Preheated (80 °C for 9 min) whey protein isolate (HWPI) was reacted with 20, 120, and 240 μmol/g (protein basis) gallic acid (GA) or epigallocatechin gallate (EGCG) at neutral pH and 25 °C. Isothermal titration calorimetry and fluorometry showed a similar trend that GA binding to HWPI was moderate but weaker than EGCG binding. However, the shift of maximal fluorescence emission wavelength in opposite directions in response to GA (blue) and EGCG (red) suggests discrepant binding patterns. Electrophoresis results showed that EGCG induced formation of HWPI complexes while GA only had a marginal effect. Both free and phenolic-bound HWPI exhibited mild antiradical activity. However, when subjected to in vitro digestion, synergistic radical-scavenging activity was produced between the phenolics and peptides with the highest synergism being observed on 120 μmol/g phenolics.
|Number of pages||8|
|Journal||Journal of Agricultural and Food Chemistry|
|State||Published - Sep 27 2017|
Bibliographical noteFunding Information:
Article number 17-07-059 approved for publication by the Director of the Kentucky Agricultural Experiment Station. This research was supported by the USDA National Institute of Food and Agriculture (Hatch Project 1005724) and an Oversea Study Fellowship from the China Scholarship Council (to Y.C.). Notes The authors declare no competing financial interest.
© 2017 American Chemical Society.
- heat-unfolded whey protein isolate
- in vitro digestion
- phenolic derivative
- synergistic radical scavenging activity
ASJC Scopus subject areas
- Chemistry (all)
- Agricultural and Biological Sciences (all)