Implementing principles of traditional concentrated grape must fermentation to the production of new generation balsamic vinegars. Starter selection and effectiveness

Abstract

In an effort to implement principles of traditional concentrated grape must fermentation to the production of new generation balsamic vinegars (BVs), the specific goals of the study were the isolation and molecular identification of the predominant yeasts in concentrated grape must (cv. Xinomavro), their technological characterization and the evaluation of the fermentative aptitude of the selected strains. Tolerance against 5-hydroxymethylfurfural (HMF) and furfural, acetic acid and glucose concentration was examined by appropriate methods and tests. The enological characteristics studied were acetic acid and H 2 S production, foaming and flocculation ability and key enzymatic activity. PCR-RFLP analysis revealed only the presence of Saccharomyces cerevisiae and Hanseniaspora uvarum among the 14 predominant osmophilic yeast isolates. Tolerance to both HMF and furfural was found strain-and dose-dependent and was suggested as a critical factor in the pre-selection of yeast starters. The most tolerant yeasts to these stress factors, a S. cerevisiae and a non-Saccharomyces strains, showed satisfactory growth in the presence of high glucose and acetic acid content (up to 600 g/L and 2 % w/w, respectively) and desirable enological characteristics. Results from the comparative evaluation of the fermentative aptitude of these strains with a commercial wine strain highlighted that the isolates had glucophilic behaviour and ability to produce desirable amounts of ethanol (100-120 g/kg) in short time (*20 d). The key volatiles useful for varietal discrimination and differentiation between the BVs and the traditional ones were also evaluated.

The Value of Indigenous <i>Saccharomyces cerevisiae</i> Strains as Useful Enzymes Producers: A Systematic Review

“…The surveyed strains appeared to have grown within a temperature range of 22 to 42 ℃ [37,42] (Table 2). However, most of the articles assessed have considered ideal temperatures as being in the range between 25 and 30 ℃ (78%) [35,30,44,47]. For the pH conditions, most of the enzymes studied were produced at a more acidic pH, ranging between 4.0 and 6.0 (Table 3), which is compatible with the optimal pH for the growth of S. cerevisiae strains.…”

Microbial Dynamics in Sour–Sweet Wine Vinegar: Impacts on Chemical and Sensory Composition

“…This is an attractive feature considering that the most osmotolerant species found in the TBV process show, in general, a fructophilic metabolism, resulting in glucose crystallization in the vinegar [16]. It is well known that Saccharomyces strains are glucophilic, so this yeast strain is also important for TBV production [72].…”