Composition of polyphenol and polyamide compounds in common ragweed (Ambrosia artemisiifolia L.) pollen and sub-pollen particles.

Phenolic composition of Ambrosia artemisiifolia L. pollen and sub-pollen particles (SPP) aqueous extracts was determined, using a novel extraction procedure. Total phenolic and flavonoid content was determined, as well as the antioxidative properties of the extract. Main components of water-soluble pollen phenolics are monoglycosides and malonyl-mono- and diglycosides of isorhamnetin, quercetin and kaempferol, while spermidine derivatives were identified as the dominant polyamides. SPP are similar in composition to pollen phenolics (predominant isorhamnetin and quercetin monoglycosides), but lacking small phenolic molecules (<450Da). Ethanol-based extraction protocol revealed one-third lower amount of total phenolics in SPP than in pollen. For the first time in any pollen species, SPP and pollen phenolic compositions were compared in detail, with an UHPLC/ESI-LTQ-Orbitrap-MS-MS approach, revealing the presence of spermidine derivatives in both SPP and pollen, not previously reported in Ambrosia species.

Sensitizing potential of enzymatically cross-linked peanut proteins in a mouse model of peanut allergy.

SCOPE: The cross-linking of proteins by enzymes to form high-molecular-weight protein, aggregates can be used to tailor the technological or physiological functionality of food products. Aggregation of dietary proteins by food processing may promote allergic sensitization, but the effects of enzymatic cross-linking of dietary proteins on the allergenic potential of food are not known. In this study, the bioavailability and the sensitizing or tolerizing potential of peanut proteins (PE) cross-linked with microbial tyrosinase from Trichoderma reesei and mushroom tyrosinase from Agaricus bisporus, were investigated. METHODS AND RESULTS: The impact of cross-linking of PE on the in vitro bioavailability of fluorescein isothiocyanate-labeled peanut proteins was tested in a Caco-2 cell monolayer and by competitive ELISA. The in vivo allergenicity or capacity to induce oral tolerance in mice were measured by serum levels of PE-specific antibodies and T cell cytokine production after exposure to PE and cross-linked PE. CONCLUSION: Enzymatic processing of peanut proteins by the two tyrosinases increased the bioavailability of major peanut allergen Ara h 2, but did not significantly change the allergenic or tolerizing properties of peanut. Enzymatic treatment of peanut proteins yielded cross-linked proteins with preserved molecular and immunological features of peanut allergens.