Explore chapters and articles related to this topic
Marine Biopolymers
Published in Se-Kwon Kim, Marine Biochemistry, 2023
The solubility is an interesting property in commercial chitosan. This property depends on three parameters. The pH of the solution is the parameter that links to the charge of D units in the polymer chain. The ionic strength is important and relates to the salting out effect. Finally, the existence of some ions as copper or molypdate, with strong selectivity, influence the solubility of chitosan. All chitosan is soluble in the pH below 6.5 and precipitate when the pH increases from 6.5 to 8. With the same pH, the solubility increases with FA (Vårum & Smidsrød, 2004) to alginate, the relationship between intrinsic viscosity [η] and of chitosan is linear (Anthonsen et al., 1993).
Towards the Importance of Fenugreek Proteins
Published in Dilip Ghosh, Prasad Thakurdesai, Fenugreek, 2022
Salt extraction (micellization) is another frequent approach in protein extraction from legumes. The procedure lies in the salting-in and salting-out phenomena of food proteins. Accordingly, proteins solubility increases at appropriate ionic strength (salting in). This is usually followed by protein precipitation through centrifugation or filtration. Similar to other extraction methods, the procedure could be accomplished by employment of a drying method. El-Nasri and El-Tinay (2007) used the micellization method for extraction of Sudanese fenugreek seed with 28.4% protein using 1 M NaCl and flour to solvent ratio of 1:10 for 30 min. The extraction was accomplished by further precipitation of protein at pI (4.5) and drying in open air. Final protein concentrate contained 73.9% protein. Abdel-Aal et al. (1986) applied a similar procedure, using 0.5 M NaCl and stirring for 1 h, for protein extraction from Egyptian fenugreek seeds, and produced protein isolate with 94.7% protein. The influential role of salt on protein extraction from legumes like fenugreek is possibly attributed to their high amount of globulins, salt soluble proteins. Globulins are the second major fraction of fenugreek and the most dominant one in others including soybean, peas, etc. (Feyzi et al., 2015).
Approaches for Identification and Validation of Antimicrobial Compounds of Plant Origin: A Long Way from the Field to the Market
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Lívia Maria Batista Vilela, Carlos André dos Santos-Silva, Ricardo Salas Roldan-Filho, Pollyanna Michelle da Silva, Marx de Oliveira Lima, José Rafael da Silva Araújo, Wilson Dias de Oliveira, Suyane de Deus e Melo, Madson Allan de Luna Aragão, Thiago Henrique Napoleão, Patrícia Maria Guedes Paiva, Ana Christina Brasileiro-Vidal, Ana Maria Benko-Iseppon
Proteins can be precipitated with acetone, trichloroacetic acid and polyethylene glycol (Bekale et al. 2015; Bose et al. 2019). However, the salting out method with ammonium sulfate is the most used method because it generally does not cause the protein’s denaturation, besides the facility to eliminate the salt of fractions obtained through dialysis (Oliveira et al. 2016; Procópio et al. 2017a). Another advantage of saline precipitation is the possibility of promoting purification, that is, the possibility of obtaining a preparation rich in the protein of interest, free from other contaminants (Santana et al. 2012). The use of different salt concentrations can result in partial or total purification of the protein since highly soluble proteins need a higher concentration of salt to be removed from the solution than those less soluble. On the other hand, if the extract contains a mixture of proteins of similar solubility, it is better to use a high saturation of the salt and obtain a fraction containing all the proteins of the mixture in a reduced volume.
Affinity enrichment for mass spectrometry: improving the yield of low abundance biomarkers
Published in Expert Review of Proteomics, 2018
Brianna Kim, Robyn Araujo, Marissa Howard, Ruben Magni, Lance A. Liotta, Alessandra Luchini
Precipitation or ‘salting out’ of proteins is another common method for concentrating proteins from large volumes. Ammonium sulfate is a common reagent used for this purpose. Increasing the concentrations of ammonium sulfate elevates the ionic strength of the solution. The increase in ionic strength reduces the repulsion of same charges of protein molecules and reduces the solvation shell around proteins. Once these forces are sufficiently reduced the proteins will interact, aggregate, and precipitate. The precipitated proteins can be collected by centrifugation and be resolubilized in a smaller volume to achieve a concentration effect. A drawback of salting out is functional disruption of biologic activity when the protein is in an insoluble state. Moreover, the proteins may not return to solution phase upon resolubilization. Commercial kits exist to conduct salting-out using proprietary reagents that protects the biological activity of the proteins, and improve resolubilization [20].
Ultra-preconcentration of common herbicides in aqueous samples using solid phase extraction combined with dispersive liquid–liquid microextraction followed by HPLC–UV
Published in Toxin Reviews, 2021
Toraj Ahmadi-Jouibari, Negar Noori, Kiomars Sharafi, Nazir Fattahi
Salt addition is frequently used to adjust the ionic strength, improve the extraction efficiency and reduce the detection limit. Depending on the nature of the target analytes, addition of salt to the sample solution can decrease the solubility of the analytes and therefore enhance extraction because of the salting-out effect. To study the ionic strength effect, the experiments were conducted at different sodium chloride concentrations of the sample solution, ranging from 0 to 5% (w/v). The EFs for herbicides obtained highest values when 1% of sodium chloride was added to the samples. Further addition of sodium chloride did not result in an increase in extraction efficiency. Therefore, subsequent experiments were carried out with adding 1% (w/v) salt.
pH-responsive release system of topiramate transported on silica nanoparticles by melting method
Published in Drug Development and Industrial Pharmacy, 2021
Janiele Mayara Ferreira de Almeida, Elmar Damasceno Júnior, Elania Maria Fernandes Silva, Lourena Mafra Veríssimo, Nedja Suely Fernandes
The volumes (μL) of aqueous solution of topiramate and extractive solvent (toluene) were measured with a calibrated micropipette in all assays. Salting solutions for the salting-out effect were prepared by dilution in ultrapure water: 5 mol/l NaCl and 3 mol/l Na2SO4. After the definition of the best volumes of aqueous sample and organic solvent by SALLE [30], the pH of the aqueous solution was studied and the salting out performance was studied according to the salt used. This variation on pH for evaluating the SALLE extraction efficiency was crucial as the topiramate release assays were performed at pH 1.2 and 7.4 simulating the gastrointestinal conditions encountered by an oral solid dosage form.