Analysis of molecular weight and structural changes in water-extractable arabinoxylans during the breadmaking process

Area of Science:

• Food Science
• Biochemistry
• Material Science

Background:

• Arabinoxylans (AX) are crucial polysaccharides influencing dough rheology and bread quality.
• Understanding the behavior of different molecular weight AX fractions during breadmaking is essential for optimizing baking processes.

Purpose of the Study:

• To investigate the changes in molecular weight and structure of water-extractable arabinoxylans (WEAX) throughout the breadmaking process.
• To differentiate the behavior of high molecular weight (HMW) and low molecular weight (LMW) WEAX during dough mixing, fermentation, and proofing.

Main Methods:

• Analysis of molecular weight distribution of WEAX using size-exclusion chromatography.
• Structural characterization of WEAX, including the determination of the arabinose to xylose ratio.
• Monitoring changes during different breadmaking stages: mixing, first fermentation, and proofing.

Main Results:

• Formation of larger AX molecules (> HMW AX) during mixing and first fermentation.
• Continuous degradation of HMW AX from mixing through proofing.
• Increased arabinose to xylose ratio during mixing and first fermentation, indicating solubilization of highly substituted AX.
• LMW AX showed minimal degradation and structural changes, but a significant decrease in weight-average molecular weight during mixing.

Conclusions:

• Water-extractable arabinoxylans exhibit distinct molecular weight and structural alterations depending on their size during breadmaking.
• These differential changes in WEAX impact dough properties and bread characteristics.