BACKGROUND The effect of marinating beef in acid whey on the antioxidant peptides generated, and their influence on lipid oxidation, colour stability, sensory analysis and protein degradation products in uncured roasted beef stored 6 weeks in vacuum conditions (T = 4 °C) were determined. Measurements of pHe, water activity, oxidation–reduction potential, colour, TBARS, the cutting force, texture and amino acid profile, the total content of peptides, and antioxidant activity of isolated peptides were conducted immediately after production and during 42 days of storage. RESULTS The non-nitrite control batch (C) was characterized by a lower a* value (6.33–6.70) during the whole storage period compared to the non-nitrite sample with acid whey (W). It also appears that meat with the worst colour stability has the poorest oxidative stability (C = 1.57 mg MDA kg−1, W = 0.76 mg MDA kg−1). Activity against reactive forms of oxygen to fraction A and fraction B (P < 0.05) showed an increasing trend with time and it was the largest in sample C and W. CONCLUSION The results indicated that bioactive peptides could be generated in uncured roasted beef. The <3.5 kDa peptides have strong antioxidant activity, as a result of which they function as inhibitors of lipid oxidation and colour discoloration during prolonged storage. © 2018 Society of Chemical Industry