|Neel, James - Jim|
Submitted to: American Society of Animal Science
Publication Type: Proceedings
Publication Acceptance Date: 6/30/2005
Publication Date: 7/24/2005
Citation: Duckett, S.K., Neel, J.P., Clapham, W.M., Fontenot, J.P. 2005. Volatile flavor compounds in beef from cattle finished on pastures or concentrates. #261, J. Anim. Sci., Vol. 83, Suppl. 1, p. 204.
Technical Abstract: Angus-cross steers (n = 68) were stockered at three growth rates (LOW, MED or HIGH) during the winter months prior to finishing on pasture (PAST) or corn silage-concentrate diet (CONC) to assess differences in volatile flavor compounds as influenced by finishing system. Ribeye steaks were broiled to an internal temperature of 71°C and served to an eight member sensory panel to determination of off-flavor intensity (0 = none; 8 = intense). Sensory off-flavor ratings were averaged for each steak and ranked from highest to lowest by finishing treatment. A sub-sample (n = 20) was selected based on sensory off-flavor ratings to represent lowest (LOW) and highest (HIGH) off-flavor scores for each finishing treatment. Steaks were broiled to a medium degree of doneness, cut into cubes, finely chopped, and samples (2.5 g, in duplicate) taken immediately for static headspace analyses of volatile flavor compounds by GLC. Flavor compounds were identified based on retention time of various aldehydes, acids and other compounds reported to impact meat flavor. Data were analyzed with finishing treatment, off-flavor score and interaction in the model. Total peak area of all flavor compounds and total aldehydes did not differ due to dietary treatment, off-flavor score, or their interaction. Hexanal, an oxidation product of linoleic acid, was present in greater (P < 0.05) amounts for CONC than PAST, regardless of off-flavor score. 2-Methyl propanal was present in greater (P < 0.01) concentration for PAST than CONC, regardless of off-flavor scores. Volatile flavor compounds did not differ between steaks of LOW or HIGH off-flavor scores but several interactions between dietary treatment and off-flavor were detected. Propanal peak area was greater (P < 0.05) for PAST-HIGH than PAST-LOW or CONC-HIGH. Three other unidentified peaks were greater for CONC-HIGH than CONC-LOW and PAST, regardless of off-flavor score. One unidentified peak, peak 48, was present in higher (P < 0.01) amounts for PAST-HIGH than PAST-LOW and CONC, regardless of off-flavor score. Equations developed to predict off-flavor score using stepwise regression included unidentified peak 48, octanal, and propanal and explained 31% of the variation in off-flavor scores.