A matrix effect in pectin-rich fruits hampers digestion of allergen by pepsin in vivo and in vitro
Article first published online: 20 APR 2007
Clinical & Experimental Allergy
Volume 37, Issue 5, pages 764–771, May 2007
How to Cite
Polovic, N., Blanusa, M., Gavrovic-Jankulovic, M., Atanaskovic-Markovic, M., Burazer, L., Jankov, R. and Velickovic, T. C. (2007), A matrix effect in pectin-rich fruits hampers digestion of allergen by pepsin in vivo and in vitro. Clinical & Experimental Allergy, 37: 764–771. doi: 10.1111/j.1365-2222.2007.02703.x
- Issue published online: 20 APR 2007
- Article first published online: 20 APR 2007
- Submitted 31 July 2006; revised 20 February 2007; accepted 23 February 2007
- Act c 2;
- digestibility assay;
- food allergy;
- matrix effect;
- thaumatin-like protein
Background It is a general belief that a food allergen should be stable to gastric digestion. Various acidic plant polysaccharides, including pectin, are ubiquitous in fruit matrixes and can form hydrogels under low-pH conditions.
Objective The purpose of this study was to investigate the effect of hydrogel forming polysaccharide-rich fruit matrixes on in vivo gastric and in vitro pepsic digestion of fruit allergens.
Methods Fruit extract proteins (kiwi, banana, apple and cherry) and a purified major kiwi allergen Act c 2 were digested with simulated gastric fluid in accordance with the US Pharmacopeia. In vivo experiments on kiwi fruit digestion were performed on four healthy non-atopic volunteers by examining the gastric content 1 h after ingestion of kiwi fruit. The Act c 2 and kiwi proteins were detected in immunoblots using monoclonal anti-Act c 2 antibodies and rabbit polyclonal antisera.
Results Crude fruit extracts were resistant to digestion by pepsin when compared with commonly prepared extracts. In the gastric content of all volunteers, following kiwi fruit ingestion and immunoblotting, intact Act c 2 was detected with anti-Act c 2 monoclonal antibodies, while kiwi proteins of higher molecular weights were detected using rabbit polyclonal antisera. Addition of apple fruit pectin (1.5% and 3%) to the purified kiwi allergen was able to protect it from pepsin digestion in vitro.
Conclusion The matrix effect in pectin-rich fruits can influence the digestibility of food proteins and thereby the process of allergic sensitization in atopic individuals.