Proteomic characterization of peanut flour fermented by rhizopus oryzae

Authors: Mattison, Chris; DUPRE, REBECCA - Oak Ridge Institute For Science And Education (ORISE); CLERMONT, KRISTEN - Oak Ridge Institute For Science And Education (ORISE); GIBBONS, JOHN - Oak Ridge Institute For Science And Education (ORISE); YU, JAE-HYUK - University Of Wisconsin

Submitted to: Heliyon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2024
Publication Date: 8/18/2024
Citation: Mattison, C.P., Dupre, R.A., Clermont, K., Gibbons, J.D., Yu, J. 2024. Proteomic characterization of peanut flour fermented by rhizopus oryzae. Heliyon. https://doi.org/10.1016/j.heliyon.2024.e34793.
DOI: https://doi.org/10.1016/j.heliyon.2024.e34793

Interpretive Summary: Fermented foods are very popular and are thought to have many health benefits including contributions from beneficial microorganisms. Food allergies affect a growing number of individuals, and peanuts are among a group of foods that commonly cause food allergies. There are likely connections between the microorganisms in our guts and the immune signaling that may cause food allergies. The fungus Rhizopus oryzae (R. oryzae) is consider safe for human consumption. It is used to create tempeh from cooked soybeans and for the industrial production of commercial enzymes. To understand how microorganisms metabolize peanut allergens we used R. oryzae as a model system. We followed the break-down of peanut allergens into smaller peptides by R. oryzae using proteomic and immunologic assays. Our results indicate that R. oryzae is able to degrade peanut allergens, but not completely. One of the primary findings is that it takes longer for R. oryzae to degrade some peanut allergens compared to others. Finally, our findings strongly indicate that R. oryzae fermented peanut products would not be safe for peanut allergic individuals.

Technical Abstract: Fermentation alters the protein content of foods. To characterize fungal metabolism of peanut proteins, defatted peanut flour was fermented by Rhizopus oryzae (R oryzae) for up to 48 hours and evaluated by SDS-PAGE, mass spectrometry, and anti-allergen antibody binding. A clear change in peanut protein migration was observed by SDS-PAGE after only 16 hours of fermentation. Mass spectrometric analysis indicated changes in allergen peptides and R. oryzae proteins. Several low molecular weight allergen fragments produced during fermentation were identified by mass spectrometry. Immunoassays using anti-peanut allergen antibodies demonstrated reduced allergen content as early as 16 hours of fermentation. However, ELISA with peanut allergic IgE indicated only slightly reduced allergen binding even after 48 hours. These results indicate that while R. oryzae fermentation efficiently metabolizes peanut allergens, significant IgE binding remains in lower molecular mass peptides, and therefore R. oryzae fermented peanut products would not be safe for peanut allergic individuals.