Extraction of methylxanthines by pressurized hot water extraction from cocoa shell by-product as natural source of functional ingredient

Cocoa beans are one of the largest cultivated crops all over the world, producing large amount of by-products. For this reason, it is necessary to valorise cocoa by-products to obtain valuable source of bioactive compounds. In this paper, a pressurized hot water extraction process for recovery of theobromine and caffeine from cocoa by-product was developed and optimized. The extraction was carried out on ASE and all parameters affected by extraction efficiency and antioxidant capacity were optimized by a chemometric approach. Theobromine and caffeine were quantified by UPLC-UV (283 nm), whereas antioxidant capacity was evaluated by in vitro assays (ABTS and DPPH). By applying the PHWE under optimized conditions (ethanol 15%, temperature 90 °C, 5 cycles and static time 6 min), the extraction efficiency increased by 156% for theobromine and 160% for caffeine in comparison with the results obtained using ultrasound assisted liquid extraction. The effect of PHWE extract on cell viability of colorectal and breast cancer cell lines was also tested. The application of PHWE to selective recovery of theobromine and caffeine from cocoa shell by-products is a green, automatic, and rapid method, representing a valid alternative to conventional extraction methods to obtain ingredients for food industries.