Effect of enzyme concentration and storage temperature on the formation ofslowly digestible starch from cooked debranched rice starch

Non-waxy and waxy starch suspensions were debranched with pullulanase follo wed by heating and cooling to form products with a mixture of rapidly diges tible (RDS), slowly digestible (SDS) and resistant starches (RS). Products with a range of digestibility were formed by controlling the enzyme concent ration (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 degreesC). Higher enzyme concentration and less time for debranching resulted in maximum formation of SDS while longer times increased RS. RDS decreased with increasing SDS a nd RS. Holding at 1 degreesC produced a product with highest proportion of SDS. Holding at 15 degreesC produced a starch that is relatively more resis tant to digestion. Holding at 30 degreesC produced the smallest amount of S DS but the same amount of RS as with samples cooled at 1 degreesC. The most SDS was produced by debranching waxy starch with 10 g of pullulanase per 1 00 g of starch for 4 h and subsequent storage at 1 degreesC. Therefore, wax y starches would be more suitable to make SDS.