Effects of Anthocyanin-Rich Sorghum Bran Extract on the Quality, Antioxidant Stability, Processing Safety, and Flavor of Taosu—A Chinese Shortbread Cookie

Sorghum bran, an abundant milling by-product, is rich in phenolics but underused as a food ingredient. Anthocyanin-rich sorghum bran extract (SBE) was added to Taosu, a traditional Chinese shortbread cookie, at 0–2%, and its effects on quality, flavor, antioxidant stability during storage, and heat-induced contaminants were evaluated. UHPLC-QTOF-MS/MS showed that SBE was rich in flavones (apigenin, luteolin) and 3-deoxyanthocyanidin apigeninidin and had strong in vitro antioxidant capacity; these phenolics transferred dose-dependently into Taosu. SBE raised the total phenolic, flavonoid, and anthocyanin contents and the radical-scavenging capacity and imparted a natural reddish color. The instrumental taste profile was essentially unchanged, whereas HS-SPME-GC-MS revealed a dose-dependent shift in the volatile profile, with more Maillard-derived furans (e.g., furfuryl alcohol) and fewer lipid-oxidation aldehydes at the highest level. At the 2% level, acrylamide and 5-hydroxymethylfurfural (5-HMF) were reduced by 30.9% and 46.0%, respectively. After 14 days of storage, the fortified cookies retained much higher phenolic and antioxidant levels than the control, with the 2% sample still exceeding the fresh control, indicating improved retention of phenolics and antioxidant capacity during the period evaluated. Overall, sorghum bran offers a route to upcycle a low-value by-product into a clean-label, multifunctional ingredient that improves the healthfulness and processing safety of traditional baked goods.