Preliminary studies on the effect of processing on the IgE reactivity tomato products

Tomatoes and tomato products, obtained from a market, from companies or prepared in research laboratories, were tested in order to investigate how different processes could modulate the IgE reactivity of these products. The protein fraction of the samples was extracted by using a low-temperature method in order to avoid degradation, and then separated on SDS PAGE to evaluate the protein profile. All the separated samples were blotted onto nitrocellulose membranes and then individually tested with pooled human sera that had been obtained from patients allergic to tomato, in order to evaluate the potential IgE binding of the protein bands. Heat treatments conventionally employed for the production of tomato-based products were found to strongly degrade proteins thus dramatically reducing their IgE reactivity; characteristic protein profiles were found for specific processes such as hot and cold break. Ultra-high-pressure treatments were found to generally preserve the integrity of tomato proteins and this was reflected by the unaltered IgE reactivity observed. (c) 2007 Society of Chemical Industry.