Healthy Fruit Skin

Chemists have uncovered another reason to leave the skin on your apple or pear when you eat it. Some varieties of the fruits contain more anti-inflammatory and anticancer compounds than previously thought. Christelle M. André and William A. Laing of the Mount Albert Research Centre, in Auckland, New Zealand, and their colleagues discovered three triterpene caffeates in some heirloom varieties of apples and pears (J. Agric. Food Chem., DOI: 10.1021/jf305190e). Members of this class of compounds, some of which are being studied for their medicinal properties, have been found in tree bark and inedible leaves before, but never in foods. Using LC/MS and NMR methods, the researchers detected betulinic acid-3-trans-caffeate and two sister compounds. The triterpene caffeates appear to be unique to varieties of fruit with rough skin, such as the Merton Russet apple. They aren’t present in waxy-skinned apple varieties such as Royal Gala. The group showed that these compounds exhibit anti-inflammatory properties and stimulate immune responses in cell cultures. “These results reinforce the importance of conserving old heritage apple varieties or pears as potential sources of previously unrecognized health-promoting compounds,” the researchers note.