scholarly journals Mannoprotein Content and Volatile Molecule Profiles of Trebbiano Wines Obtained by Saccharomyces cerevisiae and Saccharomyces bayanus Strains

Fermentation ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 66
Author(s):  
Braschi ◽  
Ricci ◽  
Grazia ◽  
Versari ◽  
Patrignani ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethyl Ester ◽  
Octanoic Acid ◽  
Acid Ethyl Ester ◽  
Principal Component ◽  
Decanoic Acid ◽  
Aroma Compound ◽  
Propanoic Acid ◽  
Saccharomyces Bayanus ◽  
Volatile Profiles

: The production of volatile compounds has become one of the major technological features for yeast selection. In fact, although the aromatic profile of the wine is the sum of varietal-, pre-, post-, and fermentative-aroma compound, yeasts affect the quality of the grape from maturation throughout fermentation, metabolizing sugars and other components into alcohols, esters, organic acids, and aldehydes. Among the new technological features, the production of mannoproteins has gained interest. From this perspective, the main aim of this work was to characterize 9 strains of Saccharomyces cerevisiae and 1 of Saccharomyces bayanus for their volatile profiles and the release of mannoproteins. The strains were inoculated in Trebbiano musts and incubated at 15 °C; at the end of fermentation the wines were evaluated by GC/MS/SPME for their volatile profiles and mannoprotein content by enzymatic assay. The strains were inoculated at level ranging between 4.9 and 6.3 log CFU/mL but only the strains L318 and 12233X6167 were able to reach values of 7.5 log CFU/mL. The aromatic profiles resulted in a strain-specific fingerprinting. According to the principal component analysis, the wines produced by the strains L288, L234, and L318 were characterized by the presence of propanoic acid, butanol, octanoic acid, and 3 methyl pentanol while the wine obtained by the strain 12233x35G2 was characterized by the presence of propanoic acid, butanol, octanoic acid and 3 methyl pentanol while the strain 12233x35G2 was characterized by the presence of decanoic acid ethyl ester, heptanoic acid ethyl ester, and acetic acid 2 phenetyl ester. Regarding mannoproteins, the highest concentration was achieved by strain12233x6167 (104 mg/L). The data allowed to select the strains endowed with the best fermentation performances in terms of aroma and mannoproteins release.

scholarly journals The Honey Volatile Code: A Collective Study and Extended Version

Foods ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 508 ◽  
Author(s):  
Karabagias ◽  
Karabagias ◽  
Badeka
Keyword(s):  
Ethyl Ester ◽  
Octanoic Acid ◽  
Solid Phase ◽  
Hierarchical Classification ◽  
Acid Ethyl Ester ◽  
Decanoic Acid ◽  
Nonanoic Acid ◽  
Dodecanoic Acid ◽  
Tetradecanoic Acid ◽  
Geranyl Acetone

Background: The present study comprises the second part of a new theory related to honey authentication based on the implementation of the honey code and the use of chemometrics. Methods: One hundred and fifty-one honey samples of seven different botanical origins (chestnut, citrus, clover, eucalyptus, fir, pine, and thyme) and from five different countries (Egypt, Greece, Morocco, Portugal, and Spain) were subjected to analysis of mass spectrometry (GC-MS) in combination with headspace solid-phase microextraction (HS-SPME). Results: Results showed that 94 volatile compounds were identified and then semi-quantified. The most dominant classes of compounds were acids, alcohols, aldehydes, esters, ethers, phenolic volatiles, terpenoids, norisoprenoids, and hydrocarbons. The application of classification and dimension reduction statistical techniques to semi-quantified data of volatiles showed that honey samples could be distinguished effectively according to both botanical origin and the honey code (p < 0.05), with the use of hexanoic acid ethyl ester, heptanoic acid ethyl ester, octanoic acid ethyl ester, nonanoic acid ethyl ester, decanoic acid ethyl ester, dodecanoic acid ethyl ester, tetradecanoic acid ethyl ester, hexadecanoic acid ethyl ester, octanal, nonanal, decanal, lilac aldehyde C (isomer III), lilac aldehyde D (isomer IV), benzeneacetaldehyde, alpha-isophorone, 4-ketoisophorone, 2-hydroxyisophorone, geranyl acetone, 6-methyl-5-hepten-2-one, 1-(2-furanyl)-ethanone, octanol, decanol, nonanoic acid, pentanoic acid, 5-methyl-2-phenyl-hexenal, benzeneacetonitrile, nonane, and 5-methyl-4-nonene. Conclusions: New amendments in honey authentication and data handling procedures based on hierarchical classification strategies (HCSs) are exhaustively documented in the present study, supporting and flourishing the state of the art.

scholarly journals Elucidation of the Volatilome of Packaged Spanish-Style Green Olives of Conservolea and Halkidiki Varieties Using SPME-GC/MS

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 75
Author(s):  
Alexandra Nanou ◽  
Athanasios Mallouchos ◽  
Efstathios Z. Panagou
Keyword(s):  
Volatile Compounds ◽  
Solid Phase ◽  
Acid Ethyl Ester ◽  
Volatile Components ◽  
Propanoic Acid ◽  
Qualitative Composition ◽  
Organoleptic Characteristics ◽  
Increasing Trend ◽  
Volatile Profiles ◽  
Over Time

Olives are characterized by a wide variety of volatile compounds, which are primarily products of microbial metabolism that contribute to the organoleptic characteristics of the final product and especially to its flavor. The volatilome in Spanish-style processed green olives of Conservolea and Halkidiki cultivars were analytically characterized. A solid phase micro-extraction (SPME) technique was used for the extraction of volatile components from the olive samples that were further identified and quantified by gas chromatography coupled to mass spectrometry (GC–MS). Eighty-eight (88) compounds were identified, including several aldehydes, ketones, acids, terpenes, but mainly esters and alcohols. Results showed that there were no significant differences in the qualitative composition of the volatile profiles between the two varieties. Acetic and propanoic acids, thymol, ethanol, 2-butanol, 1-propanol, ethyl acetate as well as ethyl propanoate were the most dominant compounds found in both cultivars. However, some quantitative differences were spotted between the two varieties regarding some of the identified volatile compounds. The quantity of 2-butanol was higher in the Halkidiki variety, while propanoic acid ethyl ester was found in higher amounts in the Conservolea variety. Furthermore, differences in the quantities of some volatile compounds over time were observed. Most of the identified compounds presented an increasing trend during storage.

scholarly journals Changes in Phenols, Polysaccharides and Volatile Profiles of Noni (Morinda citrifolia L.) Juice during Fermentation

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2604
Author(s):  
Zhulin Wang ◽  
Rong Dou ◽  
Ruili Yang ◽  
Kun Cai ◽  
Congfa Li ◽  
...  
Keyword(s):  
Octanoic Acid ◽  
Solid Phase ◽  
Principal Component ◽  
Hexanoic Acid ◽  
Morinda Citrifolia ◽  
Gas Chromatography Mass Spectrometry ◽  
Aroma Characteristics ◽  
Volatile Profiles ◽  
The Difference ◽  
Aroma Components

The change in phenols, polysaccharides and volatile profiles of noni juice from laboratory- and factory-scale fermentation was analyzed during a 63-day fermentation process. The phenol and polysaccharide contents and aroma characteristics clearly changed according to fermentation scale and time conditions. The flavonoid content in noni juice gradually increased with fermentation. Seventy-three volatile compounds were identified by solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC-MS). Methyl hexanoate, 3-methyl-3-buten-1-ol, octanoic acid, hexanoic acid and 2-heptanone were found to be the main aroma components of fresh and fermented noni juice. A decrease in octanoic acid and hexanoic acid contents resulted in the less pungent aroma in noni juice from factory-scale fermentation. The results of principal component analysis of the electronic nose suggested that the difference in nitrogen oxide, alkanes, alcohols, and aromatic and sulfur compounds, contributed to the discrimination of noni juice from different fermentation times and scales.

scholarly journals Assessment of Volatile Aromatic Compounds in Smoke Tainted Cabernet Sauvignon Wines Using a Low-Cost E-Nose and Machine Learning Modelling

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5108
Author(s):  
Vasiliki Summerson ◽  
Claudia Gonzalez Viejo ◽  
Alexis Pang ◽  
Damir D. Torrico ◽  
Sigfredo Fuentes
Keyword(s):  
Machine Learning ◽  
Ethyl Ester ◽  
Aromatic Compounds ◽  
Octanoic Acid ◽  
Low Cost ◽  
Acid Ethyl Ester ◽  
High Accuracy ◽  
High Density ◽  
Wine Aroma ◽  
Volatile Aromatic Compounds

Wine aroma is an important quality trait in wine, influenced by its volatile compounds. Many factors can affect the composition and levels (concentration) of volatile aromatic compounds, including the water status of grapevines, canopy management, and the effects of climate change, such as increases in ambient temperature and drought. In this study, a low-cost and portable electronic nose (e-nose) was used to assess wines produced from grapevines exposed to different levels of smoke contamination. Readings from the e-nose were then used as inputs to develop two machine learning models based on artificial neural networks. Results showed that regression Model 1 displayed high accuracy in predicting the levels of volatile aromatic compounds in wine (R = 0.99). On the other hand, Model 2 also had high accuracy in predicting smoke aroma intensity from sensory evaluation (R = 0.97). Descriptive sensory analysis showed high levels of smoke taint aromas in the high-density smoke-exposed wine sample (HS), followed by the high-density smoke exposure with in-canopy misting treatment (HSM). Principal component analysis further showed that the HS treatment was associated with smoke aroma intensity, while results from the matrix showed significant negative correlations (p < 0.05) were observed between ammonia gas (sensor MQ137) and the volatile aromatic compounds octanoic acid, ethyl ester (r = −0.93), decanoic acid, ethyl ester (r = −0.94), and octanoic acid, 3-methylbutyl ester (r = −0.89). The two models developed in this study may offer winemakers a rapid, cost-effective, and non-destructive tool for assessing levels of volatile aromatic compounds and the aroma qualities of wine for decision making.

Synthesis of (R)-(-)-Mandelic Acid Ethyl Ester by Asymmetric Reduction of Ethyl Benzoylformate with Yeast Cells

2012 ◽  
Vol 560-561 ◽  
pp. 273-278
Author(s):  
Zhi Min Ou ◽  
Ying Kang Nan
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethyl Ester ◽  
Mandelic Acid ◽  
Cell Concentration ◽  
Asymmetric Reduction ◽  
Acid Ethyl Ester ◽  
Yeast Cells ◽  
Biotransformation Process ◽  
Set Up ◽  
Ethyl Benzoylformate

An efficient yeast cell biotransformation process was set up for asymmetric synthesis of (R)-(-)-mandelic acid ethyl ester, a key drug intermediate. Saccharomyces cerevisiae 21 was selected as optimum strain for biotransformation. The optimum reduction conditions are as follows: substrate concentration 20 g/L, cell concentration 140 g/L, reaction time 36 h, temperature 30 0C. Conversion and enantiometric excess of (R)-(-)-mandelic acid ethyl ester reached 99.8 % and 100%.

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