Science analyzes the interaction between coffee and milk in the cup; paying off

The interaction between coffee and milk that occurs in your morning cup of joe is the focus of a new study that explored these dynamics at the molecular level.

To understand this interaction, researchers at Aarhus University in Denmark used an innovative method called 2D infrared spectroscopy. This technology allows for more precise analyzes of molecular interactions, revealing details not visible to the naked eye.

This approach was essential to understanding the interaction between coffee and milk, according to a study published in May in the academic journal ACS Food Science Technology.

Image: American Chemical Society/Disclosure

The researchers observed the molecular interaction between milk proteins and caffeine in the water in a cup of coffee. The results showed that the structure of the milk proteins remained intact, meaning they maintained their original feel and flavour.

On the other hand, adding milk to coffee causes the milk proteins to react. In practice, they can bind to or flush out compounds extracted from roasted coffee beans, potentially changing how we sense and digest these proteins.

Furthermore, milk proteins can also affect the absorption (or bioavailability) of caffeine in the human body.

Advances in molecular biology

Therefore, the study aimed to uncover these mysteries. Using 2D infrared spectroscopy, researchers evaluated several categories of lattes. They used a mixture of 3.5% milk, coffee water and milk, then cappuccino.

The results showed that the folding of milk proteins – the process by which a protein assumes its functional conformation – was not changed by the interaction with coffee in these drinks. Even in cappuccino, which contains chlorogenic acid, the folding was the same.

The study also said that there were no significant effects of caffeine on the movement or dynamics of milk proteins. According to the researchers, the results could be a good molecular parameter for components that affect coffee’s flavour, texture and nutritional properties.