Manipulating the temperature and the length of time under which cocoa beans are roasted can simultaneously preserve and even boost the potency of some bioactive and antioxidant compounds while protecting desired sensory aspects of chocolate, according to Penn State researchers.
That finding flies in the face of previous studies that indicate that roasting always results in a reduction in the polyphenol content in the beans. Cocoa polyphenols are believed to have a positive influence on human health, especially with regard to cardiovascular and inflammatory diseases, metabolic disorders and cancer prevention.
Chocolate, a food usually consumed for pleasure, in recent years has been reconsidered as a source of healthy compounds, noted lead researcher Joshua Lambert, associate professor of food science. The goal of the study, he explained, was to learn whether the roasting of cocoa beans could both preserve preferred flavor characteristics and boost health benefits.
Researchers investigated the impact of whole-bean roasting on the polyphenol content, aroma-related chemistry and pancreatic lipase inhibitory activity of cocoa under a range of roasting conditions. The inhibition of pancreatic lipase activity is a potential anti-obesity strategy.
Pancreatic lipase breaks down triglycerides into fatty acids, which then get absorbed through the lining of the small intestine. A pancreatic lipase inhibitor prevents the formation of fatty acids and therefore prevents absorption of dietary fats into the body.
In the study, total phenolics, epicatechin, and smaller proanthocyanidins were reduced by roasting at temperatures under 302 degrees Fahrenheit, Lambert pointed out. By contrast, roasting at 302 F or above increased the levels of catechin and larger proanthocyanidins, which have a greater ability to inhibit pancreas lipase.
Consistent with these changes, researchers found that cocoa roasted at 338 F better inhibited pancreatic lipase inhibitory activity than cocoa roasted at lower temperatures. Cocoa aroma-related compounds increased with roasting above 212 F, whereas deleterious sensory-related compounds formed at more severe temperatures, 338 F.
The research findings suggest that cocoa roasting can be optimized to increase the content of some polyphenols and boost anti-pancreas-lipase activity, while maintaining a favorable aroma profile, Lambert pointed out.
The findings of the research, which were recently published on-line in Food Chemistry, will be of interest to chocolate makers, Lambert believes, because of an increasing demand for chocolate products offering enhanced health benefits. He cited as an example Mars company's CocoaVia cocoa-extract supplement that promises to deliver 375 mg of cocoa flavanols antioxidants in each serving to promote good health.
Beyond cocoa and chocolate, going forward Lambert predicted that more attention will be focused on how processing can affect the health beneficial effects of food.