The Hibiscus sabdariffa calyxes’ residue (HSR) remained after the extraction of beverage is discarded
which contributes to environmental pollution. The objective of this study was to explore
the suitability of incorporating different amount of HSR (0%, 1.25%, 2.5%, 3.75%, and 5.0%)
in crackers to enhance dietary fiber and antioxidant content. Physicochemical properties, antioxidants
activity, nutritional quality, sensory profile and microstructure properties of samples
containing HSR were examined and compared with control crackers. Cracker protein and fat
levels decreased as HSR increased from 0.0% to 5% while ash increased. The total dietary fiber
DF increased from 3.36% to 8.17% where the highest DF was reached at 5% HSR. The content
of phenols increased from 5.99 to 17.57 mg/g and total flavonoid content increased from 49.36
to 104.63 mg/g of crackers incorporated with 5% HSR. DPPH radical scavenging activity
increased two fold by increasing HSR up to 5%. HSR containing crackers exhibited darker
L values than none/less HSR containing ones. In sensory ranking tests, acceptable crackers with
pleasant flavor were obtained by incorporating up to 3.75% HSR into the cracker’s formula.
Crackers prepared with 5% HSR received the poorest sensory rating compared to non/less
HSR enriched cracker. Scanning electron microscopy (EM) images of the prepared crackers
revealed marked changes caused by incorporating HSR as upon HSR addition the surface
was observed to be scratched, cracker and rougher. Overall results suggest that HSR is a potential
functional food ingredient high in fiber content and antioxidants activity that may be processed
into flour and used in food applications, such as baked goods.