University Park, PA — Scientists at Pennsylvania State University (PSU) were able to identify the “rejection threshold” to determine what amount of bitterness is acceptable in chocolate for those who prefer dark or milk chocolate.

The findings of the study were published in the online version of the Journal of Food Science. The newly devised method differs from the commonly used “detection threshold,” which only identifies undesirable flavors but gives no indication as to how much of a specific flavor is acceptable.

In the study, a group of adults were given milk chocolate compound coating with a bitter flavor added through different concentrations of sucrose octaacetate (SOA). Prior to eating the chocolate, participants identified their preference of either dark or milk chocolate. Those who preferred dark chocolate were able to handle 2.5 times more of the SOA concentration than those who preferred milk chocolate.

John Hayes, assistant professor of food science and director of the sensory evaluation center at PSU, says: “This study provides a new tool by which we can understand different segments of the market. With those segments, it becomes possible to tailor products to individual taste preferences. The idea that people segment into different groups isn't new. But with this method, we allow a rapid way for product developers to optimize their products for those different segments.”