Macrowine 2021
IVES 9 IVES Conference Series 9 Impact of industrial-scale serial filtration on macromolecules in red wines

Impact of industrial-scale serial filtration on macromolecules in red wines

Abstract

Filtration is a critical step in ensuring the clarity and microbial stability of wine prior to bottling. However the process of filtering potentially reduces red wine quality by removing some of the macromolecules that contribute to the texture of the wine. Commercial red wines, Cabernet Sauvignon (CAS) and Shiraz (SHZ), of two vintages and two grades (premium grade wines from the older vintage: CAS13 and SHZ13; and standard grade wines from a younger vintage: CAS14 and SHZ14) were filtered through industrial-scale commercial filtration units prior to bottling. Samples were taken before and after cross-flow filtration, lenticular filters, 0.65 µm and 0.45 µm pore size nylon membrane filters. The concentration and composition of macromolecules, including tannins and polysaccharides, were measured in all samples as well as particle size distribution and wine colour. Tannin concentration was measured using the methyl-cellulose precipitation assay and colours were measured with the modified Somer’s colour assay. Tannins were isolated from wines using solid-phase extraction with Oasis HLB cartridges and subsequently analysed for molecular weight and subunit composition with size-exclusion chromatography and phloroglucinolysis (acid-catalysed cleavage reactions), respectively. Polysaccharides were isolated from wine with ethanol precipitation and were subsequently dialysed and analysed using size-exclusion chromatography. The composition of the wines varied with age and variety. Both CAS wines contained more tannin and fewer polysaccharides than the SHZ wines, while both older premium wines (CAS13 and SHZ13) demonstrated more tannin and fewer polysaccharides than the younger, standard grade wines. Cross-flow filtration removed the greatest number of particles from the wine, with all other levels of finer filtration inducing no significant effect on macromolecule concentration or composition. These results suggest that sterile filtration of commercial red wines is unlikely to cause deleterious effects on wine quality.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Jacqui McRae*, Agnieszka Mierczynska-Vasile, Alison Soden, Martin Day, Paul Smith

*Australian Wine Research Institute

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Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

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