Fermentability of an enzymatically modified solubilised potato polysaccharide (SPP)

Abstract

Objective: To study processing and fermentability in the human gastro-intestinal tract of a newly isolated, enzymatically modified, soluble, and highly concentrated (>80% dietary fibres) solubilised potato fibre (SPP).

Setting: Gastroenterological laboratory.

Design, subjects and interventions: Seven healthy volunteers ingested in random order on seven different days: 20 g SPP; bread made of 180 g wheat flour served with 20 g raw SPP; bread baked of 180 g wheat flour and 20 g SPP; bread made from 180 g wheat flour; 20 g lactulose; 20 g oat bran; and 20 g wheat bran. The hydrogen breath test was used to evaluate oro-coecal transit time (OCTT) and fermentation.

Results: Fermentation of SPP yielded a measurable increase in end-expiratory H₂. The total incremental increase in end expiratory H₂ due to SPP was unaffected of whether SPP was served alone, as the raw flour served with bread, or baked into bread. The OCTT for raw SPP was significantly delayed compared to lactulose (P=0.01). The OCTT for SPP baked into bread was significantly delayed compared to raw SPP (P=0.01), indicating that SPP may be used as a marker of oro-coecal transit time for as well the fluid phase as the solid phase of a meal.

Conclusions: SPP is a fermentable, highly concentrated soluble fibre source. Baking SPP did not interfere with the fermentable properties. Thus, SPP may be interesting as a fibre-supplement in fibre-poor diets. The change in oro-coecal transit time for SPP, depending on the composition of the total meal, makes SPP interesting as a marker in studies of gastrointestinal transit.

Sponsorship: This study was supported by The National Danish Medical Research Council, and Centre for Food Research at DTU.