Phenolic compounds in natural and roasted nuts and their skins: a brief review

- Nuts and their skins have a wide variety of phenolic compounds.
- Nuts skins exhibit strong antioxidant activity and have high total phenolic contents.
- Processes, especially roasting, either increase or decrease the phenolic content.
- Nut skins could be reevaluated as a cheap source of phenolic compounds.

Almond, Brazil nut, cashew, hazelnut, macadamia nut, pecan, pine nut, pistachio, and walnut are widely consumed nuts in the world. They could be consumed either natural or after being processed. The health benefits of natural (raw) nuts are attributed to the phenolic profiles, total phenolic contents and antioxidant activities of both kernels and mostly their skins. Processes, especially roasting, cause changes in the content of phenolic compounds and antioxidant activity as well as removal of skin. As a phenolic compound-dense part of nuts, skins are being started to be suggested for reevaluation in industries such as food, pharmaceuticals and cosmetics.