Gluten-free corn cookies fortified with stinging nettle leaf flour: Effect on instrumental properties, storage stability, and health benefits.

Abstract

Background The consumption of gluten-free corn cookies is becoming very popular among non-celiac and celiac individuals. However, the absence of gluten and other nutrients in corn generally leads to cookies of lower quality in terms of nutritional value, texture, colour, and shelf-life. To improve the quality characteristics of corn cookies and thus contribute to the increasing demand for gluten-free products, this study investigated the nutritional and physicochemical effect of incorporating an underutilised herb (stinging nettle leaves) into corn cookie preparations. The storage stability at room and frozen temperatures of the formulated nettle enriched corn cookies was also investigated and compared with 100% corn cookies. Results Nettle leaf flour increased (p < 0.05) the mineral and protein content of corn cookies from 0.32 to 2.56% and 6.44 to 21.52% as well as decreased the fat content from 2.13 to 1.81% respectively. Total phenolic content and antioxidant activity also increased in all formulated nettle enriched cookies while starch digestion significantly (p < 0.05) reduced from 48.60 to 30.18%. Furthermore, cookie hardness and colour, which are important determinants of consumers acceptance of corn cookies, significantly (p < 0.05) changed indicating a softer nettle enriched corn cookies. All nettle-enriched corn cookies were within acceptable shelf-life limits in terms of water activity, peroxide value, and microbial count within six months of storage. Conclusion The incorporation of nettle leaf flour improved the nutritional, physical and shelf-life properties of gluten-free corn cookies, as well as indicated the hypoglycemic potential of nettles as a food ingredient in bakery products.