Polyphenoloxidase (PPO) inhibitors, such as l-cysteine, l-cysteine*HCl, citric acid, papain, pepsin and bromelain, respectively, were added to freshly prepared unheated strawberry (Fragaria x ananassa Duch.) purées. Subsequently, strawberry PPO was extracted, and its residual activity was determined spectrophotometrically and compared to a control without added inhibitors. To evaluate the effects of the putative inhibitors on color and anthocyanin stability, strawberry purées were stored at +20 ± 2 °C in the dark for a period of 28 days. Monomeric and polymeric anthocyanins as well as antioxidant activities (FRAP) and total polyphenols (Folin–Ciocalteu) were monitored spectrophotometrically during storage. Individual anthocyanins were determined by HPLC–DAD–MSn, and color measurements were performed using the CIE L∗a∗b∗ system.Whereas a concentration dependent inhibitory effect on strawberry PPO was observed for l-cysteine*HCl, l-cysteine and citric acid, respectively, PPO activity was not suppressed by the addition of any of the proteases. Complete PPO inactivation was only achieved by both the addition of l-cysteine*HCl and l-cysteine. However, with the exemption of papain, all additives resulted in significantly improved pigment and color stability of the strawberry purées during storage.