scholarly journals Impact of Preheating Temperature on the Separation of Whey Proteins When Combined with Chemical or Bipolar Membrane Electrochemical Acidification

2020 ◽  
Vol 21 (8) ◽  
pp. 2792
Author(s):  
Claudie Aspirault ◽  
Alain Doyen ◽  
Laurent Bazinet
Keyword(s):  
Whey Proteins ◽  
Chemical Compounds ◽  
Protein Isolate ◽  
Green Process ◽  
Bipolar Membrane ◽  
Recovery Yield ◽  
Preheating Temperature ◽  
The Impact ◽  
Β Lactoglobulin ◽  
Selective Aggregation

Separation of α-lactalbumin and β-lactoglobulin improves their respective nutritional and functional properties. One strategy to improve their fractionation is to modify their pH and ionic strength to induce the selective aggregation and precipitation of one of the proteins of interest. Electrodialysis with bipolar membrane (EDBM) is a green process that simultaneously provides acidification and demineralization of a solution without adding any chemical compounds. This research presents the impact on whey proteins separation of different preheating temperatures (20, 50, 55 and 60 °C) combined with EDBM or chemical acidification of 10% whey protein isolate solutions. A β-lactoglobulin fraction at 81.8% purity was obtained in the precipitate after EDBM acidification and preheated at 60 °C, representing a recovery yield of 35.8%. In comparison, chemical acidification combined with a 60 °C preheating treatment provides a β-lactoglobulin fraction at 70.9% purity with a 11.6% recovery yield. The combination of EDBM acidification with a preheating treatment at 60 °C led to a better separation of the main whey proteins than chemical acidification.

scholarly journals Combined microwave processing and enzymatic proteolysis of bovine whey proteins: the impact on bovine β-lactoglobulin allergenicity

2018 ◽  
Vol 56 (1) ◽  
pp. 177-186 ◽  
Author(s):  
Kamel Eddine El Mecherfi ◽  
Sébastien Curet ◽  
Roberta Lupi ◽  
Colette Larré ◽  
Olivier Rouaud ◽  
...  
Keyword(s):  
Whey Proteins ◽  
Microwave Processing ◽  
Enzymatic Proteolysis ◽  
The Impact ◽  
Β Lactoglobulin

Comparison of selective hydrolysis of α-lactalbumin by acid Protease A and Protease M as alternative to pepsin: potential for β-lactoglobulin purification in whey proteins

2019 ◽  
Vol 86 (1) ◽  
pp. 114-119
Author(s):  
Katarina Lisak Jakopović ◽  
Seronei Chelulei Cheison ◽  
Ulrich Kulozik ◽  
Rajka Božanić
Keyword(s):  
High Performance ◽  
Whey Proteins ◽  
Reversed Phase ◽  
Protein Isolate ◽  
Acid Protease ◽  
Selective Hydrolysis ◽  
Hydrolysis Conditions ◽  
Β Lactoglobulin ◽  
Hydrolysis Of ◽  
Enzyme Selectivity

AbstractThe experiments reported in this research paper examine the potential of digestion using acidic enzymes Protease A and Protease M to selectively hydrolyse α-lactalbumin (α-La) whilst leaving β-lactoglobulin (β-Lg) relatively intact. Both enzymes were compared with pepsin hydrolysis since its selectivity to different whey proteins is known. Analysis of the hydrolysis environment showed that the pH and temperature play a significant role in determining the best conditions for achievement of hydrolysis, irrespective of which enzyme was used. Whey protein isolate (WPI) was hydrolysed using pepsin, Acid Protease A and Protease M by randomized hydrolysis conditions. Reversed-phase high performance liquid chromatography was used to analyse residual proteins. Regarding enzyme selectivity under various milieu conditions, all three enzymes showed similarities in the reaction progress and their potential for β-Lg isolation.

scholarly journals Whey Protein Isolate-Xylose Maillard-Based Conjugates with Tailored Microencapsulation Capacity of Flavonoids from Yellow Onions Skins

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1708
Author(s):  
Ștefania Adelina Milea ◽  
Iuliana Aprodu ◽  
Elena Enachi ◽  
Vasilica Barbu ◽  
Gabriela Râpeanu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Whey Protein ◽  
Maillard Reaction ◽  
Protein Isolate ◽  
Added Value ◽  
Whey Protein Isolates ◽  
The Impact ◽  
Β Lactoglobulin ◽  
Yellow Onion ◽  
Modelling Approach

The objective of this study is to encapsulate flavonoids from yellow onion skins in whey protein isolates (WPI) and xylose (X), by Maillard-based conjugates, as an approach to improve the ability to entrap flavonoids and to develop powders with enhanced antioxidant activity. WPI (0.6%, w/v) was conjugated to X (0.3%, w/v) through the Maillard reaction at 90 °C for 120 min, in the presence of a flavonoid-enriched extract. Two variants of powders were obtained by freeze-drying. The glycation of WPI allowed a better encapsulation efficiency, up to 90.53 ± 0.29%, corresponding to a grafting degree of 30.38 ± 1.55%. The molecular modelling approach was used to assess the impact of X interactions with α-lactalbumin and β-lactoglobulin on the ability of these proteins to bind the main flavonoids from the yellow onion skins. The results showed that X might compete with quercetin glucosides to bind with α-lactalbumin. No interference was found in the case of β-lactoglobulin. The microstructural appearance of the powders revealed finer spherosomes in powder with WPI–X conjugates via the Maillard reaction. The powders were added to nachos, followed by a phytochemical characterization, in order to test their potential added value. An increase in antioxidant activity was observed, with no significant changes during storage.

High pressure thermal denaturation kinetics of whey proteins

2004 ◽  
Vol 71 (4) ◽  
pp. 480-488 ◽  
Author(s):  
Jörg Hinrichs ◽  
Britta Rademacher
Keyword(s):  
Whey Proteins ◽  
Protein Isolate ◽  
Linear Regression Method ◽  
Data Set ◽  
Denaturation Kinetics ◽  
One Step ◽  
Increasing Temperature ◽  
Β Lactoglobulin ◽  
Kinetics Of ◽  
Denaturation Rate

Pressure processing of foodstuff has been applied to produce or modify proteinaceous gel structures. In real pressure processing the treatment is non-isothermal, due to the adiabatic nature of the process and the heat loss from the product to the vessel. In order to estimate the effect of pressurization on milk constituents pressure and temperature dependent kinetics were determined separately from each other. In a detailed kinetic study whey protein isolate was treated under isobaric (200 to 800 MPa) and isothermal conditions (−2 to 70 °C), and the resulting degree of denaturation of β-lactoglobulin A and B and α-lactalbumin was analysed. Kinetic parameters of denaturation were estimated using a one step non-linear regression method which allowed a global fit of the whole data set. The isobaric isothermal denaturation of β-lactoglobulin and α-lactalbumin was found to follow third and second order kinetics, respectively. Isothermal pressure denaturation of both β-lactoglobulin fractions do not differ significantly and were characterized by an activation volume decreasing with increasing temperature from −10 to about −30 ml mol−1, which demonstrates that the denaturation rate is accelerated with increasing temperature. The activation energy of about 70 to 100 kJ mol−1 obtained for β-lactoglobulin A and B is not dependent to a great extent on the pressure which indicates that above 200 MPa denaturation rate is limited by the aggregation rate while pressure forces unfolding of the molecule.

scholarly journals Surface Hydrophobicity and Functional Properties of Citric Acid Cross-Linked Whey Protein Isolate: The Impact of pH and Concentration of Citric Acid

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2383 ◽  
Author(s):  
Tong Li ◽  
Chunyan Wang ◽  
Tianqi Li ◽  
Ling Ma ◽  
Dongxue Sun ◽  
...  
Keyword(s):  
Citric Acid ◽  
Whey Protein ◽  
Whey Proteins ◽  
Whey Protein Isolate ◽  
Surface Hydrophobicity ◽  
Protein Isolate ◽  
Cross Linking ◽  
Foaming Properties ◽  
Aqueous Conditions ◽  
The Impact

The effects of citric acid-mediated cross-linking under non-acidic conditions on the surface hydrophobicity, solubility, emulsifying, and foaming properties of whey protein isolate (WPI) were investigated. In this research, citric acid-mediated cross-linking could not only increase the surface hydrophobicity of whey proteins at pH 7.0 and 8.0, but it also improved its emulsifying and foaming properties. The emulsifying activity and foaming ability of WPI reached a maximum under the condition of 1% citric acid and pH 7.0. However, the solubility of WPI-CA gradually decreased with pH and the content of citric acid increased. Therefore, the cross-linking mediated by citric acid under non-acidic aqueous conditions, markedly altered the surface hydrophobicity and enhanced emulsifying and foaming properties of WPI.

scholarly journals Impact of the Simulated Gastric Digestion Methodology on the In Vitro Intestinal Proteolysis and Lipolysis of Emulsion Gels

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 321
Author(s):  
Camila Mella ◽  
Michelle Quilaqueo ◽  
Rommy N. Zúñiga ◽  
Elizabeth Troncoso
Keyword(s):  
Heat Treatment ◽  
Protein Isolate ◽  
Gastric Digestion ◽  
Human Gastrointestinal Tract ◽  
Gel Structure ◽  
Intestinal Digestion ◽  
Food Digestion ◽  
The Impact ◽  
Digestion Methods

The aim of this work was to study the impact of the methodology of in vitro gastric digestion (i.e., in terms of motility exerted and presence of gastric emptying) and gel structure on the degree of intestinal proteolysis and lipolysis of emulsion gels stabilized by whey protein isolate. Emulsions were prepared at pH 4.0 and 7.0 using two homogenization pressures (500 and 1000 bar) and then the emulsions were gelled by heat treatment. These gels were characterized in terms of texture analysis, and then were subjected to one of the following gastric digestion methods: in vitro mechanical gastric system (IMGS) or in vitro gastric digestion in a stirred beaker (SBg). After gastric digestion, the samples were subjected to in vitro intestinal digestion in a stirred beaker (SBi). Hardness, cohesiveness, and chewiness were significantly higher in gels at pH 7.0. The degree of proteolysis was higher in samples digested by IMGS–SBi (7–21%) than SBg–SBi (3–5%), regardless of the gel’s pH. For SBg–SBi, the degree of proteolysis was not affected by pH, but when operating the IMGS, higher hydrolysis values were obtained for gels at pH 7.0 (15–21%) than pH 4.0 (7–13%). Additionally, the percentage of free fatty acids (%FFA) released was reduced by 47.9% in samples digested in the IMGS–SBi. For the methodology SBg–SBi, the %FFA was not affected by the pH, but in the IMGS, higher values were obtained for gels at pH 4.0 (28–30%) than pH 7.0 (15–19%). Our findings demonstrate the importance of choosing representative methods to simulate food digestion in the human gastrointestinal tract and their subsequent impact on nutrient bioaccessibility.

Analysis of Whey Proteins Solubility at High Temperatures

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Daniela Helena Guimarães Pelegrine ◽  
Maria Thereza Moraes Santos Gomes
Keyword(s):  
Heat Exchangers ◽  
Protein Unfolding ◽  
Protein Solubility ◽  
Whey Proteins ◽  
Protein Isolate ◽  
Cow Milk ◽  
Ph Conditions ◽  
Effects Of Temperature ◽  
Ph Range ◽  
Integrated Study

Abstract This work showed the whey proteins solubility curves, according with temperature and pH conditions. The product constituted of a whey protein isolate obtained from cow milk (ALACENTM 895), acquired by New Zeland Milk Products Ltd. There is a straight analogy between fouling and protein unfolding when milk derived fluids are processed in equipments of heat exchangers, where whey proteins are unfolded in an irreversible way, exposing hidrophobic groups, and they become insoluble and form aggregates. An integrated study was conducted on the effects of temperature and pH on the solubility of whey proteins. The solubility was determined experimentally in the temperature range of 40-90 °C, and pH range of 5.0 - 6.8. The results showed that, both the temperature and pH influenced in the protein solubility; besides, the solubility values were minimum at the pH 4.0 for all temperature values. It was also observed that solubility decreased with temperature increased.

scholarly journals Transmission of Major and Minor Serum Proteins during Microfiltration of Skim Milk: Effects of Pore Diameters, Concentration Factors and Processing Stages

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 888
Author(s):  
Zhibin Li ◽  
Dasong Liu ◽  
Shu Xu ◽  
Wenjin Zhang ◽  
Peng Zhou
Keyword(s):  
Serum Proteins ◽  
Skim Milk ◽  
Transmembrane Pressure ◽  
Recovery Yield ◽  
Membrane Flux ◽  
Crossflow Velocity ◽  
Inner Diameter ◽  
Concentration Factors ◽  
20 Nm ◽  
Β Lactoglobulin

Effects of pore diameters (100, 50, and 20 nm), concentration factors (1–8) and processing stages (1–5) on the transmission of major serum proteins (β-lactoglobulin and α-lactalbumin) and minor serum proteins (immunoglobulin (Ig) G, IgA, IgM, lactoferrin (LF), lactoperoxidase (LPO), xanthine oxidase (XO)) during ceramic microfiltration (MF) of skim milk were studied. Holstein skim milk was microfiltered at a temperature of 50 °C, a transmembrane pressure of 110 kPa and a crossflow velocity of 6.7 m/s, using a tubular single stainless steel module that consisted of three ceramic tubes, each with 19 channels (3.5 mm inner diameter) and a length of 0.5 m. For MF with 100 nm and 50 nm pore diameters, the recovery yield of major serum proteins in permeate was 44.3% and 44.1%, while the recovery yield of minor serum proteins was slightly less by 0%–8% than 50 nm MF. MF with 20 nm pore diameters showed a markedly lower (by 12%–45%) recovery yield for both major and minor serum proteins, corresponding with its lower membrane flux. Flux sharply decreased with an increasing concentration factor (CF) up to four, and thereafter remained almost unchanged. Compared to the decrease (88%) of flux, the transmission of major and minor serum proteins was decreased by 4%–15% from CF = one to CF = eight. With increasing processing stages, the flux gradually increased, and the recovery yield of both major and minor proteins in the permeate gradually decreased and reached a considerably low value at stage five. After four stages of MF with 100 nm pore diameter and a CF of four for each stage, the cumulative recovery yield of major serum proteins, IgG, IgA, IgM, LF, LPO, and XO reached 95.7%, 90.8%, 68.5%, 34.1%, 15.3%, 39.1% and 81.2% respectively.

scholarly journals The mass impacts on chemosynthetic primary producers: potential implications on anammox communities and their consequences

2018 ◽  
Vol 18 (05) ◽  
pp. 440-444
Author(s):  
Noel Pérez ◽  
Jorge Luis Velazco-Vargas ◽  
Osmel Martin ◽  
Rolando Cardenas ◽  
Jesús Martínez-Frías
Keyword(s):  
Water Column ◽  
Deposition Rate ◽  
Extreme Case ◽  
Chemical Compounds ◽  
Global Scale ◽  
Biogeochemical Cycle ◽  
Potential Influence ◽  
Asteroid Impact ◽  
Global Cooling ◽  
The Impact

AbstractThe potential of a mass asteroid impact on Earth to disturb the chemosynthetic communities at global scale is discussed. Special emphasis is made on the potential influence on anammox communities and their implications in the nitrogen biogeochemical cycle. According to our preliminary estimates, anammox communities could be seriously affected as a consequence of global cooling and the large process of acidification usually associated with the occurrence of this kind of event. The scale of affectations could vary in a scenario like the Chicxulub as a function of the amount of soot, depth of the water column and the deposition rate for sulphates assumed in each case. The most severe affectations take place where the amount of soot and sulphates produced during the event is higher and the scale of time of settlements for sulphates is short, of the order of 10 h. In this extreme case, the activity of anammox is considerably reduced, a condition that may persist for several years after the impact. Furthermore, the impact of high levels of other chemical compounds like sulphates and nitrates associated with the occurrence of this kind of event are also discussed.

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