Objective: Major peanut allergens, Ara h 2 and Ara h 6, are known to be resistant to pepsin
digestion, and they sensitize individual via the gastrointestinal tract. Mikenus et al. published a
standardized static digestion method for food, based on physiological conditions emphasizing the
impact of food matrices. Immunoreactive proteins (large fragments) and peptides (short digestion
resistant peptides SDRPs; <10 kDa), to which the immune system of the gastrointestinal tract is
exposed during digestion of peanut proteins, has not been investigated under pure physiological
conditions suggested by this protocol.
Matherial and methods: Whole grain of grounded raw peanut was incubated with human α-
amylase, and pepsin, mimicking the effects of oral and gastric digestion, in total duration of 2h.
Bottom up proteomic approach, immunoblotting with allergen-specific antibodies from peanut-
sensitized patients, enzyme-linked immunosorbent inhibition assay and ImmunoCAP tests, were
used to identify and characterize peanut digesta.
Results: After 2h of oral/gastric phase we got, intact proteins, large, digestion resistant peptides
(DRP) and SDRPs, as well. Ara h 2 and Ara h 6 remained mostly intact, and short DRPs from Ara h
2 and Ara h 6 were more potent in inhibiting IgE binding than Ara h 1 and Ara 3. Ara h 1 and Ara h
3 showed preserved allergenic capacity, as well. Almost all of identified short DRPs from Ara h 1,
Ara h 2 and Ara h 3, with preserved allergenic potential, were constituents of continuous epitope
sequences found via Immune Epitope Database (www.iedb.org).
Conclusion: Processes of protein extraction from the matrix and their enzymatic digestion occur
simultaneously. Oral and gastric phase digestion products of raw peanut are intact proteins, large
and short digestion resistant peptides. Under these conditions Ara h 2 and Ara h 6 are expectedlyBook of Abstract
