Unveiling the breadmaking transformation: Structural and functional insights into Arabinoxylan.

Area of Science:

• Food Science
• Nutritional Biochemistry
• Analytical Chemistry

Background:

• Arabinoxylan (AX) is a key dietary fiber with potential health benefits.
• Understanding structural modifications of AX during food processing is crucial for predicting its bioactivity.
• Breadmaking is a common food processing technique that may alter AX properties.

Purpose of the Study:

• To investigate the structural and property changes of arabinoxylan (AX) during the breadmaking process.
• To compare the characteristics of AX extracted from bread (AX-B) with native AX.
• To evaluate the impact of breadmaking on AX's enzymatic inhibition and gut microbiota fermentability.

Main Methods:

• Multi-step enzyme digestion to re-extract AX from bread.
• High-performance size-exclusion chromatography (HPSEC) for molecular weight determination.
• High-performance anion-exchange chromatography (HPAEC), Fourier-transform infrared spectroscopy (FT-IR), methylation analysis, and 1H NMR for structural elucidation.
• In vitro assays for enzymatic inhibition (α-amylase, α-glucosidase) and gut microbiota fermentation (short-chain fatty acid production).

Main Results:

• Breadmaking significantly reduced AX molecular weight (677.1 kDa to 15.6 kDa) and increased its structural complexity (degree of branching).
• AX-B exhibited enhanced inhibition against α-amylase (76.81%) and α-glucosidase (64.43%) compared to native AX.
• Fermentation of AX-B by gut microbiota produced higher concentrations of short-chain fatty acids (54.68 mmol/L) than native AX (44.03 mmol/L).
• Covalently linked protein content increased in AX-B.

Conclusions:

• Breadmaking induces significant structural modifications in arabinoxylan, impacting its physicochemical properties.
• The altered AX (AX-B) demonstrates improved bioactivities, including enhanced enzyme inhibition and greater fermentability by gut microbiota.
• These findings provide insights into the health benefits of fiber-fortified bread and support precision nutrition strategies.