There has been increased interest in the levels of flavanols in foods in recent years due to the possible cardiovascular health benefits associated with their antioxidant activity.
Flavanol levels found in cocoa and chocolate are among the highest dietary sources of these compounds so shelf life stability is of great interest.
Researchers based at the Hershey Centre for Health and Nutrition published their findings in the Journal of Agriculture and Food Chemistry and they claim their study was prompted by the fact that recent studies have questioned the stability of these components.
“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.
These reports have gained attention in both the popular and food nutrition press because of the widespread consumer interest in natural antioxidants, especially the polyphenols, which are potential contributors to human health and might be lost during the storage of food or beverages,” state the authors.
The Hershey scientists explained that in order to analyse the shelf-life stability of cocoa products including milk and dark chocolate, cocoa powder and beans, the products were stored for one year under conditions designed to replicate retail storage at temperatures ranging from 18 to 24 °C.
And they said that they measured the antioxidant activity, total polyphenols, flavan-3-ols monomers, and procyanidin levels in all the products at successive intervals.
Results showed 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 two 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,” claimed the team.
They added that all chocolates and cocoa powders used in the studies were commercially available products from The Hershey Company.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print: DOI: 10.1021/jf901457s
Title: Stability of Cocoa Antioxidants and Flavan-3-ols over Time
Authors: W. J Hurst, M J. Payne, K B. Miller, D. A. Stuart