Formulating preservatives to enhance stability of crude extracts of food allergens used for food allergy management and immunotherapy

Abstract

Due to rapid degradation of food allergenic extracts, devising some optimal conditions is mandatory to boost shelf life of extracts for appropriate diagnosis of allergy and immunotherapy. In the current study, food extracts of Bos domesticus (cow) milk, Gallus domesticus (chicken) egg, Trititcum aestivum (wheat), Gallus domesticus (chicken) meat and Arachis hypogaea (peanut) were prepared and their protein estimation was evaluated by bicinchoninic acid (BCA) method. Stability of food extracts was evaluated under two groups of preservatives; storage with coca's solution (mixture of sodium chloride (NaCl) and sodium bicarbonate (NaHCO₃)) and stabilizing buffer (sucrose and ethylene diamine tetra-acetic acid (EDTA)). Effect of cocktail of protease inhibitors ((phenyl methyl sulfonyl fluoride (PMSF) and dithiothreitol (DTT)) and glycerol was checked on food extracts under both groups of preservatives. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS PAGE) was performed for food protein extracts after 1, 3 and 6 months under both conditions. Size of obtained protein bands were compared with allergen database (http://www.allergen.org) in order to check their potential allergenicity. Extracts stored with coca's solution remained more potent as compared to stabilizing buffer for up to 3 months except Gallus domesticus egg, whose proteins remained more potent in stabilizing buffer as compared to coca's solution. Most of the proteins deteriorated at 6 months of storage. Glycerol had shown better results under both conditions. A formulation containing a combination of coca's solution along with cocktail of protease inhibitors and glycerol improved the shelf life of food extracts for up to 3 months, showing better potential for stabilization of allergenic food extracts and their use for immunotherapy.