To encapsulate riboflavin via the external method, 0.2 g of blank
whey microbeads (prepared as per Section 2.2) were placed into
10 ml aliquots of riboflavin solutions ranging in concentration
from 0.01 to 0.1 g/L for 24 h under gentle magnetic stirring. The
concentration of riboflavin in the surrounding solution was used
to calculate a ratio of the mass of riboflavin in solution to the mass
of microbead protein (mg:g) submerged in that solution. The concentration
of riboflavin in solution was measured by HPLC before
microbead addition and after 24 h of contact. The concentration
of riboflavin in the microbead was obtained by dividing the mass
of riboflavin in the bead by the volume of the microbead. The mass
in the bead was calculated by subtracting the mass in solution at
equilibrium from the mass in the initial solution. The mass in
solution is equal to the concentration multiplied by the volume
of solution. Mass balance was performed on microbeads as per Section
2.4. The loading of microbeads with riboflavin was expressed
as the concentration of riboflavin in the microbeads as a function of
the initial ratio of the mass of riboflavin to the mass of microbead
protein in solution.