The encapsulation of low molecular weight bioactives in whey
hydrogel microbeads by bioactive addition to the microbead forming
solution results in diffusional losses during crosslinking and
washing of the microbeads. The use of blank microbeads as sorbents
for immobilisation of bioactives looks promising, as higher
concentrations of riboflavin were obtained within the blank microbeads
compared to microbeads formed by riboflavin addition to
the whey protein solution. The migration of riboflavin, amino acids
and peptides from solution into the whey microbeads was shown
to be via a process of partition influenced by hydrophobic interactions
between the compound and the microbead. There was a linear
relationship between the equilibrium constant (K) and
molecule hydrophobicity; the more hydrophobic the compound
the higher the E (%) obtained in the microbeads. Blank whey microbeads
are well suited as a food grade encapsulation system to the
encapsulation of bioactives that are water soluble but contain
hydrophobic groups.