Stability of cocoa antioxidants and flavan-3-ols over time.

Several recent reports have been published indicating that the antioxidant activity of olive oil and tea leaves is not stable over product shelf lives of about one year. We have measured the antioxidant activity, total polyphenols, flavan-3-ols monomers, and procyanidin levels in milk and dark chocolate, in cocoa powder, and in cocoa beans. Results show that for the cocoa products studied, antioxidant activity, and flavan-3-ol levels are stable over typical shelf lives of one year under controlled storage and over 2 years in ambient storage in the laboratory. We also show that 80 year old cocoa powder and 116 year old cocoa beans still show very high levels of antioxidant activity and flavan-3-ol content.