title: Application of plastic polymers in remediating wine with elevated alkyl-methoxypyrazine levels.
abstract: 3-Alkyl-2-methoxypyrazines (MPs) are odour-active compounds that elicit atypical green aromas and flavours in some wines, and are resilient to removal using traditional wine-making approaches. They originate either as contaminants from Coccinellidae beetles inadvertently introduced during wine processing ("ladybug taint") or as grape-derived constituents that are undesirable at elevated levels. In this study we investigated the capacity of a selection of plastic polymers to reduce concentrations of three MPs: isopropyl methoxypyrazine (IPMP), secbutyl methoxypyrazine (SBMP) and isobutyl methoxypyrazine (IBMP). In Trial 1, red wine was spiked with IPMP (20 ng/l), SBMP (20 ng/l) and IBMP (20 ng/l), then separately treated with 13 plastic polymers (surface area 350 cm(2)/l). Three polymers were then identified for further testing based on the results from Trial 1: silicone, ethylene and vinyl acetate (EVA) and a poly-lactic acid-based biodegradable polymer. In Trial 2, the efficacy of these selected polymers to reduce MP levels in red wine was tested as a function of contact time. Solid-phase micro-extraction multi-dimensional GC-MS was used to measure MP levels before and after treatment with the polymers. Results showed significant reductions in all target odorants after 24 h treatment: silicone reduced IPMP and IBMP by 96% and 100%, respectively, while the biodegradable polymer decreased IPMP and IBMP concentrations by 52% and 36%, respectively. EVA was less effective in lowering MP levels (7% IPMP and 23% IBMP after 24 h). Taken overall, the data suggest the potential for the use of poly-lactic acid and silicone in treating wines contaminated by ladybug taint, as well as in reducing high levels of grape-derived MPs.
authors.affiliation: a Cool Climate Oenology and Viticulture Institute , Brock University , St. Catharines , Canada.
authors.forename: Andreea
authors.initials: A
authors.lastname: Botezatu
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Pickering
mesh_terms: D005511:Food Handling / Q000379:methods; D009812:Odorants; D011108:Polymers / Q000737:chemistry*; D011719:Pyrazines / Q000737:chemistry*; D013997:Time Factors; D014920:Wine / Q000032:analysis*
chemical_list: D011108:Polymers; D011719:Pyrazines
keywords: ladybug taint; methoxypyrazines; plastic polymers; remediation; silicone; wine