scholarly journals Yeast-Free Doughs by Zymomonas mobilis: Evaluation of Technological and Fermentation Performances by Using a Metabolomic Approach

2020 ◽  
Vol 8 (6) ◽  
pp. 792 ◽  
Author(s):  
Lorenzo Nissen ◽  
Manuela Rollini ◽  
Claudia Picozzi ◽  
Alida Musatti ◽  
Roberto Foschino ◽  
...  

This research focuses on the leavening performances and development of volatile compounds of three strains of Zymomonas mobilis in the production of yeast-free doughs. Z. mobilis DSM 3580, 424, and 473 were used in doughs supplemented with glucose and with or without NaCl. Z. mobilis produced about 10 mg ethanol/g dough, with maximum dough volumes (640–680 mL) being reached after 2 h leavening. NaCl addition postponed this parameter up to 6 h. Among organic acids, hexanoic acid resulted the highest produced compound; DSM 424 and 473 formed more propanoic, butanoic and pentanoic acid, being both negatively affected by NaCl. Esters were mainly discriminated on NaCl addition, with octanoic acid (DSM 3580), butanoic acid (DSM 424), and propanoic acid (DSM 473) ethyl esters as main components. DSM 3580 specifically produced 2-heptanal, DSM 424 2-hexadecenal, (E) and DSM 473 octanal, while DSM 424 and DSM 473 produced 2-butanone-4-hydroxy better than DSM 3580. Z. mobilis unique signatures were the production of nonanoic and undecanoic acids, 2-hexadecenal, (E), L(+)-tartaric acid diethyl ester and 3-decen-5-one, 4-methyl, (E). This outcome can pave the way for using Z. mobilis in baking goods, providing innovation possibilities in the area of yeast-free leavened products.

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 69
Author(s):  
Alberto Martínez ◽  
Rocío Velázquez ◽  
Emiliano Zamora ◽  
María L. Franco ◽  
Camille Garzo ◽  
...  

The killer strains of Torulaspora delbrueckii can be used to improve the dominance of this yeast during must fermentation. The present work analyzes its usefulness for traditional sparkling wine making. T. delbrueckii killer strain dominated base wine fermentation better than non-killer strains and produced dried wines. The foam ability of T. delbrueckii base wines was very low compared to that of Saccharomyces cerevisiae. Significant positive correlations of foam parameters were found with some amounts of C4–C16 ethyl esters and proteins, and negative correlations with some antifoam alcohols. The organoleptic quality of T. delbrueckii base wines was considered unusual for cava making. While S. cerevisiae (single or mixed with T. delbrueckii) completed the second fermentation to produce dry sparkling wines with high CO2 pressure, single T. delbrueckii did not complete this fermentation, leaving sweet wines with low CO2 pressure. Death due to CO2 pressure was much higher in T. delbrueckii than in S. cerevisiae, making any killer effect of S. cerevisiae on T. delbrueckii irrelevant. However, the organoleptic quality of cava inoculated with mixtures of the two yeast species was better than that of wine inoculated exclusively with S. cerevisiae, and no deterioration in the quality of the foam was observed.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2604
Author(s):  
Zhulin Wang ◽  
Rong Dou ◽  
Ruili Yang ◽  
Kun Cai ◽  
Congfa Li ◽  
...  

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.


1998 ◽  
Vol 4 (6) ◽  
pp. 407-418 ◽  
Author(s):  
P. Hernandez Orte ◽  
A. Guitart ◽  
V. Ferreira ◽  
J. Gracia ◽  
J. Cacho

The purpose of this work is to study the effect of maceration time (with and without pectolitic en zyme addition) on the concentrations of 18 amino acids found in must and wines of the Macabeo grape variety. The presence of enzymes had a significant effect on the relative composition of the amino acids. The maceration process, with or without enzymes, led to a decrease in amino acid con tent after 2 h of maceration. After 2 h the solid parts of the grape released amino acids into the must, with the maximum concentration reached after 6 h. A certain degree of correlation given by principal component analysis was observed between the concentration of valine, isoleucine and histidine present in the musts and the aromatic compounds in the wines related to the metabolism of the fatty acids (hexanoic acid, octanoic acid, ethyl octanoate, hexanoate and decanoate). For the wines, a high corre lation was found between valine and isobutanol and a lower value for valine with isoamyl alcohol and β-phenyl ethanol.


Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1045
Author(s):  
Marian Hýbl ◽  
Andrea Bohatá ◽  
Iva Rádsetoulalová ◽  
Marek Kopecký ◽  
Irena Hoštičková ◽  
...  

Essential oils and their components are generally known for their acaricidal effects and are used as an alternative to control the population of the Varroa destructor instead of synthetic acaricides. However, for many essential oils, the exact acaricidal effect against Varroa mites, as well as the effect against honey bees, is not known. In this study, 30 different essential oils were screened by using a glass-vial residual bioassay. Essential oils showing varroacidal efficacy > 70% were tested by the complete exposure assay. A total of five bees and five mites were placed in the Petri dishes in five replications for each concentration of essential oil. Mite and bee mortality rates were assessed after 4, 24, 48, and 72 h. The LC50 values and selectivity ratio (SR) were calculated. For essential oils with the best selectivity ratio, their main components were detected and quantified by GC-MS/MS. The results suggest that the most suitable oils are peppermint and manuka (SR > 9), followed by oregano, litsea (SR > 5), carrot, and cinnamon (SR > 4). Additionally, these oils showed a trend of the increased value of selective ratio over time. All these oils seem to be better than thymol (SR < 3.2), which is commonly used in beekeeping practice. However, the possible use of these essential oils has yet to be verified in beekeeping practice.


2006 ◽  
Vol 14 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Tim Kovacs ◽  
Manfred Kerber

The performance of a learning classifier system is due to its two main components. First, it evolves new structures by generating new rules in a genetic process; second, it adjusts parameters of existing rules, for example rule prediction and accuracy, in an evaluation step, which is not only important for applying the rules, but also for the genetic process. The two components interleave and in the case of XCS drive the pop-ulation toward a minimal, fit, non-overlapping population. In this work we attempt to gain new insights as to the relative contributions of the two components. We find that the genetic component has an additional role when using the train/test approach which is not present in online learning. We compare XCS to a system in which the rule set is restricted to the initial random population (XCS-NGA, that is, XCS No Genetic Algorithm). For small Boolean functions we can give XCS-NGA all possible rules of a particular condition length. In online learning, XCS-NGA can, given sufficiently many rules, achieve a surprisingly high classification accuracy, comparable to that of XCS. In a train/test approach, however, XCS generalises better than XCS-NGA and there seem to be limitations of XCS-NGA which cannot be overcome simply by increasing the population size. This illustrates that the requirements of a function approximator tend to differ between reinforcement learning (which is typically online) and concept learning (which is typically train/test).


2011 ◽  
Vol 480-481 ◽  
pp. 1341-1345 ◽  
Author(s):  
Dang Quan Zhang ◽  
Huai Yun Zhang ◽  
Lin Lin Guo ◽  
Kuan Peng

Liriodendron chinense (Hemsl.) Sarg (Chinese tulip tree) has a long history of utilization and plantation, but the chemical components of benzene/ethanol extractives of Liriodendron chinense (Hemsl.) Sarg leaves were unrevealed. The analytical result by method of GC/MS showed that the chemical components of benzene/ethanol extractives of freeze-dried Liriodendron chinense were identified as 55 constituent, and the main components are as: 2-Propenenitrile, 2-chloro- (13.75%), 1-Mercapto-2-heptadecanon (13.10 %), 1-Mercapto-2-heptadecanon (12.77%), Ethanol, 2-butoxy- (12.03%), 1-Docosanol (10.74%), Guanidine, (4-aminobutyl)- (5.05%), 5,10-Pentadecadiyn-1-ol, acetate (4.82%), 1,2,4-Butanetriol (3.13%), Thiophene, 2-ethyltetrahydro- (2.09%), 1-Eicosanol (2.00%), 1-Butanol, 3-methyl-, formate (1.60%), Butanoic acid (1.60%), .alpha.-D-Xylofuranoside, methyl 3,5-di-O-methyl- (1.30%), Phenol, 2,6-dimethoxy-4-(2-propenyl)- (1.29%),5.alpha.-Pregnane-12,20-dione (1.12%), Cyclopentanol (0.82%), etc. As the first report here, our result by GC/MS showed that the benzene-methanol extractive of freeze-dried leaves from Liriodendron chinense (Hemsl.) Sarg can be developed into top value-added materials of medicines and spicery.


HortScience ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 200-202 ◽  
Author(s):  
Brian K. Maynard ◽  
Nina L. Bassuk

Effects of stockplant etiolation, stem banding, exogenous auxin, and catechol on the rooting response of softwood cuttings of paperbark maple (Acer griseum Pax.) were studied. Etiolated cuttings rooted better than light-grown cuttings, while stem banding did not affect rooting percentage (light-grown, 10%; light-grown + banding, 18%; etiolated, 41%; etiolated + banding, 37%). IBA did not promote, but catechol inhibited rooting (control, 31%; IBA, 37%; catechol, 17%; IBA + catechol, 21%). Root number was increased by IBA and unaffected by catechol. The distance from the cutting base to the first emerged root was measured as an indication of auxin toxicity. IBA interacted with etiolation and stem banding to increase this distance, which was greater in catechol-treated cuttings. Chemical names used: 1,2-benzenedio1 (catechol); 1H-indole-3-butanoic acid (IBA).


2000 ◽  
Vol 83 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Vêa Pacáková ◽  
Karel Ŝtulík

Abstract A method was validated for the determination of the 2 main components of bee venom, phospholipase A2 and melittin, by capillary electrophesis (CE). Optimum resolution and selectivity were attained with a running electrolyte of 150 mM phosphoric acid, pH 1.8. The repeatability and day-to-day reproducibility of the migration times were better than 0.36 and 2.8%, respectively. The repeatability and day-to-day reproducibility of the normalized peak areas were better than 1.3 and 2.6%, respectively. The response of the UV detector at 190 nm was linear over &lt; 2 concentration decades, from 0.05 to 1.5 mg/mL, with correlation coefficients of 0.9994 for phospholipase A2 and 0.9997 for melittin. The limits of detection and quantitation were 4.5 and 15 μg/mL, respectively, for phospholipase A2 and 1.6 and 6 μg/mL, respectively, for melittin. The reproducibility of the measurements with 2 different CE instruments was satisfactory; the mean concentration and relative standard deviation (RSD) values for phospholipase A2 and melittin were 14.4% (RSD, 1.3%) and 51.4% (RSD, 1.1%), respectively, with instrument I; the corresponding values with instrument II were 14.5% (RSD, 2.8%) and 52.3% (RSD, 2.2%). The accuracy was estimated by comparison with a liquid chromatographic (LC) method. Differences between the CE and LC measurements were attributed to irreversible adsorption of the analytes on the LC column. The recoveries of phospholipase A2 and melittin with the CE method were 98.8 and 101.7%, respectively.


Author(s):  
Tarek M. Mahmoud ◽  
Tarek Abd-El-Hafeez ◽  
Ahmed Omar

With the ever-growing Web, the Websites with objectionable contents like pornography, violence, racism, etc. have been augmented rapidly during recent years. Among the offensive contents, the pornography is the most harmful one affecting children safety and causing many destructive side effects. A content filter is one or more pieces of software that work together to prevent users from viewing material found on the Internet. This paper presents an efficient content based software system for detecting and filtering pornography images in Web pages. The proposed system runs online in the background of Internet Explorer (IE) for the purpose of restricting access to pornography Web pages. Skin and face detection techniques are the main components of the proposed system. Because the proposed filter works online, the authors propose two fasting techniques that can be used to speed up the filtering system. The results obtained using the proposed system is compared with four commercial filtering programs. The success rate of the proposed filtering system is better than the considered filtering programs.


Sign in / Sign up

Export Citation Format

Share Document