This study evaluated the incorporation of β-carotene, lutein and lycopene into tilapia (genetically improved farmed tilapia, GIFT) fillets supplemented through 0, 20 and 40 days, and their influence on the fatty acid composition and nutritional quality of raw and grilled fillets. A control diet and a diet containing those carotenoids were elaborated with the same lipid source (soybean oil). For carotenoids analysis, the extraction was performed according to the literature, employing acetone and hexane. The relative intensities of m/z ratios of those carotenoids ions were obtained by ultraperformance liquid chromatography-tandem mass spectrometry with chemical ionization at atmospheric pressure (UPLC-APCI MS/MS), and an increase of carotenoid concentration in the supplemented fillets was observed, especially after the grilling process (180 ºC for 15 min). An increase in the concentration of total carotenoids in grilled fillets (75 and 35% higher than raw fillets, for 20 and 40 days of supplementation, respectively, corresponding to 8.32 and 2.42 µg β-carotene g-1 sample) was also observed. Therefore, the carotenoids promoted the stability of lipid oxidation in grilled samples; fact that can be correlated with antioxidant effect of these compounds, it can be also explained by the breakdown of carotenoids physical barrier and the conditions used in the grilling process. Moreover, acceptable n-6/n-3 indices and recommended polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) values were observed in supplemented fillets. Consequently, lutein, β-carotene and lycopene were considered viable as additive on fish diet, since the supplementation promoted the increase of food quality, even after preparation for consumption.

A 22 factorial design (two factors with two levels, in triplicate) was performed to investigate the influence of factors A (soybean oil content in supplemented diet, at 2.1 and 4.2%) and B (time of treatment, 15 and 30 days) in three responses [(a) total n-3 fatty acids; (b) n-6/n-3 ratio; and (c) polyunsaturated fatty acids (PUFA)/saturated fatty acids (SFA) ratio] from lipids of Nile tilapia submitted to experimental treatment. Normality of residuals was assessed through statistical tests. Factors A and B were significant in all obtained regression models, while AB interaction was not a significant contributor for PUFA/SFA response. ANOVA and response surfaces obtained from factorial design indicated best results in tilapia that received the diet containing 4.2% of soybean oil during 30 days.

Este trabalho avaliou o efeito da suplementação com extrato etanólico de resíduo de acerola (EEAR) na capacidade antioxidante de filés de tilápias no intervalo de 60 dias. Diferentes metodologias foram utilizadas seguindo procedimento QUENCHER e foram analisadas as frações hidrofílicas e lipofílicas do ensaio de capacidade de absorção de oxigênio radical (ORAC FL). A composição em ácidos graxos também foi avaliada, sendo observadas elevadas concentrações dos ácidos linoleico e oleico nos filés, assim como, razões ácidos graxos poli-insaturados/ácidos graxos saturados (PUFA/SFA) satisfatórias. Os maiores valores de capacidade antioxidante nos ensaios 2,2-difenil-1-picrilhidrazil (DPPH) e capacidade redutora de ferro (FRAP) (1778,87 e 4892,77 µmol capacidade antioxidante equivalente ao Trolox (TEAC) g-1, respectivamente) foram encontrados em 15 dias e esses ensaios apresentaram o maior valor de correlação (R = 0,9388). O ensaio ORAC FL indicou que a fração hidrofílica é a maior contribuinte na capacidade antioxidante total (TAC). Dessa forma, o significativo aumento observado na capacidade antioxidante torna a suplementação com EEAR uma potente ferramenta na elevação da capacidade antioxidante dos filés.

This work evaluated the effect of supplementation with ethanolic extract of acerola fruit residue (EEAR) on the antioxidant capacity of tilapia fillets over a period of 60 days. Different methodologies were used following the QUENCHER procedure, and the hydrophilic and lipophilic fractions of the oxygen radical absorbance capacity (ORAC FL) assay were analysed. The fatty acid composition was also evaluated, as high concentrations of linoleic and oleic acids were observed in the fillets, as well as satisfactory polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) ratios. The highest antioxidant capacities in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays (1778.87 and 4892.77 µmol Trolox equivalent antioxidant capacity (TEAC) g-1, respectively) were found at 15 days, and these trials showed the highest correlation coefficient (R = 0.9388). The ORAC FL assay indicated that the hydrophilic fraction is the largest contributor to the total antioxidant capacity (TAC). Thus, the significant increase observed in antioxidant capacity makes supplementation with EEAR a potent tool in the elevation of the antioxidant capacity of tilapia fillets.