Disclosed herein is a preform having a preform wall. The preform wall preferably comprises a composition comprising at least one polyester component, a transition metal catalyst, and a vegetable oil. The vegetable oil may comprise at least one molecule having a double allylic structure. The at least one polyester component may comprise at least one acid unit and at least one diol unit. The concentration of double allylic structures of the vegetable oil in the composition may be greater than 5.0 meq/kg of all of the polyester components. The preform has improved aesthetic characteristics.