The effect of ball milling treatment on structure and porosity of maize starch granule

Maize starch was mechanically treated by a planetary ball mill at 500 rpm for 1, 2 and 3 h. The effect of ball-milling treatment on structure and porosity of maize starch granule was studied. The SEM and TEM analyses indicated that starch granule surfaces were significantly changed and cavities in the central region of distorted granules were observed in the company with disappearance of alternate growth rings. The FT-IR analysis showed that ball milling treatment significantly increased the intensity of band 3382 cm-1 and decreased the ratio of 1047/1018 cm-1 and 995/1018 cm-1 corresponding to the crystalline/amorphous part of starch structure. Special surface area (SBET), cumulative volume (VBJH), average diameter pores (DBJH), span and median diameter (Dv, 0.5) increased rapidly and then decreased gradually. The XRD patterns, FT-IR and 13C CP/MAS NMR spectra showed that the crystallinity of starches and content of double helices of starch chains were decreased, respectively. Industrial relevance: Ball milling is one kind of physical modified method in polymer industry. It can be used in a variety of applications, including nanomatrix composites, dispersed alloy materials, metallic refinery, ore treatment, waste disposal, and synthesis of organic materials. Starch is a natural carbohydrate polymer, it contributes greatly to the textural properties of many foods and is widely used in food and industrial applications as a thickener, colloidal stabilizer, gelling agent, bulking agent and water retention agent. However, limitations such as low solubility, high viscosity, shear resistance, thermal resistance, thermal decomposition and high tendency toward retrogradation limit its use in some food and non-food systems. After ball milling treatment, the reactivity of starch is increased. Furthermore, milled starches exhibit the adsorptive capacity which can offer new opportunity for starch application, for example as sorbent in food or pharmaceutical. © 2011 Elsevier Ltd. All rights reserved.