Structural and functional characteristics of optimised dry-heat-moisture treated cassava flour and starch

Abstract

The flexibility of hydrothermal conditions gives rise to an array of effects on the properties of starch-containing systems. This study examined and optimised moisture, temperature and time conditions with regards to functional properties of cassava flour and starch. The derived optimal conditions for cassava flour were 25%, 90 °C and 45 min, respectively, while cassava starch were 27%, 120 °C and 21 min, respectively. Consequently, effect of the optimal conditions on structural, physicochemical, rheological and melting characteristics of cassava flour and starch were studied. Optimal heat-moisture treatments changed both morphology and size distribution of cassava flour and starch granules. Relative crystallinity of cassava flour increased (34 to 40%) and cassava starch decreased (32% to 23%) following optimal-heat-moisture treatment. Both cassava flour and starch upon optimal dry-heat-moisture treatment exhibited enhanced; swelling power (15.57 to 21.62 g/g and 17.24 to 19.64 g/g, respectively), peak viscosity (3555 to 5493 cP and 6377 to 8701 cP, respectively), elasticity (tan δ) (0.31 to 0.24 and 0.58 to 0.47, respectively) and melting onset temperature to conclusion temperature range (14.66 to 15.75 °C and 23.26 to 30.69 °C, respectively). This research presents hydrothermal conditions that can effectively be applied in industry to improve the bakery potentials of cassava flour and starch.