In Vitro Starch Hydrolysis and Prediction of Glycemic Index (PGI) in “Amala” and Plantain Based Baked Products

Abstract

<p>Various levels of bambara groundnut protein cocnentrate ranging from 0 to 15% were used in the formulation of plantain paste (Amala) and plantain baked products. ‘Amala’ and cookies were produced from 85% plantain flour and 15% bamabara groundnut protein concentrate, while cakes and bread were produced from 70% wheat flour, 20% plantain flour and 10% bambara groundnut protein concentrate. Starch fractions and <em>in vitro</em> starch hydrolysis of the products were determined. The lowest total starch value was found in plantain flour (51.51%) and highest in cakes (70.62%). There was no significant difference in resistant starch between plantain flour and ‘amala’ (5.22% and 4.99%, respectively). The lowest resistant starch was observed in bread (0.94%), while digestible starch was higher in bread and cakes compared to plantain flour. Higher total starch also resulted in higher digestible starch. The kinetic constant of plantain products showed very low values suggesting generally, higher resistance to enzymatic hydrolysis. The highest hydrolysis index (HI) of 74.85%, and 74.25% were observed in cakes and bread, respectively; which also resulted in higher predicted glycemic index (PGI) of 80.79% (Cakes) and 80.45% (Bread). These values were significantly different from that obtained for ‘amala’ with H1 of 56.40% with a corresponding PGI of 70.67% while cookies recorded HI value of 62.64% and PGI of 74.10%. The lowest HI (53.98%) and PGI (69.35%) was observed in plantain flour. This study showed that the more plantain flour in the product formualtions, the lower the hydrolysis index (HI) and the predicted glycemic index (PGI).</p>