MIXED-LINKED BETA-GLUCAN FROM BREADS OF DIFFERENT CEREALS IS PARTLY DEGRADED IN THE HUMAN ILEOSTOMY MODEL

The purpose of this investigation was to study the degradation of beta -glucan in the small intestine and the molecular weight of beta-glucan in the excreta of nine ileostomy subjects after consumption of differ ent diets based on bread made with oat bran (oat bread), a fiber-rich barley fraction (barley bread), or wheat flour (wheat bread) as the ma in ingredients. Oat bread with enzymatically degraded beta-glucan was also used (oat + enzyme bread). The beta-glucan intake from the four d iets was 12.5, 12.9, 1.1, and 4.0 g/d, respectively. On the basis of d ry matter, the night effluents accounted for approximate to 15% of the total amount of the excreta, with the highest proportion (22%) being for the wheat-bread diet. A notable loss of beta-glucan (0.7-2.4 g/d, or 13-64%) was found when intake was compared with excretion. In vitro , a higher viscosity development with time for dispersions of oat brea d compared with barley bread was noted, which could be related to the higher molecular weight of the beta-glucan in this bread. There seemed to be a depolymerization of the beta-glucan both during bread making and transit through the upper gastrointestinal tract.