Physico-chemical and rheological properties of cast-tape dried sweet corn powder as affected by thermal treatment of sweet corn

Sweet corn is often processed and marketed as fresh, frozen or canned. However, if processed as powder, it can increase its shelf life and expand its commercialization by facilitating its use in formulation of various products. Alternative technologies for raw material transformations are essential for developing novelty products. Cast-tape drying (CTD) has been reported to preserve foods with low nutrient degradation. Dehydration of sweet corn pulp by CTD has not been reported in the literature and deserves further investigation. The effect of thermal treatment i.e. 15 min at 120 °C of sweet corn on the physicochemical properties of powder produced from 3 mm thick pulp dried at 98 °C using CTD was investigated. The powder samples presented final moisture content near 0.05 g g⁻¹ on a dry basis and water activity of 0.45, for drying times of 57 min (non-TT) and 98 min (TT). The Midilli model represented well the drying curves (R² > 0.98). TT powders formed packed beds with porosity 18% higher than non-TT powders and half the dispersion time. TT reconstituted pulps showed similar rheological behavior as that of fresh pulp and presented a pseudoplastic fluid behavior as reported for corn-based purees and creams. The thermal treatment and drying barely impacted the total color changes of sweet corn pulp. CTD is a suitable process for producing a convenient sweet corn powder that can be reconstituted and used as an ingredient in different formulations.