. There are small and large
molecules in milk proteins. The differences on the size of proteins
which found in a protein mixture provide a selectively ionic adsorption
of the small ones as reported in the literature [43]. This could be due to
the pores of newly synthesized HA microbeads which reduce diffusional
mass transfer resistance and facilitate convective transport. The milk
medium was about pH 7.0 and the milk was diluted with 10.0 mM
pH 7.0 phosphate buffer, so at this pH medium all of the protein components have got negative charges and compete for arriving the binging
site on HA microbeads which is positively charged. Thus the smallest
one ( α-LA) reached firstly and occupied the surface of HA microbeads.
The α-LA adsorption and diffusion depends on the accessibility of HA
which dispersed in polymeric structure.