The Hershey Company and Brunswick Laboratories (Norton, MA) scientists have shown that it is possible to preserve almost 85 percent of cocoa flavanols while baking a cake.
The researchers said that a large number of cocoa flavanols could be preserved in recipes for chocolate frosting, hot cocoa drink, and chocolate cookies.
In chocolate cakes, using a combination of baking powder and baking soda could largely retain antioxidant activity and cocoa flavanols.
Initially, the scientists saw that 50 to 95 percent of the flavanols were lost in making chocolate cakes.
But after further investigation, they found that the use of baking soda in the chocolate cake recipe was associated with increased pH of the cake, darker color, and a loss of flavanols and antioxidant activity during the baking process.
Using only baking powder in the cake recipes allowed complete retention of the antioxidant activity and cocoa flavanols, but resulted in a flat cake.
But if baking powder was partially substituted for baking soda, the cake pH was moderated and almost all of the flavanols were retained while still resulting in a cake with acceptable colour and height.
The report suggested that numerous studies have reported on the fate of naturally occurring flavanols during cocoa bean fermentation and roasting, but there's been little investigation into what happens during cooking with cocoa powder.
In the study, the researchers selected recipes from cookbooks for a variety of cocoa-containing foods such as chocolate frosting, hot cocoa drinks, chocolate cookies and chocolate cakes.
The recipes were prepared using Hershey's Natural Cocoa Powder and then measured for antioxidant activity, total polyphenols, and flavanols.
"According to our estimates, approximately one third of cocoa ingredients used in the United States is cocoa powder, which is used in a diverse array of chocolate-flavored foods including beverages, cookies, cakes, snack bars and ice cream.
Natural cocoa powder, like most dark chocolates, is a concentrated source of naturally occurring flavanols and can be a significant dietary source of flavanols," said Dr. David Stuart, Director of the Hershey Center for Health and Nutrition.
This is the first study to highlight the effect of common cooking processes on cocoa flavanols in a wide variety of products ranging from a hot cocoa drink to chocolate frosting and chocolate cake.
The study showed that the choice of leavening agent and its effect on pH during baking is a key factor in the levels of antioxidant activity and flavanols in a baked product.
The study has been published this month in the Journal of Food Science.