Optimizing the use of adsorbent resin for the amelioration of smoke tainted wine

The most effective strategies for amelioration of smoke tainted wine involve removal of smoke taint compounds (i.e., free and glycosylated phenols) by adsorbent materials. Ideally, adsorbents can be re-used if taint compounds are subsequently desorbed via a regeneration process. However, a recent study found phenolic glycosides carried over between remedial treatments that used adsorbent styrene-divinylbenzene resin (packed in a fixed-bed column), despite resin regeneration. This suggested inadequate regeneration, such that residual taint compounds remained on the resin. This study optimized resin regeneration by comparing the desorption of free and glycosylated phenols using different eluents, i.e.: aqueous sodium hydroxide vs aqueous sodium carbonate and aqueous ethanol vs aqueous isopropanol. Free and glycosylated phenols were effectively desorbed (i.e., >99% and 82-100% desorption, respectively, with no evidence of carryover) when resin was regenerated with 5 bed volumes of 2% sodium hydroxide, followed by 3-5 bed volumes of either 20% ethanol or isopropanol. Subsequent elution of regenerated resin with model wine (12% aqueous ethanol, pH 3.4) confirmed there was no further desorption (carryover) of smoke taint compounds. Following optimization of resin regeneration, nanofiltration and resin treatments were applied to three wines with varying levels of smoke taint. Analysis of untreated and treated wines demonstrated the efficacy of both amelioration and resin regeneration, i.e., ∼50% volatile phenol removal was achieved, improving sensory profiles (smoke-related aromas and flavors were less perceptible), with no saturation or carryover of phenolic glycosides. Research findings offer winemakers an improved approach to remediation of smoke tainted wine.