Influence of the Natural Ripening Stage, Cold Storage, and Ethylene Treatment on the Protein and IgE-Binding Profiles of Green and Gold Kiwi Fruit Extracts

Kiwi fruit is an important source of food allergens, the number and relevance of which are still the object of investigation. Following a comparative analysis of the protein profiles in SDS-PAGE and IgE immunoblotting, a significant influence of conditions such as the ripening stage and the extraction method on the composition of green and gold kiwi fruit extracts was observed. Furthermore, the experimental data indicate that, mostly in the green species, a ripe fruit may have a different concentration of total proteins and a different amount of single components when ripeness is reached by different means of postharvest handling, such as ethylene exposure with or without previous cold storage. In summary, this study emphasizes the level of complexity associated with the preparation of extracts when a known and defined concentration of proteins/allergens is requested.