All plant seeds that store triglycerides as future energy sources sequester these oils in specialized organelles called oleosomes. Figure 1 shoes the location of the oleosomes within a typical oil-bearing seed, in this case safflower.
The white spheres are the oil bodies that are stored within the safflower seed. The dark blue structures are protein bodies.
Spherical in shape, the oleosome consists of an inner reservoir of triglycerides, surrounded by a phospholipid layer, which in turn is surrounded or encapsulated by unique proteins called oleosins.
The oleosin protein, with a molecular weight (MW) between 20 kilodaltons (kd) and 24 kd, is made of both hydrophilic and hydrophobic portions. Some of the hydrophobic portion of the oleosin protein penetrates into the inner triglyceride core and serves as an anchor (Figure 2). The hydrophobic portion of the protein is represented by the thick area and the hydrophilic portion is represented by the thinner portion.