Green extraction of phenolic compounds from Perle Hallertau and Nuggets hop pellets

Operation conditions to recover and quantify active compounds from Perle Hallertau (PH) and Nuggets (N) hops, following a sequential combination of ultrasound and microwave assisted ethanolic extraction were studied. Ultrasound treatment (55 degrees C, 60% ethanol, 30 minutes) allowed extracts with phenolic contents of 160.43 mg GAE/g extract and ABTS radical scavenging capacity equivalent to 400.24 mg Trolox/g extract for PH. Optimal conditions for N were found at 55 degrees C, using 60% ethanol for 120 minutes (98.80 mg GAE/g extract) and 55 degrees C, 40% ethanol for 180 min (370.00 mg Trolox/g extract). The remaining solids were further processed under ethanolic microwave extraction (130-190 degrees C, 5 minutes) with the optimal results obtained at 190 degrees C for PH (77.11 and 98.67 mg GAE/g extract) and N (226.96 and 368.72 mg Trolox/g extract). Results obtained provided hops pellets as a rich source of active compounds that could be suitable for food and no food industry applications.