Flavour is an essential attribute of food: it determines both liking and intake. Excellent flavour can also steer consumers towards more healthy and sustainable food choices. The food industry recognizes this as an opportunity and is developing foods with less calories and salt, less animal protein, and communicates messages of environmental sustainability. It seeks for solutions by implementing natural plant or yeast derived ingredients, but a downside of many natural ingredients is that they tend to carry off flavours that potentially limit their application and lower their value.
Aim of this project is to develop a tongue- and nose-on-a-chip that uses the human sensory receptors expressed in a human cell line. The basic prototype platform for this (www.receptomics.com) was developed by Wageningen Plant Research in an earlier project, but was limited to taste receptors and had difficulty with the analysis of undiluted food samples due to strong sample fluorescence and nonspecific cell responses. Yet, especially in flavour analysis it is essential to study effects at their natural concentration and in the original product matrix. A solution to these challenges can be found by converting the current receptomics platform from a fluorescence readout to a bioluminescent readout. In a bioluminescent readout the probes which target calcium or cAMP messenger molecules, enzymatically generate light as a reporter of concentration. This makes the system largely independent of sample fluorescence from the matrix. In addition, there are now split-luciferase probes that produce light only when a receptor is activated and attracts a G protein. Such probes exclusively monitor the bimolecular interaction with the G protein by the receptor of interest when activated by a ligand. This makes the signal independent of non-specific cell responses and robust for applications in the food matrix. To work well the platform does need a much more sensitive camera to detect the light emitted by the bioluminescent probes, and the software will need to be updated to handle the new readout.
The results will allow the industry to improve the flavour of natural products, and lead to more sustainable production and processing methods. A switch to a bioluminescent readout of receptor cell arrays, furthermore, promises to make this receptomics technology widely available at low costs. The measurement of food quality will become affordable to many academic and industrial labs and lead to a more rapid food innovation.