Dados do Trabalho

Título

EFFECT OF PRESSURE AND TEMPERATURE ON THE SUPERCRITICAL FLUID EXTRACTION OF BIOACTIVE COMPOUNDS FROM SPENT HOP (Humulus lupulus)

Introdução

The brewing industry produces 200 billion liters of beer annually, generating large amounts of waste such as grains, hops, and yeast. During beer production, only 15% of the hop components are retained in the final product, generating a large amount of residual hop. This residue is rich in essential oils, polyphenols, and bitter acids, which can potentially prevent and treat diseases. No studies have employed supercritical fluid extraction of spent hops from dry-hopping. In this context, this work aimed to obtain extracts rich in bioactive compounds from spent hop using SFE.

Material e Métodos

SFE was performed with 10 wt.% ethanol at 15, 25, and 35 MPa, and 40, 50, and 60 °C for 30 min. The extracts were evaluated for global yield (X0), total reducing capacity (TRC) (Folin-Ciocalteu), xanthohumol yield, α and β-acids, and antioxidant capacity (ORAC).

Resultados e Discussão

The highest yields were obtained at 25 MPa and 60 ºC (reaching: X0: 36.20 ± 0.04% wt.; TRC: 27.88 ± 3.51 mg GAE (gallic acid equivalent); xanthohumol: 0.40 ± 0.01 mg; α-acids: 58.47 ± 2.47 mg; β-acids: 16.78 ± 1.37 mg and ORAC: 232.72 ± 4.10 mg TE (Trolox equivalent))/g hops on a dry basis). Temperature positively affected SFE yields. The temperature increase raises the solutes' vapor pressure, thus improving their solubility and extraction yield. The pressure increase was beneficial up to 25 MPa, showing a significant reduction in the yields of α and β-acids, and ORAC at 35 MPa. Increasing pressure generally increases solvent density and solvation power, increasing extraction efficiency. However, this study presented a behavior opposite to that reported in the literature. It is likely that, above 25 MPa, the CO2 has undergone physical changes, favoring the extraction of other compounds present in the hops, such as waxes and pigments, generating competition and reducing the extraction of the compounds of interest.

Conclusão

This study showed that SFE at 25 MPa and 60 °C efficiently obtained extracts rich in bioactive compounds with high antioxidant capacity from brewery hop waste and added value to the product that would be discarded.