Melastomataceae leaf extract for masking the bitter flavor of dark chocolate

Abstract

Bitter is one of the flavors that has low threshold. Eliminating bitter taste is one of the efforts in order to make active compounds in food can be more easily accepted by consumers. This study aims at examining the ability in reducing bitterness of leaves derived from the Melastomataceae (DM) against dark chocolate (DC) and its marker compounds, namely theobromine (TB), polyphenols and flavonoids. DM extract was prepared from maceration processby using water (aq), methanol (MeOH), and ethyl acetate (EtOAc). The concentration of polyphenols, flavonoids and percent inhibition of TB was measured by using ultra violet (UV-Vis) spectroscopy. Preliminary confirmation of changes in compound composition was observed by thin layer chromatography (TLC). Changes in the absorbance of covalent bonds were observed by Fourier transformed infra-red (FTIR). Total phenol, flavonoids, and theobromine in DC products mixed with DM extract had decreased, especially in DC combinations with EtOAc or water extract from DM. The decrease in TB concentration ranged from 62.3 to 72.8% compared to pure TB control or between 38.6 and 75.2% in DC products. From the TLC, binding of compounds was obtained at Rf between 0.337 and 0.686. These compounds were detected in Rf between 0.780 to 0.814. From the FTIR interpretation, mixing DM with DC and TB consistently decreased the bonds that were thought to consist of C=CC=O, ON=O, ONOO, RCOO, -OH, OCOCH3, COO-, and R3NO. In conclusion, DM extract had shown to reduce the bitterness of DC by binding it to TB and changing the composition of compounds in DC, and reducing certain covalent bonds.