Impact of pulsed electric field and vacuum impregnation with Chamuang leaf extract on quality changes in Pacific white shrimp packaged under modified atmosphere

Abstract

Vacuum impregnation-assisted penetration with Chamuang leaf extract (CLE; 1–2 g/100 ml) using 5 kPa absolute of vacuum, 7.5/15 min vacuum time and 15/22.5 min restoration time was studied in Pacific white shrimp subjected to prior pulsed electric field (PEF) before storage at 4 °C in modified atmosphere packaging (Ar/air; 80: 20). Lowest melanosis scores were obtained for samples treated with PEF (15 kV/cm, 800 pulses, 18 kJ/kg) and CLE (2 g/100 ml) with a 15 min vacuum time and 15 min restoration time and kept under an Ar/air atmosphere for 18 days. The control (untreated, kept in air) showed more melanosis during 18 days than treated samples (P < 0.05). Lower bacterial counts were attained in samples vacuum-impregnated with 2 g/100 ml CLE with prior PEF and stored under an Ar/air atmosphere (P < 0.05). These samples had lowest lipid oxidation, pH, total volatile bases and protein carbonyl content (P < 0.05). Higher liking scores for all attributes were noted in PEF-treated and vacuum-impregnated CLE (2 g/100 ml) samples. Thus, shrimp treated with CLE with the aid of combined processes and packaging had a shelf-life up to 18 days.