Common carp (Cyprinus carpio) aquaculture is one of the most important and rapidly growing productions around the world. However, for consumers, carp is often not acceptable due to its distinctive colour and odour. In this study, we investigated the effects of bleeding of common carp on fillet quality. The obtained results show that carp bleeding by cutting the gill arches is an effective way of reducing the total haem content, which here decreased from (9.6±1.6) in unbled carp to (2.34±0.8) μmol/kg of haemoglobin in bled carp. Furthermore, fillets from bled carp showed reduced formation of primary and secondary lipid oxidation products and growth of microorganisms during 12 days of refrigerated aerobic storage. On the last day of storage, the amount of lipid hydroperoxides decreased from (88.9±4.2) in unbled to (62.1±2.9) μmol/kg of cumene hydroperoxide in bled carp, TBARS decreased from (4.2±0.5) in unbled to (2.6±0.4) μmol/kg of malondialdehyde in bled carp, mesophilic and psychrotrophic bacteria count decreased from (6.4±0.1) and (6.2±0.3) log CFU/g in unbled to (4.0±0.2) and (4.2±0.2) log CFU/g in bled carp, respectively. These raw bled fillets showed increased lightness L*, and reduced redness a* and yellowness b* compared to unbled fillets. Sensory analysis showed improved colour, odour and overall acceptability of bled raw fillets. Overall, bleeding improves the quality of carp fillets. Thus, inclusion of bleeding into processing of carp fillets has the potential to improve their acceptance by consumers and prolong their shelf-life.
Keywords: bleeding; colour; common carp; lipid oxidation; microbiological quality; sensory quality.