Chocolate is a beloved treat, but sometimes the cocoa beans that go into bars and other sweets have unpleasant flavors or aromas, which makes the end products look bad. Surprisingly, only a few compounds associated with these stinky odors are known. Now researchers report in ACS Journal of Agricultural and Food Chemistry have identified the two compounds that cause musty and musty odors in cocoa – work that can help chocolate makers ensure the quality of their products.
Cocoa beans, when fermented properly, have a pleasant smell with sweet and floral notes. But they can have an off-putting scent when fermentation goes badly, or when storage conditions aren’t quite right and microorganisms thrive in them. If these beans go into the manufacturing process, the final chocolate can have an unpleasant odor, leading to consumer complaints and recalls. Thus, sensory professionals smell fermented cocoa beans before they are roasted, detecting any unwanted musty, musty, smoke or mushroom odor. Even with these tests in place, spoiled beans can escape the human nose and ruin batches of chocolate, so more objective evaluation is needed for quality control. In previous studies, researchers have used molecular techniques to identify compounds that contribute to unwanted smoky flavors, but a similar method has not clarified other volatile odorous compounds. Thus, Martin Steinhaus and his colleagues wanted to determine the main compounds that cause musty and musty odors in contaminated cocoa beans.
The researchers identified 57 molecules that made up the olfactory profiles of normal smelling and moldy / moldy cocoa beans using gas chromatography in combination with olfactometry and mass spectrometry. Of these compounds, four had higher concentrations in low odor samples. Then, these four compounds were fortified in unscented cocoa butter, and the researchers performed odor tests with 15 to 20 participants. By comparing the results of these tests with the molecular content of nine samples of nasty fermented cocoa beans and cocoa liquors, the team determined that (-) – geosmin – associated with musty and beet smells – and 3 -methyl-1H-indole – associated with fecal and mothball odors – are the main contributors to musty and musty odors in cocoa beans. Finally, they found that (-) – geosmin was mainly found in the bean shells, which are removed during processing, while 3-methyl-1H-indole was mainly in the bean tip which is made into chocolate. Researchers say measuring the amount of these compounds in cocoa beans could be an objective way to detect off-putting scents and flavors, keeping future batches of chocolate smelling sweet.
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