Riboflavin was dissolved in both deionised water and 100 mM
CaCl2 at 0.04 g/L. A mass of blank microbeads ranging from 0.05
to 10 g was placed in 10 ml of each solution for 24 h under gentle
magnetic stirring. The concentration of riboflavin in the water and
the CaCl2 solution was determined by HPLC before addition of the
microbeads and after 24 h. A number of samples (100 ll) were
taken prior to 24 h to ensure riboflavin equilibrium had been
reached. The encapsulation of riboflavin in microbeads from both
water and the CaCl2 solution was expressed as a percentage, E
(%) and calculated using Eq. (1).
Eð%Þ ¼
M0Maq
M0
100 ð1Þ
where Maq is mass of solute in solution at equilibrium and M0 is the
mass of solute in the initial solution.