STUDYING THE ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF PHYCOERYTHRIN TO INCREASE THE SHELF LIFE OF HAMBURGERS AT REFRIGERATOR TEMPERATURE

Abstract

Cyanobacteria represent promising sources of active biochemical compounds and natural products with antioxidant and antimicrobial properties. The present study investigated the antimicrobial and antioxidant capabilities of phycoerythrin (PE) from Nostoc sp., used it to coat hamburger samples with 40%, 75%, and 95% meat, and examined the physicochemical and sensory characteristics of the hamburger samples over 21 days. The results showed that the antioxidant activity of phycoerythrin was 2.71±0.03 mg/mL using the DPPH method. The minimum inhibitory concentration (MIC) of PE against Pseudomonas aeruginosa was significantly higher, and in Bacillus subtilis and then Bacillus cereus, it was noticeably lower than the other samples (p≤0.05). Also, PE did not show a lethal effect against any bacteria (p≤0.05). Findings indicated that no significant variations were seen in the inhibition zone diameter of PE against the examined bacteria (p˂0.05). In both the investigated temperatures and in all the time intervals, the maximum and minimum of the thiobarbituric acid and peroxide values, total bacterial counts for mesophilic, psychrophilic, E. coli, Staphylococcus aureus, and total mold and yeast observed in codes 5 and 2, respectively. In hamburger samples containing identical meat percentages, the incorporation of PE resulted in a significant enhancement of antioxidant activity (p≤0.05).