Approaches to increasing the heat stability of whey proteins

2021 ◽  
pp. 25-28
Author(s):  
Ксения Александровна Рязанцева ◽  
Наталья Евгеньевна Шерстнева
Keyword(s):  
Thermal Stability ◽  
Isoelectric Point ◽  
Whey Proteins ◽  
Practical Interest ◽  
Heat Stability ◽  
Thermal Reactions ◽  
Theoretical Approaches ◽  
Pseudoplastic Fluids ◽  
Hydrolysis Of ◽  
Thermal Stability Of

В работе обобщаются новейшие теоретические подходы к регулированию термических реакций денатурации и агрегации сывороточных белков, включая физические, химические, ферментативные, а также комбинации различных методов. Описывается поведение модифицированных сывороточных белков во время термической обработки. Среди физических способов модификации приведены существующие технологии обработки сывороточных белков с использованием ультразвука, а также обработки белка под высоким давлением в сочетании с предварительным нагревом. В обзоре подчеркивается, что любая химическая модификация сывороточных белков осуществляется посредством нарушения структуры белка за счет блокирования свободных сульфгидрильных групп. Приводятся такие способы повышения термостойкости, как создание белково-полисахаридных комплексов, которые при pH, близких к изоэлектрической точке, проявляют характеристики псевдопластических жидкостей. В обзоре отмечается способность реакции гликирования также повышать термическую стойкость сывороточных белков. Подчеркивается перспективность ферментативной модификации сывороточных белков в пищевой промышленности, способствующей повышению как термостабильности, так и растворимости белков в кислых значениях pH из-за потери вторичной структуры. Отмечается возможность применения продуктов гидролиза, обладающих растворимостью вблизи изоэлектрической точки, в технологии напитков. Представляет интерес повышение эффективности ферментативного гидролиза сывороточных белков за счет фракционирования гидролизатов молочной сыворотки с использованием ультрафильтрации. Как следствие продукты фракционирования, а именно пермеат с низкомолекулярными пептидными фракциями, прогнозируемо являются потенциальными ингредиентами в технологии напитков. Практический интерес представляет производство термостойких напитков, содержащих высокий уровень сывороточных белков. The article summarizes the latest theoretical approaches to the regulation of thermal reactions of denaturation and aggregation of whey proteins, including physical, chemical, enzymatic, as well as combinations of various methods. Describes the behavior of modified whey proteins during heat treatment. Among the methods of physical modification, the existing technologies for processing whey proteins using ultrasound, as well as processing proteins under high pressure in combination with preheating are given. The review emphasizes that any chemical modification of whey proteins is carried out by disrupting the protein structure by blocking free sulfhydryl groups. Methods for increasing thermal stability are presented, such as the creation of protein-polysaccharide complexes that exhibit the characteristics of pseudoplastic fluids at a pH close to the isoelectric point. The review notes the ability of the glycation reaction to also increase the thermal stability of whey proteins. The prospects for enzymatic modification of whey proteins in the food industry are emphasized, which contribute to an increase in both thermal stability and solubility of proteins at acidic pH values due to the loss of secondary structure. The possibility of using hydrolysis products with a solubility close to the isoelectric point in the technology of beverage production is noted. It is of interest to increase the efficiency of enzymatic hydrolysis of whey proteins due to fractionation of whey hydrolysates using ultrafiltration. Fractionation products, namely permeate with low molecular weight peptide fractions, are predictable potential ingredients in beverage technology. Of practical interest is the production of heat-resistant drinks with a high content of whey proteins.

scholarly journals Molecular Characterization of Cycloinulooligosaccharide Fructanotransferase from Bacillus macerans

2001 ◽  
Vol 67 (2) ◽  
pp. 995-1000 ◽  
Author(s):  
Hwa-Young Kim ◽  
Yong-Jin Choi
Keyword(s):  
Escherichia Coli ◽  
Thermal Stability ◽  
Striking Difference ◽  
Bacillus Macerans ◽  
Specific Manner ◽  
Specificity Constant ◽  
Processing Event ◽  
Hydrolysis Of ◽  
Thermal Stability Of

ABSTRACT Cycloinulooligosaccharide fructanotransferase (CFTase) converts inulin into cyclooligosaccharides of β-(2→1)-linkedd-fructofuranose by catalyzing an intramolecular transfructosylation reaction. The CFTase gene was cloned and characterized from Bacillus macerans CFC1. The CFTase gene encoded a polypeptide of 1,333 amino acids with a calculatedM r of 149,563. Western blot and zymography analyses revealed that the CFTase with a molecular mass of 150 kDa (CFT150) was processed (between Ser389 and Phe390 residue) to form a 107-kDa protein (CFT107) in the B. macerans CFC1 cells. The processed CFT107 was similar in its mass to the previously purified CFTase from B. macerans CFC1. The CFT107 enzyme was produced by B. macerans CFC1 but was not detected from the recombinant Escherichia coli cells, indicating that the processing event occurred in a host-specific manner. The two CFTases (CFT150 and CFT107) exhibited the same enzymatic properties, such as influences of pH and temperature on the enzyme activity, the intermolecular transfructosylation ability, and the ability of hydrolysis of cycloinulooligosaccharides produced by the cyclization reaction. However, the thermal stability of CFT107 was slightly higher than that of CFT150. The most striking difference between the two enzymes was observed in their Km values; the value for CFT150 (1.56 mM) was threefold lower than that for CFT107 (4.76 mM). Thus, the specificity constant (k cat/Km ) of CFT150 was about fourfold higher than that of CFT107. These results indicated that the N-terminal 358-residue region of CFT150 played a role in increasing the enzyme's binding affinity to the inulin substrate.

scholarly journals LAC4 IS THE STRUCTURAL GENE FOR β-GALACTOSIDASE IN KLUYVEROMYCES LACTIS

Genetics ◽  
1981 ◽  
Vol 98 (4) ◽  
pp. 729-745
Author(s):  
R Michael Sheetz ◽  
Robert C Dickson
Keyword(s):  
Thermal Stability ◽  
Structural Gene ◽  
Gel Electrophoresis ◽  
Kluyveromyces Lactis ◽  
Two Dimensional ◽  
Galactosidase Activity ◽  
Wild Type ◽  
Nonsense Suppressor ◽  
Hydrolysis Of ◽  
Thermal Stability Of

ABSTRACT Using genetic and biochemical techniques, we have determined that β-galactosidase in the yeast Kluyveromyces lactis is coded by the LAC4 locus. The following data support this conclusion: (1) mutations in this locus result in levels of β-galactosidase activity 100-fold lower than levels in uninduced wild type and all other lac- mutants; (2) three of five lac4 mutations are suppressible by an unlinked suppressor whose phenotype suggests that it codes for a nonsense suppressor tRNA; (3) a Lac+ revertant, bearing lac4–14 and this unlinked suppressor, has subnormal levels of β-galactosidase activity, and the Km for hydrolysis of o-nitrophenyl-β, D-galactoside and the thermal stability of the enzyme are altered; (4) the level of β-galactosidase activity per cell is directly proportional to the number of copies of LAC4; (5) analysis of cell-free extracts of strains bearing mutations in LAC4 by two-dimensional acryl-amide gel electrophoresis shows that strains bearing lac4–23 and lac4–30 contain an inactive β-galactosidase whose subunit co-electrophoreses with the wild-type subunit, while no subunit or fragment of the subunit is obs0ervable in lac4–8, lac4–14 or lac4–29 mutants; (6) of all lac4 mutants, only those bearing lac4–23 or lac4–30 contain a protein that cross-reacts with anti-β-galactosidase antibody, a finding consistent with the previous result; and (7) β-galactosidase activity in several Lac+ revertants of strains carrying lac4–23 or lac4–30 has greatly decreased thermostability.

Mechanochemical Assisted Modification of Parawood Microcrystalline Cellulose Using Silane Coupling Agent and their Composites Properties

2018 ◽  
Vol 775 ◽  
pp. 57-62 ◽  
Author(s):  
Patcharaporn Chuayplod ◽  
Duangdao Aht-Ong
Keyword(s):  
Thermal Stability ◽  
Microcrystalline Cellulose ◽  
Water Resistance ◽  
Surface Composition ◽  
Mechanochemical Reaction ◽  
Polypropylene Composites ◽  
Sem Micrograph ◽  
Reinforcing Material ◽  
Hydrolysis Of ◽  
Thermal Stability Of

Surface treated parawood microcrystalline cellulose (PW-MCC) performed under mechanochemical reaction using planetary ball milling at ambient temperature was used as a reinforcing material in polypropylene composites. Initially, PW-MCC was prepared by acid hydrolysis of parawood sawdust pulp. After that, PW-MCC was treated with vinyltrimethoxysilane at milling speed 400 rpm for 60 min. The surface composition from XPS indicated the existence of silicon atom on silane-treated PW-MCC. The thermal stability of PW-MCC was also improved and SEM micrograph revealed rough surface after modification reaction. The untreated PW-MCC and treated PW-MCC were applied to prepare polypropylene composites at 5-30 wt% loading content without a compatibilizer. The results demonstrated that silane-treated PW-MCC/PP composites enhanced tensile strength, thermal stability and water resistance of the composites.

Thermal Stability of Staphylococcal Enterotoxins A, B and C in a Buffered System

1987 ◽  
Vol 50 (3) ◽  
pp. 239-242 ◽  
Author(s):  
A. TIBANA ◽  
K. RAYMAN ◽  
M. AKHTAR ◽  
R. SZABO
Keyword(s):  
Thermal Stability ◽  
Heat Resistance ◽  
Saline Solution ◽  
Heat Stability ◽  
Staphylococcal Enterotoxins ◽  
Cooking Times ◽  
Phosphate Buffered Saline ◽  
Thermal Stability Of

The heat stability of staphylococcal enterotoxins A, B and C (SEA, SEB, SEC) in phosphate buffered saline solution at a concentration of 100 ng per ml indicated that normal cooking times and temperatures are unlikely to completely inactivate the toxins. The order of heat resistance of the three toxins was SEC>SEB>SEA.

scholarly journals Characterization and functional analysis of two novel thermotolerant α-l-arabinofuranosidases belonging to glycoside hydrolase family 51 from Thielavia terrestris and family 62 from Eupenicillium parvum

2020 ◽  
Vol 104 (20) ◽  
pp. 8719-8733
Author(s):  
Liangkun Long ◽  
Lu Sun ◽  
Qunying Lin ◽  
Shaojun Ding ◽  
Franz J. St John
Keyword(s):  
Thermal Stability ◽  
Glycoside Hydrolase ◽  
High Viscosity ◽  
Glycoside Hydrolase Family ◽  
Thermal Stabilities ◽  
Thielavia Terrestris ◽  
Hydrolysis Of ◽  
Gh10 Xylanase ◽  
Thermal Stability Of ◽  
Eupenicillium Parvum

Abstract Arabinofuranose substitutions on xylan are known to interfere with enzymatic hydrolysis of this primary hemicellulose. In this work, two novel α-l-arabinofuranosidases (ABFs), TtABF51A from Thielavia terrestris and EpABF62C from Eupenicillium parvum, were characterized and functionally analyzed. From sequences analyses, TtABF51A and EpABF62C belong to glycoside hydrolase (GH) families 51 and 62, respectively. Recombinant TtABF51A showed high activity on 4-nitrophenyl-α-l-arabinofuranoside (83.39 U/mg), low-viscosity wheat arabinoxylan (WAX, 39.66 U/mg), high-viscosity rye arabinoxylan (RAX, 32.24 U/mg), and sugarbeet arabinan (25.69 U/mg), while EpABF62C preferred to degrade arabinoxylan. For EpABF62C, the rate of hydrolysis of RAX (94.10 U/mg) was 2.1 times that of WAX (45.46 U/mg). The optimal pH and reaction temperature for the two enzymes was between 4.0 and 4.5 and 65 °C, respectively. Calcium played an important role in the thermal stability of EpABF62C. TtABF51A and EpABF62C showed the highest thermal stabilities at pH 4.5 or 5.0, respectively. At their optimal pHs, TtABF51A and EpABF62C retained greater than 80% of their initial activities after incubation at 55 °C for 96 h or 144 h, respectively. 1H NMR analysis indicated that the two enzymes selectively removed arabinose linked to C-3 of mono-substituted xylose residues in WAX. Compared with the singular application of the GH10 xylanase EpXYN1 from E. parvum, co-digestions of WAX including TtABF51A and/or EpABF62C released 2.49, 3.38, and 4.81 times xylose or 3.38, 1.65, and 2.57 times of xylobiose, respectively. Meanwhile, the amount of arabinose released from WAX by TtABF51A with EpXYN1 was 2.11 times the amount with TtABF51A alone. Key points • Two novel α-l-arabinofuranosidases (ABFs) displayed high thermal stability. • The thermal stability of GH62 family EpABF62C was dependent on calcium. • Buffer pH affects the thermal stability of the two ABFs. • Both ABFs enhance the hydrolysis of WAX by a GH10 xylanase.

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 hydroxyapatite whiskers derived from the hydrolysis of  -TCP

2004 ◽  
Vol 39 (7) ◽  
pp. 2531-2534 ◽  
Author(s):  
H. C. Park ◽  
D. J. Baek ◽  
Y. M. Park ◽  
S. Y. Yoon ◽  
R. Stevens
Keyword(s):  
Thermal Stability ◽  
Hydrolysis Of ◽  
Thermal Stability Of
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