screening process to determine suitability for snack manufacture.
By applying tapping mode to examine the topographies (Fig 1 of paper) of sub-optimal and optimal potato flake samples and force-volume mode to generate maps of force-displacement curves of the same samples, the study was able to show that there was a quantitative difference between the optimal and sub-optimal potato flakes.
The optimal samples had more granule-like structures than the sub-optimal ones (Fig 2 in original paper) and the optimal potato granule samples appeared stiffer (shown by the orange and yellow areas Fig 3. A and B) compared to the sub-optimal samples which appeared more compliant (as seen by the brown and red regions Fig 3C and D).
Conclusions
By employing both amplitude-modulation and force-modulation AFM, NPL demonstrated that sub-optimal potato starch flakes appeared more compliant than the optimal samples.
These results offer a compelling rationale for future experimentation to aid food industries in adopting quantitative AFM measurements to provide food industries with a differential assessment between different food samples.
Other publications using NuNano probes and Asylum Research instruments:
Characterizing the nanomechanical properties of microcomedones after treatment with sodium salicylate ex vivo using atomic force microscopy Al-Rekabi, Z., Rawlings, A. V., Lucas, R. A., Raj, N., & Clifford, C. A. (2021) International Journal of Cosmetic Science 43(5), 610-618. https://doi.org/10.1111/ics.12729