Evaluation of crisps from maize-integral grape pomace flour mix manufactured by extrusion cooking

Integral grape pomace is a significant source on nutrients and can be valorized in maize crisps production industry. Being a fiber-rich ingredient, it is important to determine the optimal amount that can be included to keep acceptable quality parameters of the final product. Thus, this paper aims to investigate the impact of integral grape pomace (red and white) on maize crisps physical properties and starch digestibility. For this, a Response Surface Methodology design was applied and the optimization was performed by using desirability function. The increase of grape pomace dose led to the reduction of lightness, expansion index, crunchiness, and WAI and the increment of browning index, cutting, compression and puncture forces, crispness, and total starch. The optimal samples containing 20.50% white grape pomace and 18.28% red grape pomace respectively showed lower L*, texture forces and functional properties compared to the control, while the porosity was enhanced. The molecular characteristics of the optimal samples were similar and some differences were found compared to the control. These results could be used for further researches on the chemical properties of the enhanced crisps and/or to develop this kind of products at an industrial level.