scholarly journals Oil Phase Solubility Rather Than Diffusivity Determines the Release of Entrapped Amino Acids and Di-Peptides from Water-in-Oil-in-Water Emulsions

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 394
Author(s):  
Esra Kocaman ◽  
Davide Rabiti ◽  
Juan Sebastian Murillo Moreno ◽  
Asli Can Karaca ◽  
Paul Van der Meeren
Keyword(s):  
Amino Acids ◽  
Release Kinetics ◽  
Phase Solubility ◽  
Acidic Ph ◽  
Acid Transport ◽  
Double Emulsions ◽  
Ph Values ◽  
Neutral Ph ◽  
Oil In Water ◽  
Kinetics Of

The permeation of amino acids and di-peptides with different hydrophobicities across the oil phase in W/O/W double emulsions was investigated at different concentrations, considering the pH of the aqueous phase. Moreover, the particle size, yield of entrapped water and release kinetics of the double emulsions was evaluated as a function of time. Regarding the release of the entrapped amino acids and di-peptides, their hydrophobicity and the pH had a significant effect, whereas the concentration of the dissolved compound did not lead to different release kinetics. The release of the amino acids and di-peptides was faster at neutral pH as compared to acidic pH values due to the increased solute solubility in the oil phase for more hydrophobic molecules at neutral pH. Regarding the effect of the type of oil, much faster amino acid transport was observed through MCT oil as compared to LCT oil, which might be due to its higher solubility and/or higher diffusivity. As di-peptides released faster than amino acids, it follows that the increased solubility overruled the effect from the decreased diffusion coefficient of the dissolved compound in the oil phase.

scholarly journals Inactivation of tyrosine aminotransferase in neutral homogenates and rat liver slices

1972 ◽  
Vol 129 (5) ◽  
pp. 1131-1138 ◽  
Author(s):  
F. Auricchio ◽  
L. Mollica ◽  
A. Liguori
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Acid Concentration ◽  
Tyrosine Aminotransferase ◽  
Amino Acid Concentration ◽  
Acidic Ph ◽  
Ph Values ◽  
Neutral Ph ◽  
Liver Slices

Inactivation of tyrosine aminotransferase induced in vivo by triamcinolone was studied in a homogenate incubated at neutral pH values. The integrity and the presence of subcellular particles together with a compartment of acidic pH are necessary for inactivation of tyrosine aminotransferase. It is suggested that tyrosine aminotransferase is inactivated inside lysosomes. The system responsible for inactivation of tyrosine aminotransferase was partially purified and identified with lysosomal cathepsins B and B1. Inactivation of tyrosine aminotransferase in liver slices is controlled by the amino acid concentration and strongly stimulated by cysteine. 3,3′,5-Tri-iodo-l-thyronine reversibly and strongly decreases the rate of inactivation of tyrosine aminotransferase. The effect is not due to an increased rate of tyrosine aminotransferase synthesis.

scholarly journals Amino acid transport by resealed ghosts from pigeon erythrocytes

1982 ◽  
Vol 202 (3) ◽  
pp. 613-621
Author(s):  
K P Wheeler
Keyword(s):  
Amino Acids ◽  
Concentration Gradient ◽  
Acid Transport ◽  
Ph Values ◽  
Intracellular Amino Acids ◽  
Net Flux ◽  
High Concentrations ◽  
Dependent Transport ◽  
Resealed Ghosts ◽  
Net Fluxes

Resealed ghosts from pigeon erythrocytes were shown to haemolyse during incubation in isotonic media with pH values greater than about 7 and high concentrations of Na+ inside the ghosts seemed to enhance this effect. At lower pH values the ghosts were stable but still highly permeable to Na+ and K+, and moderately permeable to sucrose. Under the latter conditions the ghosts transported amino acids in a way qualitatively but not quantitatively similar to intact erythrocytes. The Na+-dependent transport of serine and alanine by the ghosts consisted essentially of an exchange of extracellular for intracellular amino acids, with no significant net flux. In contrast, net fluxes of glycine in the direction of the Na+-concentration gradient across the ghost membrane were demonstrated. However, under one condition a small net influx of glycine occurred against the prevailing Na+-concentration gradient. Unlike Na+-dependent glycine uptake, the uptake of six other amino acids by intact pigeon erythrocytes was not influenced by the nature of the anion present. The significance of these findings in relation to previous work on the Na+-gradient hypothesis of membrane transport is discussed.

Inhibitory Activity of Phosphates on Molds Isolated from Foods and Food Processing Plants

2005 ◽  
Vol 68 (11) ◽  
pp. 2475-2479 ◽  
Author(s):  
V. B. SUÁREZ ◽  
L. FRISÓN ◽  
M. Z. de BASÍLICO ◽  
M. RIVERA ◽  
J. A. REINHEIMER
Keyword(s):  
Inhibitory Activity ◽  
Sodium Tripolyphosphate ◽  
Food Sources ◽  
Aspergillus Ochraceus ◽  
Plate Count ◽  
Acidic Ph ◽  
Ph Values ◽  
Neutral Ph ◽  
Plate Count Agar ◽  
Processing Plants

Six commercial phosphates were evaluated for inhibition of the growth of 17 molds isolated from food sources. The assays were performed at neutral and natural (without pH adjustment) pH values, and the molds were streaked on plate count agar with added phosphates. Phosphate concentrations of 0.1, 0.3, 0.5, 1.0, and 1.5% (wt/vol) were used, and the MIC was determined. The resistance of molds to phosphates depended on the species. At a neutral pH, Aspergillus ochraceus and Fusarium proliferatum were resistant to all phosphates at all concentrations assayed, and Byssochlamys nivea, Aureobasidium pullulans, and Penicillium glabrum were most sensitive. The most inhibitory phosphates were those with chain lengths greater than 15 phosphate units and the highest sequestering power. At natural pH values (resulting from dissolving the phosphate in the medium), inhibitory activity changed dramatically for phosphates that produced alkaline or acidic pH in the medium. Phosphates with alkaline pH values (sodium tripolyphosphate of high solubility, sodium tripolyphosphate, and sodium neutral pyrophosphate) were much more inhibitory than phosphates at a neutral pH, but sodium acid pyrophosphate (acidic pH) had decreased inhibitory activity. The results indicate that some phosphates could be used in the food industry to inhibit molds linked to food spoilage.

scholarly journals Kinetic parameters of neutral amino acid transport in hybrids between malignant and non-malignant cells

1984 ◽  
Vol 67 (1) ◽  
pp. 63-68
Author(s):  
M.K. White
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Neutral Amino Acid ◽  
Systematic Change ◽  
Acid Transport ◽  
Molecular Change ◽  
L System ◽  
Sodium Dependent ◽  
Kinetics Of

The kinetics of neutral amino acid transport were examined in isogeneic matched pairs of hybrid cells, one member of each pair being tumorigenic, the other not. The L system of transport, which is sodium-independent, was measured by the uptake of leucine, and the A system, which is sodium-dependent, by the uptake of methylaminoisobutyric acid. Although there was variation from one cell type to another in both Km and Vmax for the transport of these amino acids, no systematic change was found to be associated with tumorigenicity. This is in marked contrast with hexose uptake where tumorigenicity was invariably found to be associated with a reduction in Km. It thus appears that whatever molecular change is responsible for the alteration in the kinetics of hexose transport, it is specific, at least to the extent that it does not affect either sodium-dependent or sodium-independent transport of neutral amino acids.

scholarly journals Studies on Tetanus Toxin and Toxid. II. Isolation and Characterization of the Tetanus Toxin and Toxoid

1968 ◽  
Vol 21 (3) ◽  
pp. 559 ◽  
Author(s):  
DJ Dawson ◽  
CM Mauritzen
Keyword(s):  
Amino Acids ◽  
Tetanus Toxoid ◽  
Tetanus Toxin ◽  
Culture Medium ◽  
Deae Cellulose ◽  
Ph Values ◽  
Neutral Ph ◽  
Isolation And Characterization

Crude tetanus toxin and toxoid were prepared by methanol precipitation. The toxin was purified by a combination of TEAE�cellulose and Sephadex G�200 chromatography at pH values less than 6� o. The toxoid was purified by DEAE� cellulose at approximately neutral pH values. The nature and amount of amino acids of the culture medium which had condensed with the tetanus toxoid proteins during detoxification with formaldehyde was determined.

scholarly journals In vitro antibacterial activity of propolis extracts on 12 different bacteria in conditions of 3 various pH values

2010 ◽  
Vol 62 (4) ◽  
pp. 915-934 ◽  
Author(s):  
S. Ivancajic ◽  
I. Mileusnic ◽  
Desanka Cenic-Milosevic
Keyword(s):  
Antibacterial Activity ◽  
Ph Value ◽  
Acidic Ph ◽  
Acidic Environment ◽  
Alkaline Ph ◽  
Antibacterial Effects ◽  
Ph Values ◽  
Neutral Ph ◽  
In Vitro Antibacterial Activity

This research investigated the effects of propolis extracted by 5 different solvents and aged for 7 days on twelve species of bacteria classified into four groups according to their pathogenicity in slightly acidic (pH=6), neutral (pH=7) and slightly alkaline (pH=8) environments. Propolis extracted by the examined solvents had antibacterial effects. The strongest effects on the growth of all tested microorganisms, except on the bacteria of the Salmonella genus, regardless of the pH value of the environment, were exerted by propolis extracted by ether, acetone, toluol and chloroform. In some cases the antibacterial action of propolis was best in a slightly acidic environment (pH=6).

scholarly journals In vitro Determination of the Release Kinetics of Peptides and Free Amino Acids During the Digestion of Food Proteins

2005 ◽  
Vol 88 (3) ◽  
pp. 935-948 ◽  
Author(s):  
Laurent Savoie ◽  
Rafael A Agudelo ◽  
Sylvie F Gauthier ◽  
Johanne Marin ◽  
Yves Pouliot
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Protein Quality ◽  
Release Kinetics ◽  
In Vitro Digestion ◽  
Exchange Chromatography ◽  
Protein Sources ◽  
Kinetics Of ◽  
Peptide Fractions

Abstract The kinetics of peptide release during in vitro digestion of 4 protein sources (casein, cod protein, soy protein, and gluten) were investigated. Samples were sequentially hydrolyzed with pepsin (30 min) and pancreatin (2, 4, or 6 h) in a dialysis cell with continuous removal of digestion products. Nondialyzed digests were fractionated by ion-exchange chromatography and ultrafiltration. Animal proteins were digested at a greater rate than plant proteins. Target amino acids of specific enzymes appeared more rapidly in the dialyzed fractions when compared to other amino acids. Throughout the hydrolysis, nondialyzed digests contained a higher proportion of peptide mixtures with basic-neutral properties. Except for gluten, peptide fractions with molecular weights that exceeded 10 kDa (basic-neutral, BN > 10) were rapidly hydrolyzed during the first 2 h of pancreatin digestion. The kinetics of release and the composition of peptide fractions were different when the protein sources were compared. The analysis of amino acids revealed that threonine and proline proportions were relatively high in BN > 10 and in peptide fractions with molecular weight between 10-1 kDa (BN 10-1), while tyrosine, phenylalanine, lysine, and arginine predominated in the low molecular weight (<1 kDa) fractions. More resistant peptides were generally rich in proline and glutamic acid. The role of in vitro digestion assays in dietary protein quality evaluation is discussed.

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