The Power of Tea Compounds: How They Alter Milk Proteins

Scientists explored how different types of tea compounds, called catechins, affect the physical and chemical properties of milk proteins, known as caseins. They found that catechins with added groups (esterified) attached more strongly to caseins than those without. This binding changed the structure of caseins in significant ways. Using special light measurements and temperature analyses, they discovered that the way catechins "turn off" the light emitted by caseins is similar across different catechins. The energy needed to bind these compounds to caseins was found to be negative, showing that binding happens naturally.The strength of the bonds varied, with some catechins binding much more strongly to casein α than β. Computer models and light analyses showed that bonds like hydrogen, van der Waals, and hydrophobic forces played a big role, with hydrogen bonds being the most important. The number of hydroxyl groups and the presence of a special group called galloyl greatly influenced how well catechins could bind to casein.