Melanosis and quality changes during refrigerated storage of Pacific white shrimp treated with Chamuang (Garcinia cowa Roxb.) leaf extract with the aid of pulsed electric field

Pacific white shrimp with prior pulsed electric field (PEF) treatment before soaking in Chamuang leaf extract (CLE) at different concentrations (0.5 and 1%) for 30 min were prepared. Sample pre-treated with PEF and soaked with 1% CLE (PEF-1 CLE) showed lower melanosis score than that with 1.25% sodium metabisulfite treatment, PEF treated sample or those soaked in CLE without prior PEF and the control during storage of 10 days (P < 0.05). PEF-1 CLE sample showed lower total volatile base content, peroxide value and thiobarbituric acid reactive substances but high sensory scores than others (P < 0.05). Lower increases in mesophile, psychrophile, Pseudomonas, Enterobacteriaceae and H2S producing bacterial counts were obtained in PEF-1 CLE, compared to the control and other treated samples. The most abundant compounds from Chamuang leaf extract, including Chrysoeriol 6-C-glucoside-8-C-arabinopyranoside and veranisatin-C were found in PEF-1 CLE sample and were plausibly involved in keeping quality of shrimp.