Peanut Protein Allergens: The Effect of Roasting on Solubility and Allergenicity

Background: Peanut allergy is recognized as one of the most severe food allergies. Some studies have investigated the effects of enzymatic treatments on the in vitro immunological reactivity of members of the Leguminosae family, such as the soybean, chickpea and lentil. Nevertheless, there are only a few studies carried out with sera from patients with a well-documented allergy. Methods: Roasted peanut protein extract was hydrolyzed by the sequential and individual action of 2 food-grade enzymes, an endoprotease (Alcalase) and an exoprotease (Flavourzyme). Immunoreactivity to roasted peanut extract and hydrolyzed samples was evaluated by means of IgE immunoblot, ELISA and 2-dimensional electrophoresis using sera from 5 patients with a clinical allergy to peanuts and anti-Ara h 1, anti-Ara h 2 and anti-Ara h 3 immunoblots. Results: Immunoblot and ELISA assays showed an important decrease of IgE reactivity and Ara h 1, Ara h 2 and Ara h 3 levels in the first 30 min of hydrolyzation with Alcalase. In contrast, individual treatment with Flavourzyme caused an increase in IgE reactivity detected by ELISA at 30 min and led to a 65% inhibition of IgE reactivity at the end of the assay (300 min). Ara h 1 and the basic subunit of Ara h 3 were still recognized after treatment with Flavourzyme for 300 min. Conclusion: Hydrolysis with the endoprotease Alcalase decreases IgE reactivity in the soluble protein fraction of roasted peanut better than hydrolysis with the exoprotease Flavourzyme.

Section: Discussionmentioning

confidence: 99%

Influence of Enzymatic Hydrolysis on the Allergenicity of Roasted Peanut Protein Extract

Cabanillas

Pedrosa

Rodríguez

et al. 2011

“…Like peanut protein allergens bhetki and mackerel allergens were found to be resistant to thermal denaturation. This indicated that conformational epitopes may not always be vital and play a minor role in their allergenicity [11]. Also it may be possible that the epitopes are present at the sites of the protein that are not heat-sensitive.…”

Section: Discussionmentioning

confidence: 99%

“…It was shown that different forms of heat affected the allergenicity in different ways. While roasting increased the allergenicity of peanut protein or left it unaltered, Ara h 1, boiling or frying reduced its allergenic potential [11]. There are reports that the IgE-binding capacity of the allergen increased relatively on storage due to the formation of new peptides [12].…”

Section: Introductionmentioning

confidence: 99%

Changes in the Allergenicity during Different Preparations of Pomfret, Hilsa, Bhetki and Mackerel Fish as Illustrated by Enzyme-Linked Immunosorbent Assay and Immunoblotting

Chatterjee

Mondal

Chakraborti

et al. 2006

Background: Although the identification and characterization of several fish allergens have already been reported, there is almost no data on Indian fish allergens and the effect of thermal processing on their allergenicity. This study aimed at the evaluation of the changes in the level of allergenicity of 4 highly consumed Indian fishes, i.e. pomfret, hilsa, bhetki and mackerel, that occurred after boiling and frying. Methods: In this study 110 patients with fish hypersensitivity as evidenced by clinical history and symptoms were recruited based on their positive skin prick test results. The raw, boiled and fried muscle extracts of the 4 fishes were prepared, and each extract was tested by ELISA and immunoblotting with patients’ sera. Results: ELISA and immunoblotting studies demonstrated that the raw muscle extracts of pomfret, hilsa, bhetki and mackerel were allergenic. While the allergenicity of boiled and fried extracts of pomfret and hilsa was considerably reduced, maximum allergenicity of bhetki was demonstrated in the fried extract. The degree of allergenicity of bhetki was demonstrated in the order fried > boiled > raw while that of mackerel followed the order raw > boiled ≃ fried. Conclusion: The specificIgE-binding activity and immunoblot profile clearly showed that pomfret and hilsa fish allergens are heat-labile, while allergens of bhetki and mackerel maintained strong reactivity even after thermal treatment.

“…A finding that the roasting process reduces peanut protein solubility [33] will be used to compare the in vivo digestion of raw and processed peanut under similar physiological conditions in future studies. Reduced solubility could increase the amount of surviving particulate material available for transport through the stomach and into the small intestine for antigen sampling in the GI mucosa.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Physiological and in vitroPorcine Gastric Fluid Digestion

Kopper

West²,

Helm³

2006

Self Cite

Background: In previous studies, the major peanut allergen Ara h 1 was digested in vitro using pepsin and porcine gastric fluid. The results suggested that in vivo gastric digestion of allergen protein can be modeled accurately by peptic hydrolysis in vitro. In the current investigation, studies were designed to follow the gastrointestinal (GI) digestion of peanut allergens under true physiological conditions. In vitro digestion with porcine gastric fluid was compared with actual physiological digestion of peanut allergens in the porcine digestive tract in vivo. Methods: Analysis of physiologic digestion was performed in piglets administered a 20-gram bolus of peanut meal followed by periodic sampling and analysis of GI contents. The pH was monitored, and digesta were analyzed by SDS-PAGE and immunoblot analysis. Results: Peanut meal initially neutralized stomach contents to a pH of approximately 7, which was subsequently acidified by HCl secretion within 30 min. Acidification to pH 2–4 resulted in active pepsin digestion of soluble protein in the stomach. Soluble intact protein/allergens were rapidly degraded to pepsin-resistant peptides in the stomach followed by hydrolysis of these fragments in the small intestine. Particulate material was evident in both the stomach and small intestine that could contribute to continued release of peanut allergens Ara h 1, 2 and 3. Conclusions: Porcine gastric digestion of peanut proteins resembles true physiological digestion only under optimal physiologic conditions. Soluble proteins are rapidly digested and insoluble material continues to release IgE-reactive proteins throughout the GI tract. GI digestion of food allergens can play a prominent role when assessing allergens within the context of a food matrix or meal and during the sensitization phase of IgE-mediated allergy.