RESUMEN
Due to the increasing consumer demand, the production of low alcoholic and non alcoholic beer is the new goal of the present brewing producers. Although the beer with reduced alcohol content is currently obtained by physical methods, the use of non-Saccharomyces yeast, with low fermentations capacities, may represent an interesting biological approach. In this study the ethanol content and the volatile profile of a beer obtained using the basidiomycetous psychrophilic yeast strain Mrakia gelida DBVPG 5952 was compared with that produced by a commercial starter for low alcohol beers, Saccharomycodes ludwigii WSL17. The two beers were characterized by a low alcohol content (1.40% and 1.32% v/v) and by a low diacetyl production (5.04 and 5.20⯵g/L). However, the organoleptic characteristics of the beer obtained using M. gelida are more appreciated by the panelists, in comparison to the analogous produced with the commercial strain of S. ludwigii.
Asunto(s)
Alcoholes/análisis , Basidiomycota/metabolismo , Cerveza/análisis , Alcoholes/metabolismo , Cerveza/microbiología , Diacetil/análisis , Diacetil/metabolismo , Fermentación , Microbiología de Alimentos , Humanos , Hypericum/química , Hypericum/metabolismo , Odorantes/análisis , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , GustoRESUMEN
Thirteen strains isolated from virgin olive oil or its by-products in several Mediterranean countries were found to be phenotypically and genetically divergent from currently recognized yeast species. Sequence analysis of the large subunit (LSU) rDNA D1/D2 domain and internal transcribed spacer regions/5.8S rDNA revealed that the strains represented two novel species described as Candida adriatica sp. nov. (type strain ZIM 2334(T) = CBS 12504(T) = NCAIM Y.02001(T)) and Candida molendinolei sp. nov. (type strain DBVPG 5508(T) = CBS 12508(T) = NCAIM Y.02000(T)). Phylogenetic analysis based on concatenated sequences of the small subunit rRNA gene, the D1/D2 region of the LSU rDNA and the translation elongation factor-1α gene suggested that C. adriatica sp. nov. and C. molendinolei sp. nov. should be placed within the Lindnera and Nakazawaea clades, respectively.
Asunto(s)
Candida/clasificación , Olea/microbiología , Filogenia , Aceites de Plantas , Candida/genética , Candida/aislamiento & purificación , ADN de Hongos/genética , ADN Espaciador Ribosómico/genética , Microbiología de Alimentos , Genes de ARNr , Técnicas de Tipificación Micológica , Aceite de Oliva , Factor 1 de Elongación Peptídica/genética , ARN Ribosómico 5.8S/genética , Análisis de Secuencia de ADNRESUMEN
Hydrolysable tannins (HTs), secondary metabolites widely distributed in the plant kingdom, are generally multiple esters of gallic acid with glucose. HTs have been shown to be effective antagonists against viruses, bacteria and eukaryotic microorganisms. The present review examines the antimicrobial and antiviral activity of HTs, the mechanism(s) of action, and some structure-activity relationships.