Otimização do fracionamento das proteínas de soro de leite por operação de extração líquido-líquido em sistemas aquosos bifásicos

• Ano de defesa: 2009
• Autor(a) principal: Alcântara, Lizzy Ayra Pereira
• Orientador(a): Minim, Luis Antonio
• Banca de defesa: Bonomo, Renata Cristina Ferreira , Silva, Maria do Carmo Hespanhol da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Sistemas aquosos bifásicos; Partição; Proteínas; Soro de queijo
• Palavras-chave em Inglês: aqueous two-phase system; Partition; Proteins; Whey
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::TECNOLOGIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/2863

In this work it was studied the liquid-liquid extraction process, using aqueous two phase systems (ATPS) in order to fractionate whey proteins &#945;-lactoalbumin (&#945;-la), &#946;-lactoglobulin (&#946;-lg) and glycomacropeptide (GMP). The evaluated ATPS were composed by PEG 2000 and inorganic salts (potassium phosphate, sodium citrate and lithium sulfate). Initially a fractionated factorial design was applied in order to evaluate the influence of the factors (pH, temperature, PEG concentration, salt concentration and NaCl concentration) on the proteins partition. The results weresubmitted to a variance analysis and it was found that pH and NaCl molar concentration affected significantly (p<0,05) the partition of &#945;-la and &#946;-lg. After that, a central composite rotatable design (CCRD) was used to test different levels of pH and NaCl molar. The results obtained from the CCRD were submitted to a regression analysis and response surface analysis in order to determine the appropriate conditions to optimize the partition of such proteins, for the different salts used. On the systems PEG/citrate it was verified that for pH values higher, the increasing of NaCl leaded to higher partition coefficient values of &#946;-lg. For &#945;-la the increment of the pH increase the partition coefficient while GMP presented a maximum partition coefficient (K=0,912) in pH 6,35 e 0,441 mol L-1 of NaCl. For the PEG/phosphate systems, the increasing of NaCl leaded the partition coefficient of &#946;-lg to lower values, while for &#945;- la it was found a condition of minimum in pH 6,0 and 0,441 mol L-1 of NaCl. On the PEG/sulfato ATPS this time, it was obtained a minimum for the partition coefficient of &#946;-lg (K=0,031) in pH pH 5,67 and 0,276 mol L-1 of NaCl. The fractionation experiments were carried out on PEG/potassium phosphate (13% w/w for both), pH 5,43 and 0,290 molar of NaCl, at 25°C, using different dilutions of whey (pure, 1:1 and 1:3). The extraction yield for the aimed proteins, the purification factor for &#946;&#8211;lactoglobulin and reduction rate for &#945;-lactoalbumin were determinate on each system after 3 steps of liquid-liquid extraction. It was observed that among the ATPS tested, the ones which used pure whey presented higher reduction rate for &#945;-lactoalbumin (5,56) on the bottom phase and higher purification factor &#946;-lactoglobulin (96,25 %) on the salt phase after tree extraction stages. This study showed that ATPS can be used to fractionate the proteins &#945;-lactoalbumin, &#946;-lactoglobulina and glycomacropeptide form in natura whey.