Effects of granule size on physicochemical and digestive properties of potato powder.

The potato powder, a rich source of high-quality protein and starch, plays an important role in the production of functional foods. In this study, the ball mill processed potato powders with different particle sizes (278, 208, 129 and 62 μm) were analyzed in terms of physicochemical, pasting, rheological and digestive properties.The scanning electron microscopy and laser diffraction analysis of the samples revealed their mono-model particle size distributions. X-ray diffraction analysis confirmed the structure destruction of starch pellets. The proximate composition and physical property analysis exhibited an increase in the contents of water, ash, protein and starch. Meanwhile, the water solubility index and swelling power values were found to increase with decreasing grain size, and so were the brightness (L*) and redness (b*) values of the potato powders. With the particle size decreased to 129 μm, great changes were observed in the gelatinization properties, such as peak viscosity, trough viscosity, breakdown viscosity and final viscosity. Additionally, oscillatory rheology results showed that, with the decrease of particle size, the storage modulus (G') and loss modulus (G'') were improved with highest storage modulus (G') observed in the particle size of 129 μm. Furthermore, the hydrolysis rate and glycemic index also increased in the 129 μm potato powder.The obtained results provide useful information for improving quality characteristics via specific grain sizes in the development of potato-based products such as gluten-free products and ethnic food products with desired functional and rheological properties. This article is protected by copyright. All rights reserved.