Artículos de revistas
Cloud point extraction applied to casein proteins of cow milk and their identification by mass spectrometry
Registro en:
Analytica Chimica Acta 590 (2): 166 -172
0003-2670
Autor
Lopes, A.
Garcia, J.S.
Catharino, R.R.
Santos, L.S.
Eberlin, M.N.
Sarruda, M.A.Z.
Institución
Resumen
Leonardo Silva Santos. Universidad de Talca, Instituto de Química de Recursos Naturales, P.O. Box 747, Talca, Chile. This work describes the optimization of a cloud point extraction (CPE) method for casein proteins from cow milk samples. To promote phase separation, polyoxyethylene(8) isooctylphenyl ether (Triton® X-114) and sodium chloride (NaCl) were used as nonionic surfactant and electrolyte, respectively. Using multivariate studies, four major CPE variables were evaluated: Triton® X-114 concentration, sample volume, NaCl concentration, and pH. The results show that surfactant concentration and sample volume were the main variable affecting the CPE process, with the following optimized parameters: 1% (w/v) Triton® X-114 concentration, 50 μL of sample volume, 6% (w/v) NaCl concentration and extractions carried out at pH 7.0. At these conditions, 923 ± 66 and 67 ± 2 μg mL−1 of total protein were found in the surfactant-rich and surfactant-poor phases, respectively. Finally, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was then used to evaluate those target proteins (s1-casein, s2-casein and β-casein) separation as well as to check the efficiency of the extraction procedure, making a fingerprint of those target proteins possible.