Polyamines and Gut Microbiota

The microbiota of gut is the community of microbes living in an individual's gastrointestinal tract. Several bacterial genera and species act in a concerted manner to establish metabolic interactions with the host (1). Although there is a general high interest in the study of metabolite flow across the microbe-host, at present, only some studies are targeting specific metabolites produced by intestinal microbiota such as polyamines (PAs

Microbiological and chemical monitoring of Marsala base wine obtained by spontaneous fermentation during large-scale production

The present work was undertaken to evaluate the effect of the natural winemaking on the microbial and chemical composition of Marsala base wine. To this purpose, a large-scale vinification process of Grillo grape cultivar was monitored from harvesting to the final product. Total yeasts (TY) showed a rapid increase after must pressing and reached values almost superimposable to those registered during the conventional winemakings. Lactic acid bacteria (LAB) were registered at the highest levels simultaneously to yeast growth at the beginning of the process. Saccharomyces cerevisiae was the species found at the highest concentrations in all samples analysed. Several strains (n= 16) was registered at high levels during the alcoholic fermentation and/or aging of wine; only two of them were detected on the grape surface. Lactobacillus plantarum was the LAB species most frequently isolated during the entire vinification process. Ethanol content was approximately 14% (v/v) at the end of vinification. The value of pH did not greatly vary during the process and the volatile acidity (VA) was detected at low concentrations during the entire transformation. The concentration of malic acid rapidly decreased during the AF; on the other hand, lactic acid showed an irregular trend during the entire process. trans-caffeil tartaric acid was the most abundant hydroxycinnamoyl tartaric acid and volatile organic compounds (VOC) were mainly represented by isoamylic alcohol and isobutanol

Brettanomyces bruxellensis yeasts: impact on wine and winemaking

Yeasts belonging to the Brettanomyces/Dekkera genus are non-conventional yeasts, which affect winemaking by causing wine spoilage all over the world. This mini-review focuses on recent results concerning the presence of Brettanomyces bruxellensis throughout the wine processing chain. Here, culture-dependent and independent methods to detect this yeast on grapes and at the very early stage of wine production are encompassed. Chemical, physical and biological tools, devised for the prevention and control of such a detrimental species during winemaking are also presented. Finally, the mini-review identifies future research areas relevant to the improvement of wine safety and sensory profiles

Association between Grape Yeast Communities and the Vineyard Ecosystems

The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Acores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viti-cultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions.Joao Drumonde Neves is the recipient of a fellowship of the Azorean Government (M321/006/F/2008) and PROEMPREGO. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds through FCT by the projects FCOMP-01-0124-008775, PTDC/AGR-ALI/103392/2008 and PTDC/AGR-ALI/121062/2010.info:eu-repo/semantics/publishedVersio

Microbial dynamics in wine production

The Special Issue "Microbial dynamics in wine production" collects nine original research articles and a review concerning wine production, a complex process where microbes have a decisive role [...]

Utilization of ‘early green harvest’ and non-Saccharomyces cerevisiae yeasts as a combined approach to face climate change in winemaking

Present study aimed to ascertain whether the combination of two factors, i.e., time of harvest and type of yeast, can significantly moderate the effect of climate change on Chardonnay wine composition. In this view, three Chardonnay musts obtained from grapes at different harvest date [technological maturity ‘as control’; delayed harvest; a mixture of ‘early (green) harvest’ with delayed harvest ‘as alternative approach’] and three selected yeast strains [Saccharomyces cerevisiae ‘as control’; hybrid Saccharomyces cerevisiae/Saccharomyces paradoxus; scalar alternative approach with Starmerella bacillaris and hybrid Saccharomyces cerevisiae/Saccharomyces paradoxus] were used to design and compare six different trials, replicated at pilot level (n. total fermentations: 18). Wines were evaluated in terms of sensory and chemical parameters (alcohol, acidity, organic acids, phenolic compounds and glycerol) and results tested by statistical analysis. Although the wine alcohol content decreased at the best by ~ 1.2% v/v, whereas the total acidity increased up to ~ 2.5 g/L, the results from sensory evaluation highlighted that the proposed ‘alternative approach’ may cause excessive acidity and bitterness perception, therefore, further deacidification and fining treatments may be needed. The present approach to reduce the alcohol content of wine and increase its total acidity is simple, inexpensive and applicable in all wineries