Incorporation of madımak (Polygonum cognatum Meissn.) leaf powder into gluten-free bread formulations: Evaluation of their nutritional, antidiabetic, color, bioactive, textural, and sensory properties.

Abstract

Background: This study aimed to develop gluten-free bread from chickpea flour by incorporation of varying levels (0 (B-C), 2.5 (B-1), 5 (B-2), and 10 g kg^-1 (B-3)) of madımak leaf powder (MLP), and to investigate its effect on physicochemical and bioactive properties, glycemic index, texture, and sensory attributes.

Results: Moisture ranged from 229 (B-3) to 244 g kg^-1 (control), while ash content increased with MLP, reaching 47 g kg^-1 in B-3 compared to 15.5 g kg^-1 in the control. Fat and protein contents decreased slightly from 10.1 and 188.2 g kg^-1, respectively while starch remained stable (398.2-405.3 g kg^-1). Total dietary fiber increased from 3.22 (control) to 15.11 g 100 g^-1 (B-3), driven by rises in insoluble (1.36-11.45 g 100 g^-1) and soluble fiber (1.87-36.5 g 100 g^-1). The hydrolysis index and predicted glycemic index decreased by 35.54% and 32.66% (B-3), respectively. MLP extract demonstrated inhibitory activity against α-amylase and α-glucosidase with IC₅₀ values of 42.31 and 39.71 μg mL^-1. Bioactive analysis demonstrated increases in total phenolics (1.08-4.82 mg GAE g^-1), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (2.17-23.13 mg TE g^-1), and FRAP (ferric reducing antioxidant power) activities (16.27-90.05 μmol Fe²⁺ g^-1). L*, a*, and b* values decreased with MLP content and hardness decreased from 379.38 g (control) to 247.04 g (B-3). Sensory analysis revealed no adverse effect on overall acceptability.

Conclusion: MLP could be incorporated into chickpea flour-based gluten-free breads up to 100 g kg^-1, providing enhanced dietary fiber, antioxidant capacity, and glycemic properties. © 2025 Society of Chemical Industry.