Oscar O. Santos Júnior

Antioxidant capacity and chemical composition in seeds rich in omega-3: chia, flax, and perilla

The chemical composition and antioxidant capacity of five seeds, chia, golden flax, brown flax, white perilla, and brown perilla, were determined. The chemical properties analyzed included moisture, ash, crude protein, carbohydrates, total lipids, fatty acids, and antioxidant capacity (ABTS•+, DPPH•, and FRAP). The results showed the highest amounts of protein and total lipids in brown and white perilla. Perilla and chia showed higher amounts of alpha-linolenic fatty acid than those of flaxseed varieties, ranging between 531.44 mg g-1 of lipids in brown perilla, 539.07 mg g-1 of lipids in white perilla, and 544.85 mg g-1 of lipis in chia seed. The antioxidant capacity of the seeds, evaluated with ABTS•+, DPPH• , and FRAP methods, showed that brown perilla had greater antioxidant capacity when compared with white perilla, flax, and chia seeds.

Composição centesimal e perfil de ácidos graxos do camarão-d'água-doce

The aim of this work was to determine the centesimal composition and fatty acids profile of freshwater prawn (Macrobrachium amazonicum) for determination of its nutrient potential. Six lots (each one with 100 g) containing whole prawns with individual mass ranging from 0.9 to 1.2 g were triturated and stored for posterior chemical analysis. The average values for moisture, ash, CP and total lipids were as follows: 70.3, 1.5, 24.8, and 1.5%, respectively. It was detected 36 varieties of fatty acids, and the most abundant was the palmitic -16:0 acid with 18.2%. The major omega-3 fatty acids were: eicosapentaenoic-20:5n-3, dihomo-alpha-linolenic-20:3n-3, docosahexaenoic-22:6n-3 and alpha-linolenic-18:3n-3 with frequencies of 13.9, 9.5, 6.8, and 4.2%, respectively. The total frequencies of fatty acids were of 36.9% for omega-3 and 46.8% for polyunsaturated fatty acids. The omega-6/omega-3 (n-6/n-3) ratio and polyunsatured to satured (PUFA/SFA) ratio were of 0.3 and 1.6, respectively. All parameters indicated a good nutritional value of the M.amazonicum meat.

Antioxidant capacity, total phenolic content, fatty acids and correlation by principal component analysis of exotic and native fruits from Brazil

The antioxidant capacities of seven exotic and native fruits from Brazil were evaluated using DPPH•, ABTS•+ and FRAP assays, in addition to their total phenolic content and fatty acid composition. Murici and dovialis presented the highest total phenolic contents (243.42 and 205.98 mg GAE 100 g-1, respectively), and the highest antioxidant capacities by the FRAP assay (24.97 and 23.70 µmol Fe2+ g-1, respectively). In the DPPH• and ABTS•+ assays, dovialis presented the highest antioxidant capacity, 9.59 and 10.41 TE g-1, respectively. The highest alpha-linolenic and linoleic acid contents were found in siriguela (107.86 mg FA g-1 TL) and tomatinho do mato (215.50 mg FA g-1 TL), respectively. The principal component analysis (PCA) of fatty acids yielded three significant PCs, which accounted for 99.75% of the data set total variance. The PCA data of the antioxidant analyses yielded two significant PCs, which accounted for 97.00% of the total variance.

A simple, fast and efficient method for transesterification of fatty acids in foods assisted by ultrasound energy

E altamente desejavel desenvolver testes analiticos com resultados de elevada qualidade e reduzir o tempo que e utilizado para esta finalidade. Neste contexto, um novo metodo de metilacao de acidos graxos assistido por ultra-som, rapido e eficiente para obtencao de esteres com melhor qualidade para analise de alimentos, foi otimizado e validado atraves da aplicacao da metodologia de superficie de resposta, sendo obtido um tempo de esterificacao ideal de 11,72 min, 71% mais rapido do que o melhor metodo, que e comumente utilizado para esta finalidade. O novo processo de metanolise pode ser eficazmente aplicado a amostras com acidos graxos livres e os teores de umidade superior a 10 e 5%, respectivamente, sem o risco de oxidacao de compostos durante o processo.

A new method for lipid extraction using low-toxicity solvents developed for canola (Brassica napus L.) and soybean (Glycine max L. Merrill) seeds

Soybean (Glycine max L.) and canola (Brassica napus L.) seeds contain polyunsaturated fatty acids such as omega-3 and omega-9, which are important for the prevention of cardiovascular disease and the control of LDL cholesterol, leading to scientific interest in extracting and characterizing these lipids. To prevent the degradation of polyunsaturated fatty acids, lipid extraction should be done cold. A “new-method” for cold lipid extraction has been developed, which uses low toxicity solvents such as hexane and ethanol. This method aims to replace chloroform and methanol widely used in the Bligh & Dyer method. By employing the new method, which uses ethanol, hexane and water in the ratio of 2.5 : 2.5 : 1, an average of 28% canola and 16% soybean total lipids were extracted, and the mono- and polyunsaturated fatty acids did not suffer degradation. The amount of lipid extracted by the new method was compared with the Soxhlet and Bligh & Dyer methods. The new method uses low-toxicity solvents for lipid extraction, and the accuracy values range between 103.33% and 107.51%, proving it to be an efficient method.

Incorporation of conjugated fatty acids into Nile tilapia (Oreochromis niloticus)

BACKGROUND The aim of this work was to improve the nutritional quality of Nile tilapia meat through enriched diets with conjugated isomers of linolenic acid from tung oil. The transfer process of conjugated fatty acids (CFAs) into fish muscle tissue was evaluated by gas chromatography-flame ionization detection (GC-FID) and easy ambient sonic-spray ionization mass spectrometry (EASI-MS). RESULTS The results showed that conjugated fatty acids were transferred from enriched diet for muscle tissue of Nile tilapia. Conjugated linoleic acids biosynthesis from conjugated linolenic acids was also observed after 10 days. Other important fatty acids such as docosahexaenoic (DHA), eicosapentaenoic (EPA) and arachidonic (AA) acids were also identified over time; however, DHA showed the highest concentration when compared with EPA and AA compounds. CONCLUSION Therefore, the nutritional quality of Nile tilapia was improved through feeding with enriched diets. The ingestion of these fish may contribute to reaching adequate levels of daily CFA consumption. Furthermore, other important substances which play an important role in human metabolism, such as EPA, DHA and AA, can also be ingested together with CFA.

Rapid methodology via mass spectrometry to quantify addition of soybean oil in extra virgin olive oil: A comparison with traditional methods adopted by food industry to identify fraud

Fast and innovative methodology to monitors the addition of soybean oil in extra virgin olive oil was developed employing ESI-MS with ionization operating in positive mode. A certified extra virgin olive oil and refined soybean oil samples were analyzed by direct infusion, the identification of a natural lipid marker present only in soybean oil (m/z 886.68 [TAG+NH4]+) was possible. The certified extra virgin olive oil was purposely adulterated with soybean oil in different levels (1, 5, 10, 20, 50, 70, 90%) being possible to observe that the new methodology is able to detect even small fraud concentration, such as 1% (v/v). Additionally, commercial samples were analyzed and were observed the addition of soybean oil as a common fraud in this segment. This powerful analytical method proposed could be applied as routine analysis by control organization, as well as food industries, considering its pronounced advantages; simplicity, rapidity, elevated detectability and minor amounts of sample and solvent consumed.

Determination of trans-resveratrol in Solanum americanum Mill. by HPLC

Abstract Solanum americanum Mill. is a plant that belongs to the Solanaceae family, its respective ripe fruit is dark purple. Ripe S. americanum Mill. fruits were submitted to physicochemical characterisation, and their trans-resveratrol contents were quantified by high-performance liquid chromatography. Such determination was executed with fruits at different stages of ripeness and freeze-stored fruits as well. In natura ripe fruit pulp and peel presented average trans-resveratrol amounts of 1.07 and 0.7960 μg per gram of sample, respectively. These amounts are significantly higher when compared to freeze-stored fruit (0.1353 μg of trans-resveratrol per gram of sample) and to other berries. All ripe fruits showed significant amounts of total anthocyanins and total antioxidants. Thus, for the first time, trans-resveratrol has been identified and quantified in S. americanum Mill. fruit samples.

Fast derivatization of fatty acids in different meat samples for gas chromatography analysis

In order to analyze the composition of fatty acids employing gas chromatography as the separation method, a derivatization of lipids using esterification and transesterification reactions is needed. The methodologies currently available are time consuming and use large amounts of sample and reagents. Thus, this work proposes a new procedure to carry out the derivatization of fatty acids without the need for prior extraction of lipids. The use of small amounts of sample (100mg) allows the analysis to be performed in specific parts of animals, in most cases without having them slaughtered. Another benefit is the use of small amounts of reagents (only 2mL of NaOH/Methanol and H2SO4/Methanol). The use of an experimental design procedure (Design Expert software) allows the optimization of the alkaline and acid reaction times. The procedure was validated for five minutes in both steps. The method was validated for bovine fat, beef, chicken, pork, fish and shrimp meats. The results for the merit figures of accuracy (from 101.07% to 109.18%), precision (RSDintra-day (from 0.65 to 3.93%), RSDinter-day (from 1.57 to 5.22%)), linearity (R(2)=0.9864) and robustness confirmed that the new method is satisfactory within the linear range of 2-30% of lipids in the sample. Besides the benefits of minimizing the amount of samples and reagents, the procedure enables gas chromatography sample preparation in a very short time compared with traditional procedures.

Fish oil supplementation reverses behavioral and neurochemical alterations induced by swimming exercise in rats

Diet and exercise are known to affect learning and memory. However, the effects of these interventions in the brain under development remains to be better investigated as the effects of high-intensity exercise. Moreover, it is still unclear how long the influence of diet and exercise lasts after the interventions are ceased. To investigate this, juvenile Wistar rats (30 days old) were supplemented with fish oil rich in polyunsaturated fatty acids (PUFAs) and performed swimming training for 50 days, 45 min per day, 5 times/week. The animals were assessed for locomotor activity with the open field test and for spatial memory with the object location task. To investigate neurochemical parameters such as fatty acids incorporation within the plasma membrane and brain-derived neurotrophic factor (BDNF) levels, the animals were euthanized, and the hippocampus dissected. These investigations were made at the end of the supplementation and exercise protocols and 21 days after the protocol has ended. Results indicate that high-intensity exercise impaired the spatial memory and decreased the levels of BDNF. Although supplementation led to PUFAs incorporation in plasma membrane, it did not prevent the harmful effect of exercise on memory. After 21 days of interruption, we observed that the supplementation reversed not only the deleterious effect of exercise on memory but also increased the BDNF levels. These results point to a complex influence of diet and exercise on spatial memory of juvenile rats, persisting after 21 days of interruption.