Posted: December 2, 2022

More intense roasting of cocoa beans lessens bitterness, boosts chocolate liking.

While roasting coffee beans longer yields a more bitter cup of joe, researchers in the college found that roasting cocoa beans longer and at higher temperatures reduces bitterness and improves consumer liking of 100 percent chocolate. The finding may be useful for confection makers who want to develop no-sugar products for health-conscious consumers.

The research, conducted in Penn State's Sensory Evaluation Center in the Department of Food Science, involved 27 100-percent chocolate preparations made from cocoa beans roasted at various intensities. Participants evaluated five different samples each day for five consecutive days.

The research confirmed that bitterness is negatively correlated to consumer liking and demonstrated that the quality in chocolate can be improved through optimizing roasting, according to research team member Helene Hopfer, Rasmussen Career Development Professor in Food Science in the College of Agricultural Sciences.

For the study, research team member Alan mcclure, founder of craft chocolate company Patric Chocolate and related consultancy Patric Food & Beverage Development, partnered with Hopfer and Penn State to characterize the flavor and acceptability of the chocolates.

In findings recently published in Current Research in Food Science, the researchers reported that more intense roasting conditions led to chocolate consumers finding unsweetened chocolate the most acceptable. Conversely, research participants did not find 100 percent chocolate acceptable when made from raw or lightly roasted cacao.

High-pressure jet technology could eliminate need for additive.

Fat-free chocolate milk processed with high-pressure jet technology could eliminate the need for carrageenan, a controversial emulsifier, according to researchers in the college. The widely used food additive--which helps keep the liquid smooth and well-mixed even after days sitting on a store shelf--is not desired by many consumers, especially in organic chocolate milk.

The team, led by Federico Harte, professor of food sciences, demonstrated that the use of high-pressure jet technology to cocoa provides the industry with a processing alternative to produce clean label, yet stable, low-fat chocolate milk. Penn State has applied for a provisional patent on the process and is working with a dairy food manufacturer to develop and scale it up.

In findings published in the Journal of Dairy Science, the researchers reported that formulations with the addition of 4 percent "micellar casein"--a kind of milk protein--processed at 500 megapascals showed no phase separation over a 14-day storage period, stored at 39 degrees Fahrenheit. The addition of milk protein together with high-pressure jet processing at 500 megapascals resulted in a higher apparent viscosity that keeps cocoa particles suspended.

"We believe that structural changes in casein micelles and new casein-cocoa interactions induced by high-pressure jet processing increased cocoa stability in the chocolate milk," Harte said.

--Jeff Mulhollem