Characterization of Ziziphus jujuba seeds and optimization of waffle formulations via D-optimal mixture design

This study aimed to increase the nutritional and bioactive composition of waffles by incorporating Ziziphus jujuba seed flour without affecting their sensory quality parameters. Preliminary testing identified the nutritional composition of the seeds, followed by FTIR and SEM characterization. Using D-optimal design, 24 multigrain waffle formulations with varying proportions of jowar, bajra, wheat, and seed flour were developed. The optimal formulation containing jowar (25%), bajra (25%), wheat (40%), and jujuba seed (10%) flour achieved high nutritional and sensory scores. The formulation had a flavonoid content of 48.17 ± 0.01 mg QE per g, phenolic content of 32.39 ± 0.04 mg GAE per g, and antioxidant activity (DPPH) of 25.43 ± 0.01%. The overall acceptability score was 8.24 ± 0.02. Further analyses of proximate composition, shelf life, and antioxidant activity were conducted using two packaging materials (metallic polyester and low-density polyethylene) at three temperatures (8 °C, 25 °C, and 37 °C). The metallic polyester retained the bioactive components during the selected storage period. The results suggest that Ziziphus jujuba seed flour significantly enhances the nutritional value of waffles while maintaining sensory qualities, indicating commercial potential.