| Popis: |
Consumer liking, proximate composition, pH, Warner-Bratzler shear force, fatty acid composition, and volatile compounds were determined from the LM (longissimus thoracis) of cattle ( = 6 per diet) finished on conventional feedlot (USUGrain), legume, and grass forage diets. Forage diets included a condensed tannin-containing perennial legume, birdsfoot trefoil (; USUBFT), and a grass, meadow brome ( Rehmann; USUGrass). Moreover, representative retail forage (USDA Certified Organic Grass-fed [OrgGrass]) and conventional beef (USDA Choice, Grain-fed; ChGrain) were investigated ( = 6 per retail type). The ChGrain had the greatest (0.05) intramuscular fat (IMF) percentage followed by USUGrain, the IMF percentage of which was greater (0.05) than that of USUGrass and OrgGrass. The IMF content of USUBFT was similar (0.05) to that of both USUGrain and USUGrass. Both grain-finished beef treatments were rated greater (0.05) for flavor, tenderness, fattiness, juiciness, and overall liking compared with USUGrass and OrgGrass. Consumer liking of USUBFT beef tenderness, fattiness, and overall liking were comparable (0.05) with that of USUGrain and ChGrain. Flavor liking was rated greatest (0.05) for USUGrain and ChGrain, and that of USUBFT was intermediate (0.05) to those of ChGrain, USUGrass, and OrgGrass. Cumulative SFA and MUFA concentrations were greatest (0.05) in ChGrain and USUGrain, whereas USUGrass and OrgGrass had lower (0.05) concentrations. Concentrations of cumulative SFA and MUFA in USUBFT were intermediate and similar (0.05) to those of USUGrain and USUGrass. Each forage-finished beef treatment, USUGrass, OrgGrass, and USUBFT, had lower (0.001) ratios of -6:-3 fatty acids. Hexanal was the most numerically abundant volatile compound. The concentration of hexanal increased with increasing concentrations of total PUFA. Among all the lipid degradation products (aldehydes, alcohols, furans, carboxylic acids, and ketones) measured in this study, there was an overall trend toward greater quantities in grain-finished products, lower quantities in USUGrass and OrgGrass, and intermediate quantities in USUBFT. This trend was in agreement with IMF content, fatty acid concentrations, and sensory attributes. These results suggest an opportunity for a birdsfoot trefoil finishing program, which results in beef comparable in sensory quality with grain-finished beef but with reduced -6 and SFA, similar to grass-finished beef. |
