title: Application of the response surface methodology for optimization of whey protein partitioning in PEG/phosphate aqueous two-phase system.
abstract: In order to develop a new strategy for β-lactoglobulin (β-lg) removal from whey protein, partitioning of α-lactalbumin (α-la), β-lg and glycomacropeptide (Gmp) was studied using aqueous two phase systems (ATPS). A system composed of 13% (w/w) polyethylene glycol (PEG, average molar mass 2000 g/mol) and 13% (w/w) potassium phosphate was used at 25°C. A central composite rotatable design (CCRD) associated to the response surface methodology (RSM) was applied to investigate the effects of NaCl concentration and pH on the partition of these proteins. It was found that α-la and Gmp partitioned to the top phase rich in PEG, whereas β-lg partitioned to the bottom phase rich in salt. According to the RSM, optimal conditions for β-lg removal where found where pH was equal to 6.7 and salt concentration was 0.35 mol/L. Under these conditions, the partition coefficient K(α) was 0.48 and K(Gmp) was 0.92. On the other hand, the partition coefficient K(β) was only 0.01. In such conditions β-lg preferentially concentrates in the bottom phase, while the top phase exclusively contains the proteins α-la and Gmp. Fractionation of the proteins from fresh whey was performed in a three stage cross-flow extraction system. The extraction yield for β-lg in the bottom phase was 97.3%, while the yields for α-la and Gmp in the top phase were 81.1% and 97.8%, respectively.
authors.affiliation: Department of Food Technology, Federal University of Viçosa, Av. P. H. Rolfs - Campus, 36570-000 Viçosa, MG, Brazil.
authors.forename: Lizzy Ayra Pereira
authors.initials: LA
authors.lastname: Alcântara
authors.forename: Luis Antonio
authors.initials: LA
authors.lastname: Minim
authors.forename: Valéria Paula Rodrigues
authors.initials: VP
authors.lastname: Minim
authors.forename: Renata Cristina Ferreira
authors.initials: RC
authors.lastname: Bonomo
authors.forename: Luis Henrique Mendes
authors.initials: LH
authors.lastname: da Silva
authors.forename: Maria do Carmo Hespanhol
authors.initials: Mdo C
authors.lastname: da Silva
mesh_terms: D002364:Caseins / Q000737:chemistry / Q000302:isolation & purification; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D007768:Lactalbumin / Q000737:chemistry / Q000302:isolation & purification; D007782:Lactoglobulins / Q000737:chemistry / Q000302:isolation & purification; D008894:Milk Proteins / Q000737:chemistry / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010710:Phosphates / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry*; D012044:Regression Analysis; D012965:Sodium Chloride / Q000737:chemistry; D000067816:Whey Proteins
chemical_list: D002364:Caseins; D007782:Lactoglobulins; D008894:Milk Proteins; D010446:Peptide Fragments; D010710:Phosphates; D017680:Potassium Compounds; D000067816:Whey Proteins; C065989:caseinomacropeptide; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D007768:Lactalbumin; C013216:potassium phosphate