Effect of whey protein and riceberry flour on quality and antioxidant activity under gastrointestinal transit of gluten-free cookies

The objective of this study was to develop nutritionally enriched gluten-free cookies by using whey protein concentrate (WPC) and rice (var. riceberry) flour (RB). The effects of WPC and/or RB on physicochemical properties, antioxidant activity under simulated gastrointestinal (GI) transit, and sensorial acceptability of cookies were evaluated and compared to those with wheat flour-based cookies. The bioactive contents, total polyphenols and gamma amino-butyric acid, significantly increased with increasing RB (P < 0.05). The physical properties showed that colour parameters (L*, a* and b*), water activity, and hardness values of cookies significantly increased as the amount of WPC increased up to a level of 50%. Incorporation of 50% WPC showed markedly the highest antioxidant activity under GI digestion with the values of 4.72 +/- 0.02 mg Trolox eq./g (ABTS), 3.12 +/- 0.06 mg Trolox eq./g (FRAP), and 26.57 +/- 0.66 mg EDTA eq./g (metal chelating activity). The overall results showed that cookies with acceptable quality and improved nutrition and antioxidant activity could be produced by complete replacement of wheat flour with the WPC and/or RB. However, in order to obtain the desired cookie characteristics, the ratio of WPC to RB should be developed.