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Effects of gastrointestinal digestion and heating on the allergenicity of the kiwi allergens Act d 1, actinidin, and Act d 2, a thaumatin-like protein

Bublin, M., Radauer, C., Knulst, A., Wagner, S., Scheiner, O., Mackie, A. R., Mills, E. N. C. & Breiteneder, H., Oct-2008, In : Molecular Nutrition & Food Research. 52, 10, p. 1130-1139 10 p.

Research output: Contribution to journalArticleAcademicpeer-review

  • Merima Bublin
  • Christian Radauer
  • Andre Knulst
  • Stefan Wagner
  • Otto Scheiner
  • Alan R. Mackie
  • E. N. Clare Mills
  • Heimo Breiteneder

Kiwifruit is a significant elicitor of allergy both in children and adults. Digestibility of two kiwifruit allergens, actinidin (Act d 1) and thaumatin-like protein (Act d 2), was assessed using an in vitro digestion system that approximates physiological conditions with respect to the passage of food through the stomach into the duodenum. Act d 1 precipitated in simulated gastric fluid at pH 2 and digestion of the aggregated protein proceeded slowly. The residual precipitate redissolved completely in simulated duodenal fluid at pH 6.5 and was partially digested. Forty percent of Act d 2 remained intact during gastric digestion and were cleaved by duodenal proteases into large fragments covalently linked by disulfide bonds. Both digested allergen samples displayed nearly unchanged binding abilities. Circular dichroism spectra were used to analyze heat and acid-induced unfolding. Thermal stability of both allergens was strongly pH dependent. While Act d 1 was irreversibly destabilized in acidic Solutions, heat-induced denaturation of Act d 2 at pH 2 was fully reversible. IgE binding to Act d 2 but not Act d 1 wits detected in processed food products. The stability of Act d 1 and Act d 2 provides one explanation for the allergenic potency of kiwifruit.

Original languageEnglish
Pages (from-to)1130-1139
Number of pages10
JournalMolecular Nutrition & Food Research
Volume52
Issue number10
Publication statusPublished - Oct-2008

    Keywords

  • Actinidin, Allergen, Food allergy, Kiwifruit, Thaumatin-like protein, PLANT FOOD ALLERGENS, SIMULATED GASTRIC FLUID, IN-VITRO, BIOCHEMICAL-CHARACTERIZATION, MAJOR ALLERGEN, FRUIT, IDENTIFICATION, DIGESTIBILITY, REACTIVITY, CLASSIFICATION

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