| MadSci Network: Botany |
Anthocyanins are in plant vacuoles not in plastids such as chromoplasts. Chromoplasts contain pigments such as carotenoids and xanthophylls. Some authorities consider green chloroplasts to be a type of chromoplast while others do not. For teaching uses, anthocyanins are usually extracted using hot water, as from red or purple cabbage. Meyer et al. (1955) suggests making very thin slices of 25 grams of red cabbage tissue and placing it in 100 ml of distilled water, which is heated to 80 degrees C. The anthocyanin extract makes a good pH indicator. Witham et al. (1971) has an exercise where flower anthocyanins are separated using paper chromatography and thin-layer chromatography. What fruit peels did you extract? Some fruits, such as orange, tomato and red pepper, and the carrot root get their color from cartenoids rather than anthocyanins. What is your purpose for wanting to isolate anthocyanins? If you want to purify the anthocyanins for food use, you may want to consult the food science literature as in the two websites cited. You can do a search on the Mad Scientist site and find answers to several other questions about anthocyanins. References Meyer, B.S. et al. 1955. Laboratory Plant Physiology. Van Nostrand Reinhold: New York. Witham, F.H. 1971. Experiments in Plant Physiology. Van Nostrand Reinhold: New York. Characterization and Measurement of Anthocyanins by UV-Visible Spectroscopy Unnaturally red cherries -- naturally
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