ruskistuva
Ruskistuva is a Finnish term that generally refers to the process of browning or toasting food. It describes the Maillard reaction, a complex chemical process that occurs when amino acids and reducing sugars are heated, resulting in a desirable brown color and flavor development in many foods. This reaction is fundamental to cooking and is responsible for the characteristic taste and aroma of baked bread crusts, seared meats, roasted coffee beans, and toasted nuts.
The term can also be used more broadly to describe a state of becoming brown or tanned.