Evaluation of the quality, nutritional value and antioxidant activity of gluten-free biscuits made from corn-acorn flour or corn-hemp flour composites

The aim of this study was to evaluate the effect of substituting 20-60% of corn flour with acorn or hemp flour on the quality, nutritional, pro-health value, and sensory properties of gluten-free biscuits. Partial replacement of corn flour with the mentioned above flours resulted in a significant reduction of biscuit volume and an increase of their hardness. The biscuits in the experiment were significantly darker than the control ones. Increasing the content of both studied flours resulted in a distinct trend of color variation from yellow toward red-purple. The protein content in biscuits with the addition of acorn flour did not differ significantly in comparison with the control biscuits, whereas biscuits with flour hemp contained 40-122% more protein in comparison with the control ones. The total dietary fiber content increased correspondingly with the addition of the investigated flours. The total polyphenols content (TPC) in biscuits with the acorn flour addition increased in the range of 308-801% in relation to the control, and the addition of hemp flour increased the TPC in the range of 41-143%. It was found that acorn flour contributed to higher growth (an average of 367%) of the antioxidant activity of the biscuits in relation to the control samples than the hemp flour (an average of 114%). The control biscuits obtained the highest sensory score, similarly biscuits with 20 and 40% acorn flour addition. The most favorable replacement should be that not more than a 40% substitute of corn flour with acorn flour.