The effect of temperature on the physicochemical properties and lamellar structure of canna starch subjected to enzymatic degradation

Abstract

Canna starch was degraded thermally and enzymatically with or without α-amylase (Bacillus subtilis) at increasing temperatures (50–60 °C). Considerable disruption of the starch granules was found in enzymatically degraded canna starch (EDCS) compared to native canna starch (NCS), while only some swollen starch granules were observed in thermally degraded canna starch (TDCS) even at the critical gelatinization temperature (60 °C). With respect to physicochemical properties, both thermal and enzymatic degradation reduced the swelling power (SP) due to the internal rearrangements within the starch granules. Increased temperature narrows the gelatinization range of canna starch subjected to thermal and enzymatic degradation, however these treatments have different effects on the enthalpy. Small angle X-ray scattering (SAXS) investigation reveals that the lamellar order becomes less pronounced with enhanced temperature, both in TDCS and EDCS, however, a reduced ΔL from the correlation function indicates that the lamellar thickness distribution of TDCS and EDCS are narrower than their native counterpart.