Superfine grinding affects physicochemical, thermal and structural properties of Moringa Oleifera leaf powders

Abstract

Effects of superfine grinding on physicochemical, thermal, and structural properties of Moringa Oleifera leaf (MOL) powders were investigated. Five samples with different particle size were obtained by superfine grinding and shear pulverization methods. Superfine grinding could produce smaller MOL particles with wider particle size distribution and greater surface area. Insoluble dietary fiber and protein contents decreased after the superfine grinding processing. As the particle size decreased, bulk density, tap density, water and oil holding capacities decreased but angles of repose and slide exhibited the opposite tendency. Differential scanning calorimetry curves showed that peak temperature and enthalpy change decreased with the decrescent particle size. No new chemical functional groups were generated observed in Fourier transform infrared spectroscopy in all samples. All X-ray diffraction patterns revealed similar shapes and superfine grinding sample exhibited the highest crystallinity index value. Scanning electron microscopic images revealed that superfine grinding changed the particle shape and the surface roughness decreased with the decreasing particle size of Moringa Oleifera leaf powders.