Food Allergens: Is There a Correlation between Stability to Digestion and Allergenicity?

Abstract

Food allergy is a major health problem in the Western countries, affecting 3-8% of the population. It has not yet been established what makes a dietary protein a food allergen. Several characteristics have been proposed to be shared by food allergens. One of these is resistance to digestion. This paper reviews data from digestibility studies on purified food allergens and evaluates the predictive value of digestibility tests on the allergenic potential. We point out that food allergens do not necessarily resist digestion. We discuss how the choice of in vitro digestibility assay condition and the method used for detection of residual intact protein as well as fragments hereof may greatly influence the outcome as well as the interpretation of results. The finding that digests from food allergens may retain allergenicity, stresses the importance of using immunological assays for evaluating the allergenic potential of food allergen digestion products. Studies assessing the allergenicity of digestion products, by either IgE-binding, elicitation or sensitizing capacity, shows that digestion may abolish, decrease, have no effect, or even increase the allergenicity of food allergens. Therefore, the predictive value of the pepsin resistance test for assessing the allergenic potential of novel proteins can be questioned.

Influence of peanut matrix on stability of allergens in gastric‐simulated digesta: 2S albumins are main contributors to the IgE reactivity of short digestion‐resistant peptides

“…Food ingestion is the major route of sensitization to food allergens. A great number of allergenic proteins are remarkably resistant to proteolysis in the gastrointestinal tract, and survival of their large fragments is essential for their sensitizing capacity . There is no strict relationship between digestibility and allergenicity, and several major allergens are extremely digestion‐labile proteins.…”

“…There is no strict relationship between digestibility and allergenicity, and several major allergens are extremely digestion‐labile proteins. However, evaluation of resistance to digestion with pepsin by in vitro simulated digestion remains a central part of allergenicity safety assessment of novel proteins . In vitro methods simulating digestion processes are widely used tools because of their simplicity, low cost, reproducibility and ethical acceptability …”

Literature review in support of adjuvanticity/immunogenicity assessment of proteins

“…The data presented on susceptibility of food allergens to gastric (pepsin) as well as gastro-duodenal digestion (pepsin, followed by trypsin and chymotrypsin) clearly illustrates that even major allergens may be extremely labile as intact proteins, being digested to small peptide fragments within few minutes 101,102 . The allergenicity risk assessment usually includes an evaluation of protein stability to digestion, under the premise that intestinal exposure would be directly linked with this property.…”

Influence of heat treatment and egg matrix on the physicochemical and allergenic properties of egg custard

“…Thermal treatments, which are common and conventional during food production, potentially influence the allergenicity of food allergens by affecting the conformational changes and subsequent gastrointestinal digestibility (Verhoeckx et al., 2015). Heating‐induced conformational changes, such as unfolding and aggregation, may destroy the conformational epitopes or generate new ones, and the changes may also make the allergens either further susceptible or resistant to gastrointestinal enzymes, which may affect the allergenic potential of food allergens (Bogh & Madsen, 2016; Jimenez‐Saiz, Benede, Molina, & Lopez‐Exposito, 2015). The effect of thermal treatment on egg allergens has also been extensively investigated, and generally, thermal treatment could decrease the allergenicity of egg allergens.…”