Synthetic antioxidants such as butylated hydroxyl toluene (BHT) added to meat products have been actually restricted because of their toxic activity. This fact encourages the application of natural antioxidants as a protection from lipid oxidation process. Hence, the effect of addition of Solanum lycopresicum L. extract to pork and beef meatballs during frozen storage (-18°C/90 days) was investigated on physicochemical parameters, antioxidant activity and flavour. In the study, three kinds of meatballs were analysed: control (C) without antioxidant; with added BHT (0.01%) and with Solanum lycopresicum L. extract (1%, ET). Addition of 1% of Solanum lycopresicum L. extract to beef and pork meatballs ET resulted in a significant (P<0.05) decrease in lipid oxidation and increased redness stability. In conclusion, the addition of Solanum lycopresicum L. extract (1%) as a natural plant antioxidant to steamed beef and pork meatballs during frozen storage can result in reduced lipid oxidation level, stabilized red colour and intensity of meaty flavour. [ABSTRACT FROM AUTHOR]