The amount of protein in complex matrices such as food products is an important characteristic, at both a nutritional and a pedagogical level. There are several methods available for protein quantification, from simple UV absorption to mass spectrometry. The most common are based on the interaction of the proteins with colored compounds followed by colorimetric quantification. This work uses an approach in which the protein is first partially purified by precipitation, followed by interaction with Amido Black and colorimetric quantification. This allows the quantification of protein content in several food matrices of increasing complexity. The method used is visually very appealing, raising the interest of students from early ages. On the other hand, the interpretation of the results obtained in the different steps involved is an interesting challenge for higher level students.