Quality and estimated glycemic profile of baked protein-enriched corn chips

This study aimed to develop gluten-free protein-enriched corn snack chips and evaluate their physical properties and in vitro estimated glycemic index. Flours containing yellow corn and soybean flours, and soy protein isolate (in a proportion of 2.5:1.0:1.0 by weight respectively), cellulose gum, salt, and baking powder were homogeneously mixed followed by the addition of water and kneaded to form a dough. Response surface methodology was used to optimize baking powder levels (0-2.0%), dough sheet thickness (0.7-1.7 mm), and baking time (6-12 min) of the chips baked at 160 °C. Dough sheet thickness and baking time had significant effect on all the examined physical properties (water activity ranged from 0.15 to 0.71, hardness ranged from 377 to 2105 g, and browning index ranged from 38.4 to 60.7) (P < 0.05) except fracturability. However, all the variables had a significant quadratic effect on the fracturability (ranged from 1 to 23 peaks) of the chips (P < 0.01). The chips prepared from 1.2% baking powder, 1.2 mm dough sheet thickness, and baked for 9.0 min were considered the best and were significantly lower in the estimated GI value (48.8) (P < 0.05) when compared to non-soy corn chips (75.0). These baked protein-enriched corn chips developed could be considered as protein-rich and low glycemic index healthy snacks.