Effect of modified grapefruit peel dietary fiber on bread: baking quality, flavor characteristics, and starch digestive properties

With the increasing prevalence of diet-related chronic diseases, developing baked goods with functional properties to enhance health benefits is essential. This study developed a modified fermented soluble dietary fiber (F-SDF) bread, assessing the impact of added F-SDF on starch, protein, and volatile flavor compounds, alongside potential mechanisms. The results showed that incorporating 1.0% F-SDF effectively enhanced bread quality. Specifically, adding 1.0% F-SDF reduced total starch content (1.59%), specific volume (0.48 mL/g), ΔH (1.65°C), hardness and chewiness compared to the control (CK). Additionally, adding 1.0% F-SDF increased the resistant starch content (1.72%), α -helix value (1.74%), relative crystallinity (2.68%), the short-range ordered structure (3.78%), and bound water content of bread. Notably, both F-SDF and unmodified soluble dietary fiber (R-SDF) reduced rapidly digestible starch (RDS) without a significant difference. Furthermore, Gas chromatography-ion mobility spectrometry (GC-IMS) analysis indicated that F-SDF incorporation introduced new volatile compounds, including Butyraldehyde and 1-Hexanol, while preserving key flavor compounds such as Hexanal and Ethyl acetate. Overall, this study expands the applications of F-SDF in baked goods and offers insights into the development of fiber-rich foods.