Abstract:
Different types of electrolyzed water were used instead of ordinary water to wash raw tilapia, and the effects of acidic electrolyzed water on microorganisms on the fish surface, substances producing fishy odor, color difference, texture, and degree of lipid and protein oxidation during storage were examined. After washing the raw ingredients with acidic, weakly acidic, and neutral electrolyzed water instead of ordinary water for 3~10 min, microorganisms of the fish surface decreased from 34.55×103~24.21×103 CFU/g to 1.78×103~
0.86×103 CFU/g, 9.21×103~2.21×103 CFU/g, and 12.52×103~5.12×103 CFU/g, respectively. The concentration of geosmin (GSM) - a substance producing fishy odor - decreased from 714.15 µg/L to 412.78~198.86, 519.21~312.21, and 612.12~385.12 µg/L, respectively. The concentration of 2-MIB, another substance producing fishy odor, decreased from 334.55~224.21 ng/L to 251.78~101.21, 279.21~128.21, and 312.52~205.12 ng/L, respectively. Under storage at 0~4 ℃, there were no significant changes in the total color difference (ΔE) value, firmness, elasticity, and chewiness of all samples (P˃0.05). However, after 8 days of storage, the total volatile base-nitrogen (TVB-N) content decreased from 40.11 mg N/100 g to 28.77, 32.54, and 32.22 mg N/100 g, respectively, in samples treated with the three types of electrolytic water. The content of thiobarbituric acid reactive substances (TBARS) decreased from 0.43 mg/100 g to 0.35, 0.41, and 0.38 mg/100 g, respectively, while the protein carbonyl value decreased from 1.63 nmol/mg to 1.35, 1.41, and 1.48 nmol/mg, respectively. Conversely, the thiol value increased from 6.83 nmol/mg to 7.35, 7.11, and 7.05 nmol/mg, respectively. Therefore, washing with electrolyzed water can effectively inhibit the degree of lipid and protein oxidation in fish. These findings provide a theoretical basis for the use of electrolyzed water to extend the storage period of pre-prepared fish dishes.
