Oxidative and microbial stability of sea bass fillets containing Padina gymnospora extract stored under frozen conditions

This study evaluated the antioxidant and antimicrobial activities of ethanolic extracts from five species of red and brown algae. The best algae were used to prepare an edible coating for sea bass (Centropomus undecimalis) fillets. The species Padina gymnospora was chosen for the application of the edible coating, as it presents greater efficiency in in vitro tests. The fillets were divided into four groups: SA1% + PG (1% sodium alginate solution + 20 mg mL of Padina gymnospora), SA1% + BHT (1% sodium alginate solution + 100 mg mL of butylated hydroxytoluene), SA1% (control) and uncoated fillets. The SA1% + PG group showed lesser lipid oxidation (0.80 ± 0.08 mg MDA kg) than the uncoated group (2.10 ± 0.36 mg MDA kg), without statistical difference from the value observed for containing BHT group (0.94 ± 0.07 mg MDA kg). At 120 days, the group SA1% + PG reduced the count of psychrotrophic bacteria by 2-log cycles (p < 0.05). The colour of samples from SA1% + PG group was statistically different from that of other groups (p < 0.05), and influenced the acceptability of the coated fillets. The edible coating containing P. gymnospora extract may have potential application for the storage of perishable products such as fish, owing to its ability to reduce microbial load and lipid oxidation.