Effect of Whey Protein Concentrate on Rheological Properties of Gluten-Free Doughs and Their Performance in Cookie Applications

Gluten-free foods continue to be a hot topic and trend in the food market because more people are being diagnosed with gluten intolerance. Whey is a by- or co-product of the dairy industry and is considered a waste stream. In this study, whey protein concentrate (WPC), one of the whey products, was added at 8, 9, 10, 11 and 12% levels to sorghum and corn flours to make gluten-free products in the form of cookies. Mixograph and subjective evaluation showed that optimal water absorption (corn: 50–55%; sorghum: 55–60%) increased with increasing WPC level in both sorghum and corn flour dough systems. Increasing WPC from 8 to 12% resulted in a decrease in storage modulus (G’) and loss modulus (G’’) for both sorghum and corn doughs. Corn dough rheological properties were less affected by WPC addition as compared to sorghum. The diameter of gluten-free sorghum and corn cookies significantly increased with the fortification of WPC. The color of sorghum and corn cookies became darker as the WPC level increased. Cookies prepared with 10% WPC addition showed the most hardness and brittleness, probably due to the gelling property of WPC. This study contributes to the sustainable utilization of whey product and helps understand the performance of WPC during the processing of gluten-free products and its potential for making food snacks such as cookies in food manufacturing.