181 research outputs found
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
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
Chapter 6: Fermented sausages: a potential source of biogenic amines
Biogenic amines (BAs) occur in high amounts in fermented meat products, which is due to microbial activities, the manufacturing process, and raw materials. Tyramine is the most abundant, while putrescine and cadaverine presence is more variable. Their production manly relies on lactic acid and coagulase negative staphylococci, which are the main microbial groups associated with these fermented products. Fermented sausages comprise a variety of products from countries all around the world (i.e. chorizo in Spain, soppressata in Italy) and levels of BAs are variable in terms of quantity and type. In this chapter, the occurrence of BAs in fermented sausages is explored, focusing of decarboxylase positive microorganisms and factors influencing their content
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