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Qualidade de água na produção de alevinos de tilápia do Nilo alimentados com diferentes níveis de proteína em sistema bioflocos. Texto completo
2017
SANTOS, L. F. dos | FERRI, G. H. | ZAMBON, G. V. | CARDOSO, I. L. | SOARES, M. P. | HISANO, H.
Resumo: O objetivo deste trabalho foi avaliar a qualidade de água na produção de alevinos de tilápia-do-nilo alimentadas com diferentes níveis de proteína bruta (PB) em sistema experimental com bioflocos sem renovação de água. Foram utilizados 270 alevinos (6,31±0,40g), distribuídos aleatoriamente em 18 aquários de 200 L (15 animais/aquário), e que foram alimentados com três níveis 28%, 32% e 36% PB (tratamentos), durante 60 dias. Todas as rações experimentais foram formuladas para conter 3.200 kcal/kg de energia digestível. O delineamento experimental utilizado foi o inteiramente casualizado com três tratamentos e seis repetições. Os seguintes parâmetros de qualidade de água foram avaliados: temperatura, oxigênio dissolvido, pH, amônia, nitrito, nitrato, condutividade, alcalinidade, turbidez e volume de sólidos sedimentáveis. Os dados obtidos foram submetidos análise de variância (ANOVA), e complementadas com o teste de Tukey (p<0,05). Não foram encontradas diferenças (p>0,05) entre as médias dos parâmetros físicos e químicos da água. Por outro lado, para os valores de sólidos sedimentáveis houve diferença (p<0,05), sendo que os aquários onde os peixes foram alimentados com ração contendo 36% PB apresentaram maiores valores, quando comparado com o tratamento 28% PB, no entanto, eles não diferiram do tratamento 32% PB. O sistema bioflocos manteve os parâmetros físico-químicos da água em condições favoráveis para a produção de alevinos de tilápia-do-nilo sem renovação de água, independentemente dos três níveis utilizados de proteína das rações, resultando em melhor utilização do recurso hídrico e consequente diminuição da emissão de efluentes. Abstract: This study aimed to evaluate the water quality of Nile tilapia fingerling culture fed diets with different crude protein (CP) levels in an experimental biofloc system (BFT) with no water renovation. Fingerling (n=270, 6.31±0.40g) were distributed in 18 aquaria (200 L, 15 fish/aquarium) and fed with three levels 28%, 32% e 36% of CP (treatments), during 60 days. All experimental diets were formulated to be isoenergetic 3,200 kcal/kg of digestible energy. The experimental design was completely randomized with three treatments and six replicates. The following water quality parameters were evaluated: temperature, dissolved oxygen, pH, total ammonia, nitrite, nitrate, conductivity, alkalinity, turbidity and sedimentable solids. Experimental data were submitted to analysis of variance (ANOVA) and complemented with Tukey ́s test (p<0.05). There were no significant difference (p>0.05) among physical and chemical water parameters of different treatments. On the other hand, sedimentable solids showed statistical difference (p<0.05), and the aquaria where fish were fed with 36% CP showed the highest values compared to 28% CP; however, did not differ from 32% CP. The biofloc technology kept favorable water quality to Nile tilapia fingerling culture without water renovation independently of the three dietary protein levels, resulting in improved utilization of hydric resource, and consequent reduction of effluents emissions.
Mostrar más [+] Menos [-]Estudio de las características coagulantes/floculantes de polímeros orgánicos naturales, extraídos de materiales de desecho alimenticio, para la potabilización del agua Texto completo
2017
Buenaño Bautista, Brenda Belén
El estudio evaluó características coagulantes y floculantes de tres polímeros naturales: almidón de cáscara de plátano verde, pectina de cáscara de naranja y extracto de semilla de tamarindo en tres soluciones (agua destilada, cloruro de sodio y acetato de amonio) en la potabilización del agua cruda con turbiedad de 5,32 NTU. Los polímeros no presentaron actividad coagulante, por la baja turbiedad del agua cruda, sin embargo, presentaron actividad floculante al combinarse con sulfato de aluminio. Las combinaciones óptimas de sulfato de aluminio + polímero fueron 50 mg/L+0,2 mg/L para almidón, 60 mg/L+0,06 mg/L para pectina, 60 mg/L+0,6 mg/L para extracto de tamarindo en agua, 60 mg/L+0,5 mg/L para extracto de tamarindo en cloruro de sodio y 60 mg/L+0,2 mg/L para extracto de tamarindo en acetato de amonio. La remoción de turbiedad y color fue 87 y 92 %, respectivamente. El uso de polímeros no resultó económicamente viable debido al alto costo extracción: $ 22,45/kg almidón, $ 306,11/kg pectina y $ 25,44/kg polvo de semillas de tamarindo. Los lodos residuales no cumplieron con los límites máximos permisibles para descarga al alcantarillado y presentaron efecto tóxico en la mitosis de las raíces de cebollas a una CI50 entre 0,5 - 2 %. | In this research work, the coagulant and flocculant characteristics of three natural polymers: green plantain peel starch, orange peel pectin and tamarind seed extract in three solutions (water, sodium chloride and ammonium acetate) were evaluated in the purification of raw water with turbidity of 5,32 NTU. The natural polymers did not present coagulant activity due to the low turbidity of raw water; however they showed flocculant activity in combination with aluminum sulphate. The optimal combinations of aluminum sulphate + polymer were 50 mg/L+0,2 mg/L for starch, 60 mg/L+0,06 mg/L for pectin, 60 mg/L+0,6 mg/L for tamarind extract in water, 60 mg/L+0,5 mg/L for tamarind extract in sodium chloride and 60 mg/L+0,2 mg/L for tamarind extract in ammonium acetate. Removal value of turbidity and color was around 87% and 92%. The production of natural polymers was not economically viable due to their high extraction cost: $ 22,45/kg of starch, $ 306,11/kg of pectin and $ 25,44/kg of tamarind seed powder. The residual sludge exceeded the maximum permissible limits for discharging to the sewer system; in addition, it showed a toxic effect on the mitotic activity of onion roots at an IC50 of 0.5 to 2 %. | Aldás Sandoval, María Belén, director
Mostrar más [+] Menos [-]Determination of Cu, Zn and Cd in Soil, Water and Food Products in the Vicinity of RMG Gold and Copper Mine, Kazreti, Georgia Texto completo
2017
Avkopashvili, Guranda | Avkopashvili, Marika | Gongadze, Alexander | Tsulukidze, Manana | Shengelia, Evgenia
Functioning of polymetallic factories are considerable harming the ecological systems in the environment. Operation of RMG Gold and Copper Mine in the SE part of Georgia causes severe ecological problems in the region. It is vital that conducted monitoring near the areas where industrial activities are underway. The study is aimed at eco-monitoring of the Bolnisi municipality, Georgia. The monitoring was conducted of heavy metals (Cu, Zn, Cd) in system “water-soil-plant” in the area of Kazreti (Madneuli) – villages: Balichi, Ratevani, Naxiduri, Xidiskhuri. According to the results obtained in the soil, content of heavy metals are significantly higher than the allowable concentration limit. In spite of this in crops of the plants which were grown on this soil, content of Cu and Zn does not exceed the allowed concentration limits, Cd content was not found. Study plants were green been, mauhroom, green walnut, green pepper, cucumber, cherry, potato, tomato, walnut, garlic, dry been and corn. Study water were rivers Kazretula and Mashavera's water. Rivers Kazretula and Mashavera water content Zn and Cd concentration.
Mostrar más [+] Menos [-]Effects of dietary fibers with high water-binding capacity and swelling capacity on gastrointestinal functions, food intake and body weight in male rats Texto completo
2017
Tan, Chengquan | Wei, Hongkui | Zhao, Xichen | Xu, Chuanhui | Peng, Jian
Objective: The aim of this study was to investigate the effects of supplementation of dietary soluble fibers with high water-binding capacity (WBC) and swelling capacity (SC) on gastrointestinal tract mass, physicochemical properties of digesta, gastrointestinal mean retention time (MRT), body weight, and food intake in male rats. Methods: Thirty-two male Sprague-Dawley rats were randomized to four equal groups and fed the control diet or diet containing 2% konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PWMS+GG), andPWMS plus xanthan gum (PWMS+XG) for three weeks. Results: WBC and SC of diets followed the order of PWMS+GG > KF > PWMS + XG > control. PWMS+GG and KF groups had a lower average daily food intake than the control group, but all the groups showed no difference in final body weightand the weight gain rate. The high WBC and SC of the PWMS+GG and KF groupsled to an increase of WBC and SC in the stomach digesta, and a gain of the cecal digesta weight, due to increased cecal moisture content. Conclusion: The inclusion of the novel fiber, PWMS+GG, in the diet of male rats appears to facilitate the modulation of WBC and SC of stomach digesta and the reduction of food intake.
Mostrar más [+] Menos [-]Exposure of the endangered Milky stork population to cadmium and lead via food and water intake in Kuala Gula Bird Sanctuary, Perak, Malaysia Texto completo
2017
Rahman, Faid | Ismail, Ahmad | Omar, Hishamuddin | Mohamed Zakaria Hussin,
The Milky stork is listed as an endangered species endemic to the Southeast Asia region. In Malaysia, the population is currently being reintroduced back into the wild. However, the increase of anthropogenic activity throughout the coastal area might expose the population to hazardous chemicals such as heavy metals. This study highlights the contamination of cadmium (Cd) and lead (Pb) in the Milky stork’s diet. Additionally, this is the first time an integrated exposure model being used to assess heavy metal exposure risk to the population. Lead level (5.5–7.98mgkg⁻¹) in particular was relatively high compared to Cd (0.08–0.33mgkg⁻¹). This was probably related to the different niches occupied by the species in the aquatic environment. The results further show that the predicted exposure doses (through intake of both food and water) for all metals are much lower than the Tolerable Daily Intake (TDI) values. The total exposure dose for Cd was 0.11mgkg⁻¹d⁻¹ with TDI value of 0.54mgkg⁻¹d⁻¹ while Pb total exposure dose was 0.31mgkg⁻¹d⁻¹ with TDI value of 0.64mgkg⁻¹d⁻¹. Several possible factors that could lead to the observed pattern were discussed. In conclusion, there is an urgent need to improve the current habitat quality to protect the endangered species. The authors also emphasized on the protection of remaining Milky stork’s habitats i.e. mudflats and mangroves and the creation of buffer zone to mitigate the negative impacts that may arise from pollution activity.
Mostrar más [+] Menos [-]Using the IPAT identity and decoupling analysis to estimate water footprint variations for five major food crops in China from 1978 to 2010 Texto completo
2017
Tian, Yuanhong | Ruth, Matthias | Zhu, Dajian
Evaluations of water footprint (WF) used to enhance performance of policies on water utilization will benefit from combining WF analysis with methods from sustainability analysis. For this purpose, this paper analyzes the WF of China’s five main food crops, which together account for roughly 33 % of the nation’s water consumption. We assess distributional equity at the provincial scale and use the IPAT identity and a decoupling analysis to assess the scale of both national and provincial WF consumption, the factors influencing the WF fluctuation, and the efficiency of water allocation. Results show that although it is difficult in the short term to end the unsustainable WFs of China’s five main food crops, more efficient allocation can be achieved through appropriate agricultural policy modification. In the long term, distributional equity at the provincial level must be the key factor in achieving sustainable agriculture in China.
Mostrar más [+] Menos [-]Assessment of the Successes and Failures of Decentralized Energy Solutions and Implications for the Water–Energy–Food Security Nexus: Case Studies from Developing Countries Texto completo
2017
Guta, Dawit Diriba | Jara, José | Adhikari, Narayan Prasad | Chen, Qiu | Gaur, Varun | Mirzabaev, Alisher
Access to reliable and affordable energy is vital for sustainable development. In the off-grid areas of developing countries, decentralized energy solutions have received increasing attention due to their contributions to reducing poverty. However, most of the rural population in many developing countries still has little or no access to modern energy technologies. This paper assesses the factors that determine the successes and failures of decentralized energy solutions based on local harmonized case studies from heterogeneous contexts from Asia, sub-Saharan Africa, and South America. The case studies were analyzed through the coupled lenses of energy transition and the Water–Energy–Food Security (WEF) Nexus. The findings indicate that access to modern decentralized energy solutions has not resulted in complete energy transitions due to various tradeoffs with the other domains of the WEF Nexus. On the other hand, the case studies point at the potential for improvements in food security, incomes, health, the empowerment of women, and resource conservation when synergies between decentralized energy solutions and other components of the WEF Nexus are present.
Mostrar más [+] Menos [-]Exploring the Relationship between Structural and Air–Water Interfacial Properties of Wheat (Triticum aestivum L.) Gluten Hydrolysates in a Food System Relevant pH Range Texto completo
2017
Wouters, Arno G. B. | Fierens, Ellen | Rombouts, Ine | Brijs, Kristof | Joye, Iris J. | Delcour, Jan A.
The relationship between structural and foaming properties of two tryptic and two peptic wheat gluten hydrolysates was studied at different pH conditions. The impact of pH on foam stability (FS) of the samples heavily depended on the peptidase used and the degree of hydrolysis reached. Surface dilatational moduli were in most, but not all, instances related to FS, implying that, although the formation of a viscoelastic protein hydrolysate film is certainly important, this is not the only phenomenon that determines FS. In contrast to what might be expected, surface charge was not a major factor contributing to FS, except when close to the point-of-zero-charge. Surface hydrophobicity and intrinsic fluorescence measurements suggested that changes in protein conformation take place when the pH is varied, which can in turn influence foaming. Finally, hydrolyzed gluten proteins formed relatively large particles, suggesting that protein hydrolysate aggregation probably influences its foaming properties.
Mostrar más [+] Menos [-]Lipase‐catalyzed synthesis of sorbitol octanoate in aqueous biphasic medium and its use in a green formulation process of oil‐in‐water food nanoemulsions Texto completo
2017
Wongthongdee, Natcha | Durand, Alain | Pongtharangkul, Thunyarat | Sunintaboon, Panya | Inprakhon, Pranee
BACKGROUND: Sugar‐based surfactants are highly relevant alternative ingredients for food grade formulations. Nevertheless, the design of sustainable manufacturing processes is still ongoing. RESULTS: Sorbitol ester surfactants were synthesized by lipase‐catalyzed esterification in solvent‐free conditions. Octanoic acid was dispersed in a 70 wt% sorbitol aqueous solution (containing the enzyme). The maximal conversion of 23.5 mole % of esterified fatty acid per mole of loaded fatty acid was obtained after 48 h in optimal conditions. The performance of the reactor was affected by both the nature and amount of the reactants and the dispersion state. Detailed structural analysis demonstrated that lipase from Candida rugosa specifically catalyzed the acylation of sorbitol on primary hydroxyl groups. Sorbitol esters accumulated exclusively in the oil phase, which led to easy and efficient product recovery. Oil phase containing the sorbitol esters could be used directly for preparing oil‐in‐water nanoemulsion without adding any other stabilizer. These nanoemulsions exhibited good stability after 7 days storage at 25°C or 60°C. CONCLUSION: A green manufacturing process for food grade oil‐in‐water nanoemulsions was designed involving a lipase‐catalyzed esterification step which produced in situ the required surfactant. Nanoemulsions were prepared without using any other stabilizer. © 2017 Society of Chemical Industry
Mostrar más [+] Menos [-]Assessment of the Successes and Failures of Decentralized Energy Solutions and Implications for the Water–Energy–Food Security Nexus: Case Studies from Developing Countries Texto completo
2017
Dawit Guta | Jose Jara | Narayan Adhikari | Qiu Chen | Varun Gaur | Alisher Mirzabaev
Access to reliable and affordable energy is vital for sustainable development. In the off-grid areas of developing countries, decentralized energy solutions have received increasing attention due to their contributions to reducing poverty. However, most of the rural population in many developing countries still has little or no access to modern energy technologies. This paper assesses the factors that determine the successes and failures of decentralized energy solutions based on local harmonized case studies from heterogeneous contexts from Asia, sub-Saharan Africa, and South America. The case studies were analyzed through the coupled lenses of energy transition and the Water–Energy–Food Security (WEF) Nexus. The findings indicate that access to modern decentralized energy solutions has not resulted in complete energy transitions due to various tradeoffs with the other domains of the WEF Nexus. On the other hand, the case studies point at the potential for improvements in food security, incomes, health, the empowerment of women, and resource conservation when synergies between decentralized energy solutions and other components of the WEF Nexus are present.
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