Studying functionality of proteins using confocal Raman microscopy

Abstract: New plant-based ingredients are being developed to facilitate the transition to a more sustainable food system. However, their ability to develop structures and provide functionality are not well understood. Even more importantly, there is a limited knowledge on how to study their structural arrangement within complex food matrixes, with are often characterized by a high degree of structural heterogeneities.
Unlike traditional confocal laser scanning microscopy, which requires specific dies to distinguish different components, confocal Raman microscopy rely on spectral information. This is therefore a promising technique for studying plant protein structures at the microscale, as it allows for analyzing structural arrangement and rearrangement, with minimal disruption to the sample. The dependency of Raman spectra on the molecular structure allows for identification of different classes of molecules and their structures and map the distribution within the specimen.
In this talk, we will demonstrate how, using confocal Raman microscopy, it is possible to observe in situ structural information as impacted by formulation and processing factors. With confocal Raman Microscopy, protein spectra obtained by point, line or area scans, and evaluated, can provide localized structural information, knowledge on distribution and parameters such as protein hydration level. Due to the unique chemical fingerprinting, it is possible to distinguish between multiple components within complex matrices, including different protein sources, lipid composition and structuring or starch and complex carbohydrates. This work will also highlight some important steps which are critical during confocal Raman microscopy to ensure sound data analysis and interpretation, advocating for transparency of data manipulation.
Bright-field microscopy, polarized light microscopy, confocal laser scanning microscopy and confocal Raman microscopy are complementary techniques. It is illustrated how the combination of these can lead to new knowledge on how to fine tune processing of alternative proteins for improved functionality.