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|Title:||Physico-chemical stability of casein micelles cross-linked by transglutaminase as a function of acidic pH|
|Author:||Nogueira, Marcio H.|
Tavares, Guilherme M.
Silva, Naaman F. Nogueira
Stringheta, Paulo C.
Teixeira, Alvaro V. N. C.
Perrone, Italo T.
Carvalho, Antonio F.
|Abstract:||Casein micelles (CMs) can be used as nanocarriers in food and pharmaceutical applications, but can be destructured by changes in the physicochemical environment. Enzymatic crosslinking with transglutaminase (Tgase) is a possibility to stabilize CMs. The objective of this paper was to evaluate the stability of native CMs and CMs cross-linked by Tgase (CMs-Tgase) as a function of pH, in the presence of following destabilizing agents: urea, sodium citrate, high temperature and ethanol. Suspensions of native and CMs-Tgase were prepared at 27.5 g/L in 25 mM HEPES buffer with 2 mM CaCl2 at pH 7.10 The CMs' size and zeta-potential were determined by dynamic light scattering. Native CMs precipitated below pH of 5.5. CMs-Tgase precipitated between pH 4.5 and pH 3.5 but was stable in the pH range of 7.0-4.5 and between pH 2.0 and 3.0. Isoelectric points of CMs and CMs-Tgase were determined as been 4.6 and 4.1, respectively. CMs-Tgase were stable at pH 2.0, in the presence of 100 mM of sodium citrate, 8 M urea, 99.5% (v/v) of ethanol and presented an heat coagulation time higher than 500 s at 140 degrees C. These results were interpreted as a consequence of the formation of internal covalent bounds between casein chains, and to a covalent attachment of the kappa-caseins onto the surface of the CMs. In light of these results, it is possible to investigate CMs-Tgase as stable food-grade nanocarriers, whose characteristics can be modulated according to the chemical nature of the target biomolecule|
|Subject:||Carreadores de moléculas|
|Appears in Collections:||FEA - Artigos e Outros Documentos|
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