Allergenic power reduction of food proteins by nonthermal technologies

The great interest of the research activity in food allergies could be attributed to the increase of allergic reactions all over the world not only in infants but even in adult age. As an alternative to the development of an allergen-free diet, many works have been focused on a novel approach for the treatment of allergens: instead of eliminating the allergens from the diet, the immunoresponse can be reduced or even eliminated by inducing some modifications of their molecular structure. In fact, changes in allergen conformation can modulate its identification by the specific antibody produced by immune system in allergic reactions. Structural modifications in allergens could be induced by conventional thermal treatments as well as by non-thermal technologies, namely High Hydrostatic Pressure (HHP), Pulsed Electric Fields (PEF), Pulsed Light (PL) and -radiations. Non-thermal technologies have been widely used in the last years for food preservation, having the advantage of increasing the shelf-life and freshness of the raw food products. These technologies are able to affect the food nutritional and organoleptic properties only slightly thanks to the use of a non-thermal stress to treat foodstuffs. Among them High Hydrostatic Pressure technology has been successfully used in food pasteurization, but also in processes involving the sol-gel transition such as the production of jams, jellies and dairy products. The ability of High Pressure to determine structural changes in foods was studied in order to assess if proteins unfolding and/or aggregation and gelation can be induced and if the treatment affects the functional properties and digestibility of proteins. These effects were studied on particular proteins, namely the allergens, for which unfolding and structural modification have been proven. However, the effectiveness of the High Pressure processing on the reduction of immunoresponse reduction was not clearly assessed so far. The objective of this PhD thesis was the study of the modifications induced by High Pressure Process on allergenic proteins and the possibility of obtaining hypoallergenic peptides by means of a combined High Hydrostatic Pressure hydrolysis. In particular, the effect of the HHP on the allergens structural modification was investigated in a wide range of operating conditions, including both gelling and ungelling conditions. Rheological behavior and functional properties of HHP processed allergens was also determined. [edited by Author]