Effects of Goji Berry (Lycium barbarum) Powder on the Quality Characteristics, Pasting Properties, and Antioxidant Activity of Gluten-Free Cupcakes Prepared with Baromi2 Rice Flour

Gluten-free cakes formulated solely with rice flour frequently exhibit limited volume, weak internal structures, and rapid quality deterioration. This study investigated the effects of replacing rice flour with 0, 3, 6, 9, and 12% goji berry powder (GBP) in gluten-free cupcakes. Physical properties, texture profile, crumb porosity, crust and crumb color, flour pasting behavior, and antioxidant properties were evaluated. Moderate GBP addition improved cupcake quality, with the 6% treatment showing the greatest height (45.17 mm) and specific volume (3.64 cm3/g), the lowest hardness (327.50 g), the highest springiness (9.25 mm), and the largest average pore area (0.42 mm2). In contrast, higher substitution levels (9–12%) increased moisture and reduced baking loss but caused a decline in specific volume and a marked increase in hardness. GBP progressively darkened the product, especially the crumb, while significantly enhancing total phenolic content and DPPH radical-scavenging activity from 55.46 to 67.36 mg gallic acid equivalents (GAE)/100 g and from 4.85 to 15.08 mg ascorbic acid equivalents (AAE)/100 g, respectively. Monotonic decreases in peak, trough, final, and setback viscosities were observed, indicating reduced starch swelling and retrogradation tendencies as the GBP level increased. GBP at 6% showed the most balanced overall performance, while 12% maximized the antioxidant response at the expense of structural quality.