Triglycerides consist of three fatty acids joined to a glycerol molecule by three ester bonds in a condensation reaction.Different triglycerides have different properties because they contain different fatty acids.Fatty acids all have a -COOH group at the end. Some contain C=C double bonds and are said to be unsaturated. Others have no double bonds and are saturated.Monounsaturated fatty acids have one double bond. Polyunsaturated fatty acids have more than one double bond.