Influence of Candida pulcherrima Patagonian strain on alcoholic fermentation behaviour and wine aroma.
ABSTRACT The use of selected Saccharomyces and non-Saccharomyces strains as mixed starters in winemaking would have advantages over the traditional spontaneous fermentation, producing wines with predictable and desirable characteristics. The aim of this study was to evaluate the impact of metabolic interactions between Patagonian indigenous Saccharomyces cerevisiae MMf9 and beta-glucosidase producer Candida pulcherrima V(6) strains on alcoholic fermentation behaviour and wine aroma Three inoculation strategies, simultaneous, sequential and final, were assayed at laboratory-scale fermentations using Muscat d'Alexandrie grape juice as substrate. The fermentation and yeast growth kinetics as well as the physicochemical and the sensory quality of wine were evaluated. Results evidenced that the sequential inoculation is the most adequate strategy of strains combination. The kinetic behaviour of sequential fermentation was similar to a successful spontaneous fermentation and its wine showed differential aromatic quality as evidenced through PC analysis using physicochemical and aromatic composition data. This wine presented the highest total concentration of higher alcohol, esters and terpenols and the strongest fruity and floral aroma.
SourceAvailable from: Lucía M. Mendoza[Show abstract] [Hide abstract]
ABSTRACT: In traditional winemaking, natural fermentation of grape juice is carried out by a sequence of different yeast species. The early stages are dominated by non-Saccharomyces yeasts and are replaced by Saccharomyces cerevisiae that finish the fermentation process. In this chapter was evaluated the kinetics and metabolic behavior of Kloeckera apiculata mc1 and S. cerevisiae mc2 in composite culture. In this condition, K. apiculata showed a higher viability through the fermentation; however the cell density of both yeasts decreased. This behavior was not due to ethanol concentration, killer toxins production or competition for assimilable nitrogenous compounds between both yeasts. Despite the consistent production of secondary products by single culture of K. apiculata, desirable concentrations of these compounds were observed in mixed culture. The influence of temperature and SO 2 , on growth and metabolism of both wine yeasts was dependent of the culture type. Malolactic fermentation conducted by Oenococcus oeni is important enhancing wine quality, microbiological stability and flavour. The inclusion of K. apiculata mc1 as adjunct culture of S. cerevisiae mc2 during must fermentation improved the organoleptic characteristics of wines produced from vineyards in Argentina Northwest. In addition, sequential inoculation of O. oeni X 2 L allowed better control on the sensory quality of the fermented product.
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ABSTRACT: This work describes the utility and efficiency of a metabolic profiling pipeline that relies on an unsupervised and untargeted approach applied to a HS-SPME/GC-MS data. This non-invasive and high throughput methodology enables "real time" monitoring of the metabolic changes inherent to the biochemical dynamics of a perturbed complex biological system and the extraction of molecular candidates that are latter validated on its biochemical context. To evaluate the efficiency of the pipeline five different fermentations, carried on a synthetic media and whose perturbation was the nitrogen source, were performed in 5 and 500 mL. The smaller volume fermentations were monitored on-line by HS-SPME/GC-MS, allowing to obtain metabolic profiles and molecular candidates time expression. Non-target analysis was applied using MS data in two ways: (i) one dimension (1D), where the total ion chromatogram per sample was used, (ii) two dimensions (2D), where the integrity time vs m/z per sample was used. Results indicate that the 2D procedure captured the relevant information more efficiently than the 1D. It was also seen that although there were differences in the fermentation performance in different scales, the metabolic pathways responsible for production of metabolites that impact the quality of the volatile fraction was unaffected, so the proposed pipeline is suitable for the study of different fermentation systems that can undergo subsequent sensory validation on a larger scale.Journal of Agricultural and Food Chemistry 06/2014; 62(28). DOI:10.1021/jf502082z · 3.11 Impact Factor
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ABSTRACT: Twenty-six enological Hanseniaspora isolates were identified by ITS PCR-RFLP and D1/D2 domain of 26S rDNA sequencing and assayed for exocellular protease production. Based on qualitative data, six isolates, belonging to H. guilliermondii, H. valbyensis and H. occidentalis species, were selected to continue the study. Analytical procedure was optimised, and protease activities were quantified and characterised on the basis of different biotechnological factors. Protease activity was quite glucose, fructose and ethanol content independent, but divalent cation affects activity; these data support that they were aspartic proteases. The effect of 2-mercaptoethanol suggests the importance of disulphide bonds to maintain the structure of the active centre. Our results show these enzymes could be suitable for using in biotechnological processes at neutral pH, such as cheese, bread and meat industries. This is, to our knowledge, the first work showing the induction process to induce and characterise proteolytic activity in Hanseniaspora isolates.International Journal of Food Science & Technology 09/2014; 50(1). DOI:10.1111/ijfs.12654 · 1.35 Impact Factor