COMPOSITIONAL ANALYSIS, FUNCTIONAL PROPERTIES AND MICROSTRUCTURE OF COOKIES FORTIFIED WITH OLIVE LEAVES POWDER

Abstract

Olive leaves (OL) are a valuable source of minerals, fibers, and bioactive compounds with functional properties. The study aimed to develop fortified cookies with olive leaves powder (OLP) at varying concentrations (0, 20, 40, 60, 80, and 100 g kg^-1 flour). Fine wheat flour (FWF), OLP and composite flours were analyzed for proximate composition, mineral content, functional properties and SEM analysis. Fortified cookies were evaluated for physicochemical, sensory, mineral, and microstructural attributes. Results showed that OLP contains high concentrations of ash, fiber, fat, calcium, iron, and zinc but lower moisture, protein, nitrogen-free extract (NFE), and potassium as compared to FWF. Functional properties such as water and oil absorption capacity were high in OLP, while swelling, foaming capacity, and foaming stability were lower in OLP. In composite flours, increasing OLP levels significantly reduced wet gluten from 30.02% to 17.97% and dry gluten from 9.10% to 6.84%. SEM analysis revealed irregular protein matrices with large granules of starch, and rough fiber structures. As the concentration of OLP increased in fortified cookies, a significant reduction was observed in width, spread ratio and NFE content while increase was observed in thickness, hardness, moisture, ash, fiber, fat, protein, and minerals contents. Sensory evaluation indicated that cookies fortified with 6% OLP were highly acceptable, offering enhanced nutritional benefits and prolonged shelf life.