ESTRUTURA E ESTABILIDADE DAS MICELAS DE CASEÍNA DO LEITE BOVINO
Schlagworte:
Caseína, estabilidade térmica, estrutura micelar, hidrólise, proteínasAbstract
As proteínas do leite são veículos naturais, que fornece micronutrientes essenciais, aminoácidos, assim como componente do sistema imune, além disso, possui propriedade de fundamental importância nas características de muitos produtos lácteos. As caseínas são as principais proteínas do leite, compreendem cerca de 80% das proteínas do leite e consistem de quatro proteínas principais: as1-, as2, B- e k-caseína, as quais possuem elevada estabilidade térmica, o que proporciona as indústrias de lacticínio realizar o tratamento do leite a temperaturas elevadas, como leite ultra alta temperatura (UAT). No entanto, alguns fatores como a hidrólise enzimática da K-caseína, Temperatura, PH, excesso de Ca2+ e adição de etanol afetam a estabilidade dessa proteína, que estão em grande parte presentes no leite na forma de partículas coloidais, conhecidas como micelas. A estrutura interna da micele de caseína é constituída predominamente por as1-, as2, B-caseína e de nanopartículas de fosfato de cálcio coloidal, enquanto que a k-caseína está localizada preferencialmente na superfície da micela, assumindo importante papel na estabilidade micelar. O interesse na caseína micelar mantém-se constante ao longo dos anos, e pesquisas sobre o assunto constituem a ser realizadas, por isso a relevância de se entender a estrutura e os fatores que afetam a estabilidade micelar.
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