The biochemistry of oligofructose, a nondigestible fiber: an approach to calculate its caloric value.

Oligofructose, a natural food ingredient, is the product of partial enzymatic hydrolysis of inulin. This nondigestible oligosaccharide is fermented by colonic bacteria to produce mainly short-chain fatty acids, L-lactate, and CO2 and the energy necessary for bacterial growth. It also increases fecal mass. Based on biochemical balance charts for carbon atoms, metabolic pathways, and energy yield to the host, the caloric value of a fructosyl unit of oligofructose is calculated to be 25-35% that of a digested molecule of hexose. The caloric value of oligofructose is thus likely to be close to 1 kcal/g.