Polyphenol-Protein Reactions and their Applications in Food Technology
Summary
Phenolic compounds are typically removed from plant protein extracts due to their interaction with proteins, which can lead to undesirable sensory and techno-functional changes. However, with the growing trend toward using less refined plant protein ingredients to minimize protein loss and reduce energy-intensive processing steps, it is important to explore whether phenolic compounds can be harnessed to modulate protein functionality.
Research on model milk proteins as well as on plant protein sources such as sunflower, rapeseed, and pea suggests that phenolic compounds have a dose-dependent effect on protein properties, influencing solubility, folding, and cross-linking with other proteins depending on the protein-to-phenolic ratio. Furthermore, the impact of these compounds on protein functionality is strongly influenced by both the type of phenolic compounds (e.g., small phenolic acids versus larger tannic acids, with varying numbers of aromatic rings and hydroxyl groups) and pH, leading to either no interactions or primarily covalent or non-covalent interactions with proteins. However, predicting whether these modifications enhance or inhibit gelation or emulsion formation of the protein remains challenging, especially in complex plant protein ingredients where multiple proteins and phenolic compounds coexist.
The presentation will provide examples of how phenolic compounds can affect gelation and emulsion formation in plant proteins, and will outline further steps toward utilizing phenolic compounds for food applications. Research into protein-phenolic interactions could open new avenues for processing protein ingredients focused on functionality rather than purity.
About Dr. Julia Keppler
Julia Keppler studied Food Science at Kiel University in Germany where she also received her PhD, and was a visiting post doc at INRAe in France afterwards. She has more than 11 years of experience after acquiring her PhD in the field of food protein functionality. She started her research group in the Food Process Engineering lab at Wageningen University, the Netherlands 6 years ago with the focus on modulating the structure and functionality of food protein ingredients during processing. A key area of interest is the interactions between proteins, as well as between proteins and other food matrix components, such as phenolic compounds, and how these interactions influence food structure formation.
In that context, her group explores new food protein sources that range from plant-, single cell -, mussel-proteins, to (dairy) proteins obtained through precision fermentation. Their work delves into the intricate relationship between protein structure and function, particularly how processing techniques and interactions with other components impact these properties.
The overarching aim is to identify and create sustainable and functional ingredients for the future.
