NET ENERGY VALUE OF NONSTARCH POLYSACCHARIDE ISOLATES (SUGAR-BEET FIBER AND COMMERCIAL INULIN) AND THEIR IMPACT ON NUTRIENT DIGESTIVE UTILIZATION IN HEALTHY-HUMAN SUBJECTS

The energy value of NSP has been expressed as their metabolizable ener gy (ME) content. The aim of the present study was to determine whether differences in ME and net energy (NE) contents were similar for insol uble and soluble NSP. Nine healthy young men were offered three diets according to a Latin-square design (3 x 3) with three repetitions: die t C (control), diet B (control + 50 g sugarbeet fibre/d) and diet I (c ontrol + 50 g commercial inulin/d). After a 16 d adaptation period to NSP isolate, food intake was controlled (duplicate meal method) and fa eces and urine were collected for 8 d. A period of 60 h was devoted to measurement of energy expenditure (EE) by whole-body indirect calorim etry. NSP-isolate ingestion induced significant increases in the numbe r of defecations and stool weight resulting from increases in water, D M and microbial mass excretion. After deduction of microbial N, differ ences in faecal N excretion between diets were not significantly diffe rent. Urinary N excretion was slightly decreased by sugarbeet fibre or commercial-inulin ingestion but the N balances for the diets were not significantly different. Diet energy, N and lipid apparent digestibil ities decreased by only 1-2%. Commercial inulin was entirely fermented and fermentability of sugarbeet fibre averaged 0.886 (SD 0.117). Suga rbeet fibre and commercial inulin ME values averaged 10.7 (SD 1.2) and 13.0 (SD 2.3) kJ/g DM respectively. NSP-isolate ingestion caused sign ificant (sugarbeet) and non-significant (inulin) increases in daily EE . The maintenance NE contents of sugarbeet fibre and inulin averaged 5 .0 (SD 5.0) and 11.9 (SD 1.3) kJ/g DM respectively. Differences in mai ntenance NE contents of NSP isolates were much greater than difference s in ME values.