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Foods (Basel, Switzerland) Feb 2022The effects of different yeast strains including , , and on the taste and odour profiles of reduced-salt dry sausages were explored. Inoculation of and compensated...
The effects of different yeast strains including , , and on the taste and odour profiles of reduced-salt dry sausages were explored. Inoculation of and compensated for the lack of saltiness and umami tastes of reduced-salt sausages. Furthermore, inoculation of and resulted in an odour profile in the reduced-salt dry sausages that was similar to traditional dry sausages. According to the volatile analysis, the contents of certain alcohols, acids, esters and terpenes were higher in the inoculated sausages. Finally, the sensory evaluation indicated that the inoculation of and contributed positively to the aroma and saltiness of reduced-salt dry sausages. In conclusion, and can be employed as effective starter cultures to compensate for the flavour deficiencies of reduced-salt dry sausages.
PubMed: 35267284
DOI: 10.3390/foods11050650 -
Microorganisms Jan 2022Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final...
Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final products. The present study investigated, for the first time, the microbiota of spontaneously fermented Maiorca dough samples collected from bakeries located in Sicily (Italy). Four sourdough samples (M1, M2, M3, and M4), were produced using Host. var. Koern (Maiorca grain) were subjected to LAB and yeasts isolation and identification at the species level. The in-depth characterization of the lactobacilli population revealed that and unquestionably dominated the Maiorca sourdough ecosystem. Concerning the yeasts community, high species diversity was found. and were the most frequently isolated species. In addition, and were also detected. Investigations on both pro-technological and functional traits of the isolated strains could lead to the selection of starters for the production of baked goods.
PubMed: 35208738
DOI: 10.3390/microorganisms10020283 -
AIMS Microbiology 2021Yeasts constitute an important part of cheeses, and especially the artisanal ones. The current study reviews the occurrence of yeasts in different cheese varieties and... (Review)
Review
Yeasts constitute an important part of cheeses, and especially the artisanal ones. The current study reviews the occurrence of yeasts in different cheese varieties and the role of yeasts in cheesemaking process. The use of molecular methods for identification and strain typing has extended the knowledge for yeast diversity in cheeses. For the study of the occurrence of yeasts in different cheese types, seven categories are used, that is: 1) hard, 2) semi-hard, 3) soft, which includes soft pasta-filata and whey cheeses, 4) white brined cheeses, 5) mould surface ripened, 6) bacterial surface ripened cheeses, and 7) blue cheeses. For some cheese types, yeasts are the main microbial group, at least for some part of their ripening process, while for some other types, yeasts are absent. Differences between industrially manufactured cheeses and artisanal cheeses have specified. Artisanal cheeses possess a diverse assortment of yeast species, mainly belonging to the genera , , , , , , , , , , , , , , , and . The role of the yeasts for selected cheeses from the seven cheese categories is discussed.
PubMed: 35071942
DOI: 10.3934/microbiol.2021027 -
Indian Journal of Microbiology Mar 2022Cheese is one of the traditional fermented dairy products in Xinjiang, China. Due to its geographical location and regional feature this type of cheese harbors certain...
UNLABELLED
Cheese is one of the traditional fermented dairy products in Xinjiang, China. Due to its geographical location and regional feature this type of cheese harbors certain regional characteristics. To investigate these, here Illumina MiSeq high-throughput sequencing technology was used to target the v4-v5 interval to analyze the composition of fungal flora in Xinjiang traditional cheese. Our results showed the fungal flora of this cheese is mainly composed of (65.20%), (9.05%), (7.21%), (6.56%), (3.13%), (2.11%) and (1.64%) belonging to the Ascomycota. PcoA (Principal Co-ordinates Analysis) and an UPGMA (unweighted pair-group method with arithmetic means) based on the OTUs (Optical Transform Unit) horizontal-weighted UniFrac distances, revealed some differences in fungal community structure among 17 cheese samples. At the OTU level, nine dominant OTUs were found in all the samples, for which was the most important fungal group. Building on this, the moisture content (23.20-59.22%), water distribution, and salt content (1.13-4.84%) in cheese were also determined. We found that six of the seven dominant fungal genera had specific correlations with the above physical and chemical variables, with only uncorrelated with any variables. The results provide a theoretical basis for the development and use of cheese microbial resources in Xinjiang, China.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s12088-021-00967-x.
PubMed: 35068603
DOI: 10.1007/s12088-021-00967-x -
Microorganisms Jan 2022The yeasts (Td) and (Sc) may show a killer phenotype that is encoded in dsRNA M viruses (V-M), which require the helper activity of another dsRNA virus (V-LA or V-LBC)...
The yeasts (Td) and (Sc) may show a killer phenotype that is encoded in dsRNA M viruses (V-M), which require the helper activity of another dsRNA virus (V-LA or V-LBC) for replication. Recently, two TdV-LBCbarr genomes, which share sequence identity with ScV-LBC counterparts, were characterized by high-throughput sequencing (HTS). They also share some similar characteristics with Sc-LA viruses. This may explain why TdV-LBCbarr has helper capability to maintain M viruses, whereas ScV-LBC does not. We here analyze two stretches with low sequence identity (LIS I and LIS II) that were found in TdV-LBCbarr Gag-Pol proteins when comparing with the homologous regions of ScV-LBC. These stretches may result from successive nucleotide insertions or deletions (indels) that allow compensatory frameshift events required to maintain specific functions of the RNA-polymerase, while modifying other functions such as the ability to bind V-M (+)RNA for packaging. The presence of an additional frameshifting site in LIS I may ensure the synthesis of a certain amount of RNA-polymerase until the new compensatory indel appears. Additional 5'- and 3'-extra sequences were found beyond V-LBC canonical genomes. Most extra sequences showed high identity to some stretches of the canonical genomes and can form stem-loop structures. Further, the 3'-extra sequence of two ScV-LBC genomes contains rRNA stretches. The origin and possible functions of these extra sequences are here discussed.
PubMed: 35056622
DOI: 10.3390/microorganisms10010173 -
Frontiers in Microbiology 2021Changes are currently being made to winemaking processes to reduce chemical inputs [particularly sulfur dioxide (SO)] and adapt to consumer demand. In this study, yeast...
Changes are currently being made to winemaking processes to reduce chemical inputs [particularly sulfur dioxide (SO)] and adapt to consumer demand. In this study, yeast growth and fungal diversity were investigated in merlot during the prefermentary stages of a winemaking process without addition of SO. Different factors were considered, in a two-year study: vintage, maturity level and bioprotection by the adding yeast as an alternative to SO. The population of the target species was monitored by quantitative-PCR, and yeast and filamentous fungi diversity was determined by 18S rDNA metabarcoding. A gradual decrease of the α-diversity during the maceration process was highlighted. Maturity level played a significant role in yeast and fungal abundance, which was lower at advanced maturity, while vintage had a strong impact on spp. population level and abundance. The presence of SO altered the abundance of yeast and filamentous fungi, but not their nature. The absence of sulfiting led to an unexpected reduction in diversity compared to the presence of SO, which might result from the occupation of the niche by certain dominant species, namely spp. Inoculation of the grape juice with non- yeast resulted in a decrease in the abundance of filamentous fungi generally associated with a decline in grape must quality. Lower abundance and niche occupation by bioprotection agents were observed at the overripened stage, thus suggesting that doses applied should be reconsidered at advanced maturity. Our study confirmed the bioprotective role of and in a context of vinification without sulfites.
PubMed: 35002998
DOI: 10.3389/fmicb.2021.748416 -
Yeast (Chichester, England) Jan 2022Breweries produce an increasing selection of beer and nonbeer beverages. Yeast and filamentous fungi may compromise quality and safety of these products in several ways....
Breweries produce an increasing selection of beer and nonbeer beverages. Yeast and filamentous fungi may compromise quality and safety of these products in several ways. Recent studies on fungal communities in breweries are scarce and mostly conducted with culture-dependent methods. We explored fungal diversity in the production of alcoholic and nonalcoholic beverages in four breweries. Samples were taken for next generation sequencing (NGS) at the key contamination sites in 10 filling lines. Moreover, fungal isolates were identified in 68 quality control samples taken from raw materials, filling line surfaces, air, and products. NGS gave a comprehensive view of fungal diversity on filling line surfaces. The surface-attached communities mainly contained ascomycetous fungi. Depending on the site, the dominant genera included Candida, Saccharomyces, Torulaspora, Zygosaccharomyces, Alternaria, Didymella, and Exophiala. Sanger sequencing revealed 28 and 27 species of yeast and filamentous fungi, respectively, among 91 isolates. The most common species Saccharomyces cerevisiae, Zygosaccharomyces rouxii, and Wickerhamomuces anomalus were detected throughout production. Filling line surface and air samples showed the greatest diversity of yeast and filamentous fungi, respectively. The isolates of the most common yeast genera Candida, Pichia, Saccharomyces, and Wickerhamomyces showed low spoilage abilities in carbonated, chemically preserved drinks but could grow in products with reduced hurdles. Preservative resistant yeasts were rare, belonging to the species Dekkera bruxellensis, Pichia manschurica, and Zygosaccharomyces bailii. Penicillium spp. were dominant filamentous fungi. The results of this study help to evaluate spoilage risks caused by fungal contaminants detected in breweries.
Topics: Beer; Food Microbiology; Fungi; Quality Control; Saccharomyces cerevisiae; Yeasts; Zygosaccharomyces
PubMed: 34957597
DOI: 10.1002/yea.3687 -
International Journal of Molecular... Dec 2021The killer phenotype of (Td) and (Sc) is encoded in the genome of medium-size dsRNA viruses (V-M). Killer strains also contain a helper large size (4.6 kb) dsRNA virus...
The killer phenotype of (Td) and (Sc) is encoded in the genome of medium-size dsRNA viruses (V-M). Killer strains also contain a helper large size (4.6 kb) dsRNA virus (V-LA) which is required for maintenance and replication of V-M. Another large-size (4.6 kb) dsRNA virus (V-LBC), without known helper activity to date, may join V-LA and V-M in the same yeast. Kbarr1 killer strain contains the killer virus Mbarr1 in addition to two L viruses, TdV-LAbarr1 and TdV-LBCbarr1. In contrast, the Kbarr2 killer strain contains two M killer viruses (Mbarr1 and M1) and a LBC virus (TdV-LBCbarr2), which has helper capability to maintain both M viruses. The genomes of TdV-LBCbarr1 and TdV-LBCbarr2 were characterized by high-throughput sequencing (HTS). Both RNA genomes share sequence identity and similar organization with their ScV-LBC counterparts. They contain all conserved motifs required for translation, packaging, and replication of viral RNA. Their Gag-Pol amino-acid sequences also contain the features required for cap-snatching and RNA polymerase activity. However, some of these motifs and features are similar to those of LA viruses, which may explain that at least TdV-LBCbarr2 has a helper ability to maintain M killer viruses. Newly sequenced ScV-LBC genomes contained the same motifs and features previously found in LBC viruses, with the same genome location and secondary structure. Sequence comparison showed that LBC viruses belong to two clusters related to each species of yeast. No evidence for associated co-evolution of specific LBC with specific M virus was found. The presence of the same M1 virus in and raises the possibility of cross-species transmission of M viruses.
Topics: Amino Acid Sequence; Base Sequence; Capsid; Double Stranded RNA Viruses; Genome, Viral; Helper Viruses; RNA, Double-Stranded; RNA, Viral; Saccharomyces cerevisiae; Torulaspora; Wine
PubMed: 34948288
DOI: 10.3390/ijms222413492 -
Food Research International (Ottawa,... Dec 2021Selected yeasts for coffee fermentation are correlated with changes in chemical compounds and beverage sensory characteristics. This work aimed to evaluate the chemical...
Selected yeasts for coffee fermentation are correlated with changes in chemical compounds and beverage sensory characteristics. This work aimed to evaluate the chemical and sensory modifications of coffee fermented with one yeast (Saccharomyces cerevisiae CCMA 0543, Candida parapsilosis CCMA 0544, or Torulaspora delbrueckii CCMA 0684) and in co-inoculation (from two to two and the three together) by dry processing. Real-time PCR analyzes, total phenolic content and antioxidant activity (DPPH, ABTS, and FRAP), liquid and gas chromatography, and sensory analysis were performed. Caparaó coffees showed a higher C. parapsilosis (6.14 Log cell.g) population followed by S. cerevisiae (5.85 Log cell.g) and T. delbrueckii (4.64 Log cell.g). The total phenolic content has a strong and positive correlation with the fermentation time and the roasted beans and a moderate and positive correlation with DPPH, FRAP, and ABTS. Coffee inoculated with T. delbrueckii reduced caffeine concentration during the fermentation process. In co-cultivation, the trigonelline concentration showed the most significant decrease (around 4 mg.g) when inoculated with S. cerevisiae and T. delbrueckii. Detection of some organic acids and volatile compounds during fermentation may indicate that the starter cultures used different metabolic routes. All co-inoculation treatments presented the best sensory scores (>86 points). In the inoculated fermentation, fruity, citric, molasses, freshness, and wine notes appeared. The co-inoculated treatment with S. cerevisiae CCMA 0543, C. parapsilosis CCMA 0544, and T. delbrueckii CCMA 0684 was the best, considering the diversity of sensory notes descriptors and the final concentration of organic acids.
Topics: Coffee; Fermentation; Saccharomyces cerevisiae; Torulaspora; Wine
PubMed: 34865773
DOI: 10.1016/j.foodres.2021.110755 -
International Journal of Food... Feb 2022Oenococcus oeni is the main agent responsible for malolactic fermentation (MLF) in wine. This usually takes place in red wines after alcoholic fermentation (AF) carried...
Oenococcus oeni is the main agent responsible for malolactic fermentation (MLF) in wine. This usually takes place in red wines after alcoholic fermentation (AF) carried out by Saccharomyces cerevisiae. In recent years, there is an increasing interest in using non-Saccharomyces yeast, usually in combination with S. cerevisiae, to improve wine quality. Current studies report a stimulatory effect of non-Saccharomyces on MLF, generally related to a decrease in the inhibitor compounds found in wine. In this work, we followed a comparative multi-omics approach, including transcriptomic and proteomic analysis, to study the molecular adaptation of O. oeni in wines fermented with Torulaspora delbrueckii and Metschnikowia pulcherrima, two of the most frequently used non-Saccharomyces, in sequential inoculation with S. cerevisiae. We compared the results to the adaptation of O. oeni in S. cerevisiae wine to determine the main changes arising from the use of non-Saccharomyces. The duration of MLF was shortened when using non-Saccharomyces, to half the time with T. delbrueckii and to a quarter with M. pulcherrima. In this work, we observed for the first time how O. oeni responds at molecular level to the changes brought about by non-Saccharomyces. We showed a differential adaptation of O. oeni in the wines studied. In this regard, the main molecular functions affected were amino acid and carbohydrate transport and metabolism, from which peptide metabolism appeared as a key feature under wine-like conditions. We also showed that the abundance of Hsp20, a well-known stress protein, depended on the duration time. Thus, the use of non-Saccharomyces reduced the abundance of Hsp20, which could mean a less stressful wine-like condition for O. oeni.
Topics: Fermentation; Malates; Oenococcus; Proteomics; Saccharomyces cerevisiae; Wine
PubMed: 34844030
DOI: 10.1016/j.ijfoodmicro.2021.109490