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.

Physical properties and estimated glycemic index of protein-enriched sorghum based chips.

Sorghum is a gluten-free grain and more attention has been given to the nutritional properties and recently its usage as a wheat replacement in food products. In the present work, protein-enriched sorghum based snack chips, prepared from sorghum meal with soy protein isolates and soy flour to meet the final protein content of 35.7%, were produced. The effect of varying baking powder (1.5-2.5%), dough sheet thickness (0.7-1.7 mm), and baking time (6-12 min) on the physical properties of the snack chips was investigated using a central composite design of response surface methodology. Under baking temperature of 160 °C, with baking powder added, the water activity and puffiness of chips significantly increased. Baking time was the most significant factor for all the parameters detected except for puffiness. The optimized conditions of preparing protein-enriched sorghum chips were baking powder 2.5%, dough sheet thickness 0.7 mm, and baking time 7.66 min. The estimated glycemic index (eGI) of the protein-enriched sorghum chips (eGI = 59.8) was significantly lower than soybean-free sorghum chips. The gluten-free protein-enriched sorghum chips developed could be considered as protein rich with lower intermediate-glycemic index classified healthy snacks and potential commercialization.