Evaluation of the effect of high pressure on total phenolic content, antioxidant and antimicrobial activity of citrus peels

This study aimed to assess the effect of high pressure at 300 and 500 MPa for 3 and 10 min on the phenolic compounds, antioxidant capacity and antimicrobial activity of citrus peel extracts. Total phenolic contents (TPC) and antioxidant properties of extracts were determined as free radical-scavenging ability of DPPH and using the ABTS radical cation decolorization assay. Additionally, extracts were tested for antimicrobial activity against twenty different strains of bacteria representing both Gram-positive and Gram-negative types. Citrus peel extracts demonstrated antimicrobial activity against a wide range of bacteria. The maximum level of TPC as well as antioxidant capacity were observed at 300 MPa for 3 min. Citrus peels extracts demonstrated antimicrobial activity against a wide range of microorganisms. The antimicrobial activity of orange peel extract was the highest among the four citrus peels studied. Generally, bacteria Acinetobacter and the strain Listeria innocua were more sensitive to the peel extracts.