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The most widely used ingredients in food formulation are proteins, lipids and polysaccharides. Proteins-lipids and proteins-polysaccharides interactions play a key role in the structure, stability, sensorial and nutritional properties of formulated foods. The objective of the present study is to highlight the importance of proteins-lipids and proteins-polysaccharides interactions, on the immuno-reactivity of allergenic proteins. Two models have been studied, on the one hand refined and not refined oils (soya and sunflower) and soya lecithin, on the other hand mixtures based on peanut proteins and polysaccharides (arabic gum, pectin, xylan). STUDY OF OILS: We have extracted proteins, using a PBS buffer, from refined and not refined oils from soya, sunflower and from soya lecithin, determined protein concentrations and identified allergenic proteins using SDS-PAGE electrophoresis and immuno-blotting. Phospholipids are determined by atomic absorption spectrometry. The protein determination and SDS-PAGE show the presence of a higher amount of proteins in not refined oils and lecithin as compared to refined oils. An important amount of proteins associated to phospholipids are eliminated by degumming on the form of lecithin. On the other hand, residual proteins from refined oils are accompanied by phospholipids. Immuno-blots reveal the presence of a 56 kDa allergen in oils issued from soya seeds and soya lecithin, and the presence of a 67 kDa allergen in oils issued from sunflower seeds. We conclude that the presence or elimination of proteins, especially allergens from oils is linked to amphiphilic association to phospholipids. STUDY OF PEANUT PROTEINS-POLYSACCHARIDES MIXTURES: We have digested in vitro proteins in a dialysis bag using a multi-enzymatic method and characterized proteins and peptides using SDS-PAGE electrophoresis and immuno-blotting. Our results confirm that peanut proteins alone are digested by proteases and that a number of large peptides still have epitopes recognized by anti-peanut proteins antibodies. Our results also show that the presence of polysaccharides changes the peptidic profile after digestion and that, depending on the polysaccharide type, smaller or larger peptides can be obtained in the dialysis bag. Smaller peptides are obtained using pectin whereas larger peptides are obtained using arabic gum and xylan. In the latter case, an increasing amount of peptides reacts to antibodies. Our first observations clearly show the need to better understand modifications of proteins allergenicity induced by the presence of other ingredients such as polysaccharides and lipids, in relation to technological treatments.

Background: Allergy to sesame seeds is often associated with particularly severe reactions, with a high risk of anaphylaxis. The increase in reports of allergic reactions to sesame is probably due to the growing use of sesame seeds or sesame oil in food., Objective: To determine the molecular weights of the proteins in three variety of sesame seeds and to study the isoelectric points and the allergenicity of white sesame proteins., Methods: Extracts of white, brown and black sesame seeds were prepared. The white sesame extract, mostly used in bakery, was run on SDS-PAGE and two dimensional electrophoresis. Six sera from patients sensitized or symptomatic to sesame seed were used for Western blotting., Results: The protein patterns of the white, brown and black sesame extracts showed major quantitative differences. The white extract had the higher protein concentration and contained 15 proteins of 12-79 kDa, some of them having several acidic isoelectric points. The lowest isoelectric point was 4.9 and the highest was 6.4, giving 35 isoforms. Ten of the 15 proteins (12-57.5 kDa) were recognized by specific IgE. The 12-13 kDa and 22-33 kDa proteins could correspond to the main allergens., Conclusion: White sesame seeds contain at least 10 allergenic proteins with acidic isoelectric points. In accordance with previous results, two of them seem to contain the major allergens.

Cases of allergy to the oils of groundnut, sunflower, soya and sesame have been described in the literature. In parallel, other authors have affirmed that these oils are not allergenic. The objective of this article is to make the point on this question, to cite the procedures to which the seeds are submitted to extract the oil, to remember that the oils are not composed only of triglycerides and to describe the results of our work. Allergy of oils is a subject that is constantly submitted to controversy and the bibliography does not cease to give contradictory examples. This may be explained by the variations in extraction procedures used by the manufactures, as well as by the conditions of extraction of the proteins in the laboratory.

Background: Although allergy to sunflower seed and oil is a relatively rare occurrence, several cases of sunflower seed allergy have been observed, and we have already described one case of anaphylaxis after eating sunflower oil and margarine., Objective: The aim of our study was to determine and characterize the allergens from sunflower oil at the different steps of the refining process: crude pressed oil (step A), acidification and neutralization (step B), pregumming by centrifugation (step C), washing (step D), bleaching (step E), gumming by filtration (step F), and deodorization (step G)., Methods: A sample of oil from each step of the process (steps A to G) was heat extracted with PBS. The protein concentration of each extract was evaluated by using the micro-Bradford assay. Samples were run on SDS-PAGE. The immunoblot was performed with the serum of a patient sensitized to sunflower seed and oil., Results: The extracts obtained after each step reveal a decrease in total protein concentration from 13.6 microg/mL to 0. 22 microg/mL. The result of SDS-PAGE shows 5 bands, from 67 kd to 145 kd, with the most abundant being the 67-kd protein. The amount of this protein decreases after each step of the process. It is, however, still present in trace amounts in the refined oil. The 67-kd protein, which is mainly present in the crude oil and slightly in the refined oil, has been shown to be allergenic., Conclusion: Because of the presence of allergenic proteins, refined sunflower oil may pose a threat to people highly sensitized to sunflower seeds.