However, unsweetened chocolate is too bitter for most people, so researchers experimented with roasting treatments to modify the flavour to make it more acceptable for consumers.

In the study conducted at Penn State’s Sensory Evaluation Center, 27 100%-chocolate preparations were made from cocoa beans roasted at various intensities. According to the results, bitterness and astringency are negatively correlated to consumer liking, and demonstrated that those qualities in chocolate can be reduced through optimizing roasting – with longer roasting at higher temperatures, 100% chocolate with no added sugar and acceptable taste could be produced.

However, during roasting, besides aromatic and flavour compounds, hazardous chemicals such as acrylamide, acrolein and PAHs are also formed. With optimized processes, the amount of these compounds can be kept as low as reasonably possible, however, the new study and the trends of home-roasting focuses on the taste of the product and consumer acceptance and encourages roasting at higher temperatures and longer time intervals that might pose an elevated risk of acrylamide intake to the consumers.

Related publications:

Ofosu et al., 2019: Estimated daily intake and risk of prevailing acrylamide content of alkalized roasted cocoa beans

Żyżelewicz et al., 2016: Effects of various roasting conditions on acrylamide, acrolein, and polycyclic aromatic hydrocarbons content in cocoa bean and the derived chocolates

Farah et al., 2012: Effect of Roasting Process on the Concentration of Acrylamide and Pyrizines in Roasted Cocoa Beans from Different Origins