Effect of Enzyme Concentration and Storage Temperature on the Formation of Slowly Digestible Starch from Cooked Debranched Rice Starch

Non-waxy and waxy starch suspensions were debranched with pullulanase followed by heating and cooling to form products with a mixture of rapidly digestible (RDS), slowly digestible (SDS) and resistant starches (RS). Products with a range of digestibility were formed by controlling the enzyme concentration (2 and 10 g of pullulanase per 100 g of starch), time of hydrolysis (2 to 24 h) and cooling temperature (1, 15, and 30 °C). Higher enzyme concentration and less time for debranching resulted in maximum formation of SDS while longer times increased RS. RDS decreased with increasing SDS and RS. Holding at 1 °C produced a product with highest proportion of SDS. Holding at 15 °C produced a starch that is relatively more resistant to digestion. Holding at 30 °C produced the smallest amount of SDS but the same amount of RS as with samples cooled at 1 °C. The most SDS was produced by debranching waxy starch with 10 g of pullulanase per 100 g of starch for 4 h and subsequent storage at 1 °C.Therefore, waxy starches would be more suitable to make SDS.