The physicochemical and simulated digestive characteristics of yam flours processed by different thermal processing...

Area of Science:

• Food Science
• Nutritional Biochemistry
• Microbiology

Background:

• Dioscorea fordii yam flour is a potential source of nutrients.
• Processing methods significantly impact yam flour's nutritional and physiological properties.
• Understanding starch digestibility and colonic fermentation is crucial for developing functional foods.

Purpose of the Study:

• To investigate the effects of steaming-refrigeration (SRY), extrusion-refrigeration (ERY), and baking (BY) on Dioscorea fordii flour.
• To evaluate the resistant starch content, estimated glycemic index (eGI), and bioactive component accessibility.
• To analyze the colonic fermentation characteristics, including short-chain fatty acid (SCFA) production and microbial enrichment.

Main Methods:

• Simulated in vitro digestion and colonic fermentation models were employed.
• Resistant starch content was quantified.
• Estimated glycemic indices (eGI) were calculated.
• Bioactive components (allantoin, saponins, polyphenols) were analyzed.
• SCFA production and bacterial populations (Bifidobacterium, Ligilactobacillus) were assessed.

Main Results:

• SRY and ERY yielded significantly higher resistant starch content compared to BY.
• SRY and ERY demonstrated medium eGI values, while BY had a high eGI.
• Allantoin was preserved in all processing methods.
• ERY showed reductions in saponins and polyphenols.
• BY released more bioaccessible bioactive compounds, whereas SRY and ERY enhanced SCFA production and beneficial bacteria.

Conclusions:

• Steaming-refrigeration and extrusion-refrigeration effectively modulate yam flour's starch digestibility.
• These processing methods promote SCFA production and enrich beneficial gut microbiota, potentially benefiting glucose metabolism.
• SRY and ERY are more suitable for developing glucose-friendly food products compared to baking.