A synthesis of double modified: Irradiated and oxidized corn starch and its microstructural and physicochemical properties

Abstract

A low cost, environmentally friendly route to synthesize highly transparent, low-viscosity starch solution is in demand. In this work, pure corn starch was chosen and irradiated by an electron beam (EB) in air with dose up to 60 kGy, then, oxidized by Dess-Martin periodinane (DMP). Then, variations in chemical structure, surface morphology, thermal-stability, transparency, viscosity and gelatinization process were explored. Main results reveal that both irradiation and DMP treatment introduced molecular chain scission and hydrophilic structure generation, destroyed surface morphology, increased thermal-stability, transparency and viscosity-stability but decreased coagulation, viscosity and gelatinization temperature. Irradiation seems being more efficient than DMP treatment on starch modification and a dose of 4–10 kGy irradiation can be effective. DMP treatment can modify starch while the efficiency is dose-dependent. At low dose such as 4–10 kGy it is visible while at higher dose it is moderate. Generally, via a combined low dose such as 4–10 kGy irradiation and a middle level DMP treatment highly transparent, low-viscosity, viscosity-stable starch solution can be formed, possibly having a potential use in the food or textile industry.