Fatty acids and nutrients in the flour made from tilapia (Oreochromis niloticus) heads

The objective of this work was to analyze the fatty acid composition and nutrient potential of flour made from tilapia heads, which are normally discarded during the filleting operation. Significant differences were found between the proximate composition (moisture, ash, protein and total lipids) of the in natura tilapia and the flour, due to the drying process. The predominant fatty acids in the heads (in natura and in the flour) were palmitic acid (1,999 mg.100 g-1 and 7,699 mg.100 g-1, respectively), oleic acid (3,128 mg.100 g-1 and 11,447 mg.100g-1, respectively), and linoleic acid (1,018 mg.100 g-1 and 3,784 mg.100 g-1, respectively). The results lead us to conclude that tilapia head flour offers high levels of protein (38.41%), total lipids (35.46%), and ash (minerals) (19.38%). The content of omega-3 (731 mg.100 g-1) were proved to be satisfactory. Also, n-6/n-3 ratio was 6.15 and PUFA/SFA ratio was 0.47, which are in agreement with the recommended levels. Thus, tilapia heads can be used as a low-cost raw material for food fit for human consumption.

Characterization of a hydrolyzed oil obtained from fish waste for nutraceutical application

The fish industry generates high volume of waste from fish oil that can have the extraction of its lipids used as nutraceuticals and foods. The objective of this study was to produce unsaturated fatty acids from industrialized fish oil by means of a differentiated hydrolysis process. The samples used were crude fish oil obtained from Campestre industry and characterized through physical-chemical parameters, according to AOCS: acidity, peroxide, saponification, iodine and percentage of free fatty acids and also obtained the fatty acid profile through derivatization method for gas chromatography. The results obtained for the oleochemical indices for refined oil were similar to the data found on the literature. The content of polyunsaturated fatty acids (PUFA) was found of 32,78%, with 9,12% of docosahexaenoic (DHA) and 10,36% of eicosapentaenoic (EPA), regarding monounsaturated fatty acids (MUFA) content was of 30,59% in the hydrolyzed fish oil in relation to refined (20,06%). Thus, it can be concluded that the hydrolysis process used for oils from fish-waste was satisfactory on the production of absolute yield of lipids in the process and significant preservation on the percentages of EPA and DHA, interesting on the production of nutraceuticals and nutrition of aquatic animals, including shrimp in captivity.

Effect of different substrates in aquaponic lettuce production associated with intensive tilapia farming with water recirculation systems

ABSTRACT The integration of fish farming in intensive system and plant production, called "aquaponics" is practiced successfully in countries like the USA, Australia and Europe. In Brazil, this integration has attracted the attention of researchers and producers. In this context, the aim of this study was to evaluate the effect of two substrates (crushed stone number 3, CS III and flexible polyurethane foam, FPF) on the production of aquaponic lettuce, moreover, to show that the residual water from intensive tilapia production provides sufficient qualitative characteristics for competitive production of lettuce without adding commercial fertilizers. The treatment in which FPF was used provided higher concentrations of macro and micronutrients in the shoots, higher production of fresh matter of shoots (95.48 g plant-1) and a larger number of leaves (14.90) relative to CS III. These results were attributed to the lower post-transplanting stress and the higher water retention time provided by the FPF. The residual water from tilapia intensive farming can provide sufficient nutrients for the production of lettuce, making the supplementary fertilization with commercial products unnecessary. Thus, the FPF presents the most suitable conditions to be used as substrate in aquaponics system with recirculation of the residual water from the intensive tilapia farming.

Nutritional aspects of nile tilapia (Oreochromis niloticus) silage

One third of the world's fishing produce is not directly used for human consumption. Instead, it is used for making animal food or is wasted as residue. It would be ideal to use the raw material thoroughly and to recover by-products, preventing the generation of residues. With the objectives of increasing the income and the production of the industry, as well as minimizing environmental and health problems from fish residue, chemical silage from Tilapia (Oreochromis niloticus) processing residues was developed after homogenization and acidification of the biomass with 3% formic acid: propionic, 1:1, addition of antioxidant BHT and maintenance of pH at approximately 4.0. Analyses to determine the moisture, protein, lipids and ash were carried out. The amino acids were examined in an auto analyzer after acid hydrolysis, except for the tryptophan which was determined through colorimetry. The tilapia silage presented contents that were similar to or higher than the FAO standards for all essential amino acids, except for the tryptophan. The highest values found were for glutamic acid, lysine and leucine. The results indicate a potential use of the silage prepared from the Nile tilapia processing residue as a protein source in the manufacturing of fish food.

Thermal properties of defatted meal, concentrate, and protein isolate of baru nuts (Dipteryx alata Vog.)

Baru (Dipteryx alata Vog.), a species of legume found in the Brazilian savannas, was investigated in this study for the composition of its flesh and seed. Thermal analyses, Thermogravimetry (TG), and Differential Scanning Calorimetry (DSC) were used to investigate the proteins in defatted meal, concentrate, and protein isolate. The protein concentrate was extracted at pH 10, followed by a precipitation at the isoelectric point to obtain the isolate that was spray dried. The thermogravimetric curves were obtained under a nitrogen atmosphere with a 100 mL/minutes flow. The initial, final and peak temperatures and mass loss were analyzed. Within the performed temperature ranges studied, the defatted meal and concentrate presented four steps of mass loss, while the isolate showed only two steps. The protein content of defatted meal from Baru nuts was higher than that of the isolate. On the other hand, there was a reduction in enthalpy, which suggests that the process applied to obtain the baru concentrate and isolate led to protein denaturation.

Extruded snacks with the addition of different fish meals

Abstract Tilapia, salmon, tuna and sardine meals were prepared to develop and analyze extruded snacks with residue meal from fish processing. Residue meals were included in five types of corn snacks: control (0% fish meal) and four with 9% tilapia, salmon, tuna and sardine meals. Although moisture, lipids and carbohydrates rates did not differ among the snacks, protein rates increased with the increment of fish meal, reaching 11.85% in the tuna snack. Tuna and sardine snacks had the highest iron levels. The most abundant fatty acids were linoleic, oleic, palmitic, linolenic and stearic acids, with sardine, salmon and tuna snacks presenting the highest values of n-3 series fatty acids. Greater luminosity rate was reported for salmon snack, followed by tilapia, tuna and sardine snacks. The highest sensory acceptance index was verified in tilapia (78.07%) and salmon (72.40%). A 9% addition of residue meals of tilapia, salmon and tuna improved the nutritional value of the snacks.

Multivariate study of Nile tilapia byproducts enriched with omega-3 and dried with different methods

Abstract The present work aimed at studying the effect of different drying methods applied to tilapia byproducts (heads, viscera and carcasses) fed with flaxseed, verifying the contents of omega-3 fatty acids. Two diets were given to the tilapia: a control and a flaxseed formulation, over the course of 60 days. After this period, they were slaughtered and their byproducts (heads, viscera and carcasses) were collected. These fish parts were analyzed in natura, lyophilized and oven dried. Byproducts from tilapia fed with flaxseed presented docosapentaenoic, eicopentaenoic and docosahexanoic fatty acids as a result of the enzymatic metabolism of the fish. The byproducts from the oven drying process had lower levels of polyunsaturated fatty acids. In the multivariate analysis, the byproducts from fish fed with flaxseed had a greater composition of fatty acids. The addition of flaxseed in fish diets, as well as the utilization of their byproducts, may become a good business strategy. Additionally, the byproducts may be dried to facilitate transport and storage.

Life cycle of Triatoma ryckmani (Hemiptera: Reduviidae) in the laboratory, feeding patterns in nature and experimental infection with Trypanosoma cruzi

A cohort initiated with 121 eggs, yielding 105 first instar nymphs (eclosion rate: 86.78%), allowed us to observe the entire life cycle of Triatoma ryckmani under laboratory conditions (24ºC and 62% relative humidity), by feeding them on anesthetized hamsters. It was possible to obtain 62 adults and the cycle from egg to adult took a mean of 359.69 days with a range of 176-529 days (mortality rate of nymphs: 40.95%). Mean life span of adults was of 81 days for females and 148 days for males. The developmental periods of 4th and 5th nymphs were longer than those of the other instars. This suggests that young siblings have a better chance of taking a hemolymph meal from older ones, in order to survive during fasting periods during prolonged absences of vertebrate hosts from natural ecotopes. The stomach contents of 37 insects showed blood from rodents (15 cases), lizards (7 cases), birds (6 cases) and insect hemolymph (7 cases). Out of 10 insects fed by xenodiagnosis on a Trypanosoma cruzi infected mouse, all but one became infected with the parasite.

Avaliação quimiométrica da distribuição de metais pesados em composto de lixo urbano domiciliar

The main obstacle to the use of compost from urban waste in agriculture is the presence of heavy metals. Once in the soil, their effect is accumulative and they may contaminate crops and water. The present study reports the evaluation of the chemical distributions of Cu, Pb, Mn and Zn in three different sized fractions (unsieved, < 1,18mm and > 1,18mm) of compost, by means of a sequencial extraction procedure and a chemometric analysis of the total content of all metals in each fraction. The pattern recognition methods showed significant differences in total heavy metal contents for the different fractions. The finest one was the most contaminated. Meanwhile, this fraction presented lower amounts of metals in avaliable forms. This behavior can be attributed to the presence of metal particles in their elemental states in this fraction.

Corantes têxteis

A dye is a colored substance used to impart permanent color to other substances. Its most important use is in coloring textile fibers and fabrics. The removal of colour from dyehouse waste waters is currently a major problem in the textile sector. This paper provides an overview of the treatment technologies that can currently be used by the textile processor and the developments over the past decade with respect to the toxicological and ecotoxicological properties of synthetic organic dyes.

Preparação de carvão ativado em baixas temperaturas de carbonização a partir de rejeitos de café: utilização de FeCl3 como agente ativante

Ferric chloride as a new activating agent was used to obtain activated carbons from agroindustrial waste. This material was prepared at three temperatures of pyrolysis, 200, 280 and 400 ºC. The carbonaceous materials obtained after the activation processes showed high specific surface areas (BET), with values higher than 900 m² g-1. The materials showed different behaviors in the adsorption of methylene blue dye and reactive red textile dye in water solutions. An important fact in the use of FeCl3 as an activating agent is that the activation temperature is at 280 ºC, well below of those commonly employed in chemical or physical activations described in the literature.

Pilhas de combustíveis microbianas utilizadas na produção de eletricidade a partir de rejeitos orgânicos: uma perspectiva de futuro

In this review is presented an innovative technology for use of animal and vegetable waste with high pollution levels in microbial fuel cell (MFC) as an alternative to waste remediation and simultaneously producing electricity and fertilizer for agriculture. A brief history of MFC, the studies about the electron transfer mechanisms, discussion of the biological nanowires in bacteria and the use of chemical mediators or carriers of electrons are explained. The factors influencing the performance of MFCs, the application in waste and sewage treatment and power generation are also discussed.

Química e sustentabilidade: novas fronteiras em biocombustíveis

This contribution discusses the state of the art and the challenges in producing biofuels, as well as the need to develop chemical conversion processes of CO2 in Brazil. Biofuels are sustainable alternatives to fossil fuels for providing energy, whilst minimizing the effects of CO2 emissions into the atmosphere. Ethanol from fermentation of simple sugars and biodiesel produced from oils and fats are the first-generation of biofuels available in the country. However, they are preferentially produced from edible feedstocks (sugar cane and vegetable oils), which limits the expansion of national production. In addition, environmental issues, as well as political and societal pressures, have promoted the development of 2nd and 3rd generation biofuels. These biofuels are based on lignocellulosic biomass from agricultural waste and wood processing, and on algae, respectively. Cellulosic ethanol, from fermentation of cellulose-derived sugars, and hydrocarbons in the range of liquid fuels (gasoline, jet, and diesel fuels) produced through thermochemical conversion processes are considered biofuels of the new generation. Nevertheless, the available 2nd and 3rd generation biofuels, and those under development, have to be subsidized for inclusion in the consumer market. Therefore, one of the greatest challenges in the biofuels area is their competitive large-scale production in relation to fossil fuels. Owing to this, fossil fuels, based on petroleum, coal and natural gas, will be around for many years to come. Thus, it is necessary to utilize the inevitable CO2 released by the combustion processes in a rational and economical way. Chemical transformation processes of CO2 into methanol, hydrocarbons and organic carbonates are attractive and relatively easy to implement in the short-to-medium terms. However, the low reactivity of CO2 and the thermodynamic limitations in terms of conversion and yield of products remain challenges to be overcome in the development of sustainable CO2 conversion processes.

Nutritional composition of Annona crassiflora pulp and acceptability of bakery products prepared with its flour

Annona crassiflora offers an edible fruit native to the Savanna. This study aimed to develop a flour meal from Annona crassiflora pulp; analyze the chemical composition of the fresh pulp and its flour; develop and verify the acceptance of formulations with different concentrations of the flour of Annona crassiflora pulp. Fruit used were selected and processed. The pulp was dried in an oven at 60-65 ºC/48h. We analyzed the chemical composition, and two formulations of breads were prepared with 10 and 20% Annona crassiflora pulp. The results showed that the drying of Annona crassiflora pulp enriched its nutritional value. The Annona crassiflora pulp showed important chemical components, as insoluble fibers (pulp and flour), minerals (potassium, calcium, manganese and others) and antioxidant compounds. The formulations were well-accepted in a sensory point of view and proved to be a good alternative to the exploitation of the fruit.

Temporal differences in blood meal detection from the midguts of Triatoma infestans

We used genus/species specific PCRs to determine the temporal persistence of host DNA in Triatoma infestans experimentally fed on blood from six common vertebrate species: humans, domestic dogs, guinea pigs, chickens, mice, and pigs. Twenty third or fourth instar nymphs per animal group were allowed to feed to engorgement, followed by fasting-maintenance in the insectary. At 7, 14, 21, or 28 days post-feeding, the midgut contents from five triatomines per group were tested with the respective PCR assay. DNA from all vertebrate species was detected in at least four of five study nymphs at seven and 14 days post-feeding. DNA of humans, domestic dogs, guinea pigs, pigs, and chickens were more successfully detected (80-100%) through day 21, and less successfully (20-100%) at day 28. Findings demonstrate that species-specific PCRs can consistently identify feeding sources of T. infestans within two weeks, a biologically relevant time interval.