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Food Technology and Biotechnology Dec 2022Wine yeasts are a heterogeneous microbial group with high enzymatic potential that makes them a useful tool in winemaking. With a better understanding of their...
RESEARCH BACKGROUND
Wine yeasts are a heterogeneous microbial group with high enzymatic potential that makes them a useful tool in winemaking. With a better understanding of their oenological properties, selection procedures can be optimised to obtain more efficient strains. The present study aims to isolate and select yeasts from wine grape surface by studying their production of enzymes that hydrolyse plant cell wall polymers and by linking them to different technological parameters and antioxidant activity of wines.
EXPERIMENTAL APPROACH
Yeasts that are able to produce carbohydrolases and related enzymes of oenological importance were firstly selected on plates and subsequently identified. Then, a secondary selection of yeasts was carried out according to technological effects of their extracellular enzyme extracts on short macerations. In this way, the colour extraction, total polyphenol content, clarification, filterability and antioxidant activity were studied. This approach makes it possible to correlate the microorganism capacity to produce cell wall-depolymerizing enzymes with their technological effects.
RESULTS AND CONCLUSIONS
From 366 isolates, 96 strains (26.2%) showed at least one of the polysaccharidase activities and 55 strains (57.3%) of them exhibited activities of multiple enzymes that degrade plant cell wall polymers. Sixteen strains were selected and identified as , , and . Pectinolytic enzymes had the highest hydrolytic activity. had a broader enzyme blend and higher activity, dominated by pectinases and followed by xylanases and cellulases. Moreover, the m7-2 strain produced high amounts of polysaccharidase and this was strain-dependent. Strains that produced enzyme extracts with a wide range of activities that were also the highest, also had the best chromatic and technological properties. Cluster analysis confirmed that R-22, m11-2, m86-1 and m86-2 and m7-2 could be correlated with a better effect on filterability, clarification and extraction of bioactive compounds, encouraging future studies regarding their application in winemaking.
NOVELTY AND SCIENTIFIC CONTRIBUTION
The study of yeast multi-enzymatic systems impacting the grape maceration process enables a proper selection criterion for wine yeasts to improve colour extraction, technological parameters and antioxidant activity of Malbec wine. This work shows that and have a high enzymatic potential for oenological purposes.
PubMed: 36816877
DOI: 10.17113/ftb.60.04.22.7777 -
Journal of Fungi (Basel, Switzerland) Oct 2022The aim of this study was to investigate the effects of purified β-glucosidases from SLY-4, F2-24, and HX-13 (named as SLY-4E, F2-24E, and HX-13E, respectively) on...
The aim of this study was to investigate the effects of purified β-glucosidases from SLY-4, F2-24, and HX-13 (named as SLY-4E, F2-24E, and HX-13E, respectively) on the flavor complexity and typicality of wines. Cabernet Sauvignon wines were fermented by with the addition of SLY-4E, F2-24E, and HX-13E; the fermentation process and characteristics of wines were analyzed. The addition of SLY-4E, F2-24E, and HX-13E into must improved the contents of terpenes, higher alcohols, and esters, and decreased the contents of C compounds and fatty acids, which enhanced the fruity, floral, and taste aspects, reducing the unpleasant green of wines with no significant difference in their appearance. β-glucosidases from different yeast species produced different aroma compound profiles which presented different flavor and quality. F2-24EW had the best effect on flavor and quality of wine followed by SLY-4EW and HX-13EW. These research results can provide references for the use of β-glucosidases from non- yeasts to improve the flavor complexity, typicality, and quality of wines.
PubMed: 36294622
DOI: 10.3390/jof8101057 -
Foods (Basel, Switzerland) Aug 2023Exploitation of the biodiversity of native wine yeast is a means of modifying the sensory characteristics of wine. Samples from different regions in China were analysed...
Exploitation of the biodiversity of native wine yeast is a means of modifying the sensory characteristics of wine. Samples from different regions in China were analysed to screen native isolates as potential starter cultures. Through morphological and molecular biological analyses, we found six species, belonging to four genera (, , and ). These species were subjected to stress tolerance assays (ethanol, glucose, SO and pH), enzymatic activity tests (sulphite reductase activity, β-glucosidase activity and protease activity) and fermentation tests. showed a high tolerance to ethanol and completed fermentation independently. demonstrated good enzymatic activity and completed sequential fermentation. The fermentation experiment showed that the PCT4 strain had the best aroma complexity. This study provides a reference for selecting new starters from the perspective of flavour enzymes and tolerance and diversifying the sensory quality of wines from the region.
PubMed: 37628071
DOI: 10.3390/foods12163073 -
Foods (Basel, Switzerland) May 2023The use of indigenous yeasts for the production of wines is a tool to defend the typicity of a particular region. The selection of appropriate indigenous yeasts ensures...
The use of indigenous yeasts for the production of wines is a tool to defend the typicity of a particular region. The selection of appropriate indigenous yeasts ensures the maintenance of oenological characteristics by simulating spontaneous alcoholic fermentation (AF) while avoiding the risks of stuck or sluggish fermentations. In this study, autochthonous yeasts from Verdejo grape juice (Appellation of Origin Rueda) were selected, identified, and characterized to exploit the characteristics of the 'terroir'. The fermentation capacity of seven strains was studied individually at the laboratory scale. The most suitable strains (: , , and ) and co-inoculated with were characterized at the pilot scale. The fermentation kinetics, bioproduct release, volatile composition, and sensory profile of the wines were evaluated. Significant differences were found, especially in the aroma profile. In particular, and co-inoculated with produced higher amounts of ethyl esters and acetates and lower amounts of higher alcohols than the spontaneous AF. Wines inoculated with indigenous yeasts had higher sensory scores for fruit aromas and overall rating. The selection of indigenous yeasts improved the aroma of Verdejo wines and could contribute to determining the wine typicity of the wine region.
PubMed: 37174426
DOI: 10.3390/foods12091888 -
Frontiers in Microbiology 2022Milky disease caused by fungus has significantly harmed the Chinese mitten crab aquaculture industry. However, the effect of infection on the metabolism and...
Milky disease caused by fungus has significantly harmed the Chinese mitten crab aquaculture industry. However, the effect of infection on the metabolism and intestinal flora of the crab remains unclear. In this study, we aimed to explore the changes in the metabolism and intestinal flora after 48 h of infection with , using metabolomic and metagenomic analyses. Metabolomic analysis results revealed 420 significantly different metabolites between the infected and control groups, and these metabolites were enriched in 58 metabolic pathways. infection decreased the levels of metabolites related to amino acid biosynthesis, the tricarboxylic acid cycle, as well as lysine, histidine, linolenic, arachidonic, and linoleic acid metabolism. These results indicated that infection significantly affected the energy metabolism, growth, and immunity of . The results of metagenomic analysis showed that the anaerobes and ascomycetes populations significantly increased and decreased, respectively, after infection. These changes in intestinal flora significantly upregulated metabolic and synthetic pathways while downregulating immunity-related pathways. The results of integrated metabolomic and metagenomic analyses showed that 55 differentially expressed genes and 28 operational taxonomic units were correlated with 420 differential metabolites. Thus, the intestinal flora changes caused by infection also affected the metabolites. This study provides novel insights into the metabolic-and intestinal microflora-based effects of infection in , as well as a theoretical basis for the interaction between fungi and crustaceans.
PubMed: 36212869
DOI: 10.3389/fmicb.2022.990737 -
Journal of Food Science and Technology Dec 2020The effects of the inoculation method of BV818 and non- yeast P3-3 and the fermentation temperature on the volatile profiles of red pitaya wine were investigated in...
The effects of the inoculation method of BV818 and non- yeast P3-3 and the fermentation temperature on the volatile profiles of red pitaya wine were investigated in the present study. Although the growth of P3-3 was inhibited by BV818 in the mixed inoculations, simultaneous and sequential inoculations promoted the production of seven volatiles, including higher alcohols (propan-1-ol, 3-methyl-1-butanol and phenethyl alcohol), esters (ethyl decanoate and diethyl succinate), acid (2-ethylhexanoic acid), and ketone (acetoin). Sequential inoculation produced the largest total content of volatile compounds and exhibited the best in the global aroma. The red pitaya wine produced in different inoculations can be separated by its main volatile components. Furthermore, the highest total content was yielded at 25 °C for alcohols and at 21 °C for esters and acids. Within an experimental range of 17 °C to 29 °C, the contents of benzaldehyde and acetoin decreased with the increase in temperature, whereas the change in 4-ethyl-2-methoxyphenol content was the opposite. The similarly high total contents of volatiles and global aroma score were yielded via sequential inoculation at 21 °C and 25 °C. Therefore, the desired red pitaya wine can be effectively produced by modulating the inoculation method and fermentation temperature.
PubMed: 33087960
DOI: 10.1007/s13197-020-04484-5 -
Microbial Biotechnology Sep 2020In winemaking, the use of alternative yeast starters is becoming increasingly popular. They contribute to the diversity and complexity of wine sensory features and are...
In winemaking, the use of alternative yeast starters is becoming increasingly popular. They contribute to the diversity and complexity of wine sensory features and are typically used in combination with Saccharomyces cerevisiae, to ensure complete fermentation. This practice has drawn the interest on interactions between different oenological yeasts, which are also relevant in spontaneous and conventional fermentations, or in the vineyard. Although several interactions have been described and some mechanisms have been suggested, the possible involvement of extracellular vesicles (EVs) has not yet been considered. This work describes the production of EVs by six wine yeast species (S. cerevisiae, Torulaspora delbrueckii, Lachancea thermotolerans, Hanseniaspora uvarum, Candida sake and Metschnikowia pulcherrima) in synthetic grape must. Proteomic analysis of EV-enriched fractions from S. cerevisiae and T. delbrueckii showed enrichment in glycolytic enzymes and cell-wall-related proteins. The most abundant protein found in S. cerevisiae, T. delbrueckii and L. thermotolerans EV-enriched fractions was the enzyme exo-1,3-β-glucanase. However, this protein was not involved in the here-observed negative impact of T. delbrueckii extracellular fractions on the growth of other yeast species. These findings suggest that EVs may play a role in fungal interactions during wine fermentation and other aspects of wine yeast biology.
Topics: Candida; Extracellular Vesicles; Fermentation; Hanseniaspora; Metschnikowia; Phylogeny; Proteomics; Saccharomyces cerevisiae; Saccharomycetales; Vitis; Wine
PubMed: 32578397
DOI: 10.1111/1751-7915.13614 -
Parasitology Sep 2022Transgenerational plasticity can help organisms respond rapidly to changing environments. Most prior studies of transgenerational plasticity in host–parasite...
Transgenerational plasticity can help organisms respond rapidly to changing environments. Most prior studies of transgenerational plasticity in host–parasite interactions have focused on the host, leaving us with a limited understanding of transgenerational plasticity of parasites. We tested whether exposure to elevated temperatures while spores are developing can modify the ability of those spores to infect new hosts, as well as the growth and virulence of the next generation of parasites in the new host. We exposed to its naturally co-occurring fungal parasite , rearing the parasite at cooler (20°C) or warmer (24°C) temperatures and then, factorially, using those spores to infect at 20 and 24°C. Infections by parasites reared at warmer past temperatures produced more mature spores, but only when the current infections were at cooler temperatures. Moreover, the percentage of mature spores was impacted by both rearing and current temperatures, and was highest for infections with spores reared in a warmer environment that infected hosts in a cooler environment. In contrast, virulence was influenced only by current temperatures. These results demonstrate transgenerational plasticity of parasites in response to temperature changes, with fitness impacts that are dependent on both past and current environments.
Topics: Animals; Daphnia; Host-Parasite Interactions; Parasites; Temperature; Virulence
PubMed: 36043359
DOI: 10.1017/S0031182022001056 -
Annals of Botany Jun 2018Flowers can be highly variable in nectar volume and chemical composition, even within the same plant, but the causes of this variation are not fully understood. One...
BACKGROUND AND AIMS
Flowers can be highly variable in nectar volume and chemical composition, even within the same plant, but the causes of this variation are not fully understood. One potential cause is nectar-colonizing bacteria and yeasts, but experimental tests isolating their effects on wildflowers are largely lacking. This study examines the effects of dominant species of yeasts and bacteria on the hummingbird-pollinated shrub, Mimulus aurantiacus, in California.
METHODS
Wildflowers were inoculated with field-relevant titres of either the yeast Metschnikowia reukaufii or the bacterium Neokomagataea sp. (formerly Gluconobacter sp.), both isolated from M. aurantiacus nectar. Newly opened flowers were bagged, inoculated, harvested after 3 d and analysed for microbial abundance, nectar volume, and sugar and amino acid concentration and composition.
KEY RESULTS
Yeast inoculation reduced amino acid concentration and altered amino acid composition, but had no significant effect on nectar volume or sugar composition. In contrast, bacterial inoculation increased amino acid concentration, enhanced the proportion of nectar sugars comprised by monosaccharides, and reduced nectar volume.
CONCLUSIONS
The results presented suggest that microbial inhabitants of floral nectar can make nectar characteristics variable among flowers through divergent effects of yeasts and bacteria on nectar chemistry and availability, probably modifying plant-pollinator interactions.
Topics: Amino Acids; Flowers; Gluconobacter; Metschnikowia; Mimulus; Plant Nectar; Sugars
PubMed: 29562323
DOI: 10.1093/aob/mcy032 -
Microorganisms Jan 2022() is responsible for grape infection and damage to the winemaking and table grape sectors. Although anti- chemicals are available, they are considered unsustainable...
BACKGROUND
() is responsible for grape infection and damage to the winemaking and table grape sectors. Although anti- chemicals are available, they are considered unsustainable for resistance phenomenon and adverse effects on the environment and human health. Research is focused on developing alternative approaches, such as exploiting biological control agents (BCAs). In this context, 19 yeasts of the genera , , , and were tested as antimicrobial agents against development.
METHODS
A combination of in vitro tests based on dual-culture methods, volatile organic compound production assay, laboratory tests on grape berries (punctured and sprayed with yeasts) and field experiments based on yeast treatments on grapes in vineyards allowed the selection of two potential BCAs.
RESULTS
DiSVA 269 and DiSVA 211 exhibited the best ability to contain the development of , showing the severity, the decay and the McKinney index lower than a commercial biological formulation consisting of a mixture of two different strains, which were used as positive controls.
CONCLUSIONS
The results indicated that the selected strains were effective BCA candidates to counteract in the field, applying them in the partial or total replacement of conventional treatments.
PubMed: 35208653
DOI: 10.3390/microorganisms10020200