The naked microscope
Working with inventor Sunney Xie at Harvard University, Unilever scientists utilised state-of-the-art microscopy to further our understanding of the effects of cosmetics on skin and the distribution of fats and proteins in food
The forerunners of SRS either took hours to collect enough data, interpreting the results was hampered by background noise or the lasers were so strong that the sample was damaged. Traditionally ‘tagging’ is used to overcome these problems, but the tag itself can interfere with the results. SRS allows us to study delicate biological samples quickly and easily, and look at the molecule in its naked state.
Soya drinks & mayonnaise
To a large extent the microstructure of food determines its appearance, texture, taste and handling properties. And emulsions are major structure and structure-forming units within many foods. So taking several of our products as study samples, scientists from our R&D centres in Trumbull and Vlaardingen joined Sunney when he was in the final stage of perfecting the technique.
We used SRS to explore the distribution of lipids, protein and water in Adez™ soya drink, with the results featuring in a Nature special entitled ‘Microscopy Marvels’. We also studied mayonnaise which is an oil in water emulsion made primarily from vegetable oil and egg yolk.
This new 3D non-invasive imaging has advantages over previous methods as it offers background-free, purely chemical contrast. SRS has proven to be very useful for the imaging of low fat emulsions. However, for high fat emulsions the imaging is hampered by strongly overlapping lipid bonds.
Currently the Xie group is further optimising the SRS system and investigating its applicability to other foods such as fat spreads. As Marjolein van Ruijven of Unilever R&D says, “I felt privileged that I could use such leading-edge technology at Harvard University. And when we could image our samples without any labelling, we were even more excited. It is amazing to be present at the birth of a new technique.”
Reference: Microscopic Marvels. Nature 2009, 459, 636 - 637