Anthocyanins turn reddish in acid and bluish in alkali, so red cabbage juice can be used to test acidity.
Tips
usage
花 'flower' + 青 'blue' + 素 'pigment'. It gives the purple, red and blue of 紫米, 紫甘蓝, 蓝莓 and grape skins, and food labels like to say 富含花青素 (rich in anthocyanins).
