Ohmic heating-based extraction of biocompounds from cocoa bean shell

Abstract

Cocoa bean shell (CBS), a by-product of the chocolate industry, was employed as substrate for the sustainable recovery of bioactive compounds using ohmic heating (OH). Total phenolic content and antioxidant activity of the treated CBS were optimized by experimental design. Maximum extraction of antioxidant phenolic compounds (23 mg GAE/g CBS) was obtained at 67 °C, 50 min and 44% ethanol (v/v). The antioxidant activity of the extracts obtained under of the central point conditions was 284.5 μM Fe2+/g extract (FRAP) and 36.4 μM TE/g extract (DPPH). The use of OH increased the extraction of bioactive phenolic compounds when compared to the conventional process (CH) (approximately 40%). An increased on the chemical antioxidant activity was also observed, ranging from 4 to 20%. The metabolic activity of the extracts obtained by the two methods (OH and CH) was evaluated in non-tumoral (HEK293T and L929) and tumoral cell lines (Caco-2, HT-29, and HeLa). The CBS extracts presented low toxicity in non-tumoral cells and ROS preventive effects. These characteristics make them ideal to be used in food processing and formulation, as well as nutraceutical products due to their antioxidant protection. The use of OH results in an extract with higher phenolic content and higher antioxidant activity and low environmental impact.