Abstract: To inhibit starch retrogradation and enhance the quality of steamed cakes during storage, in this study, we investigated the effects of different addition levels of adzuki bean powder (ABP) (0%, 8%, 16%, 24%, and 32%) on the water-holding capacity (WHC) and oil-holding capacity (OHC) of composite flour (wheat flour, glutinous rice flour, yam flour, and taro flour at a mass ratio of 15:5:3:2), and on the texture, antioxidant activity, color, specific volume, protein content, and sensory properties of the resulting steamed cakes. Low-field nuclear magnetic resonance (LF-NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to elucidate the anti-retrogradation mechanisms. The results showed that as ABP content increased, the WHC of the composite flour significantly rose from 0.97 g/g to 1.43 g/g (P<0.05). Meanwhile, the OHC exhibited an initial increase followed by a decrease. For the steamed cakes, the specific volume increased from 1.80 mL/g to 2.48 mL/g, protein content rose from 2.17% to 2.72%, and hardness decreased from 683.95 g to 498.59 g. Redness (a*) increased significantly (P<0.05), while brightness (L*) and adhesiveness significantly decreased (P<0.05). At the 24% addition level, the total antioxidant capacity, total reducing power, and ABTS⁺ · radical scavenging activity peaked. After 7 d of storage at 4 ℃, the hardness of all the ABP-supplemented groups remained significantly lower than that of the control group (P<0.05). Mechanistic analysis showed that ABP was deeply integrated into the starch-gluten system by strengthening the hydrogen bond network. Addition of 16%~24% effectively sequestered moisture and significantly reduced the short-range molecular order of starch. The proportion of deeply bound water increased by 12.13% to 44.19% relative to the control. This further inhibited starch molecular rearrangement from the perspectives of long-range order and thermodynamics, decreasing the relative crystallinity from 12.08% to 9.01%~9.15% and reducing the retrogradation enthalpy by 15.11%~41.49% compared to the control. In conclusion, the addition of 16%~24% ABP significantly enhanced the quality of steamed cakes and effectively inhibited starch retrogradation during storage.