Fermentation of Resistant Starches: Influence of In Vitro Models on Colon Carcinogenesis

Abstract:

Resistant starch type 2 (RS2) and type 3 (RS3) containing preparations were digested using a batch (a) and a dynamic in vitro model (b). Furthermore, in vivo obtained indigestible fractions from ileostomy patients were used (c). Subsequently these samples were fermented with human feces with a batch and a dynamic in vitro method. The fermentation supernatants were used to treat CACO2 cells. Cytotoxicity, anti-genotoxicity against hydrogen peroxide (comet assay) and the effect on barrier function measured by trans-epithelial electrical resistance were determined. Dynamically fermented samples led to high cytotoxic activity, probably due to additional compounds added during in vitro fermentation. As a consequence only batch fermented samples were investigated further. Batch fermentation of RS resulted in an anti-genotoxic activity ranging from 9–30% decrease in DNA damage for all the samples, except for RS2-b. It is assumed that the changes in RS2 structures due to dynamic digestion resulted in a different fermentation profile not leading to any anti-genotoxic effect. Additionally, in vitro batch fermentation of RS caused an improvement in integrity across the intestinal barrier by approximately 22% for all the samples. We have demonstrated that batch in vitro fermentation of RS2 and RS3 preparations differently pre-digested are capable of inhibiting the initiation and promotion stage in colon carcinogenesis in vitro.

Acknowledgments and Notes

The authors would like to thank Adele Boyd and Vicky Mc Gilligan for their technical assistance. The discussions and inputs from Fred Brouns (Cargill R&D Centre, Vivoorde, Belgium) and Koen Venema (TNO, Zeist, The Netherlands) are kindly acknowledged. This project was carried out with the financial support from the Commission of the European Communities, Marie Curie Program Training Site Grant No. HPMT-CT-2001-00287 (Grant: Marie curie fellowship from the 5th framework HMPT-CT-2001-00287). It does not necessarily reflect the Commission's views and in no way anticipates its future policy in this area.

Notes

∗n = 1.