Focused microwaves-assisted extraction of theobromine and caffeine from cacao

With the aim of improving the extraction efficiency of Theobromine (TB) and Caffeine (CF) from cacao, a focused microwaves assisted method was developed. To optimize the extraction a 23 factorial design was used with optimum values: 5 min of irradiation time, 210 W of power and 100 mL of the extractant (water). To quantify TB, a study about the reagents that must be added to the extracts (Carrez reagents: (Zn(CH3COO)2 and K4Fe(CN)6) and a Pb(CH3COO)2 solution) in order to eliminate interferences (molecular weight high compounds) was carried out. The extraction method was applied to cacao seeds, cacao powder and cacao peels. The focused microwave method was more efficient compared with a standard mechanic stirring method: for TB from 15.0% (in cacao seeds) to 72% (in cacao peels) and from 36% (in cacao peels) to 153% (in cacao seeds) for CF.