Effects of Wheat Matrix and Jujube Incorporation Form on the Quality and Antioxidant Properties of Whole-Wheat Steamed Bread

The incorporation form of fruit-derived ingredients may influence the quality and antioxidant responses of whole-wheat steamed bread. Jujube was incorporated into white- and colored-wheat whole-wheat flours either as dry powder or as prehydrated pulp at 5%, 10%, and 15% on a dry-matter basis, while the total water addition was kept constant across all formulations. Product geometry, surface color, texture, cross-sectional appearance, anthocyanin content, and ABTS radical scavenging activity were evaluated. Specific volume showed relatively limited variation across the tested formulations, including a range of 1.59–1.67 mL/g in the white-wheat powder series. Colored-wheat flour contained 4.24 mg/100 g anthocyanins compared with 0.99 mg/100 g in white-wheat flour, and anthocyanin content in steamed bread was governed mainly by wheat matrix. ABTS activity was affected by wheat matrix, jujube form, addition level, and their two-way interactions, reaching 66.15% in colored-wheat steamed bread containing 15% jujube pulp. Among the formulations tested, 10% jujube pulp in the colored-wheat system provided a more balanced response in product shape and antioxidant activity, whereas increasing the level to 15% further enhanced ABTS activity but reduced several instrumental texture attributes.