IMPACT OF FINING WITH K-CARRAGEENAN, BENTONITE, AND CHITOSAN ON PROTEIN STABILITY AND MACROMOLECULAR COMPOUNDS OF ALBARIÑO WHITE WINE PRODUCED WITH AND WITHOUT PRE-FERMENTATIVE SKIN MACERATION

Abstract

Pre-fermentative skin maceration is a technique used in white wine production to enhance varietal aroma, but it can increase protein concentration, leading to protein instability and haze formation [1]. To prevent protein instability, wine producers typically use fining agents such as bentonite, before wine bottling, which can negatively impact sensory characteristics and produce waste [2,3]. The aim of this study was to understand the impact of alternative techniques such as the application of polysaccharides (k-carrageenan and chitosan) on protein stability and on the wine macromolecular composition. The results showed that k-Carrageenan reduced the content of pathogenesis-related proteins (thaumatin-like proteins and chitinases), and consequently the protein instability in Albariño wines obtained with and without pre-fermentative skin maceration, and it was more efficient than sodium and calcium bentonites. Fungal chitosan was unable to heat stabilise both wines, and pathogenesis-related protein levels remained unchanged. Besides the impact on the protein content and wine protein instability, the use of k-carrageenan, chitosan, sodium, and calcium bentonites also differently impacted the wine polysaccharide content. Fungal chitosan decreased the wine polysaccharide content by 60%. Sodium and calcium bentonite also decreased the levels of wine polysaccharides although to a lower extent (16% to 59%) [4]. k-Carrageenan did not affect the wine polysaccharide composition. In conclusion, the results indicate that k-carrageenan is a suitable solution for white wine protein stabilisation, having a more desirable impact on the wine macromolecular fraction than the other fining agents tested, reducing the levels of the wine pathogenesis-related proteins without impacting polysaccharide composition. Funding : This work was funded by the Project AgriFood XXI (NORTE-01-0145-FEDER-000041) co-financed by the European Regional Development Fund through NORTE 2020 (Programa Operacional Regional do Norte 2014/2020).
Acknowledgments : The authors acknowledge Fundação para a Ciência e Tecnologia (FCT-Portugal) to CQ-VR (UIDB/00616/2020 and UIDP/00616/2020), Bodegas la Caña, S.L. do Grupo Jorge Ordoñez Selections for performing the vinification process of the wines used in this study, Ceamsa, Spain, for sup-plying the k-carrageenan sample used in this study and SAI Enology, Portugal, for performing the FTIR analysis.