The triacylglycerol and the cholesteryl esters that are resynthesised are very hydrophobic in nature and aggregate in an aqueous environment. Therefore, they need to be packaged as lipid droplets surrounded by a thin layer of proteins, phospholipids, and unesterified cholesterol. These packages stabilise the lipids and increase their solubility. The lipids that are packaged with the proteins and phospholipids are known as lipoproteins.