Aug. 14, 2009 (United Press International) -- The choice of leavening agent is a key factor in the levels of cocoa anti-oxidant activity and flavanols in a baked product, U.S. researchers said.

Scientists at The Hershey Co. (NYSE:HSY) and Brunswick Laboratories in Norton, Mass., found more than 85 percent of cocoa flavanols were preserved in recipes for chocolate frosting, hot cocoa drink and chocolate cookies.

The scientists initially saw that 50 percent to 95 percent of the flavanols were lost in making chocolate cakes. 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 anti-oxidant activity during the baking process.

The study, published in the Journal of Food Science, found use of only baking powder in the cake recipes allowed complete retention of the anti-oxidant activity and cocoa flavanols, but the cake was flat. However, by partially substituting baking powder for the baking soda, the cake pH was moderated and almost all of the flavanols were retained while still resulting in a cake with acceptable color and height, the study said.