Freshness and Nutritional Composition of Several Species of Chilled Seafood Marketed in Luanda (Angola) and in Faro (Portugal)

Abstract

Given that the chemical composition of seafood species reflects the conditions characterizing their geographic area of origin, this study aims to describe and compare the nutritional composition of several seafood species marketed in Luanda (Angola) and in Faro (Portugal), namely octopus (Octopus sp.), large-eye dentex (Dentex macrophthalmus), hake (Merluccius sp.) and barracuda (Sphyraena guachancho). In addition, a sensory-based methodology (the Quality Index Method, QIM) was carried out and a set of physicochemical parameters (pH, total volatile basic nitrogen (TVBN) and thiobarbituric acid reactive substances (TBARS)) were determined to assess the degree of freshness and quality of the different species. The results showed that location significantly (t-test, p < 0.05) influences some parameters of the nutritional composition, viz. moisture, protein content and lipid content. Quality indexes (QI) resulting from sensory analyses using QIM schemes were less than five (out of a maximum of 16–19 demerit points) indicating seafood’s high quality. In terms of physicochemical quality parameters, the values of pH varied between 6.11 for octopus and 6.78 for large-eye dentex, TVBN content ranged from 5.4 mg N/100 g for octopus and 9.6 mg N/100 g for barracuda in Luanda, and TBARS concentrations varied between 0.43 mg MDA/kg for large-eye dentex in Faro and 2.09 mg MDA/kg for hake in Faro. For every species studied the values were well below acceptable limits for consumption considering EU regulations (25–35 mg N/100 g for TVBN) and literature (7-8 µg MDA/g for TBARS), both in Luanda and in Faro. This study provides original results about nutritional composition and sensory and physicochemical indicators of seafood freshness and quality for the studied species in Luanda.