The Mighty Purple Cabbage

Purple cabbage is well known by people because of its attractive colour possessed. Most often it is pickled, raw shredded red cabbage also makes a striking addition to traditional green salads. (Peggy Trowbridge Filippone, 2006)



The purple color in red cabbage comes from a class of pigment molecules called anthocyanins. It turns out that anthocyanins are found in flower petals, leaves (it makes them turn red in the fall!) and some fruits such as blueberries. Anthocyanins are plant pigments known as flavenoids and produce red, pink, violet and magenta colors in the various plant parts. ("Where does the color come from in purple cabbage?.", 2000)

The anthocyanidin group controls the color of the pigment. The electrons of the ring structures interact with incoming light and absorb various frequencies. The molecule shown below appears purplish red because its electrons absorb the yellow, green and blue portions of the visible spectrum. ("Where does the color come from in purple cabbage?.", 2000)

One of the things that changes the color on anthocyanins is the level of acid or alkali (i.e., pH) around the molecule. Because the color of the anthocyanin is affected by the pH of the environment, these molecules can tell you the pH of any substance. If you make an extract of red cabbage juice, it will change color when mixed with solutions of various pH. The anthocyanin turns bright pink in acids, reddish-purple in neutral solutions and green in alkaline or basic solutions. ("Where does the color come from in purple cabbage?.", 2000)

The Molecule



Here is the generalized structure for a purplish red anthocyanin molecule. Chemically, anthocyanins are made of a sugar molecule attached to a nonsugar part called anthocyanidin. This anthocyanidin has three rings, two 6-carbon (i.e. benzene) rings linked to another ring containing five carbons and one oxygen. The various anthocyanins differ from one another with respect to (1) the number and type of chemical groups, either hydroxyl groups (OH) or methoxy (OCH3) groups attached to the rings of the anthocyanidin and (2) to the sugar that forms the glycoside linkage (i.e. the bond between the sugar and the anthocyanidin. ("Where does the color come from in purple cabbage?.", 2000)

Benefits of Purple Cabbage

Therapeutic value As inexpensive as cabbage is, it is one of the richest when it comes to protective vitamins. Raw cabbage cleans the waste from the stomach and upper bowels, which improves digestion and reduces constipation. Hailed as a cancer inhibitor, particularly colon cancer, cabbage also stimulates the immune system, kills harmful bacteria, soothes ulcers, and improves circulation. The outer leaves are a good source of vitamin E, making it good for the complexion. Also rich in vitamin C, raw cabbage juice can be mixed with a milder juice, such as celery or tomato. Cabbage is alkaline in reaction, high in cellulose or roughage, and has a very low calorie count. Besides containing many minerals, cabbage is rich in calcium and potassium, and contains chlorine, iodine, phosphorous, sodium, and sulphur. Raw cabbage offers a fair amount of vitamin A and vitamin B. Red cabbage has more calcium, but slightly less of the other minerals than white and green cabbage. Red and white cabbage contain nearly the same vitamins and minerals and are used the same therapeutically. All these benefits are yours at only 24 calories per 3.5 ounces. (Peggy Trowbridge Filippone, 2006)