Effect of Prunus serotina Ehrh. Fruit Extract on the Oxidative Stability, Colour and Quality of Pork Burgers During Refrigerated Storage

Oxidative deterioration limits the quality and acceptability of fresh meat products during refrigerated storage, creating interest in plant-derived antioxidant ingredients. This study evaluated the effects of an ethanolic Prunus serotina Ehrh. fruit extract (PSE) on the physicochemical characteristics, oxidative stability, colour and sensory quality of raw pork burgers stored at 4 °C for 72 h. Four formulations were prepared: a control without extract and burgers containing 2, 5 and 10% (w/w) PSE. The mineral and individual phenolic profiles of the fruit extract were characterized by ICP-OES and HPLC-DAD-MS (ESI+), respectively. Sixteen phenolic compounds were identified, with flavonols accounting for 96.08% of the total identified phenolics; isorhamnetin-rhamnoside-rhamnoside-glucoside was the predominant flavonol, and delphinidin-rutinoside was the major anthocyanin. PSE incorporation increased the total phenolic content and DPPH antioxidant capacity of the burgers in a concentration-dependent manner and resulted in lower pH values than in the control. Although TBARS and metmyoglobin increased during storage in all formulations, their accumulation was lower in PSE-fortified burgers, particularly at the 5 and 10% PSE levels. At 72 h, the control reached 43.14 ± 0.10% metmyoglobin, whereas all PSE-fortified formulations exhibited lower values. PSE also influenced instrumental colour and visual appearance through the combined effects of its intrinsic pigments and antioxidant capacity. Sensory evaluation showed that formulations containing 5 and 10% PSE generally retained more favourable appearance and odour scores during storage. These findings indicate that PSE can enhance the antioxidant status and delay lipid and pigment oxidation in raw pork burgers during short-term refrigerated storage. Further research is required to establish its microbiological effectiveness, cooking stability, consumer acceptance and industrial applicability.