A team of UNSW food scientists has shown that enzymatic cross-linking between pea and whey proteins enhances their emulsifying and encapsulation properties, providing a new way to design plant-dairy protein networks to protect lipophilic bioactive compounds.
The researchers – Woojeong Kim, Yong Wang, Qianyu Ye and Prof. Cordelia Selomulya, all from UNSW Sydney’s School of Chemical Engineering, and Yin Yao from UNSW Sydney’s Electron Microscope Unit – were exploring new ways to improve the functionality of commercial plant proteins essential for food application. They developed an alternative strategy for modifying the structure of pea protein: using microbial transglutaminase-induced cross-linking with whey protein to enhance its emulsifying and encapsulation properties.
‘The protein structures and the physicochemical stability of β-carotene-loaded emulsions were investigated subject to protein ratio and cross-linking,’ the paper’s authors explain. ‘Formation of disulphide and isopeptide bonds between heteroproteins according to cross-linking changed protein structures by exposing the hydrophobic sites of proteins with stiffer network[s]. ‘
The team found that at a protein ratio of 2:1, the cross-linked pea-whey protein complexes formed a stable emulsion, with a droplet size of 0.10 µm, that showed no phase separation even after 30 days of storage. The cross-linked pea-whey protein also had an impressive encapsulation efficiency of 92%.
The research provides a novel strategy by which to design plant-dairy protein networks to protect lipophilic bioactive compounds. Replacing half or more dairy protein with plant protein, they note, could also help bring about gradual change towards sustainable plant-based diets.
The team’s findings will be published in the May 2023 edition of Food and Bioproducts Processing (Volume 139, Pages 204-215)
Download the article ‘Enzymatic cross-linking of pea and whey proteins to enhance emulsifying and encapsulation properties’ until 9 June 2023.
Lead image: Whey protein. Credit: Shutterstock