The effect of lamellar structure ordering on the retrogradation properties of canna starch subjected to thermal and enzymatic degradation

Abstract

The starch retrogradation is the main cause of quality deterioration in starchy food during storage. The current work evaluates the retrogradation properties of degraded canna starches with the aim of probing the retrogradation mechanism. Degraded canna starches were prepared thermally (TDCS) and enzymatically (EDCS) with or without α-amylase (Bacillus subtilis) at increasing temperatures. The retrogradation behavior was assessed by morphology, transmittance, syneresis, and texture changes. At earlier stage of retrogradation, the starch gel has a smooth surface, with the time progressed, a coarse surface was formed, finally changed to hollow network structure. This process lead to a decrease of transmittance, and an increase of syneresis rate (SR) and hardness. Among the degraded starches, TDCS has a lower retrogradation tendency than native canna starch (NCS) and EDCS. Overall, the higher the lamellar structure ordering has, the easier the starch retrograde, therefore thermal and enzymatic degradation possess the potential capacity to reduce the degree of retrogradation by decreasing the lamellar structure ordering.