Date of Award:

5-2015

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Jerrad Legako

Committee

Jerrad Legako

Committee

Silvana Martini

Committee

Jennifer MacAdam

Abstract

Consumer evaluation, proximate data, Warner-Bratzler shear force (WBSF), fatty acid (FA) composition and volatile compounds were analyzed from the ribeye steaks (LT) finished on conventional feedlot (FL) and forages, including a perennial legume, birdsfoot trefoil (BFT; Lotus corniculatus), and a grass, meadow brome (Bromus riparius Rehmann, Grass). Representative retail forage (USDA Certified Organic Grass-fed, COGF) and conventional beef (USDA Top Choice, TC) were investigated (n = 6) for LT. Additionally, the effects of diet on round (GM) and chuck (TB) muscles FL, BFT and Grass were explored. Forage-finished beef was less liked in most of the affected attributes except BFT, which was similar to grain-finished beef. Flavor liking of BFT was similar to Grass. In GM and TB, GM was rated superior among forage-finished beef except juiciness and in FL, TB was similar to GM except juiciness where it scored greater. Grain-feeding produced more perceived tenderness meat in LT. The fat percent was found to be greatest in TC beef followed by BFT and FL being similar. A nutritionally beneficial ratio of fat components was observed in forage-finished diet. The volatile compound that evokes a buttery sensation was affected by diet and had a greater concentration in GM across all the diets. One among the compounds contributing to roasted flavor was impacted by diet among LT steaks and was greatest in BFT. All the roasted flavor compounds differed between TB and GM and were greater in GM. These results indicate that when consumers evaluated finishing diets of beef, conventional feedlot finished beef was rated most highly. However, these results further reveal that not all forages produce similar “grass-finished” beef. The perennial legume, BFT, was rated similar by consumers for all attributes, with the exception being flavor having lower values compared with FL. The chemical composition of BFT beef was found to be intermediary and similar to both FL and Grass beef in many cases. Diet was found to interact with muscle type for sensory and chemical measures. The GM and TB of FL did not differ, while within forage treatments sensory response and chemical composition were varied. These results indicate the meat quality of secondary beef muscles is more greatly impacted by forage diets. Thus more careful selection of muscles from forage finished beef is required in order to ensure quality.

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