Development and characterization of sugar-free therapeutic biscuits fortified with red kidney bean powder, potato flour and stevia

Abstract

The rising prevalence of lifestyle-related diseases has increased demand
for sugar-free, protein-enriched, and functional foods. This study
developed sugar-free therapeutic biscuits formulated with red kidney
bean (RKB) powder, potato flour, and stevia as a natural sweetener. A
total of four formulations were prepared, including a control with 100%
wheat flour and sugar, and three therapeutic formulations incorporating
5–10% red kidney bean powder and 10–20% potato flour, where stevia
was used as a sugar substitute. Proximate analysis revealed that the
formulated biscuits (S2–S4) had significantly higher protein (22.93–
23.48%) and ash content (2.45–2.72%) than the control (S1), along with
increased dietary fiber (0.49–0.54%) and lower carbohydrate content
(44.69–48.16%). Moisture and fat contents were not significantly
different. Physical evaluation showed that RKB and potato flour
incorporation increased biscuit weight and thickness but reduced
diameter and spread ratio, resulting in denser structures. Sensory
evaluation indicated that moderate substitution (S2) achieved
comparable acceptability to the control, while higher substitution levels
slightly reduced taste and appearance scores due to legume-associated
flavors and darker color. Bioactive profiling demonstrated substantial
enhancement of total phenolic content (0.33 to 3.24 mg GAE/100 g),
total flavonoid content (37.60 to 50.72 mg QE/100 g), and antioxidant
activity (1.70 to 3.32 µmol TE/100 g) with increasing RKBP and potato
flour levels. These findings show that sugar-free therapeutic biscuits
made with locally available legumes and tubers can offer a healthy
option for diabetic and health-conscious people, while also promoting
sustainability and supporting the development of functional bakery
products that meet today’s nutritional needs.