Kinetics of the Solid-Liquid Extraction Process of Phenolic Antioxidants and Antioxidant Capacity from Hop (Humulus lupulus L.)

Abstract

The influence of solvent concentration, pH, temperature, sampler solid ratio, and extraction time on the extractability of total phenolics and antioxidants from hop was investigated. The mechanism of extraction is confirmed to occur in the following steps: first, the dissolution of the phenolic compounds near the particle surface (washing), and second, the diffusion from the solid particles to the bulk of the liquid extract (slow extraction). The process is described mathematically using two concepts of the unsteady diffusion through plant material and Ponomaryov’s empirical equation. The data obtained are used to establish the kinetics and thermodynamics of the extraction process.

Keywords:

• solid-liquid extraction
• hop
• total phenols
• antioxidant capacity
• kinetics
• thermodynamics parameters

Additional information

Funding

This research was supported by grant number 31060 and 172047 from the Serbian Ministry of Science and Environmental Protection. The authors are grateful for the financial support provided by this Ministry.