pectins and Food-Hypersensitivity

Patients exquisitely sensitive to cashew/pistachio are at risk for allergic reactions to citrus seeds and pectin.. In this study, we sought to evaluate whether pectin is contaminated with citrus seeds, to identify a culprit antigen in citrus seeds, and to assess for cross-reactivity among allergens in citrus seeds, citrus pectin, and cashew or pistachio.. Proteins from orange seed coats, orange seed endosperms, lemon seeds, grapefruit seeds, citrus pectin, apple pectin, and grapefruit pectin were extracted. Protein concentrations in all extracts were determined and visualized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique. Immunoglobulin E-binding capacity was determined with Western blot analyses and tandem mass spectrometry for the identification of the culprit allergen in citrus seeds and pectin.. In subjects with citrus seed, pectin, and cashew allergies, there was strong immunoglobulin E-reactivity to bands between 17 to 28 kDa and 28 to 38 kDa. The tandem mass spectrometry analysis of these bands indicated the presence of citrin as the culprit allergen. Citrin and Ana o 2 are both 11S globulins belonging to the cupin superfamily, and significant homology was found between these proteins.. Citrus pectin may be contaminated with citrus seeds. Citrin, a newly identified allergen in citrus seeds, seems to be the culprit antigen in citrus seeds and contaminated citrus pectin. Citrin is highly homologous with Ana o 2 in cashew and Pis v 2 in pistachio, suggesting potential for cross-reactivity and providing an explanation for co-allergenicity of cashew or pistachio, citrus seeds, and citrus pectin.

Topics: Allergens; Anacardium; Citrus; Food Hypersensitivity; Humans; Immunoglobulin E; Nut Hypersensitivity; Pectins; Pistacia; Plant Proteins; Seeds

Topics: Allergens; Anaphylaxis; Child; Cross Reactions; Diet Therapy; Female; Food Hypersensitivity; Fruit; Humans; Immunoglobulin E; Male; Nuts; Pectins; Yogurt

It is a general belief that a food allergen should be stable to gastric digestion. Various acidic plant polysaccharides, including pectin, are ubiquitous in fruit matrixes and can form hydrogels under low-pH conditions.. The purpose of this study was to investigate the effect of hydrogel forming polysaccharide-rich fruit matrixes on in vivo gastric and in vitro pepsic digestion of fruit allergens.. Fruit extract proteins (kiwi, banana, apple and cherry) and a purified major kiwi allergen Act c 2 were digested with simulated gastric fluid in accordance with the US Pharmacopeia. In vivo experiments on kiwi fruit digestion were performed on four healthy non-atopic volunteers by examining the gastric content 1 h after ingestion of kiwi fruit. The Act c 2 and kiwi proteins were detected in immunoblots using monoclonal anti-Act c 2 antibodies and rabbit polyclonal antisera.. Crude fruit extracts were resistant to digestion by pepsin when compared with commonly prepared extracts. In the gastric content of all volunteers, following kiwi fruit ingestion and immunoblotting, intact Act c 2 was detected with anti-Act c 2 monoclonal antibodies, while kiwi proteins of higher molecular weights were detected using rabbit polyclonal antisera. Addition of apple fruit pectin (1.5% and 3%) to the purified kiwi allergen was able to protect it from pepsin digestion in vitro.. The matrix effect in pectin-rich fruits can influence the digestibility of food proteins and thereby the process of allergic sensitization in atopic individuals.

Topics: Actinidia; Allergens; Animals; Digestion; Disaccharides; Food Hypersensitivity; Fruit; Gastric Juice; Humans; Mice; Monosaccharides; Pectins; Pepsin A; Plant Extracts; Plant Proteins; Rabbits

The specific effects of heat treatment and/or addition of low/high-methylated pectin (LMP/HMP) on the allergenicity of beta-lactoglobulin (beta-Lg) and its hydrolysis products were investigated through a two-step in vitro digestion approach. beta-Lg was first hydrolyzed by pepsin and then by a trypsin/chymotrypsin (T/C) mixture done in a dialysis bag with a molecular weight cutoff of 1000. The protein digestion was followed by SDS-PAGE electrophoresis performed on each digestion product, and their in vitro allergenicity was analyzed by immunoblotting. Such procedure was applied on beta-Lg samples mixed with the two kinds of pectin before or after heating (80 degrees C, 25 min) to determine the respective impact of heat treatment and pectin addition. Heat denaturation improved significantly the susceptibility of beta-Lg against the pepsin and the T/C. This effect, which was coupled to a reduction in immunoreactivity of the digested beta-Lg, appeared to be distinctively modulated by LMP and HMP. Through nonspecific interaction with the beta-Lg, pectin could reduce the accessibility of cleavage sites and/or epitope sequences. This mechanism of action is discussed in relation to the intra- and intermolecular interactions between beta-Lg and pectin initiated under the experimental conditions.

Topics: Allergens; Chymotrypsin; Food Hypersensitivity; Hot Temperature; Hydrolysis; Lactoglobulins; Methylation; Particle Size; Pectins; Pepsin A; Protein Denaturation; Trypsin

Topics: Adult; Cross Reactions; Female; Food Hypersensitivity; Histamine Release; Humans; Immunoglobulin E; Nuts; Pectins; Radioallergosorbent Test; Skin Tests

Rats received dietary supplement of milk whey concentrate (KSP) being manufactured from skimmed milk by addition of apple pectin (Pec), KSP ultrafiltrated fractions and pure Pec during 21 day. A part of animals were sensitized i/p with chicken ovalbumin and finally subjected to systemic anaphylaxis (SA) by i/v antigen challenge. Gastrointestinal barrier macromolecular permeability (MP) for polyethylene glycol 4000 (PEG-4000) was measured by its urinary excretion after an intragastric load. MP increased significantly in nonsensitized rats after feeding with KSP and its high molecular (HM) fraction but not after feeding with low molecular (LM) KSP fraction compared to NaCl fed group. Feeding with Pec dramatically (5-fold) increased permeability. On the contrary the permeability decreased in sensitized rats subjected to SA when fed with KSP, its LM and particularly HM fraction the later group permeability being normalized down to normal value found in nonsensitized animals. It's concluded that KSP whey protein may be recommended for incorporation into specialized foods for patients with impaired gastrointestinal function.

Topics: Anaphylaxis; Animals; Cell Membrane Permeability; Drug Evaluation, Preclinical; Food Hypersensitivity; Immunization; Intestinal Mucosa; Intestines; Macromolecular Substances; Male; Milk Proteins; Molecular Weight; Pectins; Polyethylene Glycols; Rats; Rats, Wistar; Time Factors; Whey Proteins