Grapes, and their processed products such as juices and preserves, contain considerable amounts of chemicals generally referred to as phenolic compounds. These phenolic compounds are primarily characterized structurally as flavonoid (which includes the fruit skin pigments known as anthocyanins), hydroxycinnamate, stilbene, and hydroxybenzoate derivatives, having at least one moiety of phenol that they each share in common. Phenolic compounds have been identified as being an important source of nutrition in the human diet, reported in the scientific literature to have antioxidant attributes that delay or inhibit cardiovascular deterioration, cancer, and aging. This Classroom Activity employs a colorimetric visualization test that allows a student to simply and rapidly screen grape juice for phenolic content from fresh, bottled, or frozen concentrate samples. Students also use the visualization test to examine whether they can detect differences in phenolic content of juice samples based on different variety, or processing, of grapes. The Activity can pedagogically and safely be used in the field, vineyard, classroom, or lab.
More Information
Citation
Sady, Michael B. J. Chem. Educ.2005 82 1808A.
Keywords
Food Science; Hands-On Learning / Manipulatives; High School / Introductory Chemistry; Laboratory Instruction; Natural Products; Phenols; Plant Chemistry
The "Chemistry Teacher Connection" (CTC) is especially for high school chemistry teachers. For only $40/year, it offers an online-only subscription to CLIC along with membership in the Division of Chemical Education, normally $65/year. CTC subscribers receive access to all articles and supplements from 1996 through the current issue.
Through special arrangement with the ACS, JCE High School CLIC is now able to provide subscribers with online access to Chemical & Engineering News articles that have been selected specifically for secondary science instructors and their students.
Occasionally, collections of JCE back issues become available for donation to individual teachers, schools, or libraries. JCE matches collections with interested recipients. Recipients pay shipping costs or pick up the collection.
For journals in other fields of chemistry visit ACS Publications.
Citation
Always in the