Using a technique called multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy to image the digestion of fat droplets containing ingredients like vitamin D3, researchers noted that the concentration of D3 increased as digestion continued, showing that the bioactive remained confined within the shrinking drop.
Researchers from Unilever R&D Vlaardingen (The Netherlands) and the FOM Institute for Atomic and Molecular Physics in Amsterdam report their findings in the Journal of the American Chemical Society.
Dr Krassimir Velikov from Unilever R&D Vlaardingen (The Netherlands) and co-author of the study, told NutraIngredients that this is the first report using CARS for the “investigation of the physico-chemical processes during digestion of lipid and lipid-soluble bioactive molecules, like, for example, vitamins, nutraceuticals and drugs”.
“The knowledge generated from this development is very important for both understanding the mechanism of action and improving formulation technology for foods in general,” he added.
Led by the FOM’s Professor Mischa Bonn, the researchers examined the digestion of various model lipid systems using the CARS technique – a chemically specific form of microscopy in which different levels of molecular vibrations are used to produce contrast in an image. The technique allowed Prof Bonn and his co-workers to discriminate between the undigested fat – which showed up as red in the image – and digestion products – which showed up green.
Taking the technique further, the scientists included bioactive compounds, including the female hormone progesterone and vitamin D3 into fat droplets.
The results showed that the concentration of the bioactive increased as the fat droplet was digested, which showed that the ingredient remained within the shrinking fat droplet.
Commenting on the next phase of the research, the researchers said they would continue to build an understanding on how to control the composition and size of the lipid droplets formed inside cells after absorption of digestion products.
Commenting on the practicality of the technique, Dr Velikov explained that the technique is as fast as the digestion process which is being observed. “The techniques however delivers knowledge which needs to be creatively translated by R&D in to product compositions and microstructures that also take into account other product functionality aspects such as appearance, texture, taste and stability,” he added.
“This technique is one of the several techniques which help us to study and understand the complex digestion process in vitro. We believe that understanding and monitoring the digestion using in vitro models can be a cost-effective method for evaluation of early product design and development,” said Dr Velikov.
Source: Journal of the American Chemical Society
Volume 132, Issue 24, Pages 8433–8439, doi: 10.1021/ja102069d
“Label-Free Imaging of Lipophilic Bioactive Molecules during Lipid Digestion by Multiplex Coherent Anti-Stokes Raman Scattering Microspectroscopy”
Authors: J.P.R. Day, G. Rago, K.F. Domke, K.P. Velikov, M. Bonn