Effect of pulsed electric field treatments on melanosis and quality changes of Pacific white shrimp during refrigerated storage

摘要

Pacific white shrimps were subjected to the pulsed electric field (PEF) at varyingspecific energy densities (54–483 kJ/kg) and pulse numbers (200–600). The polyphenoloxidase (PPO) activity in cephalothorax was decreased as both parametersincreased (p < .05). Shrimp treated with PEF at highest level (PEF‐T3) (483 kJ/kg, 600pulses) had lower melanosis score than other samples, packaged in polystyrene traysand wrapped with shrink film, during 10 days of storage at 4℃ (p < .05). Highestshear force values were noticed for the PEF‐T3‐treated sample at Day 10 (p < .05).Microstructural gaping between shrimp muscle fibers was higher in PEF‐T3. No proteindegradation was observed for all samples, regardless of PEF treatments. Lowermesophilic and psychrophilic microbial counts in shrimp were obtained when PEF‐T3was implemented. After 10 days, higher sensory scores of PEF‐T3‐treated sampleswere attained, compared to others (p < .05). Quality deterioration of shrimp wastherefore retarded with PEF.Practical applicationsPacific white shrimp is an economically imporatnt crustacean, which undergoes discoloration(melanosis) during the extended storage. Melanosis, in which the formationof a black spot occurs as triggered by polyphenol oxidase, is the major problem in theshrimp industry. It is of primary concern to delay melanosis associated with qualityloss. Pulsed electric field (PEF) can significantly inactivate shrimp polyphenol oxidaseand spoilage causing microorganisms. PEF is additive‐free and nonthermal technologythat does not alter the organoleptic properties of shrimp. Industrially, PEF can serveas a promising and eco‐friendly technology for the prevention of quality loss in shrimp.