Abstract

Black rice contains abundant phytochemicals and amylose, which contribute to health benefits. Amylose aids in resistant starch (RS) formation. This study evaluated the effect of microwave heating duration (1, 3, and 5 min) on RS formation in Indonesian black rice flour using a completely randomized design. Microwave treatment altered the physicochemical and structural properties of starch without significantly affecting proximate composition (except protein) or total starch content. Heating increased amylose, RS, and water absorption capacity, with the 3-min treatment yielding the highest RS content (19.58%) and crystallinity (25.78%). However, it also reduced swelling power, solubility, holding capacities, and some bioactive components. The 3-min microwave treatment was identified as the most effective condition, producing the highest RS content with improved crystallinity, amylose content, and water absorption capacity, indicating functional properties of black rice flour.

Key words: Black rice, Flour, Microwave, Resistant starch.