The parallel experiment of grapevine protection against fungal diseases on selected vineyard (1 ha) in the Slovene winegrowing region Primorska was performed: biotic grape protection with natural agent Kanne-Brottrunk and traditional protection with permitted pesticides. The goal of the experiment was a comparative analysis of the physico-chemical composition and sensorial wine quality of grape cultivar 'Ribbola', must and final wine in dependence of grapevine protection as well as must prefermentation treatment (with or without cold maceration for 12 hours at 8 degreesC). Musts, young wines after first racking, and bottled wines were analysed on further physico-chemical parameters: pH value, buffer capacity, reducing sugars, titratable and volatile acidity, individual organic acids (tartaric, malic, citric and lactic acid), total phenolic compounds, ash and its alkalinity, total and sugar-free extract, alcohol, acetaldehyde, proline, free amino nitrogen, free and total sulphur dioxide. All these physico-chemical parameters are correlated to the wine quality (sensorial analysis). Sensory evaluation of bottled wines (Buxbaum method) was carried out after six weeks of maturation at 8 degreesC; seven trained panellists evaluated the wines and classified them into the group of quality wines. A statistical analysis was carried out by means of least square method and GLM procedure; values of individual parameters differed statistically significantly among different grapevine protections, as well as must prefermentation treatments. Further investigations are required to assess the possibility of a partial pesticide substitution for the grapevine protection.
