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).