Surface hydrophobicity of the MP was determined by using the hydrophobic
chromophore, bromophenol blue (BPB) (Cui, Xiong, Kong,
Zhao, & Liu, 2012). Free BPB in the supernatant was measured at
595 nm. Control was prepared by the same procedure as the above
but without MP. The percent of bound BPB (μg) by MP was calculated
as an index of hydrophobicity: