Isolation of Sesame OBs
The water extract was separated into floating, skim, and precipitate
fractions by centrifugation (3000g for 15 min at 4 °C; CR21N,
Hitachi, Tokyo, Japan). The three fractions were respectively collected,
and their yields and lipid contents were determined. It was calculated
that 87% of total lipids in water extract was distributed in the
floating fraction, followed by skim (7%) and precipitate (6%)
fractions.
In order to remove the proteins which did not interact with OBs, the
floating fraction was dispersed into precooled DI water with a
volume/volume ratio of 1/10, and mixed in an ice water bath for 15 min.
Then this mixture was centrifuged (5000g for 15 min at 4 °C) to
float the OBs, which was deemed as pH 7-OB in this study. The contents
of solids, lipids, and proteins in pH 7-OB were respectively 67.97,
64.43, and 1.92%.
Furthermore, the pH 7-OB was dispersed into precooled DI water with a
volume/volume ratio of 1/10, and adjusted to pH 9.5 by 1 M NaOH
solution. This mixture was mixed in an ice water bath for 15 min, which
was centrifuged (5000g for 15 min at 4 °C) to obtain floating
fraction (deemed as pH 9.5-OB).