In vitro fermentability of differently digested resistant starch preparations.

Area of Science:

• Microbiology
• Nutritional Science
• Gastroenterology

Background:

• Resistant starch (RS) offers prebiotic benefits by escaping digestion and reaching the colon.
• Understanding the in vitro fermentability of different RS types is crucial for dietary applications.

Purpose of the Study:

• To compare the in vitro fermentability of resistant starch type 2 (RS2) and type 3 (RS3) using human colonic microbiota.
• To evaluate the impact of different digestion models (batch, dynamic, in vivo) on RS fermentability.

Main Methods:

• In vitro digestion using batch (ba) and dynamic (dy) models.
• Fermentation of digested RS residues with human colonic microbiota for 24 h (batch) and 72 h (dynamic).
• Analysis of metabolite production (e.g., short-chain fatty acids) and starch degradation rates.

Main Results:

• RS2 and RS3 showed similar fermentation profiles in batch models, with dynamic models yielding higher metabolite production.
• In vivo digested RS3 (RS3il) exhibited the lowest fermentability.
• Increased butyrate ratios were observed across all preparations, with propionate increasing at the expense of butyrate in most cases.
• A microbiota adaptation period of over 24 hours was needed for efficient RS fermentation.

Conclusions:

• Both RS2 and RS3 are fermentable by human colonic microbiota, with dynamic models providing a better simulation of in vivo conditions.
• The choice of digestion and fermentation model significantly influences observed fermentability.
• Further research is needed to elucidate the specific roles of different RS types and their impact on gut microbiota composition and function.