Abstract

Sucrose thermolysis oligosaccharides caramel (STOC) was prepared by thermal treatment (160°C) under vacuum of acidified sucrose using citric acid as caramelization catalyst. Total carbohydrate content was 59.95% in STOC, which was constituted by kestose, mono- and di-oligosaccharide. In addition to carbohydrates, STOC also contained structurally unknown melanoidins. STOC was further subjected to in vitrofermentation with human fecal microbiota. After 24 h of incubation with human fecal suspension, STOC was extensively degraded (84.3%). Moreover, the results of total cell counts, major bacterial groups and short-chain fatty acid analysis indicated that STOC were the preferred substrates for human fecal microbiota. Significant increases after 24 h occurred in the total bacterial cells, Bifidobacteria and Bacteroides-Prevotella group in the presence of STOC (p<0.01). The increase in amounts of acetic and propionic acid was consistent with the role of these bacteria in the degradation of STOC.

Key words: Caramelization, oligosaccharide, intestinal microbiota, short-chain fatty acid