In this Activity, students use a colorimetric visualization test to screen grape juice for phenolic content. Students use the test to examine differences in phenolic content of juices prepared with different processing methods. Most of the materials are readily available at the supermarket. The Activity could be adapted for use with other fruit juices and might be included in a biology or nutrition class. This Activity could be further extended with a trip to a farm or vineyard for analysis of ripe grapes.
Michael B. Sady, J. Chem Educ. 2005, 82, p1808A.