Influence of leaf removal and reflective mulch on phenolic composition of white wines

Abstract

Aim: The aim of this research was to evaluate if leaf removal and red geotextile reflective mulch "Vitexsol" could affect phenolic composition of wines from three white cultivars, Riesling italico, Traminer, and Manzoni bianco. Methods and results: A two-year study was conducted to evaluate the effects of leaf removal and reflective mulch on the phenolic composition of white wines from Zagreb vineyards in northwestern Croatia. Leaf removal (LR) and reflective mulch (RM) "Vitexsol", made from weave of aluminum platelets protected by a transparent film and sewn together with red polypropylene threads, were tested separately and combined (LR + RM) on vines of Traminer, Riesling italico and Manzoni bianco in 2008 and 2009. LR and RM had no consistent effect on must sugar content and titratable acidity. All treatments resulted in higher total phenol and flavan-3-ol content in wines of all cultivars, but in different years. LR + RM generally resulted in the highest phenolic acid and individual flavan-3-ol content in all wines except Traminer. RM treatment had the least effect on phenolic composition of wines. Conclusion: LR + RM generally resulted in the highest content of most phenolic compounds, especially when compared to control wines. Significance and impact of the study: This work provides some useful informations for adjusting vineyard practices and thus optimizing phenolic quality of white wines.