Effect of particle size on compositional, structural, rheological, and thermal properties of shallot flour as a source of thickening agent

Abstract

AbstractInfluence of three particle size (<180, 180, and 250 μm) of shallot flour on compositional, structural, rheological, and thermal properties were studied. Carbohydrate, starch, fiber, amylose, amylopectin, color, and other functional properties showed the indirect effect with an increase in particle size and were found to be higher in lowest particle size, whereas, protein, bulk, true density were lower and ash, fat, moisture, aw, was unaffected by particle size. Rheological properties at concentration (0.5, 1.0, 1.5, and 2.0% [w/w]), temperature (20, 30, 40, 60, and 80°C) and pH (4, 7, and 10) revealed Non‐Newtonian, shear thinning behavior of all samples with flow behavior index (n) <1 and coefficient of determination (R2) >0.90, using power law model. Examined pasting property showed higher viscosity values, holding strength and lower peak time and temperature for sample with lower particle size. Thermal parameters (T o, T p, and T c) and change of enthalpy ( ΔH) values increased with increase in particle size.Practical applicationA comprehensive study of rheological, thermal, and structural properties concludes application of shallot flour as a thickener in various food products. The particle size of shallot flour (<180 μm) was found to be most suitable for their application as a thickener, evident from proximate, physiochemical, functional, rheological, pasting, and thermal parameters. SEM results also reveal the application of shallot flour (<180 μm) as a thickener. Shallot flour can not only improve the texture of the food products as natural thickener but can also enhance the flavor profile.