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

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.

Cork powder as a new natural and sustainable fining agent to reduce negative volatile phenols in red wine

“…Identical results were observed in malvidin-3-glucoside. On contrary, in total phenols were observed a significant difference ( p < 0.05) between CKNI and CKFI, CKFI75250 and CKFI75500), with CKFI, CKFI75250 and CKFI75500, showing the lower total phenols content relative to the untreated wine, however the absolute total phenols content is slight different in all samples, that means that otimised cork powder does not change significantly, the red wine phenolic composition [27].…”

“…As observed previously the air removal and ethanol impregnation of both cork samples increased significantly the decrease observed for the total headspace aroma abundance (CKNI 32% and CKFI 37%). Again, the decrease in the particle size of the CKF differ significantly on the removal of headspace aroma compounds relative to CKFI75250 [27]. The duplication in application dose of CKFI75 resulted in a significant decrease of the total abundance of headspace aroma by more 29% (Fig.…”

“…A B Figure 2. Structure of cork as observed by SEM in the two main sections: A) tangential section, perpendicular to the tree's radial direction; B) transverse section, perpendicular to the tree's axial direction (adapted from [27]).…”

Air-Depleted and Solvent-Impregnated Cork Powder as a New Natural and Sustainable Fining Agent for Removal of 2,4,6-Trichloroanisole (TCA) from Red Wines

“…This by-product obtained from the cork industry is an abundant, natural, and cheap material recently exploited in its raw form and after optimizing its adsorption properties by simple physicochemical treatments, such as air removal and simultaneous impregnation with ethanol. This treatment makes the cell wall components more accessible, demonstrating an increase of at least 4 times its adsorption capacity after treatment, which could be a new sustainable fining agent for wines [ 25 , 26 ]. This by-product was a good solution for the removal of volatile phenols without affecting the wine quality and sensory profile [ 25 , 26 ].…”

“…This treatment makes the cell wall components more accessible, demonstrating an increase of at least 4 times its adsorption capacity after treatment, which could be a new sustainable fining agent for wines [ 25 , 26 ]. This by-product was a good solution for the removal of volatile phenols without affecting the wine quality and sensory profile [ 25 , 26 ]. The use of cork dust waste produced in the cork stopper industry can increase its economic value and thus reduce the entry of new materials into the wine production chain.…”