Project description:During fermentation Saccharomyces yeast produces various aroma-active metabolites determining the different characteristics of aroma and taste in fermented beverages. Amino acid utilization by yeast during brewer´s wort fermentation is seen as linked to flavour profile. To better understand the relationship between the biosynthesis of aroma relevant metabolites and the importance of amino acids, DNA microarrays were performed for Saccharomyces cerevisiae strain S81 and Saccharomyces pastorianus var. carlsbergensis strain S23, respectively. Thereby, changes in transcription of genes were measured, which are associated with amino acid assimilation and its derived aroma-active compounds during fermentation.
Project description:During fermentation Saccharomyces yeast produces various aroma-active metabolites determining the different characteristics of aroma and taste in fermented beverages. Amino acid utilization by yeast during brewer´s wort fermentation is seen as linked to flavour profile. To better understand the relationship between the biosynthesis of aroma relevant metabolites and the importance of amino acids, DNA microarrays were performed for Saccharomyces cerevisiae strain S81 and Saccharomyces pastorianus var. carlsbergensis strain S23, respectively. Thereby, changes in transcription of genes were measured, which are associated with amino acid assimilation and its derived aroma-active compounds during fermentation. 48 samples were used in this experiment
Project description:The aim of the study was to decipher metabolisms responsible (i) for the peculiar adaptation of L. plantarum during soy juice fermentation and (ii) for the release of aroma compounds, amino and short-chain fatty acid, and metabolites with health-promoting properties in soy yogurt. The strategy was the sequencing and annotation of a strain (L. plantarum CIRM-BIA777, PRJEB77707) able to degrade galacto- oligosaccharides, the sampling of soy yogurt, RNA-seq to identify differentially expressed genes of L. plantarum and corresponding metabolisms throughout the kinetics of fermentation. Acids and volatile compounds were also quantified.
Project description:Saccharomyces cerevisiae (SC) is the main driver of alcoholic fermentation however for aroma and flavour formation in wine non-Saccharomyces species can have a powerful effect. This study aimed to compare untargeted volatile compound profiles from SPME-GCxGC-TOF-MS and sensory analysis data of Sauvignon blanc wine inoculated with six different non-Saccharomyces yeasts followed by SC. Torulaspora delbrueckii (TD), Lachancea thermotolerans (LT), Pichia kluyveri (PK) and Metschnikowia pulcherrima (MP) where commercial starter strains, while Candida zemplinina (CZ) and Kazachstania aerobia (KA), were isolated from wine grape environments. Each fermentation produced a distinct profile both sensorially and chemically. SC and CZ were the most distinct in both of these cases. SC had guava, grapefruit, banana, and pineapple aromas while CZ was driven by fermented apple, dried peach/apricot, and stewed fruit as well as sour flavor. Chemically over 300 unique features were identified as significantly different across the fermentations. SC had the highest number of esters in the highest relative concentration but all the yeasts had distinct ester profiles. CZ displayed the highest number of terpenes in high concentration but also produced a large amount of acetic acid. KA was high in ethyl acetate. TD had fewer esters but three distinctly higher thiol compounds. LT showed a relatively high number of increased acetate esters and certain terpenes. PK had some off odor compounds while the MP had high levels of different methyl butyl-, methyl propyl-, and phenethyl esters. Overall, this study gives a more detailed profile of these yeasts than anything previously reported.
2015-08-19 | MTBLS212 | MetaboLights
Project description:Chinese traditional fermented tomato sour soup