More Intense Roasting Of Cacao Beans Cuts Bitterness In Chocolate

Confection makers who want to develop products containing 100% chocolate and no sugar for health-conscious consumers can reduce bitterness and optimize flavor acceptance by roasting cocoa beans longer and at higher temperatures, ScienceDaily reported.

Photo Insert: Farmers ferment cacao beans to make chocolate.

That's the conclusion of a team of researchers who conducted a new study in Penn State's Sensory Evaluation Center in the Department of Food Science. The study involved 27 100%-chocolate preparations made from cocoa beans roasted at various intensities and 145 people who came to the center on five consecutive days, evaluating five different samples each day.

The research confirmed that bitterness and astringency are negatively correlated to consumer liking, and demonstrated that those qualities in chocolate can be reduced through optimizing roasting, according to Helene Hopfer, Rasmussen Career Development Professor in Food Science in the College of Agricultural Sciences. The study was published in the journal Current Research in Food Science.

"More and more people these days are eating darker chocolates with less sugar and more cacao because they are trying to cut down on sugar intake or they want to take advantage of perceived health benefits," she said.

"Dark chocolate is particularly high in flavonoids, particularly a subtype called flavan-3-ols and their oligomers, which are all considered functional ingredients due to their associated health effects."

However, unsweetened chocolate is too bitter for most people to enjoy, so researchers experimented with roasting treatments to modify the flavor -- investigating more than basic tastes such as sour and bitter -- making it more acceptable for consumers, Hopfer explained.

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. McClure chose cocoa beans from three origins -- Madagascar, Ghana, and Peru, harvested in 2018 and 2019.

He roasted and ground all samples into cocoa liquor at his factory in Columbia, Missouri, and then shipped the solidified 100% chocolate to Penn State, where he and Hopfer remelted and portioned out the chocolates into small discs for sensory evaluation. McClure found the reaction of study participants to his 27 100% chocolate preparations especially interesting.

The more intense roasting conditions -- such as 20 minutes at 340 degrees Fahrenheit, 80 min at 275 F, and 54 min at 304 F -- all led to chocolate consumers finding unsweetened chocolate the most acceptable. Conversely, research participants did not find 100% chocolate acceptable when made from raw or lightly roasted cacao, such as beans roasted 11 minutes at 221 F, or 55 minutes at 147 F.

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