-
International Journal of Molecular... Jan 2021The surfaces of grapes are covered by different yeast species that are important in the first stages of the fermentation process. In recent years, non- yeasts such as ,... (Review)
Review
The surfaces of grapes are covered by different yeast species that are important in the first stages of the fermentation process. In recent years, non- yeasts such as , , , and have become popular with regard to winemaking and improved wine quality. For that reason, several manufacturers started to offer commercially available strains of these non- species. stands out, mainly due to its contribution to wine aroma, glycerol, ethanol yield, and killer factor. The metabolism of the yeast allows it to increase volatile molecules such as esters and varietal thiols (aroma-active compounds), which increase the quality of specific varietal wines or neutral ones. It is considered a low- or non-fermentative yeast, so subsequent inoculation of a more fermentative yeast such as is indispensable to achieve a proper fermented alcohol. The impact of is not limited to the grape wine industry; it has also been successfully employed in beer, cider, durian, and tequila fermentation, among others, acting as a promising tool in those fermentation processes. Although no species other than is available in the regular market, several recent scientific studies show interesting improvements in some wine quality parameters such as aroma, polysaccharides, acid management, and color stability. This could motivate yeast manufacturers to develop products based on those species in the near future.
Topics: Bioengineering; Ecology; Fermentation; Food Quality; Industrial Microbiology; Pichia; Vitis; Wine
PubMed: 33530422
DOI: 10.3390/ijms22031196 -
New Microbes and New Infections 2022
PubMed: 36177393
DOI: 10.1016/j.nmni.2022.101018 -
Foods (Basel, Switzerland) May 2023Traditional kombucha is a functional tea-based drink that has gained attention as a low or non-alcoholic beverage. The fermentation is conducted by a community of...
Traditional kombucha is a functional tea-based drink that has gained attention as a low or non-alcoholic beverage. The fermentation is conducted by a community of different microorganisms, collectively called SCOBY (Symbiotic Culture of Bacteria and Yeast) and typically consists of different acetic acid bacteria and fermenting yeast, and in some cases lactic acid bacteria that would convert the sugars into organic acids-mostly acetic acid. In this study, the effect of including a starter culture in a kombucha fermentation was investigated. additions led to a quicker accumulation of acetic acid along with the production of several acetate esters including isoamyl acetate and 2-phenethyl acetate. A subsequent tasting also noted a significant increase in the fruitiness of the kombucha. The significant contribution to the aroma content shows the promise of this yeast in future microbial formulations for kombucha fermentations.
PubMed: 37238757
DOI: 10.3390/foods12101938 -
FEMS Yeast Research Jan 2021Alcoholic fermentation is influenced by yeast strain, culture media, substrate concentration and fermentation conditions, which contribute to taste and aroma. Some...
Alcoholic fermentation is influenced by yeast strain, culture media, substrate concentration and fermentation conditions, which contribute to taste and aroma. Some non-Saccharomyces yeasts are recognized as volatile compound producers that enrich aromatic profile of alcoholic beverages. In this work, 21 strains of Pichia kluyveri isolated from different fermentative processes and regions were evaluated. A principal component analysis (PCA) showed statistical differences between strains mainly associated with the variety and concentration of the compounds produced. From the PCA, two strains (PK1 and PK8) with the best volatile compound production were selected to evaluate the impact of culture media (M12 medium and Agave tequilana juice), stirring speeds (100 and 250 rpm) and temperatures (20°C, 25°C and 30°C). Increased ester production was observed at 250 rpm. Greatest effect in alcohols and ester production was found with A. tequilana, identifying PK1 as higher alcohol producer, and PK8 as better ester producer. Regarding temperature, PK1 increased ester production with decreased fermentation temperature. PK8 presented maximum levels of ethyl acetate and ethyl dodecanoate at 20°C, and finally isoamyl acetate increased its production at 30°C. Therefore, P. kluyveri strains are of great interest to produce different aromatic profiles that are affected by factors including medium, agitation and temperature.
Topics: Alcoholic Beverages; Alcohols; Culture Media; Esters; Fermentation; Industrial Microbiology; Odorants; Pichia; Temperature; Volatile Organic Compounds
PubMed: 33316048
DOI: 10.1093/femsyr/foaa067 -
Current Research in Food Science 2023Wheat-gluten, the protein-rich portion of wheat, can be processed to produce a highly savory sauce product after solid and liquid-state fermentation (SSF and LSF) with...
Wheat-gluten, the protein-rich portion of wheat, can be processed to produce a highly savory sauce product after solid and liquid-state fermentation (SSF and LSF) with the inoculation of selected lactic acid bacteria (LAB) and yeast under salt-free condition. However, limited research has been done on the impact of different types of microbes in this process. This work studied the flavour impact on fermented wheat-gluten by the single inoculation of or one yeast ( or ). Glucose was depleted during LSF in all treatments. Lactic acid production increased over time in -fermented samples but not in yeast-fermented samples. Cysteine, serine and arginine remained low over LSF in -fermented samples but increased in yeast-fermented samples. More fruity esters such as isoamyl acetate and isobutyl acetate were detected in samples fermented by , while boosted the production of alcohols such as 3-methyl butanol and 2-phenylethyl alcohol. Principal component analysis revealed a clear difference in volatile profiles of the samples fermented with different strains. Therefore, the fermented sauce can potentially be processed into different flavor directions, and based on the flavor profile, be used in different food applications.
PubMed: 37033740
DOI: 10.1016/j.crfs.2023.100492 -
Food Microbiology May 2022This study used a double-compartment fermenter to assess yeast growth, fermentation activity, and aroma production in response to cell-cell contact during mixed culture...
This study used a double-compartment fermenter to assess yeast growth, fermentation activity, and aroma production in response to cell-cell contact during mixed culture fermentation of Pinot noir grape must with Pichia kluyveri and Saccharomyces cerevisiae. Furthermore, amino acids were analyzed in order to study yeast interactions and possible reasons for aroma modulation as a response to cell-cell contact. Our results show that cell-cell contact between the two yeasts decreased cell viability of each yeast during mixed culture fermentation, and that it increased acetate and ethyl ester production and decreased varietal volatile levels. Moreover, it increased the consumption of glutamic acid and the biosynthesis of some specific amino acids related to cell growth, mainly histidine, glycine and proline, while suppressing the production of higher alcohols through the Ehrlich pathway. These results may contribute to an improved understanding, and thus control, of aroma production in mixed culture wine fermentations.
Topics: Amino Acids; Fermentation; Pichia; Saccharomyces cerevisiae; Wine
PubMed: 35082077
DOI: 10.1016/j.fm.2021.103960 -
Current Research in Food Science 2021This study evaluated the effects of yeast extracts (YE) addition (0 % and 0.25 %, w/v) on the no-volatile and volatile compounds of spent coffee grounds (SCG)...
The potential of spent coffee grounds hydrolysates fermented with and for developing an alcoholic beverage: The yeasts growth and chemical compounds modulation by yeast extracts.
This study evaluated the effects of yeast extracts (YE) addition (0 % and 0.25 %, w/v) on the no-volatile and volatile compounds of spent coffee grounds (SCG) hydrolysates fermented with single-cultures of two non- wine yeasts, and . The added YE improved the growth of both and , especially , resulting in higher ethanol production (1.98 % vs 1.47 %, v/v) by the latter yeast. In addition, the added YE did not impact on most of the alkaloids production regardless of yeast type, while significantly decreasing the contents of chlorogenic, and caffeic acids in SCG hydrolysates fermented with . Furthermore, more odor-active compounds such as acetate esters and 2-phenylethyl alcohol were produced when YE was added, and generated significantly higher amounts of esters compared to that of . Moreover, YE addition showed a more noticeable effect on the fermentation performance of relative to that of . These findings indicated the potential of SCG hydrolysates fermented with evaluated non- yeasts and may expand the applications on utilizing SCG to develop new value-added alcoholic products.
PubMed: 34382007
DOI: 10.1016/j.crfs.2021.07.004 -
Data in Brief Aug 2023strain APC 11.10 B was isolated from apple bark in Switzerland and exhibited strong antagonistic activity against plant pathogenic fungi (e.g., or isolates). In...
strain APC 11.10 B was isolated from apple bark in Switzerland and exhibited strong antagonistic activity against plant pathogenic fungi (e.g., or isolates). In order to identify the mechanisms underlying this antagonism, we have sequenced the genome of this isolate by long- and short-read sequencing technologies. The sequence data were assembled into nine scaffolds and a fully resolved circularized mitogenome. The total genome size was 10.9 Mbp and 7451 potential open reading frames (ORFs) and 202 tRNA genes were predicted. In comparison to two genomes deposited at the NCBI (of strains X31-10 and CBA6002), the APC 11.10 B strain seemed to represent a hybrid because backmapping of sequencing reads resulted in a high rate of heterozygous and structural variants in the nuclear genome (this was not observed for the mitochondrial genome). The (APC 11.10 B) draft genome represents a first step and resource for genome mining, comparative and functional genomics (e.g., identifying the biocontrol mode of action), and evolutionary studies. Since the genus comprises many biotechnologically relevant yeasts, the genome data may be used in a variety of fields and disciplines.
PubMed: 37496519
DOI: 10.1016/j.dib.2023.109394 -
Food Microbiology Dec 2019This paper describes a mixed fermentation model made by assembling block hosting models for the growth of lactic acid bacteria (Lactobacillus plantarum) and a yeast...
This paper describes a mixed fermentation model made by assembling block hosting models for the growth of lactic acid bacteria (Lactobacillus plantarum) and a yeast strain (Pichia kluyveri), metabolic production and the physical-chemical changes which occur during the fermentation of gowé. The growth model for P. kluyveri was developed on a synthetic medium following the gamma concept taking into account the effect of pH, temperature, concentrations in glucose, lactic acid and ethanol. Additional parameters for the previously defined L. plantarum growth model were also determined (glucose and ethanol concentrations). The model was validated in three different gowé processing conditions. Even if the model underestimates LAB growth, it explains what occurs in the product and enables in silico extrapolation to various fermentation conditions. The predicted hydrolysis rates of native and gelatinised starches showed that increasing malt content is not an efficient way to increase the sweetness of gowé in contrast to increasing the level of pre-cooking. The builing-block model developed in this study could be applied to many other fermented foods and particularly to non-alcoholic but acid and sweet cereal based beverages.
Topics: Fermentation; Fermented Foods; Hydrolysis; Lactobacillus plantarum; Models, Biological; Pichia
PubMed: 31421747
DOI: 10.1016/j.fm.2019.103242 -
Foods (Basel, Switzerland) Apr 2023Pellicle formation is the most typical characteristic of deteriorating fermented vegetable products. essential oil (PEO) is widely used as a useful natural...
Pellicle formation is the most typical characteristic of deteriorating fermented vegetable products. essential oil (PEO) is widely used as a useful natural preservative. However, few studies have addressed the antifungal activity and mechanism of PEO in pellicle formation microorganisms, and it is still unclear whether it can inhibit pellicle formation and affect its volatile compounds in Sichuan pickles. The current study showed that PEO can inhibit pellicle formation during fermentation of Sichuan pickles as it had significant antifungal activity against the pellicle formation microorganisms SH1 and SH2. The minimum inhibitory concentration (MIC) of PEO against SH1 and SH2 was determined to be 0.4 μL/mL, and the minimum fungicidal concentrations (MFCs) were 1.6 μL/mL and 0.8 μL/mL, respectively. The antifungal mechanism was activated as a result of damage to the cell membrane, an increase in the cell permeability, a decrease in the mitochondrial membrane potential, and the inhibition of ATPase activity. Meanwhile, the addition of PEO to Sichuan pickles can enrich the profiles of volatile compounds during fermentation, including limonene, myrcene, 1,8-cineole, linalool, perilla ketone, heptanal, hexanal, α-thujone and β-terpineol and thus improve the overall sensory acceptability. These results indicated that PEO has the potential to be used as a novel food preservative to control pellicle formation in fermented vegetables.
PubMed: 37107388
DOI: 10.3390/foods12081593