Ball milled starch aerogel structures as novel additive for food applications

Starch, a biodegradable polysaccharide, is a key functional ingredient in the food sector, though its native state has limited industrial applications. Physical, chemical, and enzymatic modification strategies enhance its usability [1]. Ball milling (BM), an eco-friendly physical technique, can induce structural and morphological changes in food biomolecules, improving their technological performance [2]. This study, for the first time, examines the impact of ball-milling treatment (BMT) duration on the structural and textural properties of starch aerogels. Native starch (corn (CS, 21.23% amylose) and high amylose corn (HACS, 52.6% amylose)) were subjected to BM at varying milling durations (5, 15, and 30 minutes) at a constant rotational speed (350 rpm). Aerogels were obtained via thermal gelation (15% w/w starch concentration), moulded, followed by retrogradation, solvent exchange with ethanol and supercritical drying with carbon dioxide (C0 2 ). After the resulting gels underwent retrogradation, starch cryogels were obtained through freeze-drying of the same hydrogels for comparative analysis. Samples (native and treated) were analyzed for their textural properties (surface area, pore diameter, pore volume), density, porosity and water holding capacity (WHC). Mechanical stability, microstructural and textural properties of the resulting dried gels were significantly impacted by BM treatment and the drying technique employed. Aerogels resulted mesoporous (pore diameter ≤ 25 nm), whereas cryogels showed macro porosity (pore diameter ≤ 200 µm). Specific surface area, porosity (> 80%) and WHC of the aerogels increased with prolonged milling time (p<0.05) correlating to lower density. The highest surface area (237 m 2 /g) was observed in 10 min BM-HACS aerogels. WHC of BM cryogels was twice higher than the corresponding aerogels BM can significantly affect the structural and textural properties of starch aerogels and cryogels, favoring their application in several sectors including food industry. List of References 1. Han, N., Fan, J.L., Chen, N. And Chen, H.Q., Journal of Cereal Science, 104 (2022),103439. 2. Soe, M.T., Chitropas, P., Pongjanyakul, T., Limpongsa, E. And Jaipakdee, N., Carbohydrate Polymers, 232 (2020), 115812.