scholarly journals Effect of heat treatment on re-solubility of potato proteins isolated from industrial potato fruit juice

2008 ◽  
Vol 54 (No. 4) ◽  
pp. 170-175 ◽  
Author(s):  
V. Bártová ◽  
J. Bárta
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Molecular Weight ◽  
Protease Inhibitors ◽  
Fruit Juice ◽  
Protein Isolate ◽  
Tuber Protein ◽  
Sds Page ◽  
Carboxypeptidase Inhibitor ◽  
Thermal Stability Of

The contribution deals with thermal stability and re-solubility of potato tuber proteins isolated by ethanol precipitation from industrial potato fruit juice. The protein isolate was exposed to the temperatures ranging from 25°C to 70°C. Patatin, the tuber protein with a high nutritious value, was detected by SDS-PAGE in the region of 39–43 kDa. Patatin was evaluated as thermal sensitive – temperatures above 30°C caused its strong insolubility. Potato protease inhibitors were detected in the region from 4.3 to 24 kDa. Thermal stability of potato protease inhibitors (region from 25 to 14 kDa) was higher, although the temperatures above 45°C caused denaturation and insolubility of most of the protease inhibitors. Extremely thermo-stable was potato carboxypeptidase inhibitor with molecular weight of 4.3 kDa that remained soluble even after having been exposed to the highest temperatures.

Thermostable α-glucosidase produced by Bacillus caldovelox DSM411

1987 ◽  
Vol 33 (7) ◽  
pp. 614-618 ◽  
Author(s):  
Mary Giblin ◽  
Catherine T. Kelly ◽  
William M. Fogarty
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Isoelectric Point ◽  
Gel Filtration ◽  
Single Band ◽  
Original Activity ◽  
Protamine Sulphate ◽  
Barium Strontium ◽  
Sds Page ◽  
Thermal Stability Of

Bacillus caldovelox produces an intracellular α-glucosidase (EC 3.2.1.20). It is the most thermostable microbial α-glucosidase reported to date and a number of its properties are outlined here. It was purified by treatment with protamine sulphate and gel filtration on Sephadex G-150 and gave a single band on SDS–PAGE. The enzyme had highest activity on p-nitrophenyl-α-D-glucoside, which was 2.04 times higher than the activity on maltose, and it was inactive towards isomaltose. It had a molecular weight of 30 000 and an isoelectric point of pH 5.0. The enzyme operated most efficiently at pH 5.5–6.0 and at 50–60 °C. It possessed considerable pH stability, retaining 80% or more activity in the range pH 4.0–9.0. α-Glucosidases tend to be very unstable, but this enzyme was fully stable up to 60 °C for 1 h and retained 51% of its original activity on incubation at 70 °C over the same period. The presence of histidine, cysteine, and manganous ions improved the thermal stability of the enzyme considerably. EDTA, α,α′-dipyridyl, o-phenanthroline, barium, strontium, manganous ions, and glucose stimulated activity, while Tris, ribose, glucono-δ-lactone, and phenyl-α-D-glucoside inhibited activity.

Thermal stability of phase-separated nanograin structure during heat treatment

2021 ◽  
Vol 875 ◽  
pp. 160055
Author(s):  
Hua Guo ◽  
Fawei Tang ◽  
Yong Liu ◽  
Zhi Zhao ◽  
Hao Lu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Stability Of

scholarly journals Physicochemical characteristics of chitosan from swimming crab (Portunus trituberculatus) shells prepared by subcritical water pretreatment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gengxin Hao ◽  
Yanyu Hu ◽  
Linfan Shi ◽  
Jun Chen ◽  
Aixiu Cui ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Sodium Hydroxide ◽  
Subcritical Water ◽  
Physicochemical Characteristics ◽  
Ash Content ◽  
Portunus Trituberculatus ◽  
Swimming Crab ◽  
Water Pretreatment ◽  
Thermal Stability Of

AbstractThe physicochemical properties of chitosan obtained from the shells of swimming crab (Portunus trituberculatus) and prepared via subcritical water pretreatment were examined. At the deacetylation temperature of 90 °C, the yield, ash content, and molecular weight of chitosan in the shells prepared via subcritical water pretreatment were 12.2%, 0.6%, and 1187.2 kDa, respectively. These values were lower than those of shells prepared via sodium hydroxide pretreatment. At the deacetylation temperature of 120 °C, a similar trend was observed in chitosan molecular weight, but differences in chitosan yield and ash content were not remarkable. At the same deacetylation temperature, the structures of chitosan prepared via sodium hydroxide and subcritical water pretreatments were not substantially different. However, the compactness and thermal stability of chitosan prepared via sodium hydroxide pretreatment was lower than those of chitosan prepared via subcritical water pretreatment. Compared with the chitosan prepared by sodium hydroxide pretreatment, the chitosan prepared by subcritical water pretreatment was easier to use in preparing oligosaccharides, including (GlcN)2, via enzymatic hydrolysis with chitosanase. Results suggested that subcritical water pretreatment can be potentially used for the pretreatment of crustacean shells. The residues obtained via this method can be utilized to prepare chitosan.

The effect of methyl and methoxy substituents on dianilines for a thermosetting polyimide system

2020 ◽  
Vol 32 (7) ◽  
pp. 801-822 ◽  
Author(s):  
John J La Scala ◽  
Greg Yandek ◽  
Jason Lamb ◽  
Craig M Paquette ◽  
William S Eck ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Glass Transition ◽  
Elevated Temperature ◽  
Methyl Substituent ◽  
Glass Transition Temperatures ◽  
High Performing ◽  
Methoxy Substituent ◽  
Acidic Conditions ◽  
Thermal Stability Of

4,4′-Methylenedianiline (MDA) is widely used in high-temperature polyimide resins, including polymerization of monomer reactants-15. The toxicity of MDA significantly limits the manufacturability using this resin. Modifying the substitution and electronics of MDA could allow for the reduction of toxicity while maintaining the high-performing properties of the materials derived from the modified MDA. The addition of a single methyl substituent, methoxy substituent, location of these substituents, and location of the amine relative to the phenolic bridge were modified as were other non-aniline diamines. Various anilines were condensed with paraformaldehyde under acidic conditions to yield dianilines. These dianilines and diamines were reacted with nadic anhydride and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in methanol to form the polyamic acid oligomers and heated at elevated temperature to form polyimide oligomers. It was found that the molecular weight of the oligomers derived from MDA alternatives was generally lower than that of MDA oligomers resulting in lower glass transition temperatures ( T gs) and degradation temperatures. Additionally, methoxy substituents further reduce the T g of the polymers versus methyl substituents and reduce the thermal stability of the resin. Methyl-substituted alternatives produced polyimides with similar T gs and degradation temperatures. The toxicity of the MDA alternatives was examined. Although a few were identified with reduced toxicities, the alternatives with properties similar to that of MDA also had high toxicities.

Thermal Stability of Soybean Protein Isolate-Based Oleic Acid/Stearic Acid Blend Edible Films

2013 ◽  
Vol 469 ◽  
pp. 171-174 ◽  
Author(s):  
Ning Zhang ◽  
Si Yao Sui ◽  
Zhe Wang ◽  
Zhong Su Ma
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Stearic Acid ◽  
Soybean Protein ◽  
Soy Protein Isolate ◽  
Edible Films ◽  
Protein Isolate ◽  
Soybean Protein Isolate ◽  
The Matrix ◽  
Thermal Stability Of

Edible films were prepared using soy protein isolate (4g/100g), oleic acid (0-2g/100g) and stearic acid (0-2g/100g). Effects of the type and ratio of fatty acids (oleic acid and stearic acid) on the thermal properties of soybean protein isolate-based films were investigated. The results indicated that the addition of oleic acid and stearic acid take a significant effect on the thermal stability of soybean protein isolate-based films, as may attribute to that oleic acid is an amphiphilic substance that interacts with both polar and hydrophobic sites on proteins, thus it could improve the functional properties of the films. Besides, the solid state and hydrophobic nature of stearic acid could help limit water diffusion in the matrix more efficiently when it is well-integrated in the matrix through the surfactant action of oleic acid.

Effect of Pre-Strain Rolling on Annealing Behavior of Friction-Stir Welded AA6061-T6 Aluminum Alloy

2018 ◽  
Vol 385 ◽  
pp. 355-358 ◽  
Author(s):  
Sergey Mironov ◽  
Sergey Malopheyev ◽  
Igor Vysotskiy ◽  
Daria Zhemchuzhnikova ◽  
Rustam Kaibyshev
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloy ◽  
Cold Rolling ◽  
Grain Growth ◽  
Rolling Schedule ◽  
Annealing Behavior ◽  
Friction Stir ◽  
Welding Direction ◽  
Thermal Stability Of

In this work, the effect of pre-strain cold rolling on thermal stability of friction-stir welded AA6061-T6 alloy was studied. The pre-strain rolling was found to be very effective in suppression of abnormal grain growth during standard post-weld T6 heat treatment. It was also shown that the efficiency of this approach essentially depends on rolling path and the rolling along welding direction was the most effective rolling schedule.

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