Influence of kenaf (Hibiscus cannabinus L.) leaves powder on the physico-chemical, antioxidant and sensorial properties of wheat bread

Hibiscus cannabinus L. or commonly known as kenaf is a multipurpose crop with various medicinal and nutritional properties. The aim of this study was to determine the antioxidant, nutritional, and functional properties of kenaf leaves powder. In addition, the effect of kenaf leaves powder fortification in bread properties and consumer acceptability were evaluated by production of three formulations of bread with 0% (control), 4% and 8% substitution of kenaf leaves powder per weight of flour used. From the sensory evaluation, 4% leaves powder bread was the most preferred by the panelists followed by 0% leaves powder bread then 8% leaves powder bread. Therefore, 4% leaves powder bread was chosen as the best formulation for this study and it showed significantly higher value of DPPH free radical scavenging capacity (8.05 mg TE/100 g), total phenolic content (12.9 mg GAE/100 g) and total flavonoid content (13.3 mg QE/100 g) compared to control bread (1.38 mg TE/100 g, 8.17 mg GAE/100 g and 8.77 mg QE/100 g, respectively). Besides, 4% leaves powder bread also showed improvement in calcium and total dietary fibre compared to control bread. Given these results, kenaf leaves powder can be used in baking formulation up to 4% with flour to enhance the functional properties of baking formulation without compromising eating quality.