Impact of varying sodium bicarbonate concentrations on carp skin structure and carcass pH

Abstract This preliminary study investigated the effects of washing common carp ( Cyprinus carpio ) carcasses with different concentrations of sodium bicarbonate solution (0%, 2%, 5%, and 7%) on skin morphology and carcass pH levels, which could potentially affect shelf life for consumers. Skin biopsies were analyzed histologically using AB/PAS staining, and pH was measured during a seven-day storage period under refrigerated conditions. Results showed that increasing sodium bicarbonate concentrations led to progressive skin degeneration, with the 5% and 7% groups showing the most superficial loss of the epithelial layer. However, no statistically significant differences were observed among the groups. Washing fish carcasses with sodium bicarbonate solution is a promising way to reduce the amount of mucus on the surface and in the fish skin, which could potentially extend the storage life of carp meat. However, further microbiological studies are needed to confirm these preliminary findings and to investigate the optimal concentration and duration of washing with sodium bicarbonate for different fish species, as well as its impact on the product’s sensory qualities and nutritional value.