The sensory profile of unfermented cocoa beans and its changes after moisture treatments

Abstract

Unfermented cocoa bean has an astringent and bitter taste in addition to a weak cocoa aroma. It lacks of precursors of aroma due to incomplete enzymatic processes within the cotyledon. The enzymes responsible for development of aroma precursors could be reactivated by incubating it in moist condition. Unfermented cocoa beans were dried, cleaned from shelled, ground and pressed to produce powder. It was mixed with distilled water at ratio 1 g :1.5 ml and was incubated for 4, 8, or 16 hours. Fermented cocoa was prepared in the same manner without moisture treatment, as a control. Parameters observed were total polyphenols, reducing sugars, and sensory properties. Principal Component Analysis (PCA) and Pearson’s Correlational analysis were performed to assess the relationship between parameters. The sensory evaluation shows that unfermented cocoa is characterized with green, earthy, astringent, and bitter notes. Fermented cocoa has a well-defined chocolate, caramel and nutty notes. Moisture treatment of unfermented cocoa for 4 hours and 8 hours treatments enhanced the sweet and caramel note. There was a strong positive correlation between polyphenol content and bitter (r=0.95, p<0.05) and astringent (r=0.93, p<0.05) notes, as well as between reducing sugar and sweet, chocolate, caramel and nut notes. These correlations indicates that polyphenols and reducing sugar content could predict the sensory quality of cocoa. This study demonstrates the potential of moisture treatment to improve sensory quality of unfermented cocoa.