Bioactive compounds and antioxidant activities of Brazilian hop (<i>Humulus lupulus</i> L.) extracts

Abstract

Summary Bioactive compounds from Brazilian hop ( Humulus lupulus L.) cultivars were extracted by ultrasound and their phenolic profile compared with commercial hop from the USA. The most effective extraction conditions (solution of ethanol 49%, at 52 °C and a solid/liquid ratio of 1 g per 34 mL) for the total phenolic compounds (TPC) were determined using a Central Composite Rotatable Design. The Brazilian hop showed higher content of TPC (33.93 ± 0.67 mg GAE g −1 ), total flavonoids (54.47 ± 0.10 mg QE g −1 ) and higher antioxidant activity (ABTS: EC 50 21.29 ± 1.36 μL mL −1 ; DPPH: EC 50 3.91 ± 0.17 μL mL −1 ) when compared with the USA hop. The main phenolic compounds present in the extracts were the flavonoids isoquercitrin and quercetin. The antioxidant properties of the Brazilian hop extract had not been reported yet in the literature for this raw material, thus showing potential to be incorporated in polymeric films used as active packaging.