Upcycling Carrot and Broccoli Industrial Residues for Sponge Cake Formulations: Effect of Replacement Level in Wheat and Gluten-Free Systems

Fruit and vegetable processing generates large amounts of underutilized waste that can be valorized as functional food ingredients. This study evaluated the effects of incorporating hot-air-dried powders obtained from carrot and broccoli industrial residues on the color, texture, antioxidant properties, and other physicochemical attributes of sponge cakes formulated with wheat flour (gluten-containing) and gluten-free chickpea (legume)- and rice (cereal)-based flours. Cakes containing no vegetable powder or 5, 10, 20 or 30% flour replacement by vegetable powder were evaluated within 24 h after baking and after one week of storage. Overall, the effects of vegetable powder incorporation depended on flour type, powder type, and replacement level. Carrot powder improved water retention and preserved cake height, whereas broccoli powder produced denser structures with reduced expansion. Both powders enhanced phenolic and flavonoid contents and antioxidant activity in a dose-dependent manner, with broccoli powder showing the greatest effect. Storage had limited effects on antioxidant properties but increased hardness, with carrot powder mitigating firmness development in chickpea-based cakes. Considering the interest in developing gluten-free products, rice-based cakes with 20% flour replacement by carrot powder emerged as promising formulations, showing characteristics closer to those of wheat-based control cakes while providing enhanced antioxidant properties.