Identification of Compounds Responsible for Fruity Flavor Defect of Experimental Cheddar Cheeses1,2

Abstract

The volatile constituents of Cheddar cheese possessing the fruity flavor defect were compared to the volatile constituents of normal cheese manufactured under identical conditions except for the type of starter organisms employed. Sensory evaluation of the components isolated from fruity cheese by a molecular distillation technique and separated by gas-liquid chromatography (GLC) implicated ethyl butyrate and ethyl hexanoate as the compounds primarily responsible for the defect. Positive identification of these components was accomplished by mass spectrometry.GLC analysis of the volatiles entrained from the fat from fruity and normal cheese pairs demonstrated that ethyl butyrate and ethyl hexanoate were present at levels from two to ten times greater in the fruity samples. Levels of ethanol from 6 to 16 times greater were found in the fruity cheeses. These observations suggest that excessive production of ethanol may be responsible for the accentuated esterification of free fatty acids, thus resulting in highest levels of ethyl esters.