From Granules to Gels: Exploring physical and technological properties of ball-milled starches from different origins.

Aim: Ball milling (BM) is a mechanical technology able to modify technological functionality and structural properties of food biomolecules. Starch is largely used in the food industry but has limited applications in its native state. Physical modifications, such as BM, expand its usability across various sectors. In this study, the effect of BM treatment time on the techno-functional and structural properties of starches from different botanical sources and their transformation into aerogels and cryogels was investigated. Method: Native starches (high amylose corn (HACS), tapioca (TS), potato (PS)) were subjected to BM at varying milling durations (5, 15, 30 and45 min) at a constant rotational speed (350rpm). Analyses of the samples (native and treated) included morphology, thermal properties, gelatinization behavior, water holding capacity (WHC), swelling power (SP), and cold-water solubility (CWS). Hydrogels were prepared using native and BM starches, followed by evaluation of their rheological properties. Aerogels and cryogels were prepared and subsequently characterized for their density (bulk and skeletal) and textural properties (porosity,surface area, pore diameter and volume) and WHC. Results: BM starches exhibited lower temperature and enthalpy of gelatinization than their native counterparts. Techno- functional properties demonstrated a statistically significant correlation with treatment duration (p < 0.05). BM-TS exhibited a three-fold increase in SP, whereas BM-PS showed a substantial rise in CWS (p < 0.05). Treatment of BM- TS for 30 min resulted in a pronounced WHC enhancement. Prolonged milling impacted the granular morphology, leading to the formation of aggregatesAerogels were mesoporous (pore diameter ≤ 25.4 nm), while cryogels exhibited macroporosity (pore diameter ≤ 200 μm). HACS aerogels exhibited a progressive improvement in textural properties, correlating with enhanced porosity and reduced bulk density. BM-HACS aerogels subjected to 30-min treatment achieved the highest surface area (280 m2/g). Conversely, PS showed a decrease in specific surface area and porosity, accompanied by increased bulk density over BM time. The WHC of BM cryogels was twice that of aerogels. Conclusion: This study for the first time produced high-value modified starches used to prepare aerogels and cryogels, highlighting BM as an effective technique for tailoring starch-based materials for food applications