Continuous ultrasound and pulsed ultrasound: Selective extraction tools to obtain enriched antioxidants extracts from cocoa beans (Theobroma cacao L.)

In this study, the effect of continuous assisted extraction (CUAE) and pulsed ultrasound assisted extraction (PUAE) of phenolic compounds from cocoa beans was evaluated. Frequency (25/45 kHz) and extraction time (15/30 min) were varied. Phenolic acids were identified as catechin-(+), epicatechin-(+), procyanidin B1 and procyanidin B2 were quantified on each extract by HPLC-DAD. Then, total phenolic content (TPC), total flavonoids content (TFC), flavan-3-ols, non-flavonoids content (NF) and proanthocyanidins (PAC) were determined. The experimental findings indicated the highest extraction yields of TPC and flavonoids subclasses when prolonged PUAE was used. Additionally, an increase of 282% in epicatechin yield was obtained compared with CUAE. However, the prolonged use of continuous sonication increased the non-flavonoids extraction yield in 23% compared with pulsed sonication. The scavenging and iron chelating activity depended on the chemical composition of each extract and was not correlated directly to TPC.