scholarly journals Release of Major Peanut Allergens from Their Matrix under Various pH and Simulated Saliva Conditions—Ara h2 and Ara h6 Are Readily Bio-Accessible

Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1281 ◽  
Author(s):  
Stef Koppelman ◽  
Mieke Smits ◽  
Monic Tomassen ◽  
Govardus de Jong ◽  
Joe Baumert ◽  
...  
Keyword(s):  
Oral Mucosa ◽  
Protein Solubility ◽  
Low Ph ◽  
Peanut Flour ◽  
Remarkable Difference ◽  
Extraction Kinetics ◽  
Roasted Peanut ◽  
Ara H1 ◽  
Peanut Allergens ◽  
Ph Range

The oral mucosa is the first immune tissue that encounters allergens upon ingestion of food. We hypothesized that the bio-accessibility of allergens at this stage may be a key determinant for sensitization. Light roasted peanut flour was suspended at various pH in buffers mimicking saliva. Protein concentrations and allergens profiles were determined in the supernatants. Peanut protein solubility was poor in the pH range between 3 and 6, while at a low pH (1.5) and at moderately high pHs (>8), it increased. In the pH range of saliva, between 6.5 and 8.5, the allergens Ara h2 and Ara h6 were readily released, whereas Ara h1 and Ara h3 were poorly released. Increasing the pH from 6.5 to 8.5 slightly increased the release of Ara h1 and Ara h3, but the recovery remained low (approximately 20%) compared to that of Ara h2 and Ara h6 (approximately 100% and 65%, respectively). This remarkable difference in the extraction kinetics suggests that Ara h2 and Ara h6 are the first allergens an individual is exposed to upon ingestion of peanut-containing food. We conclude that the peanut allergens Ara h2 and Ara h6 are quickly bio-accessible in the mouth, potentially explaining their extraordinary allergenicity.

scholarly journals Impact of cold plasma processing on major peanut allergens

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Harshitha Venkataratnam ◽  
Orla Cahill ◽  
Chaitanya Sarangapani ◽  
P. J. Cullen ◽  
Catherine Barry-Ryan
Keyword(s):  
Cold Plasma ◽  
Plasma Reactor ◽  
Protein Solubility ◽  
Cd Spectroscopy ◽  
Microbial Inactivation ◽  
Peanut Flour ◽  
Ara H 2 ◽  
Ara H 1 ◽  
Peanut Allergens ◽  
Allergen Structure

Abstract Cold plasma is emerging as a novel food processing technology, with demonstrated efficacies for microbial inactivation and residual chemical dissipation of food products. Given the technology’s multimodal action it has the potential to reduce allergens in foods, however data on the efficacy and mechanisms of action are sparse. This study investigates the efficacy of cold plasma on major peanut allergens (Ara h 1 and Ara h 2). For this purpose, dry, whole peanut (WP) and defatted peanut flour (DPF) were subjected to an atmospheric air discharge using a pin to plate cold plasma reactor for different treatment durations. With increases in plasma exposure, SDS-PAGE analysis revealed reduced protein solubility of the major peanut allergens. Alterations in allergenicity and structure of Ara h 1 and Ara h 2 were examined using ELISA and circular dichroism (CD) spectroscopy. Competitive ELISA with proteins purified from plasma treated WP or DPF revealed reduced antigenicity for both Ara h 1 and Ara h 2. The highest reduction in antigenicity was 65% for Ara h 1 and 66% Ara h 2 when purified from DPF. Results from CD spectroscopy analysis of purified proteins strongly suggests the reduction in antigenicity is due to modifications in the secondary structure of the allergens induced by plasma reactive species. Cold plasma is effective at reducing peanut protein solubility and causes changes in allergen structure leading to reduced antigenicity.

scholarly journals Common Loon, Gavia immer, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

2009 ◽  
Vol 123 (2) ◽  
pp. 146 ◽  
Author(s):  
Robert Alvo
Keyword(s):  
Breeding Success ◽  
Low Ph ◽  
Single Pair ◽  
Gavia Immer ◽  
Common Loon ◽  
Sulphur Deposition ◽  
Acidic Lakes ◽  
Ph Range ◽  
Lake Size ◽  
Critical Ph

I monitored Common Loon (Gavia immer) breeding success in relation to lake pH (range 4.0–8.5) between 1982 and 2007 on 38 single-pair lakes (5–88 ha) in the Sudbury, Ontario, area. No chicks fledged on lakes with pH < 4.4. Chicks fledged on lakes with slightly higher pH only if the lakes were relatively large. Acidic lakes became less acidic as sulphur dioxide emissions from the Sudbury smelters and sulphur deposition from other long-range sources decreased. Two lakes initially too acidic to support successful loon reproduction eventually had successful reproduction. One loon pair used two large acidic lakes (combined area 140 ha) connected by shallow rapids, and one of the adults made extremely long dives (average = 99 s) while foraging for the chicks. One chick died on that lake after apparently ingesting a very large food item; the lack of smaller items was attributed to the lake’s acidity. My results suggest that a shortage of food for chicks is the main reason why low pH reduces breeding success. I suggest that, for lakes without high levels of dissolved organic carbon (DOC), the critical pH for loon breeding success is approximately 4.3, and the suboptimal pH is approximately 4.4–6.0.

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 THE ABSORPTION SPECTRUM OF VISUAL PURPLE

1938 ◽  
Vol 21 (4) ◽  
pp. 411-430 ◽  
Author(s):  
Aurin M. Chase ◽  
Charles Haig
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Light Transmission ◽  
Low Ph ◽  
The Other ◽  
Distilled Water ◽  
Color Purity ◽  
Chemical Combination ◽  
Ph Range ◽  
Sensitive Group

The absorption spectra of visual purple solutions extracted by various means were measured with a sensitive photoelectric spectrophotometer and compared with the classical visual purple absorption spectrum. Hardening the retinas in alum before extraction yielded visual purple solutions of much higher light transmission in the blue and violet, probably because of the removal of light-dispersing substances. Re-extraction indicated that visual purple is more soluble in the extractive than are the other colored retinal components. However, the concentration of the extractive did not affect the color purity of the extraction but did influence the keeping power. This suggests a chemical combination between the extractive and visual purple. The pH of the extractive affected the color purity of the resulting solution. Over the pH range from 5.5 to 10.0, the visual purple color purity was greatest at the low pH. Temperature during extraction was also effective, the color purity being greater the higher the temperature, up to 40°C. Drying and subsequent re-dissolving of visual purple solutions extracted with digitalin freed the solution of some protein impurities and increased its keeping power. Dialysis against distilled water seemed to precipitate visual purple from solution irreversibly. None of the treatments described improved the symmetry of the unbleached visual purple absorption spectrum sufficiently for it to resemble the classical absorption spectrum. Therefore it is very likely that the classical absorption spectrum is that of the light-sensitive group only and that the absorption spectra of our purest unbleached visual purple solutions represent the molecule as a whole.

scholarly journals Effect of pH on the interaction of botulinum neurotoxins A, B and E with liposomes

1989 ◽  
Vol 259 (1) ◽  
pp. 47-53 ◽  
Author(s):  
C Montecucco ◽  
G Schiavo ◽  
B R Dasgupta
Keyword(s):  
Fatty Acid ◽  
Botulinum Neurotoxin ◽  
Structural Changes ◽  
Polar Region ◽  
Low Ph ◽  
Hydrophobic Core ◽  
Head Groups ◽  
Botulinum Neurotoxins ◽  
Ph Range ◽  
Lipid Interaction

The interaction of botulinum neurotoxin serotypes A, B and E with membranes of different lipid compositions was examined by photolabelling with two photoreactive phosphatidylcholine analogues that monitor the polar region and the hydrophobic core of the lipid bilayer. At neutral pH the neurotoxins interacted both with the polar head groups and with fatty acid chains of phospholipids. At acidic pHs the neurotoxins underwent structural changes characterized by a more extensive interaction with lipids. Both the heavy and light chain subunits of the neurotoxins were involved in the process. The change in the nature and extent of toxin-lipid interaction occurred in the pH range 4-6 and was not influenced by the presence of polysialogangliosides. The present data are in agreement with the idea that botulinum neurotoxins enter into nerve cells from a low pH intracellular compartment.

Simultaneous determination of major peanut allergens Ara h1 and Ara h2 in baked foodstuffs based on their signature peptides using ultra-performance liquid chromatography coupled to tandem mass spectrometry

2019 ◽  
Vol 11 (12) ◽  
pp. 1689-1696 ◽  
Author(s):  
Jingshun Zhang ◽  
Yuwei Hong ◽  
Zengxuan Cai ◽  
Baifen Huang ◽  
Junlin Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
Tandem Mass Spectrometry ◽  
Ultra Performance Liquid Chromatography ◽  
Tandem Mass ◽  
Ara H1 ◽  
Peanut Allergens ◽  
Signature Peptides

A robust UPLC-MS/MS method was established for the quantitative analysis of the major peanut allergens Ara h1 and Ara h2 in baked foodstuffs based on their signature peptides.

scholarly journals Chemoenzymatic synthesis of the pH responsive surfactant octyl β-D-glucopyranoside uronic acid

2019 ◽  
Vol 104 (3) ◽  
pp. 1055-1062 ◽  
Author(s):  
Ngoc T. N. Ngo ◽  
Carl Grey ◽  
Patrick Adlercreutz
Keyword(s):  
Substrate Concentration ◽  
Uronic Acid ◽  
Catalyst System ◽  
Low Ph ◽  
Chemoenzymatic Synthesis ◽  
Ph Responsive ◽  
Ph Values ◽  
Wide Ph Range ◽  
Carboxyl Derivative ◽  
Ph Range

AbstractMethodology was developed to expand the range of benign alkyl glycoside surfactants to include also anionic types. This was demonstrated possible through conversion of the glycoside to its carboxyl derivative. Specifically, octyl β-D-glucopyranoside (OG) was oxidised to the corresponding uronic acid (octyl β-D-glucopyranoside uronic acid, OG-COOH) using the catalyst system T. versicolor laccase/2,2,6,6-tetramethylpiperidinyloxy (TEMPO) and oxygen from air as oxidant. The effects of oxygen supply methodology, concentrations of laccase, TEMPO and OG as well as reaction temperature were evaluated. At 10 mM substrate concentration, the substrate was almost quantitatively converted into product, and even at a substrate concentration of 60 mM, 85% conversion was reached within 24 h. The surfactant properties of OG-COOH were markedly dependent on pH. Foaming was only observed at low pH, while no foam was formed at pH values above 5.0. Thus, OG-COOH can be an attractive low-foaming surfactant, for example for cleaning applications and emulsification, in a wide pH range (pH 1.5–10.0).

An aminoquinoline based biocompatible fluorescent and colourimetric pH sensor designed for cancer cell discrimination

2018 ◽  
Vol 42 (24) ◽  
pp. 19818-19826 ◽  
Author(s):  
Jayanta Mandal ◽  
Pravat Ghorai ◽  
Paula Brandão ◽  
Kunal Pal ◽  
Parimal Karmakar ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Cancer Cell ◽  
Low Cost ◽  
Ph Sensor ◽  
Low Ph ◽  
Cell Permeability ◽  
Ph Range ◽  
Cell Discrimination

A simple, low cost aminoquinoline based pH sensor,HLwas prepared and it works at a low pH range.HLexhibits cell permeability and used as an effective tool for differentiating between normal and cancer cells.

Characteristics of an Acidophilic Bacillus Strain Isolated from Shelf-Stable Juices

1995 ◽  
Vol 58 (3) ◽  
pp. 319-321 ◽  
Author(s):  
SHERI MCINTYRE ◽  
JUDY Y. IKAWA ◽  
NINA PARKINSON ◽  
JOHN HAGLUND ◽  
JENNIFER LEE
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Economic Loss ◽  
Low Ph ◽  
Potato Dextrose Agar ◽  
Bacillus Species ◽  
Potato Dextrose Broth ◽  
Bacillus Strain ◽  
Ph Range ◽  
Shelf Stable

An acidophilic sporeformer was isolated from several varieties of shelf-stable juices. The organism sporulated on potato dextrose agar (pH 3.5) at 37°C within 24 hours and grew well in fruit and berry juices. The pH range of growth in potato dextrose broth was 3.0 to 5.3. The D87.8°C' D91.1°C' and D95°C determined in berry juice were 11.0, 3.8, and 1.0 min, respectively. The ability of this organism to grow at low pH and to survive pasteurization poses a threat of economic loss by spoilage to beverage producers. The organism could not be identified based on its characteristics or the fatty acid profile comparison to those of other Bacillus species, including the acidophilic B. acidocaldarius.

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