Analysis of fatty aldehyde composition, including 12-methyltridecanal, in plasmalogens from Longissimus muscle of concentrate- and pasture-fed bulls

In a large study, 64 German Holstein and German Simmental bulls were randomly allocated to either an indoor concentrate system or periods of pasture feeding followed by a finishing period on a concentrate containing linseed to enhance the contents of beneficial fatty acids in beef. This paper reports the diet effects on the concentration of 12-methyltridecanal (12-MT) and further fatty aldehydes released from plasmalogens in the phospholipids of longissimus muscle of the bulls. Because of the trace level of the important odorant 12-MT in beef, the determination of fatty aldehydes in phospholipids was done by acidic hydrolysis and the reaction of the aldehydes with 2,4-DNPH followed by high-pressure liquid chromatography (HPLC) analysis. The diet affected the 12-MT concentrations in the muscle phospholipids of both breeds. Pasture feeding significantly increased the 12-MT concentrations up to 350 mu g/100 g fresh muscle in the muscle phospholipids of German Holstein and German Simmental bulls as compared with the concentrate-fed bulls. Furthermore, pasture feeding resulted in a significant increase of n-octadecanal in the muscle phospholipids of both breeds up to 39.5 mg/100 g fresh muscle. The concentration of n-hexadecanal was not affected by the diet. Pasture feeding as compared to concentrate feeding significantly decreased the concentration of n-octadec-9-enal in the muscle phospholipids. Summarizing, pasture feeding increased the 12-MT concentration, which can be associated with meat of more intensive aroma and better taste.