Production of Thermal-Resistant Cornstarch-Alginate Beads by Dripping Agglomeration

Abstract

Abstract This work investigated the agglomeration of native cornstarch and production of microcapsules by dripping of sodium alginate suspensions into calcium chloride solution. The crosslinking reaction formed a calcium alginate that worked as an encapsulation matrix and coated the cornstarch granules. The spherical beads produced were rigid and compact, and resistant to mechanical handling. The differential scanning calorimetry (DSC) computed the thermal resistance of the cornstarch-alginate beads. Particles containing 50 % w/w calcium alginate showed an increased gelatinization peak compared to particles with a higher starch content. The increase in alginate fraction resulted in beads with a higher particle density. Scanning electron micrographs showed the coating of cornstarch by the calcium alginate matrix. The beads were compact and with no superficial pores. DSC thermograms of native cornstarch showed a gelatinization temperature of 70.0 °C, and the gelatinization range was 64.6–80.4 °C, while beads containing 50 % alginate had an increased peak at 79.5 °C and the gelatinization interval was 71.0–90.2 °C. When compared with the native cornstarch, cornstarch-alginate beads had a lower water absorption, and the gelatinization occurred at a higher temperature and over a wider temperature range.