Effect of particle size and concentration on the chemical, physical and functional properties of rice-cornsilk composite flour paste

Abstract

This study aimed to investigate the effect of cornsilk particle size and concentration on the properties of rice flour-cornsilk composite. Ground cornsilk (CS) was classified into sizes ranging from smaller than 45 to 300 µm and was added to rice flour (RF) at different concentrations (5 to 20% by weight). The RF-CS composite samples were analyzed for chemical, physical, and functional properties. The RF-CS composite flour samples had higher protein and fiber contents and showed higher water-binding capacity than the RF sample but lower swelling power at 90 °C. Lower solubility was observed when CS particles smaller than 125 µm were added. Adding large CS particles (>150 µm) caused the average pasting temperature of RF-CS to increase but reduced peak viscosity, breakdown, and setback significantly at all addition levels. The addition of smaller-sized CS particles (<125 µm) reduced peak viscosity significantly from the 10% addition level onwards but tended to increase the breakdown and setback viscosity. RF-CS composite paste had decreasing gel strength with increasing CS addition level. Lower gel syneresis after several freeze-thaw cycles was noted when adding CS. A more significant reduction in flour gel syneresis was observed with the addition of CS smaller than 75 µm. Cornsilk particle is a potential flour additive to increase protein and fiber content. Due to the ability to reduce syneresis, cornsilk particles could be used to produce a high amylose flour gel that can withstand freeze-thaw cycles.