Green extraction of phenolic compounds from Perle Hallertau and Nuggets hop pellets
Vanesa Sanz, María Dolores Torres, José Manuel López Vilariño, Herminia Domı́nguez
Abstract
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 °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 °C, using 60% ethanol for 120 minutes (98.80 mg GAE/g extract) and 55 °C, 40% ethanol for 180 min (370.00 mg Trolox/g extract). The remaining solids were further processed under ethanolic microwave extraction (130–190 °C, 5 minutes) with the optimal results obtained at 190 °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.