Preparation of products rich in slowly digestible starch (SDS) from rice starch by a dual-retrogradation treatment

In this work, a dual-retrogradation treatment (gelatinization-retrogradation-gelatinization-retrogradation) was designed for preparing slowly digestible starch (SDS) products from rice starch. The results showed that a maximum SDS yield in the tested samples increased from 39.3% to 56.7% by the dual retrogradation with the time interval of 36 h. The dual retrogradation also seemed to increase with the melting temperature range (T-c-T-o) of the SDS products. This increase indicated that more imperfect crystallites were formed during the dual-retrogradation treatment. Furthermore, compared to the single retrogradation, the dual retrogradation generated larger cavities and more solid connection parts in the SDS products. This internal microstructure could result in the increase of slow digestibility. These findings suggest that the dual retrogradation can be used in starchy products to increase the yield of SDS. (C) 2012 Elsevier Ltd. All rights reserved.