Effect of the rice flour particle size and variety type on water holding capacity and water diffusivity in aqueous dispersions

The aim of this study was to evaluate water binding capacity of selected varieties of rice flours as prospective processing parameter for manufacturing gluten-free products. Water retention capability was determined by measuring the effective diffusivity coefficient, DSC, water absorption index and water solubility index. It was found that with decreasing particles size of flour the water binding capacity was increasing. This phenomenon was dependent also on the saccharides and proteins content of individual materials. There was measured gelatinization temperature and enthalpy of fusion. It was found to be 2.08 J/g for black and 5.8 J/g for fine rice flour. Effective moisture diffusivities of 6.167 x 10(-10) m(2) s(-1) for black and of 5.030 x 10(-10) m(2) s(-1) for fine rice flours were found. The latter were of the lowest magnitudes from the set of the studied samples, indicating their highest ability to retain water in their microstructure. There was confirmed structural binding of water based on rheological testing.

Automated summary

This study evaluated the water binding capacity of different varieties of rice flours, finding that smaller particle size led to higher water binding capacity. Additionally, the saccharides and proteins content of different materials also influenced the water retention capability.