scholarly journals Impact of Ultrasound Treatment and pH-Shifting on Physicochemical Properties of Protein-Enriched Barley Fraction and Barley Protein Isolate

Foods ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1055 ◽  
Author(s):  
Pia Silventoinen ◽  
Nesli Sozer
Keyword(s):  
Particle Size ◽  
Colloidal Stability ◽  
Protein Solubility ◽  
Protein Isolate ◽  
Ultrasound Treatment ◽  
Liquid Food ◽  
Alkaline Ph ◽  
Ph Values ◽  
Ph Shifting ◽  
Barley Protein

Ultrasonication alone or in combination with a pH-shifting method could be applied as means for improving the techno-functional properties and performance of barley protein ingredients in liquid food matrix. Ultrasound technology was utilised with and without pH-shifting to 3, 7 and 9 aiming at investigating their impact on primary protein structure, protein solubility, particle size and colloidal stability of an air-classified protein-enriched barley fraction and a barley protein isolate. Shifting the pH of sample dispersion to 9 followed by neutralisation to pH 7 improved protein solubility and colloidal stability of the isolate whereas it had less impact on the protein-enriched fraction. Ultrasound treatment improved both protein solubility and colloidal stability of the protein-enriched fraction at alkaline pH and particle size reduction by ultrasonication was observed at all the studied pH-values. For protein isolate, ultrasonication improved protein solubility at all pH-values and colloidal stability was improved at acidic and neutral pH whereas the sample was inherently stable at alkaline pH. The protein profiles of both ingredients remained unaffected by ultrasound treatment. The results suggest adopting ultrasonication as a promising tool for improving applicability of barley protein ingredients in liquid food systems.

scholarly journals Rheological and Solubility Properties of Soy Protein Isolate

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 3015
Author(s):  
Timothy D. O′Flynn ◽  
Sean A. Hogan ◽  
David F. M. Daly ◽  
James A. O′Mahony ◽  
Noel A. McCarthy
Keyword(s):  
Heat Treatment ◽  
Soy Protein ◽  
Water Solubility ◽  
Protein Solubility ◽  
Soy Protein Isolate ◽  
Protein Isolate ◽  
Ph Values ◽  
Low Viscosity ◽  
Alkaline Conditions ◽  
Low Amplitude

Soy protein isolate (SPI) powders often have poor water solubility, particularly at pH values close to neutral, which is an attribute that is an issue for its incorporation into complex nutritional systems. Therefore, the objective of this study was to improve SPI solubility while maintaining low viscosity. Thus, the intention was to examine the solubility and rheological properties of a commercial SPI powder at pH values of 2.0, 6.9, and 9.0, and determine if heat treatment at acidic or alkaline conditions might positively influence protein solubility, once re-adjusted back to pH 6.9. Adjusting the pH of SPI dispersions from pH 6.9 to 2.0 or 9.0 led to an increase in protein solubility with a concomitant increase in viscosity at 20 °C. Meanwhile, heat treatment at 90 °C significantly improved the solubility at all pH values and resulted in a decrease in viscosity in samples heated at pH 9.0. All SPI dispersions measured under low-amplitude rheological conditions showed elastic-like behaviour (i.e., G′ > G″), indicating a weak “gel-like” structure at frequencies less than 10 Hz. In summary, the physical properties of SPI can be manipulated through heat treatment under acidic or alkaline conditions when the protein subunits are dissociated, before re-adjusting to pH 6.9.

scholarly journals Determining the effect of pH-shifting treatment on the solubility of pumpkin seed protein isolate

2021 ◽  
Vol 5 (11 (113)) ◽  
pp. 29-34
Author(s):  
Dan Gao ◽  
Anna Helikh ◽  
Zhenhua Duan
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Functional Properties ◽  
Soluble Protein ◽  
Seed Protein ◽  
Average Particle Size ◽  
Protein Isolate ◽  
Average Particle ◽  
Pumpkin Seed ◽  
Ph Shifting

Pumpkin seed protein is a high-quality plant protein, which has all essential amino acids for the human body and can also supply essential amino acid histidine for children. When it is introduced to food products, it needs to meet some functional properties, such as solubility, emulsifying ability, foaming ability, and so on. Among them, solubility is very important because it has a great influence on other functional properties of protein. In this study, pH-shifting treatment, which is a novel method to modify protein, is applied to improve the solubility of pumpkin seed protein isolate (PSPI). PSPI treated by pH-shifting treatment was investigated at different pH values (pH 2, pH 4, pH 6, pH 8, pH 10, and pH 12), which were labeled as PSPI 2, PSPI 4, PSPI 6, PSPI 8, PSPI 10, and PSPI 12, respectively. Compared to that of control PSPI (45.6 %), only the solubility of PSPI 8 (55.5 %) showed increased (p<0.05) value, while the solubility of PSPI 2 (13.7 %), PSPI 4 (10.8 %), PSPI 10 (41.8 %), and PSPI 12 (13.4 %) showed decreased (p<0.05) value. Then the average particle size, zeta potential of the soluble protein in PSPI were analyzed, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was performed. PSPI 2, PSPI 4, and PSPI 12 showed decreased (p<0.05) average particle size after the pH-shifting process. And PSPI 2, and PSPI 12 showed decreased (p<0.05) zeta potential. While other samples didn’t show any significant difference in these two indicators. Besides, the molecular weight of the increased abundance of soluble protein bands was observed at 33 kDa and 25 kDa of PSPI 8. As the solubility of PSPI 8 increased (p<0.05) significantly, it might suggest the PSPI after pH-shifting treatment under pH 8 has more advantages to be used in the food industry

Functional Properties of the Protein Isolate and Major Fractions of Pine Nut Proteins Prepared from the Changbai Mountain in China

2014 ◽  
Vol 881-883 ◽  
pp. 766-775 ◽  
Author(s):  
Dan Wu ◽  
Wei Hong Min ◽  
Jing Sheng Liu ◽  
Li Fang ◽  
Hong Mei Li ◽  
...  
Keyword(s):  
Amino Acids ◽  
Functional Properties ◽  
Protein Solubility ◽  
Essential Amino Acids ◽  
Protein Isolate ◽  
Absorption Capacity ◽  
Changbai Mountain ◽  
Major Protein ◽  
Pine Nut ◽  
A Value

The functional properties of protein isolate and major protein fractions prepared from Changbai Mountain pine nuts were investigated. Albumin, globulin, glutelin, and protein isolates were obtained after the Osborne method and alkaline dissolution and acid precipitation, and protein contents of the fractions are 48.02%, 81.93%, 83.02%, and 89.69%, respectively. For the sulfhydryl contents, albumin is the highest, and glutelin is the lowest. In a disulphide bond, the protein isolate content is the highest with a value of 28.74 μmol/g, and the glutelin content is the lowest with the value of 13.46 μmol/g. For the four kinds of proteins, the essential amino acids in percentage of total amino acids are 31.13%, 34.22%, 30.30%, and 34.54%, respectively. The pH dependent protein solubility profile reveals that the minimum solubility is at pH 5.0, which corresponds to the isoelectric point. Protein isolate has the minimum water absorption capacity with a value of 0.59 ml/g. On the other hand, albumin has the minimum oil absorption capacity with a value of 2.11 ml/g. The emulsifying activity and stability and the foaming activity and stability increased with increasing concentration of four kinds of proteins. SDS-PAGE results showed that these four kinds of proteins have different molecules.

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 Effect of alkaline pH on photosynthetic water oxidation and the association of extrinsic proteins with Photosystem Two

1989 ◽  
Vol 258 (2) ◽  
pp. 357-362 ◽  
Author(s):  
D J Chapman ◽  
J De Felice ◽  
K Davis ◽  
J Barber
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Binding Sites ◽  
Partial Recovery ◽  
Alkaline Ph ◽  
Ph Values ◽  
Extrinsic Proteins ◽  
Reversible Phase ◽  
Photosynthetic Water Oxidation ◽  
Optimal Ph

Incubation of a membrane preparation enriched in Photosystem Two (PSII) at alkaline pH inhibited the water-splitting reactions in two distinct steps. Up to pH 8.5 the inhibition was reversible, whereas at higher alkalinities it was irreversible. It was shown that the reversible phase correlated with loss and rebinding of the 23 kDa extrinsic polypeptide. However, after mild alkaline treatments a partial recovery was possible without the binding of the 23 kDa polypeptide when the assay was at the optimal pH of 6.5 and in a medium containing excess Cl-. The irreversible phase was found to be closely linked with the removal of the 33 kDa extrinsic protein of PSII. Treatments with pH values above 8.5 not only caused the 33 kDa protein to be displaced from the PSII-enriched membranes, but also resulted in an irreversible modification of the binding sites such that the extrinsic 33 kDa protein could not reassociate with PSII when the pH was lowered to 6.5. The results obtained with these more extreme alkaline pH treatments support the notion that the 23 kDa protein cannot bind to PSII unless the 33 kDa protein is already bound. The differential effect of pH on the removal of the 23 kDa and 33 kDa proteins contrasted with the data of Kuwabara & Murata [(1983) Plant Cell Physiol. 24, 741-747], but this discrepancy was accounted for by the use of glycerol in the incubation media.

Modification of foaming properties of soy protein isolate by high ultrasound intensity: Particle size effect

2015 ◽  
Vol 26 ◽  
pp. 48-55 ◽  
Author(s):  
Rocío Morales ◽  
Karina D. Martínez ◽  
Víctor M. Pizones Ruiz-Henestrosa ◽  
Ana M.R. Pilosof
Keyword(s):  
Particle Size ◽  
Size Effect ◽  
Soy Protein ◽  
Soy Protein Isolate ◽  
Particle Size Effect ◽  
Protein Isolate ◽  
Foaming Properties ◽  
Ultrasound Intensity

scholarly journals Functional properties of protein isolates from camelina (Camelina sativa (L.) Crantz) and flixweed (sophia, Descurainis sophia L.) seed meals

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Na Thi Ty Ngo ◽  
Fereidoon Shahidi
Keyword(s):  
Functional Properties ◽  
Protein Extraction ◽  
Protein Profile ◽  
Protein Solubility ◽  
Protein Isolate ◽  
Absorption Capacity ◽  
Foaming Properties ◽  
Oil Absorption ◽  
Protein Isolates ◽  
Water Holding

AbstractCamelina and flixweed (sophia) seed protein isolates were prepared using both the conventional extraction and ultrasonic-assisted extraction methods at 40 kHz for 20 min, and their functional properties investigated. SDS-PAGE showed that both ultrasound-assisted and conventional extractions resulted in a similar protein profile of the extract. The application of ultrasound significantly improved protein extraction/content and functional properties (water holding capacity, oil absorption capacity, emulsifying foaming properties, and protein solubility) of camelina protein isolate and sophia protein isolate. The water-holding and oil absorption capacities of sophia protein isolate were markedly higher than those of camelina protein isolate. These results suggest that camelina protein isolate and sophia protein isolate may serve as natural functional ingredients in the food industry. Graphical Abstract

Proteins recovered from milks heated at alkaline pH values

1987 ◽  
Vol 40 (4) ◽  
pp. 82-85 ◽  
Author(s):  
M B GRUFFERTY ◽  
D M MULVIHILL
Keyword(s):  
Alkaline Ph ◽  
Ph Values
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