Abstract
The effects of Perilla frutescens leaf extract (PLE) on the quality of surimi fish balls were investigated in the present study. Firstly, the extract was prepared by solvent extraction using 95% ethanol. Then, the phenolics in the extract were analyzed by instrumental analysis. The total phenolic content in the PLE was found to be 14.51 mg gallic acid equivalent (GAE)/g dry weight (DW). The amount of caffeic acid, ferulic acid, rosmarinic acid, quercetin, and apigenin, determined by high-performance liquid chromatography (HPLC), was 4.80, 5.10, 2.95, 6.46, and 3.93 mg/g DW, respectively. Furthermore, the PLE was found to show high free radical scavenging activity toward DPPH and ABTS radicals with IC(50) values of 12.15 and 7.26 μg/ml, respectively. When PLE was fortified into surimi fish balls at 0.03% and stored at 4°C, it was found to slow down lipid and protein oxidation during storage of surimi fish balls as evidenced by the significant reduction in TBARS values and protein carbonyl contents (p < 0.05). PLE (0.03%) also decreased the formation of total volatile basic nitrogen (TVB-N) and inhibited the growth of E. coli compared with the control group (p < 0.05). In addition, the overall acceptability of PLE-added (0.03%) samples was higher than control samples during the storage process (p < 0.05) by sensory analysis. Overall, PLE have the potential to be used as a natural food additive to improve the shelf life and sensorial qualities of surimi fish ball.