Air Depleted and Solvent Impregnated Cork Powder as a New Natural and Sustainable Wine Fining Agent

Luís Filipe da Mota Ribeiro, Maria Fernanda Gil Cosme Martins and Fernando Hermínio Ferreira Milheiro Nunes

### Abstract

We recently proposed a simple methodology to improve cork powder waste adsorption properties through vacuum degassing and solvent impregnation, to use this abundant and cheap material as a new wine fining agent. Its applicability was first shown for red wine 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) reduction. Nowadays, the presence of 4-EP and 4-EG is a serious problem in the wine industry, known as "Brett character", by the negative aroma imparted by these volatile phenols (VPs) to red wine. There are only some curative treatments to remove these compounds without impacting negatively on wine quality. Optimised cork powder was used successfully as a new treatment for the reduction of these negative VPs (41–75% for 4-EP and 40–69% for 4-EG) increasing at the same time wine sensory performance. Wine treated with cork powder reduced 6.9% phenolic acids and catechin and 2.3% monomeric anthocyanins without any significant change in colour intensity. In this chapter, the cork complex structure is discussed, besides the impact of its use in wine containing VPs on physicochemical composition and quality. This new application of this natural, abundant and cheap material has the potential of being a new wine fining agent with low environmental impact.

Keywords: cork composition, adsorption properties, red wine, volatile phenols, aroma, phenolic compounds, sensory attributes
