Characterization of resistant waxy maize dextrins prepared by simultaneous debranching and crystallization

Waxy maize starch was debranched using isoamylase and simultaneously crystallized in the same batch at 50 °C for 7 days. The crystallized starch dextrins were isolated as precipitates and characterized for chain length distribution, crystallinity, thermal transition property, morphology, and in vitro digestibility. The long B chains released from the amylopectin crystallized more readily than the short A chains. The dextrins exhibited a typical A-type crystalline arrangement with high thermal stability. The recovery yield from the waxy maize starch was 70.4% after 7 days. The amount of resistant starch (RS) in the crystallized dextrin treated for 7 days was 83% (uncooked) or 46% (cooked). The simultaneous debranching and crystallization process was effective for the formation of dextrin crystals from waxy maize starch with thermal stability and good resistance to digestive enzymes.