Current trends show that the food industry is moving away from synthetic colorants and looking for natural alternatives. Anthocyanins (ACN) are plant flavonoids with vivid colors that range from red to blue, but their application as food colorants is restricted by their limited stability, particularly at pH close to neutral. Nevertheless, some studies have shown that ACN have higher stability in dairy systems than in buffers at the same pH. We hypothesized that milk components such as proteins can interact with ACN, and that certain ACN may have a higher affinity for proteins due to specific structural conformations. Our objective was to evaluate whether whey proteins can interact with ACN leading to enhanced color and stability. Model solutions were prepared by diluting ACN from different sources with pH 3 citric acid – Na₂HPO₄ buffer until a λ_vis-max absorbance of 0.7 was reached, followed by addition of whey protein isolate (WPI) at different concentrations (0, 0.01, 0.05, 0.1, 0.5 and 1.0 mg/mL model solution). Absorption spectra was measured after 15 min and color parameters (CIELab) were calculated using ColorBySpectra software. Model solutions were heated to 90°C for up to 500 min to test heat stability, with samples taken every 50 min. ACN content was measured using the pH differential method. Addition of WPI resulted in a significant absorption increase (P < 0.05) at the λ_vis-max up to 17%. Color of the model solutions was enhanced (ΔE >5), becoming noticeably darker with WPI concentrations as low as 0.05 mg/mL for Berberis boliviana, 0.5 mg/mL for purple corn and grape skin, and 1.00 mg/mL for black carrot and red cabbage. The absorption increase at the λ_vis-max was dependent on WPI concentration, some fitting a linear model while others an exponential one, suggesting that some ACN may have higher affinity for WPI than others. Also, WPI addition significantly increased thermal resistance of ACN (P < 0.05). Further studies will focus on different anthocyanin chemical structures and the possible utilization of acid whey to stabilize ACN pigments. This could facilitate the transition from synthetic colorants to natural and healthier alternatives.