Improving the sensory properties of unfermented cocoa press cake via hydration, yeast, and bromelain treatments

Fermentation is essential for developing the characteristic flavor of high-quality cocoa powder. However, in Indonesia, cocoa beans are commonly processed without fermentation and primarily used for cocoa butter extraction. Reutilizing these beans for cocoa powder could increase their economic value, yet the resulting press cake lacks desirable sensory qualities. This study explored post-processing strategies - hydration, yeast, and bromelain treatments - to enhance the flavor of unfermented cocoa press cake. The untreated press cake showed low levels of flavor precursors and a strong bitter-astringent profile with minimal chocolate or caramel notes. Hydration treatment effectively reduced phenolic content and astringency but had little impact on aroma. Yeast treatment increased reducing sugars and introduced sweet, fruity, and floral notes, yet failed to produce cocoa-specific aromas. In contrast, bromelain treatment significantly increased amino acid concentrations and led to the development of distinct chocolate and caramel notes. Although the combinatory treatment increased both types of precursors, it also caused off-flavors such as sour and cheesy notes. Principal component analysis confirmed that the bromelain-treated sample most closely resembled the fermented cocoa press cake in its sensory profile. These findings suggest that bromelain treatment is a promising strategy for enhancing the sensory quality of unfermented cocoa press cake through targeted enrichment of aroma precursors.