Abstract This study evaluated the effect of including clove essential oil (EOcl) in Nile tilapia diets on animal performance and antioxidant power, lipid oxidation, gene expression, texture, pH, color and sensory analysis in fillets. Three levels of EOcl in the diets were evaluated (0.70, 1.05 and 1.40 g/kg), provided over three periods before slaughtering the animals (15, 45 and 60 days). The antioxidant power in the diets increased after including EOcl. There was an interaction effect between the level and period of inclusion of EOcl on the antioxidant power and lipid oxidation of fillets stored up to 14 days after slaughter. Lipid oxidation was reduced by 43.3% compared with the control group. EOcl inclusion in the diet, regardless of level and period, improved texture and promote less gene expression of catalase and glutathione synthetase. This demonstrates that the antioxidant in the tilapia diet acts against the oxidative stress process. Considering the results for the interactions and parameters evaluated, including 1.05 g/kg of clove essential oil in the rations for 15 days before slaughter is indicated because it contributes to a higher fillet quality.

ABSTRACT. Flaxseed oil is recognized as the plant source richest in α-linolenic acid, whereas clove leaf essential oil has a strong antioxidant capacity. The objective of this study was to determine the in vitro antioxidant capacity of diets containing a combination of flaxseed oil (FO) and clove leaf essential oil (CLEO), as well as to use zebrafish (Danio rerio) to assess their effect on the animals’ growth. Fifty days after hatching, a total of 420 male specimens (0.29 ± 0.04 g) were divided into seven groups for each diet and fed for 55 days to be used, with the diets being: control, absent FO and CLEO; 3% FO + 0.5% CLEO; 3% FO + 1% CLEO; 6% FO + 0.5% CLEO; 6% FO + 1% CLEO; 9% FO + 0.5% CLEO and 9% FO + 1% CLEO. Antioxidant activity was determined through DPPH (2,2-diphenyl-1-picrylhydrazyl) tests, showing interaction effect between factors (FO x CLEO, p < 0.05); the diets containing 1% combined with 3, 6 or 9% of FO presented means higher than those of the 0.5% diets. No mortality was observed during the experiment. For final weight and weight gain, there was no interaction effect (p > 0.05), only isolated effect for FO, with the fish fed 6 and 9% diets having the best results. Final total length and specific growth rates showed interaction effect (p < 0.05). As for specific growth rates, the best response was that of the diet with 6% FO and 0.5% CLEO. Final length showed increase with FO levels, even when there was association with 0.5 or 1% of CLEO. Therefore, combined use of 9% of FL with 0.5% of CLEO is recommended for zebrafish.

The investigation of the distribution of antioxidant compounds between emulsions phases, employing natural sources of these compounds directly in the emulsions, is rarely addressed. The use of ultra performance liquid chromatography coupled to a mass spectrometer (UPLC-MS), combined with accelerated oxidation tests and oxygen radical absorbance capacity method (ORAC), using the fluorescein (FL) decay curve (ORACFL) assay, enable an improved evaluation of the distribution of the antioxidant compounds and their lipid protection abilities. The lipid protection tendency observed was in agreement with the polar paradox theory. The ORACFL results reported here are higher than other reported in the literature, even when performing a sample extraction directly into one of the emulsion phases, thus demonstrating the effectiveness of this direct addition regarding the antioxidant activity. The analysis of the mass spectra of the emulsions enabled to verify the existence and distribution of some phenolic compounds in both phases. The direct extraction in the aqueous and oil phases of the emulsion increased, in a general way, the amount of identified compounds in each phase.

Omega-3 fish oil supplements are widely consumed as source of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, presenting beneficial effects on human health. This study aimed to evaluate fifteen brands of omega-3 fish oil supplements available in Brazilian market in order to estimate the Brazilian reality regarding those supplements. Twelve fatty acids were quantified by gas chromatography with a flame ionization detector (GC-FID), and lipid profile were obtained via mass spectrometry fingerprinting using direct electrospray ionization mass spectrometry (ESI-MS) to assess the form in which fatty acids are present as well as the possible fraud existence. Among all analyzed samples, thirteen brands were revealed as EPA and DHA sources (90.2-440.3 and 77.8-302.3 mg g-1lipid, respectively) in triacylglycerols (TAG) or ethyl esters (EE) form. However, two brands were discovered with addition of large amounts of soybean oil, leading the final consumer to ingest this low-cost oil believing that they are consuming adequate doses of EPA and DHA.

In this study, the fatty acid (FA) composition of the Japanese grape (Hovenia dulcis) seed oil (JGSO) was firstly evaluated. It was found that the seed oil is rich in alpha-linolenic acid (LNA), containing approximately 425 mg LNA g-1 of total lipids. A fish diet supplemented with JGSO was prepared and supplied to Nile tilapia to investigate the FA composition of the fillets. For this, Nile tilapia were submitted to two feeding treatments: a control diet with 4.2% of soybean oil, and a diet supplemented with 4.2% of JGSO. The LNA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) values increased significantly (406, 153 and 126%, respectively) with JGSO in the diet and with an increase in feeding time, while the nutritional quality indexes, n-6/n-3 ratio and index of thrombogenicity, decreased 2.8 and 1.4 times, respectively. Thus, the replacement JGSO in the diet raised the nutritional lipid quality in Nile tilapia.

Response surface methodology was used to optimize the total phenolic content (TPC) result in white rice, using a new methodology that employed Fast Blue BB (FBBB) reagent, which reacts more specifically with phenolic compounds, along with direct QUENCHER procedure. This is the first time in which such conciliation between FBBB reagent and QUENCHER was done. The obtained model allowed to evaluate how the factors influenced the method linearity (R2), improving the choice of the optimal system condition. Furthermore, the similarity between experimental results and values generated by the model indicated the method validity within the studied region. Thus, the optimal condition determined in the present work was 30 min reaction time, 0.17 mL FBBB reagent and use of 5% NaOH as the catalyst for the reaction. This optimized condition suggested that the combination of the method, which used FBBB reagent and the direct QUENCHER procedure, was rapid and effective, yielding high TPC values (1488.73 mg of gallic acid equivalent per 100 g).

The use of synthetic antioxidants in human consuming products is in disuse due to health toxic related issues. The search for substances to substitute synthetic antioxidants boosts studies concerned with the findings of sources of natural antioxidants. Thus, the aim of this work was to evaluate the use of comminuted leaves of rosemary (Rosmarinus officinalis L.) as source of natural antioxidants for the lipid protection of different emulsion compositions using central composite rotary experimental design. The Oxitest analysis (oxidation test reactor) revealed rosemary to be an excellent source of antioxidants for emulsions, even with addition of low quantities, and the gain of induction point tripled. The oxygen radical absorbance capacity (ORACFL) results of emulsion obtained separately for the hydrophilic and lipophilic phases showed that the presence of polar compounds was in higher concentration, about 500 more than of non-polar ones. The polar compounds are major responsible for the antioxidant action in the system.

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.

This study quantified the fatty acids and evaluated the proximate composition, antioxidant activity (using the Quencher procedure), and total phenolic compound concentrations in Brazilian rice cultivars. The cultivars studied showed high amounts of unsaturated fatty acids, such as linoleic and oleic acid. The ratios of polyunsaturated and saturated fatty acids obtained were high. Regarding the antioxidant activity, the best results were found using the ABTS method and the worst in the DPPH assay. The results of the DPPH and FRAP assays showed the highest correlation. The antioxidant capacity results obtained were also much higher than those reported for other varieties worldwide. Therefore, the Quencher procedure is highly suitable for application in cereals such as rice, especially when combined with the ABTS radical capture method.

O perfil de ácidos graxos (AG) é um parâmetro importante de qualidade e tipificação para alimentos em geral. Esses perfis funcionam como uma espécie de "impressão digital", e podem ser úteis para monitorar fraudes e deterioração em diversos tipos de alimentos. Para os óleos vegetais, o perfil de AG é geralmente determinado após hidrólise, metilação e análise por cromatografia gasosa (CG). Neste trabalho, a metilação do óleo de soja por métodos de catálise básica e ácida foi monitorada por CG-DIC e também por espectrometria de massas ambiente com ionização sonic-spray (EASI-MS). Os principais parâmetros monitorados por EASI-MS foram o perfil de AG e a possível geração de hidroperóxidos dos ésteres metílicos, que foram comparados. O método catalisado por base mostrou-se superior em relação aos demais, por ser mais barato, menos tóxico, não originar produtos de oxidação e ter maior rendimento (95,66% m/m contra 92,86% e 94,51% dos métodos catalisados por ácido).

The fatty acids (FA) profile is an important parameter for quality control and typification for foods in general. These profiles work as a sort of "fingerprint", and may be useful to monitor frauds and deterioration of diverse types of foods. For vegetable oils, the FA profile is commonly determined after hydrolysis, methylation and gas chromatography (GC) analysis. In this work, the acid and base-catalyzed soybean oil methylation methods was monitored via GC-FID and also by ambient sonic-spray ionization mass spectrometry (EASI-MS). The base-catalyzed method is much superior regarding other esterification assays, because it is cheaper, less toxic, no oxidation products are formed and its reaction yield is greater (95.66% m/m against 92.86% and 94.51% from acid-catalyzed methylation methods, respectively).

Este estudo avaliou a composição centesimal de ácidos graxos e a atividade antioxidante total de pães utilizando um design Box-Behnken composto de quinze experimentos e três fatores. Os pães estudados tiveram parte do seu tempo de cozimento alterado, assim como parte da sua farinha de trigo substituída por sementes de chia e folhas de cenoura. Os resultados de capacidade antioxidante de cada experimento foram superiores aos obtidos para um pão controle (495,33 µmol TEAC g-1 para ensaio DPPH e 413,85 µmol TEAC g-1 para ensaio FRAP), mostrando níveis de aumento de até 97 e 102% para os ensaios DPPH e FRAP, respectivamente. Os pães modificados também mostraram aumentos de até 216,69 e 18,88% na quantidade de ácido alfa-linolênico e na razão PUFA:SFA, respectivamente, em relação ao mesmo pão controle (este com 34,03 mg g-1 de ácido alfa-linolênico e razão de 2,86), bem como máxima redução de 70,01% na razão omega-3:omega-6 (15,59 para o pão controle).

This work determined the proximate/fatty acid composition and the antioxidant activity of breads using a Box-Behnken design composed of fifteen experiments and three factors. The studied breads had altered baking times and the wheat flour was partially substituted by chia seeds and carrot leaves. Total antioxidant capacity results were superior to those obtained from control bread (495.33 µmol TEAC g-1 for DPPH assays and 413.85 µmol TEAC g-1 for FRAP assays), showing increased levels of 97 and 102% for DPPH and FRAP assays, respectively. The addition of chia seeds and carrot leaves led to maximal alpha-linolenic acid increase of 216.69% and maximum PUFA:SFA ratio increase of 18.88% in relation to control bread (this with alpha-linolenic acid amount of 34.03 mg g-1 total lipid and a 2.86 ratio value), as well as a maximum omega-3:omega-6 ratio reduction of 70.01% (15.59 ratio value for control bread).