Native strainsof non-saccharomyces yeasts isolated from the epiphytic mocrobiota of fruit: oenological potential and fermentation kinetics of Prokupac grape must

[S. S. Mančić]

291 str.

Biografija: str. [292]. Bibliografija: str. 203-274.

Food technology and biotechnology

Modern winemaking approaches introduce the concept of microbial terroir, which provides a structure for determining ideal grape variety-yeast combinations for the development of regionally unique, high-quality wines. In accordance with this concept, the doctoral thesis's goal was to isolate non-Saccharomyces yeast strains from the epiphytic microbiota of fruits and vine plant materials, define their oenological characteristics, and determine the quality, aromatic, and sensory characteristics of wine produced from the indigenous grape variety Prokupac. A total of 58 yeast isolates were isolated, of which 17 isolates (Candida famata, Hanseniaspora uvarum, Pichia kluyveri, Metschnikowia pulcherrima, Rhodotorula glutinis, and Papiliotrema laurentii) were selected for microvinification of pasteurized grape must Prokupac based on cluster analysis. Among these, the strains P. kluyveri K-1, M. pulcherrima K-5, and H. uvarum (Kr-2, Šd-1, and Š-2) were selected for laboratory-scale vinification (7 L) due to their ability to produce pleasant aromas, to consume more than half of the available sugars, and to produce glycerol above 4 g/L. These strains were used in both pure and sequential fermentations with a commercial Saccharomyces cerevisiae strain. The obtained wines had an optimal acid profile, sugar content below 4 g/L, up to 9% lower alcohol content, and 20% higher glycerol content compared to the control. GC/MS analysis identified 86 volatile compounds, of which 29 significantly contributed to the formation of the aromatic profile of wines. Non-Saccharomyces strains enhanced color intensity, varietal typicity, aromatic complexity, and fruity and floral notes. Based on these findings, P. kluyveri K-1 was selected for investigation under pilot and semi-industrial vinification scales. Wines produced under these conditions showed reduced volatile acidity (20%) and increased concentrations of acetate esters, higher alcohols, lactones, and terpenes. Optimization of cell growth conditions for industrial-scale vinification (21.9 °C, 184 rpm, and 48 g/L glucose) resulted in the maximum viable cell count and biomass yield of the strain P. kluyveri K-1.

ne-saccharomyces kvasci, prokupac, HPLC analiza, GC/MS analiza, senzorna analiza

non-saccharomyces yeasts, prokupac, HPLC analysis, GC/MS analysis, sensory analysis

663.2:663.12(043.3)

T430

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