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Journal of Food Science and Technology Dec 2022Canastra's Minas artisanal cheese [QMA (Minas artisanal cheese)] is a protected geographical indication traditional food. The influence of fungi on the cheese ripening...
Canastra's Minas artisanal cheese [QMA (Minas artisanal cheese)] is a protected geographical indication traditional food. The influence of fungi on the cheese ripening process is of great importance. This study aimed to apply culture-dependent and -independent methods to determine the mycobiota of QMA produced in the Canastra region, as well as to determine its physicochemical characteristics. Illumina-based amplicon sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry were the culture-independent methods used. The physicochemical analysis results showed that the QMA has a moisture content ranging 18.4-28.2%, fat content ranging 20.5-40%, sodium chloride percentage of approximately 0.9%, and pH ranging 5.2-5.5. The population of fungi ranged between 6.3 and 8 log colony-forming unit/g. spp., , spp., , , spp., , , spp., spp. and spp. were the most prevalent fungi. The methods used to evaluate the mycobiota provide a better understanding of which species are present in the final product and eventually contribute to the characteristics of QMA. and . were identified as promising species for future studies on product quality.
PubMed: 36276518
DOI: 10.1007/s13197-022-05548-4 -
Frontiers in Microbiology 2022Non-conventional yeasts such as () have been proposed for sparkling winemaking. Unfortunately, this yeast has poor efficiency in completing wine fermentation as...
Non-conventional yeasts such as () have been proposed for sparkling winemaking. Unfortunately, this yeast has poor efficiency in completing wine fermentation as compared to (). New mutants with increased resistance to SO, ethanol, and high CO pressure were previously isolated from spore clones of . Although these mutants showed improved capability for base wine fermentation, there is still room for genetic improvement of yeasts until the fermentative capacity of is achieved. As an alternative approach, yeast mixture for eventual hybridization of with was assayed in this study. The new yeast mixture clones (-mixed ) showed an intermediate phenotype between both parent yeasts for some relevant biotechnological properties, such as resistance to SO, ethanol, copper, high CO pressure, and high temperature, as well as flocculation potential. These properties varied depending on the specific -mixed clone. Several mixture clones showed improved capability for base wine fermentation as compared to the parent strain, approaching the fermentation capability of the parent strain. The organoleptic quality of sparkling wine was also improved by using some mixture clones and this improved quality coincided with an increased amount of acetate and ethyl esters. The genetic stability of some -mixed clones was good enough for commercial yeast production and winery applications.
PubMed: 36274726
DOI: 10.3389/fmicb.2022.1006978 -
Brazilian Journal of Microbiology :... Dec 2022In recent years, ample research has focused on applying wild (especially non-Saccharomyces) yeasts in producing alcoholic beverages. Common characteristics of wild yeast...
In recent years, ample research has focused on applying wild (especially non-Saccharomyces) yeasts in producing alcoholic beverages. Common characteristics of wild yeast strains include simultaneous high production of fruity and floral aroma compounds and low ethanol production. In this study, mead starter cultures were selected based on preliminary screening of wild yeast strains from a Brazilian culture collection (n = 63) for their ability to produce aroma-active compounds. The selected strains included one strain of Saccharomyces cerevisiae and three non-Saccharomyces strains (Pichia jadinii, Torulaspora delbrueckii, and Kluyveromyces lactis). These strains were used to ferment honey must prepared with Aroeira honey, adjusted to 24°Brix, which took 36 days to complete. Single culture fermentations and co-fermentations with S. cerevisiae and non-Saccharomyces strains were carried out. The quality of the produced beverages was evaluated by sugar consumption and production of alcohols and organic acids, analyzed with high-performance liquid chromatography. The volatile organic compound composition was analyzed with gas chromatography-mass spectrometry. Meads with various ethanol amounts (4.7-11.0% v/v) and residual sugar contents (70.81-160.25 g l) were produced. In addition, in both single-strain fermentation and co-fermentation with S. cerevisiae, meads produced with either Torulaspora delbrueckii or Kluyveromyces lactis had a roughly three-fold higher content of honey-aroma compound phenethyl acetate and a higher hedonic impression score than meads produced with only S. cerevisiae. These results demonstrated non-Saccharomyces yeasts' ability to increase aroma complexity and improve the sensory quality of low-alcoholic meads.
Topics: Odorants; Saccharomyces cerevisiae; Torulaspora; Yeasts; Fermentation; Ethanol; Wine
PubMed: 36269554
DOI: 10.1007/s42770-022-00840-z -
Foods (Basel, Switzerland) Oct 2022There is a lack of studies evaluating the metabolic contribution of non- yeasts in early fermentation phases. This study aimed to investigate the volatile aroma profiles...
There is a lack of studies evaluating the metabolic contribution of non- yeasts in early fermentation phases. This study aimed to investigate the volatile aroma profiles produced by various non- yeasts just before sequential inoculation with to provide an insight into the particular effects they induce at this stage. The grape must of Malvazija istarska was inoculated with monocultures of , , , , and , alongside a control. Eighty volatile compounds were quantified via headspace solid-phase microextraction and gas chromatography-mass spectrometry, and the data were statistically elaborated. Volatile profiles of non- yeasts differed significantly from the control. Most treatments caused increases in linalool and β-damascenone, decreases in higher alcohols and fatty acids, and improved synthesis of odoriferous esters. and produced compounds not commonly found in fermented wines. Multivariate statistical analysis linked the investigated yeasts to specific, particularly abundant compounds. Future studies should explore to what degree these contributions persist after sequential inoculation with in diverse grape must matrices.
PubMed: 36230163
DOI: 10.3390/foods11193088 -
Foods (Basel, Switzerland) Oct 2022Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra,...
Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra, Eastern Slovakia, and Tokaj. This study focuses on the detection of microbiota in soil samples, grape leaves and berries, and samples taken from fermenting must and young wine (the variety Tramín červený) in relation to the detected concentrations of biogenic amines during the fermentation process. In the examined samples, the number of yeasts and molds (from 3.8 to 6.8 log cfu/g or mL) and TVC (from 3.7 to 6.5 log cfu/g or mL) were determined via culture examination. At the same time, the number of LAB (from ˂3.0 to 4.4 log cfu/g or mL) was determined, which was the highest on day 4 of the must fermentation process and was related to the detected of the highest concentration of biogenic amines (histamine and tyramine) on day 6 in the investigated must samples using the UHPLC system. Mycobiota species were identified by MALDI-TOF MS, PCR, ITS-PCR-RFLP, and PCR sequencing of the amplified products. The study confirmed the presence of the yeasts . At the same time, the presence of molds ( and ) was also confirmed in soil samples, leaves, grape berries, and fresh grape must. The study confirmed the reduction in the species diversity of the microbiota during the must fermentation process, which resulted in decreases in the concentrations of the monitored biogenic amines in the early stages of the must fermentation process and young wine of the variety Tramín červený.
PubMed: 36230137
DOI: 10.3390/foods11193061 -
Microbiology Resource Announcements Nov 2022Torulaspora quercuum is an ascomycete yeast first isolated in 2009. Here, we present the genome sequence of T. quercuum isolate UCD657, which was isolated from soil in...
Torulaspora quercuum is an ascomycete yeast first isolated in 2009. Here, we present the genome sequence of T. quercuum isolate UCD657, which was isolated from soil in Ireland. This genome is 10.4 Mb and was assembled into 8 chromosome-sized scaffolds of >1 Mb in size, plus a mitochondrial genome scaffold.
PubMed: 36214680
DOI: 10.1128/mra.00952-22 -
Frontiers in Bioengineering and... 2022Glycerol is the main organic by-product of the biodiesel industry and it can be a source of carbon for fermentations or a substrate for biotransformations. This work...
Glycerol is the main organic by-product of the biodiesel industry and it can be a source of carbon for fermentations or a substrate for biotransformations. This work investigates a process that uses pulsed electric field (PEF) to enhance polyol and propanediols extraction from a glycerol/glucose fermentation broth. Three different commercial, non- strains, Prelude (Hansen), Biodiva 291 (Lallemand) and (Lallemand) were studied. The results revealed that PEF had a positive impact on the extraction of polyols ranging from 12 to 191%, independently of fermentation conditions. Biodiva 291 (Lallemand) was found to be more efficient at pH 7.1. An optimized chromatography-based method for the qualitative and quantitative determination of the formed products evaluated. The experiments were carried out either in flasks or in a bioreactor.
PubMed: 36177179
DOI: 10.3389/fbioe.2022.964174 -
Microorganisms Sep 2022Non-conventional yeasts (NCY) (i.e., non-) may be used as alternative starters to promote biodiversity and quality of fermented foods and beverages (e.g., wine, beer,...
BACKGROUND
Non-conventional yeasts (NCY) (i.e., non-) may be used as alternative starters to promote biodiversity and quality of fermented foods and beverages (e.g., wine, beer, bakery products).
METHODS
A total of 32 wine-associated yeasts (Campania region, Italy) were genetically identified and screened for decarboxylase activity and leavening ability. The best selected strains were used to study the leavening kinetics in model doughs (MDs). A commercial strain of was used as the control. The volatile organic profiles of the inoculated MDs were analyzed by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS).
RESULTS
Most of strains belonged to the NCY species , , , , and , while a few strains were . Most strains of lacked decarboxylase activity and showed a high leaving activity after 24 h of incubation that was comparable to the strains. The selected strains generated a different flavor profile of the doughs compared to the strains. In particular, NCY reduced the fraction of aldehydes that were potentially involved in oxidative phenomena.
CONCLUSIONS
The use of NCY could be advantageous in the bakery industry, as they can provide greater diversity than -based products, and may be useful in reducing and avoiding yeast intolerance.
PubMed: 36144451
DOI: 10.3390/microorganisms10091849 -
3 Biotech Oct 2022The rhizosphere yeast is known to produce indole acetic acid (IAA) and to solubilize minerals. Due to the prospective use of this yeast as a biostimulant for...
The rhizosphere yeast is known to produce indole acetic acid (IAA) and to solubilize minerals. Due to the prospective use of this yeast as a biostimulant for agricultural applications, this work aimed to optimize the cultural conditions for both IAA production and phosphate solubilization. For phosphate solubilization, the temperature (20, 25 and 30 °C), initial medium pH (3.0, 5.0, and 7.0), and shaker speed (without mixing, 100 rpm, 150 rpm, and 200 rpm) were considered using the one-factor-at-a-time (OFAT) design. Temperature of 25 °C, initial medium pH 7.0, and static cultures were the conditions of greatest phosphate solubilization, with 40% of the total phosphorus content solubilized from calcium phosphate (419.86 mg L) after 48 h. By using the response surface methodology, the maximum IAA production (217.73 µg mL) was obtained with the highest initial pH 7.0, the lowest nitrogen, and glucose concentrations (5 g L and 10 g L, respectively) and the lowest agitator speed (100 rpm). Further tests indicated that nitrogen affected significantly IAA production and the absence of nitrogen in the medium promoted higher IAA production (457 µg mL). The results obtained here may contribute to the scaling up for industrial and agricultural applications of a yeast-based product with .
PubMed: 36091086
DOI: 10.1007/s13205-022-03322-z -
International Journal of Food... Nov 2022The current use of non-Saccharomyces yeasts in mixed fermentations increases the relevance of the interactions between yeast species. In this work, the interactions...
The current use of non-Saccharomyces yeasts in mixed fermentations increases the relevance of the interactions between yeast species. In this work, the interactions between Saccharomyces cerevisiae and Torulaspora delbrueckii were analyzed. For this purpose, fermentations with and without contact between strains of those yeast species were performed in synthetic must. Fermentation kinetics, yeast growth and dynamics were measured over time. Additionally, the effects of nitrogen and other nutrient supplementations on the mixed fermentations were determined. Our results showed that S. cerevisiae did not always dominate the sequential fermentations, and experiments without yeast contact (in which T. delbrueckii cells were removed from the medium before inoculating S. cerevisiae at 48 h) resulted in stuck fermentations except when the inoculum size was increased (from 2 × 10 to 10 cells/mL) or there was a supplementation of thiamine, zinc and amino acids at the same concentration as initially found in the synthetic must. Our findings highlight the importance of inoculum size and ensuring the availability of enough micronutrients for all yeast species, especially in sequential fermentations.
Topics: Amino Acids; Fermentation; Micronutrients; Nitrogen; Saccharomyces cerevisiae; Thiamine; Torulaspora; Wine; Zinc
PubMed: 36084391
DOI: 10.1016/j.ijfoodmicro.2022.109915