Preparation and slowly digestible properties of β-cyclodextrins (β-CDs)-modified starches.

The β-cyclodextrin (β-CD)-, maltosyl-β-CD (Mal-β-CD)- and hydroxypropyl-β-CD (HP-β-CD)-modified rice starches were prepared and their slowly digestible properties were estimated. The results showed that β-CD, Mal-β-CD and HP-β-CD significantly increased the slow digestibility of β-CDs-modified starches (P<0.05). The optimum conditions for the modification were obtained: amylose, 4.76%; free lipids, 0.24%; β-CD, Mal-β-CD and HP-β-CD, 3%; water, 80%; and equilibrium temperature, 25°C. The maximum yield of slowly digestible starch (SDS) was 52.1% when β-CD was used as a denaturant (β-CD, 3%; water, 80%; and equilibrium temperature, 25°C). This higher SDS yield was probably attributed to the better compatibility of β-CD and starch molecules. Furthermore, β-CD-, Mal-β-CD- and HP-β-CD-modified starches generated slowly digestible curves during enzymatic digestion and showed the intermediate predicted glycemic indexes (pGI) of 58.7, 69.1 and 70.3, respectively. These findings suggest that the β-CDs-induced modification is one of promising techniques for preparing the SDS products in food and pharmaceutical industries.