Effect of temperature and PH value on the stability of bioactive compounds and antioxidative activity of juice from colour‐fleshed potatoes

2019 ◽  
Vol 55 (6) ◽  
pp. 2335-2343
Author(s):  
Elżbieta Rytel ◽  
Agnieszka Tajner‐Czopek ◽  
Agnieszka Kita ◽  
Anna Sokół‐Łętowska ◽  
Alicja Z. Kucharska ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Antioxidative Activity ◽  
Ph Value ◽  
Effect Of Temperature ◽  
The Stability

Study on the Stability of Fruit Bromelain

2011 ◽  
Vol 421 ◽  
pp. 19-22 ◽  
Author(s):  
Hong Yu Liang ◽  
Mei Li ◽  
Ming Shi ◽  
An Ping Liao ◽  
Ru Chun Wu
Keyword(s):  
Metal Ions ◽  
Production Process ◽  
Ph Value ◽  
Inactivation Rate ◽  
Effect Of Temperature ◽  
Reduce Activity ◽  
Activity Loss ◽  
The Stability

In order to prevent the activity loss of bromelain activity in the production process, the effect of temperature, pH value and metal ions on bromelain activity of the extraction solution was studied. In the range, inactivation rate of bromelain activity for the extraction solution would be increased significantly when temperature exceeds 60°C. The most suitable for bromelain of casein acids hydrolysate temperature was 50-60°C;the fruit bromelain was stability at original pH value; Fe3+ and Cu2+ can strongly make bromelain reduce activity; at the same time, when the extraction solution diluted times was more than 200 times, bromelain activity didn’t basically changed.

LiMn2O4 nanopowders synthesized via gelatin-assisted sol–gel method: Optimization of pH and calcination temperature

2019 ◽  
Vol 33 (08) ◽  
pp. 1950063
Author(s):  
Nasrin Azad ◽  
Hadi Arabi ◽  
Shaban Reza Ghorbani ◽  
Ali Davodi
Keyword(s):  
Calcination Temperature ◽  
Ph Value ◽  
Sol Gel ◽  
Chelating Agent ◽  
The Other ◽  
Effect Of Temperature ◽  
Gel Method ◽  
Sol Gel Method ◽  
The Fourier Transform ◽  
The Stability

In this research, LiMn2O4 nanopowders were synthesized via sol–gel method using gelatin as a novel chelating agent. The effect of temperature and pH on the structure, morphology and particle size of synthesized powders has been investigated by the differential thermal analysis (DTA), the X-ray diffraction (XRD), the Fourier transform infrared (FTIR) and the field-emission scanning electron microscope (FESEM). The crystal structure of LiMn2O4 was completely formed without any impurity phase at a calcination temperature of 750[Formula: see text]C. The peak intensity ratio of I[Formula: see text]/I[Formula: see text], which presents the stability of LiMn2O4 structure, is bigger for the sample with pH[Formula: see text]=[Formula: see text]4 than that of the samples with pH[Formula: see text]=[Formula: see text]7 and 8. The sample with pH[Formula: see text]=[Formula: see text]4 has smaller particles of about 70 nm, with more homogeneity and less agglomeration than that of the other samples. At calcination temperature to 850[Formula: see text]C, the size of the particles has become bigger and the particle surfaces show more clarity in all samples. The effect of the pH value on electrochemical properties was studied by galvanostatic charge/discharge tests. The results show more capacity lost for the sample with pH[Formula: see text]=[Formula: see text]8 with regards to the other samples.

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

scholarly journals Solubility Data of Potential Salts in the MgO-CaO-SO2-H2O-O2 System for Process Modeling

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 50
Author(s):  
Barbara D. Weiß ◽  
Michael Harasek
Keyword(s):  
Process Modeling ◽  
Ph Value ◽  
Process Models ◽  
Solubility Data ◽  
Solid Base ◽  
International Union ◽  
The Stability ◽  
Experimental Values ◽  
So2 Absorption ◽  
Reliable Basis

This review studies unwanted precipitation reactions, which can occur in SO2 absorption processes using a magnesium hydroxide slurry. Solubility data of potential salts in the MgO-CaO-SO2-H2O system are evaluated. The reviewed data can serve as a reliable basis for process modeling of this system used to support the optimization of the SO2 absorption process. This study includes the solubility data of MgSO3, MgSO4, Mg(OH)2, CaSO3, CaSO4, and Ca(OH)2 as potential salts. The solubility is strongly dependent on the state of the precipitated salts. Therefore, this review includes studies on the stability of different forms of the salts under different conditions. The solubility data in water over temperature serve as a base for modeling the precipitation in such system. Furthermore, influencing factors such as pH value, SO2 content and the co-existence of other salts are included and available data on such dependencies are reviewed. Literature data evaluated by the International Union of Pure and Applied Chemistry (IUPAC) are revisited and additional and newer studies are supplemented to obtain a solid base of accurate experimental values. For temperatures higher than 100 °C the available data are scarce. For a temperature range from 0 to 100 °C, the reviewed investigations and data provide a good base to evaluate and adapt process models for processes in order to map precipitations issues accurately.

scholarly journals The stability of pH value in the waters of Jiaozhou Bay

2021 ◽  
Vol 829 (1) ◽  
pp. 012021
Author(s):  
Dongfang Yang ◽  
Danfeng Yang ◽  
Haixia Li ◽  
Dong Lin ◽  
Qi Wang
Keyword(s):  
Ph Value ◽  
Jiaozhou Bay ◽  
The Stability

Studies on the Coordination Reaction of VO2+ and Tannic Acid in the Tannin Extract Desulfurization

2012 ◽  
Vol 239-240 ◽  
pp. 1573-1576
Author(s):  
Zhu Qing Gao ◽  
Xiao Dong Cai ◽  
Kai Cheng Ling
Keyword(s):  
Stability Constants ◽  
Tannic Acid ◽  
Ph Value ◽  
Protonation Constants ◽  
Conditional Stability ◽  
Tannin Extract ◽  
Acid Effect ◽  
Different Temperatures ◽  
The Stability ◽  
Apparent Stability

At different temperatures, the protonation constants of tannic acid and the complex apparent stability constants between tannic acid and VO2+ were determined by using pH potentimetric method. The results showed that the protonation constants and the complex apparent stability constants slightly decreased with the raising temperature. In accordance with the pH value in the tannin extract technology, the conditional stability constants of the complex were calculated on the basis of the acid effect of tannic acid and the hydrolysis effect of VO2+. It was found that pH greatly affected the stability constants of the complex , so pH must be strictly controlled in the tannin extract technology.

The effect of temperature and time on the properties of 2D Cs2ZnBr4 perovskite nanocrystals and its application in a Schottky barrier device

2021 ◽  
Author(s):  
Olusola Akinbami ◽  
Grace N Ngubeni ◽  
Francis Otieno ◽  
Rudo Kadzutu-Sithole ◽  
Cebisa Linganiso ◽  
...  
Keyword(s):  
Solar Cell ◽  
Schottky Barrier ◽  
Effect Of Temperature ◽  
Inorganic Perovskite ◽  
Perovskite Nanocrystals ◽  
The Stability ◽  
Barrier Device

2D hybrid perovskites are promising materials for solar cell applications, in particular, cesium based perovskite nanocrystals as they offer the stability that is absent in organic-inorganic perovskite. However, the most...

scholarly journals A Novel Approach to Fabricate Foam Ceramics from Steel Slag

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Yu Zheng ◽  
Xudong Luo ◽  
Jinlong Yang ◽  
Wenlong Huo ◽  
Chi Kang
Keyword(s):  
Compressive Strength ◽  
Ph Value ◽  
Steel Slag ◽  
Raw Material ◽  
Solid Loading ◽  
Insulation Material ◽  
Ceramic Foams ◽  
Novel Approach ◽  
The Stability ◽  
First Time

A novel approach is used for fabricating steel slag foam ceramics based on the particle-stabilized foaming method. In this work, steel slag was used as the raw material and propyl gallate (PG) was used as the surface modifier. For the first time, steel slag ceramic foams were successfully fabricated based on particle-stabilized foams. The results show that the stability of the ceramic foams was closely related to the pH value and PG concentration. The porosity and compressive strength could be controlled by changing the solid loading of steel slag and sintering temperature. The porosity of steel slag foam ceramics ranged from 85.6% to 62.53%, and the compressive strength was from 1.74 MPa to 10.42 MPa. The thermal conductivity of steel slag foam ceramics was only 0.067 W (m·K)−1, which shows that it could be used as a thermal insulation material.

Experimental Study of Propagation Stage of Pitting Corrosion of 20Cr13 Steel

2008 ◽  
Vol 38 ◽  
pp. 238-247
Author(s):  
A.D. Davydov ◽  
V.S. Shaldaev
Keyword(s):  
Pitting Corrosion ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Ph Value ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Pitting Potential ◽  
Free Corrosion Potential ◽  
External Power Source ◽  
Corrosion Of Steel

The initiation and development of pitting corrosion of steel 20Cr13 in the NaCl solutions with various concentrations, temperatures, and pH values are studied under the potentiostatic conditions and at the free-corrosion potential. The pitting and repassivation potentials are determined using the method of cycling voltammetry. In spite of the fact that thus determined pitting potential is more positive than the corrosion potential (the open-circuit potential Eo.c.), the long-term experiments, which were performed at the free-corrosion potential, showed that pitting corrosion takes place without imposing a potential using an external power source. It is concluded that the probability of pitting corrosion of steel should be determined by comparing the corrosion potential (the open-circuit potential) with the repassivation potential Erp. Steel 20Cr13 is prone to the pitting corrosion, because Erp is more negative than Eo.c.. In the potentiostatic experiments, the variation of the depth and diameter of pits and their number with the time and the effect of temperature and electrode rotation on the pit propagation are studied. The results, which were obtained at the free-corrosion potential, are much less reproducible. In this case, in contrast to the potentiostatic conditions, the pit depth increased only slightly and the pit width increased to a larger extent. The effect of concentration, pH value, and temperature of NaCl solutions on the pit propagation is considered. It is concluded that the data on the development of pitting corrosion under the potentiostatic conditions can be hardly extended to the conditions of free corrosion potential.

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