By roasting cocoa beans longer and at higher temperatures, confectioners can eliminate bitterness and improve flavor acceptance in products containing 100 percent chocolate and no sugar for health-conscious consumers.
A group of experts from Penn State’s Sensory Evaluation Center in the Department of Food Science came to this conclusion after conducting a new investigation.
The study included 27 100 percent chocolate concoctions created from cocoa beans roasted at varying intensities, as well as 145 participants who came to the center for five days in a row to evaluate five different samples.
According to Helene Hopfer, Rasmussen Career Development Professor in Food Science in the College of Agricultural Sciences, “the research confirmed that bitterness and astringency are negatively correlated with consumer liking and demonstrated that those qualities in chocolate can be reduced through optimizing roasting.”
“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.”
Our research was intended to learn about bitterness perception and the liking of chocolate made from cacao roasted with a variety of roasting profiles to see if wide consumer acceptability of 100% chocolate is possible.Helene Hopfer
Unsweetened chocolate, on the other hand, is too bitter for most people to enjoy, so researchers experimented with roasting techniques to change the flavor, looking beyond basic flavors like sour and bitter to make it more consumer-friendly, according to Hopfer.
To define the flavor and acceptability of the chocolates, research team member Alan McClure, creator of handmade chocolate brand Patric Chocolate and related consultancy Patric Food & Beverage Development, collaborated with Hopfer and Penn State.
McClure chose cocoa beans harvested in 2018 and 2019 from three origins: Madagascar, Ghana, and Peru, as part of his doctoral dissertation research. At his facility in Columbia, Missouri, he roasted and crushed all samples into cocoa liquor, then delivered the solidified 100 percent chocolate to Penn State, where he and Hopfer remelted and portioned the chocolates into little discs for sensory evaluation.
McClure found the reactions of study participants to his 27 100% chocolate preparations particularly fascinating, and he suggested that what he learned from this research will help him, as well as roasting staff at other chocolate manufacturing companies, create future products by improving scientific understanding of the complex changes that occur during cocoa roasting.
The researchers revealed in Current Research in Food Science that more intensive roasting conditions, such as 20 minutes at 340 degrees Fahrenheit, 80 minutes at 275 degrees Fahrenheit, and 54 minutes at 304 degrees Fahrenheit, all led to chocolate consumers preferring unsweetened chocolate.
However, when produced from raw or lightly roasted cacao beans, such as those roasted 11 minutes at 221 F or 55 minutes at 147 F, test participants did not find 100 percent chocolate satisfactory.
Scientists’ understanding of the variance in cacao-related bitterness has traditionally derived from instrumental exploration of the bitter chemicals found in cocoa beans, according to Hopfer, but the Penn State study is unique in that it uses human sensory judgment to quantify such variation.
“Our research was intended to learn about bitterness perception and the liking of chocolate made from cacao roasted with a variety of roasting profiles to see if wide consumer acceptability of 100% chocolate is possible,” she said.
“A chocolate maker doesn’t have many other options to influence the flavor quality of 100% chocolate except to vary how he or she roasts the beans, and our results show optimal roasting can adequately reduce bitterness.”
Ingolf Gruen, an associate professor in the University of Missouri’s Department of Food Science, contributed to the study.
The Professional Manufacturing Confectioners Association and the National Institute of Food and Agriculture of the United States Department of Agriculture funded this research.