Citric acid is a weak organic acid that occurs naturally in produce, such as citrus fruits. It is used in food, cosmetics, and cleaning products. Share on Pinterest vkbhat/Getty Images Citric acid is ...

Caffeic acid (3,4-dihydroxy-cinnamic acid) is an organic compound and a potent antioxidant. It can be found naturally in a wide range of plants. Caffeic acid is a type of polyphenol, a class of ...