Characterization of fructans and dietary fibre profiles in raw and steamed vegetables.

Dietary fibre (DF) has many positive effects on human health associated with its functionality in the gastrointestinal tract. These benefits vary according to the type of DF. Vegetables can be a natural source of DF in the diet. However, to provide adequate nutritional advice, the content and profile of their various DF types must be characterised. This study aimed to determine the DF profile of 29 vegetables cultivated in Wallonia (Belgium) and the impact of steaming on these profiles. Using a combination of enzymatic, gravimetric and chromatographic methods, fructans, total dietary fibre (TDF), low- and high-molecular-weight soluble dietary fibre (SDF), and insoluble dietary fibre (IDF) were analysed. Results show that the DF content varies considerably among the 29 investigated vegetable varieties and species, but the influence of steaming is limited to a shift from IDF to high-molecular-weight SDF for 18 of the 29 tested vegetables, while fructans are preserved with not actual reduction in the DP

In vitro approach to evaluate the fermentation pattern of inulin-rich food in obese individuals.

Alterations of the gut microbiome have been associated with obesity and metabolic disorders. The gut microbiota can be influenced by the intake of dietary fibres with prebiotic properties, such as inulin-type fructans. This study tested the hypothesis that obese individuals subjected for 12 weeks to a inulin-enriched versus inulin-poor diet have differential faecal fermentation patterns. The fermentation of cellulose and inulin hydrolysates, of six different inulin-rich and inulin-poor vegetables of both groups was analysed in vitro on faecal inocula. The results showed that the microbiota from obese patients who received fructan-rich diet for three weeks produce more gas and total short-chain fatty acid (SCFA) compared to the microbiota taken of the same individuals before the treatment. Obese individuals fed with a low-fructan diet produce less gas and less SCFA compared to the treated group. This study highlighted profound changes in microbiota fermentation capacity obtained by prebiotic intervention in obese individuals, which favors the production of specific bioactive metabolites