Titanium dioxide (TiO2) has been widely used as a food whitening agent in confectionery and other food products. Given its potential safety concerns, the development of alternative whitening materials is of considerable importance. To evaluate the whitening performance of starch and calcium carbonate in a representative food system, gummy candy was selected as the model matrix. Visible-light reflectance was used to characterize the light-scattering performance of the powders. The whitening effects of quinoa starch (QS), rice starch (RS), corn starch (CS), potato starch (PS), and calcium carbonate with different particle sizes (CaCO3-I and CaCO3-II) were compared. The stability of QS and small-particle calcium carbonate (CaCO3-I) under heat treatment, citric acid addition, and storage conditions was further investigated. In addition, the effects of different powder addition levels on the texture properties of gummy candy were evaluated. The results showed that the whitening effect of the powders in gummy candy was closely related to their light-scattering performance. Powders with higher refractive indices exhibited higher attainable whitening levels, while smaller particle sizes within the same powder category resulted in better whitening performance. The whitening effect also increased significantly with increasing addition level. After screening powders with different particle sizes, QS and CaCO3-I showed relatively superior whitening performance within the starch and calcium carbonate groups. At an addition level of 10 wt.%, the lightness (L*) and whiteness index (WI) values of QS-containing gummies were 86.22 and 81.96, respectively, while those of CaCO3-I-containing gummies were 87.41 and 83.48. These values were higher than those of the 0.1 wt.% TiO2 group. After heat treatment at 60 °C for 30 min, the L* and WI values of QS-containing gummies decreased by 2.16 and 1.82 units, respectively, whereas those of CaCO3-I-containing gummies changed only slightly to 87.43 and 83.45. After the addition of 0.15 wt.% citric acid, the changes in L* and WI for both powders were within 0.06 units. After storage at 20 °C for 30 d, the L* and WI values of QS-containing gummies decreased by only 0.23 and 0.25 units, respectively, whereas no significant changes were observed for CaCO3-I-containing gummies. Texture analysis showed that the texture parameters of the 5 wt.% QS group were generally similar to those of the blank and TiO2 groups, whereas the 10 wt.% QS and CaCO3-I groups generally exhibited higher hardness, gumminess, and chewiness. Overall, both QS and CaCO3-I showed promising potential as whitening alternatives to TiO2. However, their practical application should take into account the whitening effect, addition level, acidity, and texture quality, providing experimental support for the screening of alternative food whitening agents and the design of application formulations.