Desensitizing mechanism of thermal processing on pumpkin seed protein: allergen structure alteration and immune...

Pumpkin seeds are commonly consumed nuts. While their allergic potential has been neglected, major allergens existing in pumpkin seed proteins (PS pro) are not clarified yet. Thermal processing has been reported as an effective desensitizing method. However, neither the desensitization effect of heat treatment on PS pro nor the working mechanism is clarified.

Protein bands with molecular weight around 15, 35 and 55 kDa are the major allergens identified in PS pro. Proteins around 10-15 kDa showed more resistance to thermal processing compared with other bands. Hydrophobic bonds contributed to the preserved antibody-binding capacity of baked allergens, whereas the reduced secondary structures resulted in a decrease in allergenicity of boiled allergens. A murine model allergic to PS pro with a relatively longer sensitization period was constructed, and the parameters (baking at 120 °C for 25 min) were proved to be capable of decreasing the sensitivity. The desensitizing mechanism was explored in three aspects: (i) Th2 responses in both the spleen and mesenteric lymph nodes were suppressed; (ii) gut microbial community was changed, the Firmicutes/Bacteroidata ratio decreased and the abundance of both Clostridium_citroniae and Lactobacillus_johnsonii increased; and (iii) the content of acetic acid, butyric acid and isobutyric acid increased.

Thermal processing could decrease the sensitivity of PS pro from the aspects of allergen structural changes and in vivo reactions in allergic mice. Our research could provide valuable processing parameters for the production of both desensitized food and allergy vaccines, and give a realistic view for allergy pathogenesis study. © 2025 Society of Chemical Industry.