Estudo do processamento de soro de leite bovino através da coagulação com quitosana e secagem

Exportado OPUSMade available in DSpace on 2019-08-14T06:48:12Z (GMT). No. of bitstreams: 1 disserta__o_am_lia_lu_sa.pdf: 90426 bytes, checksum: d61b2166f57984fa406dee1ff2697ead (MD5) Previous issue date: 19O soro de leite é um subproduto da indústria de queijo. É uma fonte de aminoácidos essenciais e suas propriedades físico-químicas proporcionam propriedades funcionais de grande interesse tecnológico. Contém cerca de 6% de sólidos, retendo 55% dos nutrientes presentes no leite. Quase metade do total de soro produzido mundialmente vem sendo destinado à alimentação de suínos ou ainda descartado inadequadamente em rios e na rede de esgotos públicos. Sendo assim, se faz necessário o desenvolvimento de tecnologias capazes de reaproveitar seus nutrientes, acessíveis a pequenos e médios produtores. A quitosana, um polímero natural, de baixo custo, renovável e biodegradável, já vem sendo bastante utilizada na recuperação da biomassa de resíduos de processamento alimentares, sendo empregada como agente coagulante. A secagem em secador de bandeja é amplamente utilizada por ser o tipo mais simples de secador, de fácil manutenção e baixo custo, sendo um equipamento acessível. Neste contexto, este trabalho visa avaliar a eficiência da quitosana como coagulante, analisando o efeito da sua concentração e da temperatura neste processo na remoção da turbidez do soro lácteo e o posterior estudo da secagem em estufa convectiva do coagulado obtido. Análises de caracterização (extrato seco total, cinzas, lactose, proteínas, lipídios, DQO) foram realizadas a fim de se avaliar o uso de quitosana na recuperação dos sólidos presentes no soro de leite. Ensaios de coagulação foram realizados utilizando planejamento fatorial Rotacional Central Composto, em condições de pH natural do soro, temperatura entre 6 e 34°C e concentração entre 280 e 420 mg/L. Os ensaios de coagulação apresentaram alta eficiência de remoção da turbidez para as concentrações de 300, 350 e 400ppm de quitosana em solução 1% de ácido acético e à temperatura mais baixas (em torno de 10°C). A condição de coagulação considerada ideal foi de 350mg/L de quitosana. A partir do coagulado assim obtido, ensaios de secagem em estufa convectiva foram realizados nas temperaturas de 55, 60, 65°C para levantamento das curvas cinéticas e a curva de atividade de água também foi determinada. Os ensaios demonstraram que a temperatura de 55ºC mantida por 30 minutos é suficiente para obter um sólido cuja umidade é inferior a 5% e atividade de água de 0,5, condição que previne a contaminação microbiana. O modelo matemático para a isoterma de sorção para ajuste dos dados obtidos foi o modelo Langmuir para atividade de água superior a 0,5 e de BET linearizado para atividade de água abaixo de 0,5. Nestes processos obteve-se eficiência média de remoção da turbidez, extrato seco total, cinzas e DQO de, respectivamente, 99,21%, 12,49%, 0,22%, 2,67%. O coagulado foi caracterizado com 67% de gordura, 15% proteínas, 8,8% quitosana e 2,43% lactose. Este produto, rico em lipídios benéficos e também proteínas, apresenta potencial para ser utilizado como aditivo em alimentos, melhorando seu valor nutricional e propriedades sensoriais, como também em cosméticos e produtos farmacêuticos. Desta forma, propôs-se uma rota de processamento acessível ao pequeno e médio produtor, agregando valor a um subproduto, podendo tornar-se uma fonte de renda para o produtor e dando-lhe melhor finalidade e facilitando o tratamento do resíduo gerado.Whey is a byproduct of cheese industry. It is a essential amino acids source and their physicochemical properties provide functional properties of great technological interest. Contains about 6% of solids, retaining 55% of milk nutrient. Almost a half of the total worldwide whey produced is being used to feed pigs or discarded, improperly, into rivers and public sewer system. Therefore, it is necessary to develop technologies capable to recycling its nutrients available to small and medium producers. Chitosan, a natural polymer, low cost, renewable and biodegradable, has been widely used in recovery of processing food biomass waste, being used as a coagulating agent. The drying tray dryer is widely used because it is the simplest type of dryer, easy maintenance and low cost, wich make it affordable. In this context, this study aims to evaluate the effectiveness of chitosan as a coagulant, analyzing the effect of its concentration and processing temperature, in whey turbidity removal and subsequent study of the coagulated drying in a convective oven dryer. Characterization analyzes (total solids, ash, lactose, protein, lipid, COD) were performed in order to assess the use of chitosan in the recovery of solids present in whey. Coagulation assays were performed using the factorial design Rotational Center Compound, in conditions of natural whey pH, temperature between 6 and 34°C and concentration between 280 and 420 mg/L. The coagulation assays showed high efficiency of turbidity removal for concentrations of 300, 350 and 400ppm chitosan in 1% solution of acetic acid and at lower temperature (around 10°C). The optimal condition considered for coagulation was 350mg/L of chitosan. From the obtained coagulate, tests in a convective oven dryer were carried out at temperatures of 55, 60, 65°C, kinetic curves and the curve of water activity was determined. The drying studies have shown that the temperature of 55°C maintained for 30 minutes is sufficient to obtain a solid whose humidity is lower than 5% and a water activity of 0.5, as ensuring the microbial contamination. The mathematical model for the sorption isotherm for adjustment of the data was the Langmuir model for water activities greater than 0.5 and BET linearized for water activity below than 0.5. In these processes yielded an average efficiency of turbidity removal, total solids, ash and COD, respectively, 99.21%, 12.49%, 0.22%, 2.67%. The coagulated was characterized with 67% fat, 15% protein, 2.43% lactose and 8.8% chitosan. This product, rich in beneficial lipids and proteins also may have potential for use as a feed additive, improving its nutritional value and sensory properties, such as cosmetics and pharmaceuticals. Thus, we propose a route processing accessible for small and medium producer, adding value into a byproduct, could become a source of income for the producer and giving him a better purpose and facilitating the treatment of the waste generated

Oxidized Renewable Materials for the Removal of Cobalt(II) and Copper(II) from Aqueous Solution Using in Batch and Fixed-Bed Column Adsorption

Batch and continuous adsorption of Co2+ and Cu2+ from aqueous solutions by oxidized sugarcane bagasse (SBox) and oxidized cellulose (Cox) were investigated. The oxidation reaction of sugarcane bagasse and cellulose was made with a mixture of H3PO4‒NaNO2 to obtain SBox and Cox, with the introduction of high number of carboxylic acid functions, 4.5 and 4.8 mmol/g, respectively. The adsorption kinetics of Co2+ and Cu2+ on SBox and Cox were modeled using two models (pseudo-first-order and pseudo-second-order) and the rate-limiting step controlling the adsorption was evaluated by Boyd and intraparticle diffusion models. The Sips and Langmuir models better fitted the isotherms with values of maximum adsorption capacity Qmax of 0.68 and 0.37 mmol/g for Co2+ and 1.20 and 0.57 mmol/g for Cu2+ adsorption on Cox and SBox, respectively. The reuse of both spent adsorbents was evaluated. Adsorption of Cu2+ and Co2+ on SBox in continuous was evaluated using a 22 factorial design with spatial time and initial metal concentration as independent variables and Qmax and effective use of the bed as responses. The breakthrough curves were very well described by the Bohart–Adams original model and the Qmax values for Co2+ and Cu2+ were 0.22 and 0.55 mmol/g. SBox confirmed to be a promising biomaterial for application on a large scale

Modeling mono- and multi-component adsorption of cobalt(II), copper(II), and nickel(II) metal ions from aqueous solution onto a new carboxylated sugarcane bagasse. Part I: Batch adsorption study.

A new carboxylated-functionalized sugarcane bagasse (STA) was prepared through the esterification of sugarcane bagasse with trimellitic anhydride. The optimized synthesis conditions yield STA with a percent weight gain of 73.9% and the number of carboxylic acid groups accounted for 3.78 mmol/g. STA was characterized by FTIR, elemental analysis, TGA, PZC, and SEM. Adsorption kinetics followed a pseudosecond- order model. The adsorption rate constant showed the following order: k2,Ni 2+ > k2,Cu 2+ > k2,Co 2+. Four mono- and multi-component isotherm models were used to model the adsorption systems. Monocomponent experimental data were fitted to Langmuir and Sips models; whereas, multicomponent data were fitted to modified extended Langmuir and P-factor models. The maximum adsorption capacities (Qmax,mono) obtained from the Langmuir model were 1.140, 1.197, and 1.563 mmol/g for Co2+, Cu2+, and Ni2+, respectively. The competitive studies demonstrated that the multicomponent adsorption capacity (Qmax,multi) was smaller than Qmax,mono, as a result of the interaction between the metal ions. Desorption studies showed that all metal ions could be fully desorbed from STA