scholarly journals Subcritical Water Extraction of Phenolic Compounds from Onion Skin Wastes (Allium cepa cv. Horcal): Effect of Temperature and Solvent Properties

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1233
Author(s):  
Óscar Benito-Román ◽  
Beatriz Blanco ◽  
María Teresa Sanz ◽  
Sagrario Beltrán
Keyword(s):  
High Temperature ◽  
Phenolic Compounds ◽  
Subcritical Water ◽  
Agricultural Waste ◽  
Added Value ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Total Flavonoids ◽  
Onion Skin ◽  
Solvent Properties

The valorization of onion skin wastes (OSW) through the extraction, identification, and quantification of phenolic compounds was studied in this work, using subcritical water in a semicontinuous extractor (2.5 mL/min; 105–180 °C; 5 MPa). The extraction of flavonoids resulted to be fast (<30 min) and temperature sensitive (maximum at 145 °C; total flavonoids, 27.4 ± 0.9 mg/g dry OSW (DOSW)). The experimental results were fitted to the Weibull model. The influence of the solvent properties on the flavonoids quantification was found to be critical. A precipitate was formed once the extracts cooled down. If removed, a significant fraction of the high temperature extracted flavonoids (as much as 71%, at 180 °C) was lost. Such a condition affected especially those compounds that show extremely low solubility in water at room temperature, whereas quercetin glycosylated derivatives were less affected by the polarity change of the medium induced by the temperature change. It was demonstrated that it is necessary to re-dissolve the subcritical water extracts by the addition of ethanol, which led to a medium with a polarity equivalent to that obtained with water at high temperature. At 145 °C, quercetin (15.4 ± 0.4 mg/g DOSW) and quercetin-4′-glucoside (8.4 ± 0.1 mg/g DOSW) accounted for the 90% of the total flavonoids identified. By recovering high added value bioactive compounds from OSW the principles of circular economy were fulfilled, providing a new use for this agricultural waste.

Computational Models for High-Temperature Multilayered Composite Plates and Shells

1992 ◽  
Vol 45 (10) ◽  
pp. 419-446 ◽  
Author(s):  
Ahmed K. Noor ◽  
W. Scott Burton
Keyword(s):  
High Temperature ◽  
Computational Models ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Composite Plates ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Composite Models ◽  
Sandwich Plates And Shells ◽  
Plates And Shells

The focus of this review is on the hierarchy of composite models, predictor-corrector procedures, the effect of temperature-dependence of material properties on the response, and the sensitivity of the thermomechanical response to variations in material parameters. The literature reviewed is devoted to the following eight application areas: Heat transfer; thermal stresses; curing, processing and residual stresses; bifurcation buckling; vibrations of heated plates and shells; large deflection and postbuckling problems; and sandwich plates and shells. Extensive numerical results are presented showing the effects of variation in the lamination and geometric parameters of temperature-sensitive angle-ply composite plates on the accuracy of thermal buckling response, and the sensitivity derivatives predicted by nine different modeling approaches (based on two-dimensional theories). The standard of comparison is taken to be the exact three-dimensional thermoelasticity solutions. Some future directions for research on the modeling of high-temperature multilayered composites are outlined.

scholarly journals Improving the Quality of Bio-Oil Produced from Rice Husk Pyrolysis by Extraction of its Phenolic Compounds

2020 ◽  
Vol 8 (2) ◽  
pp. 90-100 ◽  
Author(s):  
Dewi Selvia Fardhyanti ◽  
Achmad Chafidz ◽  
Bayu Triwibowo ◽  
Haniif Prasetiawan ◽  
Novia Noor Cahyani ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Distribution Coefficient ◽  
Phenolic Compound ◽  
Rice Husk ◽  
Agricultural Waste ◽  
Raw Material ◽  
Effect Of Temperature ◽  
Bio Oil

Rice husk is an agricultural waste which contains 50% cellulose, 25%-30% lignin and 15%-20% silica. It can be used as raw material of bio-oil. Bio-oil is liquid which produced by pyrolysis process. Bio-oil can be produced from the rice husk at 773 and 873 K. The main component of Bio-oil from rice husk pyrolysis at 773 and 873 K is phenolic compounds about 47.98% and 62.65%, respectively. It causes corrosive, low heating value, high acidity, high viscosity and unstable that causing an engine damage. The presence of phenolic compound decreases the quality of bio-oil. Therefore, it needs a process such as liquid-liquid extraction to reduce the phenolic compound using 80% methanol and 80% chloroform as a solvent. The extract and raffinate phase were analyzed using UV-Vis spectrophotometer. The aim of this research determine the effect of temperature pyrolysis for the characterization of bio-oil, the stirring speed and the temperature of the extraction for the distribution coefficient and the yield of phenolic compound. The results showed that the characterization of bio-oil produced from rice husk pyrolysis at 773 and 873 K are densities 1,040 and 1,042 Kg/m3; viscosities 9.3488 and 9.5007 cSt; acid numbers 46.75 and 52.45 mg KOH/g; pH 2.5 and 3; flash points 426 and 423 K and heating values 3.229 and 3.339 MJ/kg, respectively. The highest distribution coefficient and yield were obtained at 323 K and a stirring speed of 250 rpm. The distribution coefficient of bio-oil produced by pyrolysis at 773 and 873 K is 1.504, and 1.528, respectively. The yields of bio-oil produced by pyrolysis at 773 and 873 K are 58.885%, and 48.429%, respectively.  

scholarly journals By-Products of Camu-Camu [Myrciaria dubia (Kunth) McVaugh] as Promising Sources of Bioactive High Added-Value Food Ingredients: Functionalization of Yogurts

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 70 ◽  
Author(s):  
Natália Conceição ◽  
Bianca R. Albuquerque ◽  
Carla Pereira ◽  
Rúbia C. G. Corrêa ◽  
Camila B. Lopes ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Phenolic Compounds ◽  
Food System ◽  
Food Additives ◽  
Added Value ◽  
Phenolic Profile ◽  
Food Ingredients ◽  
Myrciaria Dubia ◽  
By Products ◽  
Fruit Part

Camu-camu (Myrciaria dubia (Kunth) McVaugh) is a fruit economically relevant to the Amazon region, mostly consumed in the form of processed pulp. Our aim was to perform an unprecedented comparative study on the chemical composition and bioactivities of the camu-camu pulp and industrial bio-residues (peel and seed), and then the most promising fruit part was further explored as a functionalized ingredient in yogurt. A total of twenty-three phenolic compounds were identified, with myricetin-O-pentoside and cyanindin-3-O-glucoside being the main compounds in peels, followed by p-coumaroyl hexoside in the pulp, and ellagic acid in the seeds. The peel displayed the richest phenolic profile among samples, as well as the most significant antibacterial (MICs = 0.625–10 mg/mL) and anti-proliferative (GI50 = 180 µg/mL against HeLa cells) activities. For this reason, it was selected to be introduced in a food system (yogurt). Taken together, our results suggest the possibility of using the camu-camu peel as a source of food additives.

scholarly journals The modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo, China

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rui Zhang ◽  
Yujie Meng ◽  
Hejia Song ◽  
Ran Niu ◽  
Yu Wang ◽  
...  
Keyword(s):  
Air Pollution ◽  
High Temperature ◽  
Air Pollutants ◽  
Meteorological Data ◽  
Effect Of Temperature ◽  
Distributed Lag ◽  
Modification Effect ◽  
Incidence Risk ◽  
The Impact ◽  
The Relationship

Abstract Background Although exposure to air pollution has been linked to many health issues, few studies have quantified the modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo, China. Methods The data of daily incidence of influenza and the relevant meteorological data and air pollution data in Ningbo from 2014 to 2017 were retrieved. Low, medium and high temperature layers were stratified by the daily mean temperature with 25th and 75th percentiles. The potential modification effect of temperature on the relationship between air pollutants and daily incidence of influenza in Ningbo was investigated through analyzing the effects of air pollutants stratified by temperature stratum using distributed lag non-linear model (DLNM). Stratified analysis by sex and age were also conducted. Results Overall, a 10 μg/m3 increment of O3, PM2.5, PM10 and NO2 could increase the incidence risk of influenza with the cumulative relative risk of 1.028 (95% CI 1.007, 1.050), 1.061 (95% CI 1.004, 1.122), 1.043 (95% CI 1.003, 1.085), and 1.118 (95% CI 1.028, 1.216), respectively. Male and aged 7–17 years were more sensitive to air pollutants. Through the temperature stratification analysis, we found that temperature could modify the impacts of air pollution on daily incidence of influenza with high temperature exacerbating the impact of air pollutants. At high temperature layer, male and the groups aged 0–6 years and 18–64 years were more sensitive to air pollution. Conclusion Temperature modified the relationship between air pollution and daily incidence of influenza and high temperature would exacerbate the effects of air pollutants in Ningbo.

scholarly journals Genetic analysis of temperature-sensitive lethal mutants of Salmonella typhimurium.

Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 625-633 ◽  
Author(s):  
M B Schmid ◽  
N Kapur ◽  
D R Isaacson ◽  
P Lindroos ◽  
C Sharpe
Keyword(s):  
High Temperature ◽  
Genetic Analysis ◽  
Salmonella Typhimurium ◽  
Complex Medium ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Anaerobic Conditions ◽  
Temperature Growth ◽  
Lethal Phenotype ◽  
Lethal Mutations

Abstract We have isolated 440 mutants of Salmonella typhimurium that show temperature-sensitive growth on complex medium at 44 degrees. Approximately 16% of the mutations in these strains have been mapped to 17 chromosomal locations; two of these chromosomal locations seem to include several essential genes. Genetic analysis of the mutations suggests that the collection saturates the genes readily mutable to a ts lethal phenotype in S. typhimurium. Physiological characteristics of the ts lethal mutants were tested: 6% of the mutants can grow at high temperature under anaerobic conditions, 17% can grow when the medium includes 0.5 M KCl, and 9% of the mutants die after a 2-hr incubation at the nonpermissive temperature. Most ts lethal mutations in this collection probably affect genes required for growth at all temperatures (not merely during high temperature growth) since Tn10 insertions that cause a temperature-sensitive lethal phenotype are rare.

scholarly journals Exploiting RNA thermometer-driven molecular bioprocess control as a concept for heterologous rhamnolipid production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philipp Noll ◽  
Chantal Treinen ◽  
Sven Müller ◽  
Lars Lilge ◽  
Rudolf Hausmann ◽  
...  
Keyword(s):  
High Titer ◽  
Production Capacity ◽  
Batch Process ◽  
Product Formation ◽  
Effect Of Temperature ◽  
Industrial Biotechnology ◽  
Temperature Sensitive ◽  
Translation Control ◽  
Rhamnolipid Production ◽  
Rna Thermometer

AbstractA key challenge to advance the efficiency of bioprocesses is the uncoupling of biomass from product formation, as biomass represents a by-product that is in most cases difficult to recycle efficiently. Using the example of rhamnolipid biosurfactants, a temperature-sensitive heterologous production system under translation control of a fourU RNA thermometer from Salmonella was established to allow separating phases of preferred growth from product formation. Rhamnolipids as bulk chemicals represent a model system for future processes of industrial biotechnology and are therefore tied to the efficiency requirements in competition with the chemical industry. Experimental data confirms function of the RNA thermometer and suggests a major effect of temperature on specific rhamnolipid production rates with an increase of the average production rate by a factor of 11 between 25 and 38 °C, while the major part of this increase is attributable to the regulatory effect of the RNA thermometer rather than an unspecific overall increase in bacterial metabolism. The production capacity of the developed temperature sensitive-system was evaluated in a simple batch process driven by a temperature switch. Product formation was evaluated by efficiency parameters and yields, confirming increased product formation rates and product-per-biomass yields compared to a high titer heterologous rhamnolipid production process from literature.

Effect of temperature on the microbial ecology of a hydrocarbon-contaminated Antarctic soil: Implications for high temperature remediation

2008 ◽  
Vol 53 (1) ◽  
pp. 115-129 ◽  
Author(s):  
Susan H. Ferguson ◽  
Shane M. Powell ◽  
Ian Snape ◽  
John A.E. Gibson ◽  
Peter D. Franzmann
Keyword(s):  
High Temperature ◽  
Microbial Ecology ◽  
Effect Of Temperature ◽  
Antarctic Soil
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