Antioxidant and antimicrobial characteristics of mangosteen peel extract and synergistic capacity in beef burger preservation

Abstract

This study aimed to investigate the efficiency of mangosteen peel extract (MPE) in preservation of beef burgers. MPE was first evaluated for its total phenolic content (TPC), total flavonoid content (TFC) and antioxidant and antimicrobial activities. Subsequently, beef burgers were prepared with different MPE amounts (0–1%) and stored for 1 day, 3 days and 5 days. The synthetic antioxidant 2,6-di-tert-butyl-4-methyl phenol (BHT) and synthetic antimicrobial sodium benzoate (SB) were used for comparison. The changes of burgers in physicochemical parameters (moisture, cooking loss, storage loss and pH), lipid and protein oxidation (peroxide value, PV; thiobarbituric acid reactive substances, TBARS and carbonyl content), microbiological (total viable count, TVC) and sensory characteristics were assessed. The results revealed that MPE contained a high TPC of 128.93 mg gallic acid equivalent g−1 dry extract and TFC of 62.98 mg rutin equivalent g−1 dry extract. These bioactive compounds rendered MPE with its antioxidant activity approximately equivalent to ascorbic acid and antimicrobial activities against Escherichia coli and Staphylococcus aureus comparable with SB. MPE-combined burger samples had higher moisture and cooking loss (P < 0.05) but almost equal storage loss and pH value compared with the control samples (P > 0.05). However, the incorporation of MPE into beef burgers did not affect the sensory attributes and preferences of consumers (P > 0.05). The burger with 1% MPE had lower values of PV, TBARS and carbonyl content than all other samples (P < 0.05), including the one added with BHT, indicating the strong potential of MPE as natural antioxidant alternative to prevent the oxidation of lipids and proteins. Through the TVC test, 1% MPE was demonstrated to result in the safe preservation of burgers up to 5 days of storage, equivalent to SB (P > 0.05). Therefore, MPE could become a natural synergistic alternative to both synthetic antioxidant and antimicrobial in the preservation of meat and meat products.