No abstract

The objective of this study was to evaluate processing methods for frozen beef subprimals; the effects of freezing and thawing rates on tenderness, sensory properties, and retail display were evaluated. There were 6 treatments: fresh, never frozen 14 d wet aged (14D); fresh, never frozen 21 d wet aged (21D); blast frozen-fast thawed (BF); blast frozen-slow thawed (BS); conventionally frozen-fast thawed (CF); and conventionally frozen-slow thawed (CS). All frozen beef subprimals were aged for 14 d before freezing. Three beef subprimal cuts, rib eye roll (n=90), strip loin (n=90), and top sirloin butt (n=90), were used with 3 replications of 5 samples per treatment per week (total of 9 wk, n=270). Blast freezing occurred by placing spacers between the boxes of meat on pallets at -28°C with high air velocity for 3 to 5 d. Conventional freezing occurred with boxes of meat stacked on pallets and placed in a -28°C freezer with minimal air movement for at least 10 d. Fast thawing of subprimals (to an internal temperature of -1°C to 1°C) occurred by immersion in a circulating water bath (<12°C) for 21 h, and slow thawing of subprimals occurred over a 2-wk period by placing individual subprimals on tables at 0°C. Steaks (2.5 cm thick) were cut from the longissimus thoracis (LT), longissimus lumborum (LL), and gluteus medius (GM) for Warner-Bratzler shear force (WBS), trained sensory evaluation, and retail display. For LL and GM beef steaks, frozen treatments were equal or lower in WBS values to 14D and 21D beef steaks. No differences were detected in WBS among the treatments applied to GM beef steaks (P=0.08). There were no differences in sensory tenderness among the LL, LT, and GM (P>0.05). All LL and LT beef steaks had approximately 4 d to 40% discoloration, and all GM steaks had over 3 d to 40% discoloration. Steaks from the LL and LT began to discolor at about 3 d, and the GM began to discolor after 1 d. For all beef subprimals, purge loss during storage and thawing was significantly greater for the slow-thawed subprimals (P<0.01), and all fast-thawed subprimals were equal or superior to 14D and 21D (P<0.01) in storage and thawing purge. During retail display, the greatest purge loss occurred in fast-thawed treatments (P<0.01). Overall, freezing rate did not affect purge loss, and neither freezing nor thawing rates had significant meaningful effects on WBS, and sensory properties were comparable with fresh, never-frozen subprimals.

No abstract

Wet distillers grains contain approximately 65% moisture. A partially dried product [modified distillers grains plus solubles (MDGS)] contains about 50% moisture. However, both have similar nutrient composition on a dry matter basis. The objective of this study was to investigate the effects of finishing diets varying in concentration of MDGS on marbling attributes, proximate composition, and fatty acid profile of beef. Yearling steers (n = 268) were randomly allotted to 36 pens, which were assigned randomly to 0, 10, 20, 30, 40 and 50% MDGS (DM basis) and fed for 176 d before harvest. The 48-h postmortem marbling score, marbling texture, and marbling distribution were assessed by a USDA grader and 1 ribeye slice (longissimus thoracis) 7 mm thick was collected from each carcass for proximate and fatty acid analyses. Treatments did not significantly alter marbling score or marbling distribution (P ≥ 0.05). United States Department of Agriculture Choice slices had coarser marbling texture when compared with USDA Select. Although dietary treatment affected marbling texture, no consistent pattern was evident. Diets did not influence fat content, moisture, or ash of the ribeye (P ≥ 0.05). For treatments 0, 10, 30, 40 and 50%, there were positive linear relationships between marbling score and fat percentage in the ribeye (P ≤ 0.05), and all slopes were similar (P = 0.45). Feeding MDGS linearly increased stearic, linoelaidic, linoleic, linolenic, PUFA, and n-6 fatty acids. As dietary MDGS increased, linear decreases were observed in all n-7 fatty acids and cubic relationships were detected for the 18:1 trans isomers [trans-6-8-octadecenoic acid (6-8t), elaidic acid (9t), trans-10-octadecenoic acid (10t), and trans vaccenic acid (11t)]. No effects were observed for saturated fatty acids containing 6 to 14 carbons. Feeding MDGS resulted in increased PUFA, trans, and n-6 fatty acids, minimal effects on marbling texture, and no effects on the relationship of marbling to intramuscular fat content relationship.

No abstract