Slaughtering procedures on the flesh quality of frozen stored pacu

Pamela Jenny Montes Girao,Mariza Pires De Melo,Elisabete Maria Macedo Viegas,Humber Agrelli De Andrade,Paulo Roberto Campagnoli De Oliveira Filho

doi:10.5935/1806-6690.20210015

Pamela Jenny Montes Girao, Mariza Pires De Melo + Show 3 more

Open Access

https://doi.org/10.5935/1806-6690.20210015

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Abstract

Pacu ( Piaractus mesopotamicus ) is one of the most important fish farmed species in Brazil due to its hardy, fast growing, omnivorous feeding behavior, and good consumers acceptance. However, studies on the effect of different slaughtering procedures on quality of frozen pacu fillets have not been carried out. Therefore, this study aimed to evaluate the effect of electrical stunning, CO 2 narcosis, or water/ice immersion on the quality (lipid oxidation - TBARS, protein oxidation - carbonyl and thiols, protein denaturation, and instrumental color – L*, a*, and b*) of frozen (-18 °C) pacu fillets stored for up to 6 months. Electrical stunning became the fillets darker and red, besides leading to higher protein oxidation (carbonyl and thiols), and protein denaturation. CO 2 narcosis resulting in more pale flesh, with higher protein oxidation. The slaughtering by water/ice immersion was the best alternative for obtaining high quality frozen pacu fillets with lower oxidation and protein denaturation. A quality loss was observed for all pacu fillets stored at -18 °C over the months, as evidenced by the increase in lipid and protein oxidation, color changes, and higher protein denaturation. Additionaly, a maximum storage period of 3 to 4 months is recommended for frozen pacu fillets

Highlights

Cold shock by ice water immersion is a slaughtering method widely used by fish processing industries in Brazil, and has been the subject of studies about flesh quality of fresh water (OLIVEIRA FILHO et al, 2015), and marine fish species (ALVAREZ et al, 2008)
A decrease (P < 0.05) in carbonyl values was observed during frozen storage of pacu fillets subjected by electrical stunning (ES), with few variations in fish slaughtered by IW or CO2 narcosis (CN) (Figure 2a)
Differences in b* values were not observed in several species, including Nile tilapia (Oreochromis niloticus) slaughtred by CO2 narcosis or water/ice immersion (OLIVEIRA FILHO et al, 2015), turbot (Psetta maxima) slaughtered by bleeding, electric shock or cranial percussion

Summary

INTRODUCTION

Cold shock by ice water immersion is a slaughtering method widely used by fish processing industries in Brazil, and has been the subject of studies about flesh quality of fresh water (OLIVEIRA FILHO et al, 2015), and marine fish species (ALVAREZ et al, 2008). Another slaughtering procedure studied is the immersion in CO2 saturated water (OLIVEIRA FILHO et al, 2015; VARGAS et al, 2013). The aim of this study was to evaluate the effect of slaughtering methods on physicochemical variables of pacus fillets kept frozen at -18 °C for up to 6 months

MATERIAL AND METHODS

AND DISCUSSION

Findings

CONCLUSIONS