Effects of trehalose and corn starch on the mechanical glass transition temperature and texture properties of deep-fried food with varying water and oil contents

Abstract

The effects of trehalose and corn starch on the mechanical glass transition temperature (Tg) and texture properties of a deep-fried sample (particles of deep-fried batter) with varying water and oil contents were investigated. Tg decreased linearly with increases in both water and oil contents, attributable to their plasticizing effects. Tg was elevated by the addition of trehalose, likely due to its anti-plasticizing effect. Corn starch had a negligible effect on Tg. The critical water content and water activity (water content and water activity at Tg = 25 °C) were determined by extrapolation, and obtained values were validated by isothermal mechanical relaxation. The texture of the samples changed from brittle to ductile near the critical water content and water activity. The trehalose-added sample maintained a brittle texture at a higher water content than the non-additive and corn starch-added samples, as trehalose elevated the critical water content of the deep-fried samples.