scholarly journals Changes in the Concentration of Carbonyl Compounds during the Alcoholic Fermentation Process Carried out with Saccharomyces cerevisiae Yeast

2017 ◽  
Vol 66 (3) ◽  
pp. 327-334 ◽  
Author(s):  
Grzegorz Kłosowski ◽  
Dawid Mikulski ◽  
Aleksandra Rolbiecka ◽  
Bogusław Czupryński

The aim of the study was to determine the influence of the source material and the applied S. cerevisiae strain on the concentrations of carbonyl fractions in raw spirits. Acetaldehyde was the most common aldehyde found, as it accounted for 88–92% of the total amount of aldehydes. The concentration of acetaldehyde in maize, rye and amaranth mashes was highly correlated with fermentation productivity at a given phase of the process, and reached its highest value of 193.5 mg/l EtOH in the first hours of the fermentation, regardless of the yeast strain applied. The acetaldehyde concentration decreased over the time with the decreasing productivity, reaching its lowest value at the 72nd hour of the process. The final concentration of acetaldehyde depended on the raw material used (ca 28.0 mg/l EtOH for maize mashes, 40.3 mg/l EtOH for rye mashes, and 74.4 mg/l EtOH for amaranth mashes). The effect of the used yeast strain was negligible. The overall concentration of the analyzed aldehydes was only slightly higher: ca 30.3 mg/l EtOH for maize mashes, 47.8 mg/l EtOH for rye mashes, and 83.1 mg/l EtOH for amaranth mashes.

2008 ◽  
Vol 59 (4) ◽  
Author(s):  
Neculai Catalin Lungu ◽  
Maria Alexandroaei

The aim of the present work is to offer a practical methodology to realise an Arrhenius type kinetic model for a biotechnological process of alcoholic fermentation based on the Saccharomyces cerevisiae yeast. Using the experimental data we can correlate the medium temperature of fermentation with the time needed for a fermentation process under imposed conditions of economic efficiency.


2010 ◽  
Vol 11 (2) ◽  
pp. 107 ◽  
Author(s):  
Jenifer Criollo ◽  
Dagoberto Criollo ◽  
Angélica Sandoval Aldana

<p>La almendra de copoazú como producto promisorio para la industria de cosméticos, chocolate, bebidas, licores y conservas, se evaluó el proceso de fermentación variando el tiempo de remoción de la masa (24 y 48 horas) y la pulpa inicial (30 y 100%). Se tuvieron en cuenta las condiciones de los productores en el acceso a equipos de despulpado. Se cuantificó la temperatura de la masa en tres puntos (superior, medio e inferior), acidez, pH, humedad, prueba de corte y análisis sensorial. Se encontró bajo desarrollo de la temperatura de fermentación en los tratamientos con 100% de pulpa y se registraron las máximas temperaturas entre 35 y 36°C que indican deficiencias en el proceso; no se alcanzó los 40°C requeridos para la muerte del embrión. El 30% de pulpa inicial y la remoción cada 24 horas por 9 días, fueron las mejores condiciones encontradas. La optimización con 0,1% de levadura (Saccharomyces cerevisiae) aumentó la temperatura de fermentación hasta 44°C, los granos fermentados hasta 56,14% y el mayor desarrollo de sabores frutales con intensidad de 4, mostrando un mejor proceso de fermentación. El panel sensorial mostró que los licores de copoazú tienen notas frutales destacadas y bajos valores de otros sabores evaluados. Los resultados son semejantes a los cacaos criollos, conocidos en el mundo como materia prima de licores finos y de aroma.</p><p> </p><p><strong>Fermentation of the copoazu kernel (Theobroma grandiflorum [Willd. ex Spreng.] Schum.): Assessmente and process optimization</strong></p><p>The fermentation of copoazu kernels (a promising product for the cosmetics industry, chocolate, beverages, liquors and preserves) was evaluated varying the time of mass removal (24 and 48 hours) and the initial pulp (30 and 100%). This study took into account the degree of access the producers had to pulping equipment. We quantified temperature of the mass at three points (top, middle and bottom), acidity, pH, moisture, cutting test and sensory analysis. The observed temperatures during fermentation in the treatments with 100% pulp reached a maximum range between 35 and 36°C which indicated deficiencies in the process as the 40°C required for the death of the seed was not attained. Thirty percent initial pulp with removal every 24 hours for 9 days yielded the best results. Optimization with 0.1% yeast (Saccharomyces cerevisiae) increased the fermentation temperature to 44°C, augmented fermented beans to 56.14% and saw a development of fruit flavors with an intensity of 4, demonstrating a better fermentation process. The sensory panel showed that copoazu liquors have outstanding fruity notes and low levels of other evaluated flavors. The results are similar to the criollo cacao, known worldwide as a raw material for fine liquors and fragrances.</p>


2010 ◽  
Vol 72 (11-12) ◽  
pp. 1149-1156 ◽  
Author(s):  
Georgia Ch. Lainioti ◽  
John Kapolos ◽  
Lambros Farmakis ◽  
Athanasia Koliadima ◽  
George Karaiskakis

Author(s):  
José Duarte ◽  
Vera Lourenço ◽  
Belina Ribeiro ◽  
Maria Céu Saagua ◽  
Joana Pereira ◽  
...  

During the last years there has been an increasing interest in using ethanol as a substitute for fossil fuels. The bioethanol used today is mainly produced from sugar cane and cereals, but reducing the production costs of ethanol is still crucial for a viable economic process. Cellulose from vegetable biomass will be the next cheap raw material for second generation fuel ethanol production and agricultural by-products with a low commercial value, as corn stover, corn fiber and cane bagasses would become an attractive feedstock for bioethanol production.In this study, different strains of Saccharomyces cerevisiae have been screened for the ability of bioethanol production. Yeasts were grown in a synthetic liquid medium containing sucrose in batch regime and the growth rates, ethanol and biomass productions were determined as well as their growth ability in cane molasses.The results indicate that a flocculent yeast, isolated in our lab and designated by strain F, was the most promising yeast strain among those tested for continuous ethanol production. This strain was isolated from corn hydrolysates, obtained from a Portuguese distillery facility (DVT, Torres Novas, Portugal) showing highest growth rate (0.49h-1), highest ethanol yield (0.35g/g) and high flocculation capacity.The study on ethanol production in continuous reactor process with the selected yeast strain (strain F) was made on sucrose and cane molasses at different dilution rates (0.05-0.42 h-1). A steady flocculating yeast fluidized bed reactor system was established allowing the functioning of the reactor for 1000 h. Data shows that when the dilution rate rose to 0.42h-1, the highest productivity (20g/Lh) was obtained attaining an ethanol concentration in the reactor of 47g/L for sucrose and molasses media.


Author(s):  
Tatyana YONCHEVA ◽  
◽  
Hristo SPASOV ◽  
Georgi KOSTOV ◽  
◽  
...  

The influence of temperature and inoculum amount of yeast culture on the ability of the strains Saccharomyces cerevisiae Badachoni and Saccharomyces cerevisiae 24-6 to synthesize higher alcohols and aldehydes was studied. Yeast showed the highest fermentation activity at a temperature of 28oC. Neural networks had been applied and mathematical models were derived, describing with high accuracy the experimental data on the change of the total amount of higher alcohols and aldehydes in the fermentation process depending on the conditions. The higher alcohols ratio had increased during the process. The Badachoni strain revealed better ability to synthesize the studied metabolite as compared to the 24-6 strain. The Badachoni had produced the greatest amount of higher alcohols when the process occurred at 28°C, whereas the 24-6 at 24oC. The aldehydes synthesis had reached its peak during the rapid fermentation, thereafter it began to go down. The studied yeast synthesized more aldehydes when the process took place at a lower temperature. For both strains the maximum was observed under the conditions 20oС/4%. The analysis of the obtained wines had confirmed that quantitatively Badachoni produced more total higher alcohols and the 24-6 more total aldehydes. In both strains within one temperature range, in all variants, with increasing the inoculum amount of yeast culture the studied metabolites ratio went up too.


1999 ◽  
Vol 45 (4) ◽  
pp. 343-346 ◽  
Author(s):  
C Tamayo ◽  
J Ubeda ◽  
A Briones

Hydrogen sulphide formation is a problem in winemaking. One of the factors affecting formation of this unwanted metabolite is the yeast strain responsible for the process. In this experiment wines were made on a laboratory scale with different strains of H2S-producing Saccharomyces cerevisiae. The relationship between H2S production and various fermentation conditions was examined (SO2, methionine, (NH4)2SO4, (NH4)3PO4, steel, and steel-lees). The results show that in fermentations in the presence of stainless steel and lees, H2S formation is high but declines when (NH4)3PO4is added to the must.Key words: H2S formation, wine-yeast, steel-lees, wine-making, alcoholic fermentation.


2014 ◽  
Vol 62 (4) ◽  
pp. 918-926 ◽  
Author(s):  
Dongxu Cao ◽  
Maobing Tu ◽  
Rui Xie ◽  
Jing Li ◽  
Yonnie Wu ◽  
...  

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 512 ◽  
Author(s):  
Shafkat Shamim Rahman ◽  
Md. Mahboob Hossain ◽  
Naiyyum Choudhury

Bioethanol obtained from microbial fermentation can replace conventional fossil fuels to satisfy energy demand. In this respect, a fermenting isolate of Saccharomyces cerevisiae, obtained from date juice, was grown in YEPD medium as a part of a previous published research project. In this study, the isolate was tentatively characterized for alcoholic fermentation in organic kitchen waste medium, prepared from discarded fruit and vegetable peels. Fermentation in shaking condition resulted in the production of 7.3% (v/v) ethanol after 48 h, after which the pH of the medium increased slightly in response. Further research should be conducted to assess the potential of kitchen waste as a raw material in ethanol fermentation.


2019 ◽  
Vol 16 (12) ◽  
pp. 5228-5232
Author(s):  
Kiagus A. Roni ◽  
Dorie Kartika ◽  
Hasyirullah Apriyadi ◽  
Netty Herawati

Sorghum is one of the plants that can be used as raw material for making bioethanol. Sorghum has seeds with a starch composition of 73.8%, which is potential as a raw material for making bioethanol. Sorghum starch can be converted into bioethanol through the hydrolysis process (the process of converting carbohydrates into glucose) which consists of liquefaction and saccharification processes and is followed by a fermentation process. The hydrolysis method is carried out enzymatically. In this study alpha amylase and gluco amylase enzymes were used with various types of yeast including Saccharomyces cerevisiae, Rhizopus oryzae, Acetobacter xylinum, Mucor sp, and Aspergilus niger which varied with liquefaction temperatures including 80, 85, 90, 95, and 100 °C. Obtained the most optimal yeast is Saccharomyces cerevisiae with an optimal temperature of 95 °C resulting in a bioethanol concentration of 4.3%. After getting the optimal yeast and temperature, the fermentation step of the two variables is used in the next step. In the fermentation process, variations of yeast concentration and duration of fermentation were used, the optimum yeast concentration was at 2.5% with 48 hours of fermentation resulting in bioethanol concentration of 11%.


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