Document Type

Thesis - University Access Only

Award Date

2001

Degree Name

Master of Science (MS)

Department / School

Animal Science

Abstract

The objectives of this research were to evaluate intramuscular tenderness variation and alternative fabrication techniques for the beef wholesale chuck and the beef wholesale round. Rib/chuck rolls (RCR)(n = 30) consisting of the ribeye roll and chuck eye roll subprimals (2nd through 12th rib locations) were cut into 22 steaks each (two steaks per rib location), and Warner-Bratzler shear force and consumer purchase preference were evaluated for steaks at each rib location. Steaks from different locations of the RCR were comprised of differing proportions of several muscles: longissimus muscle (LM), spinalis dorsi and multifidus dorsi (SP), and complexus (CO). The LM (4th rib to 12th rib) contained three tenderness regions: 7th rib through 12th rib, 5th and 6th ribs, and 4th rib regions (lowest, intermediate, aI?,d highest shear force values, respectively; P < 0.01 ). Shear force differed (P < 0.05) among rib locations for the SP (2nd rib to 9th rib), but no logical pattern was evident. The CO (2nd rib to 7th rib) was more tender toward the anterior end (P < 0.05). The region of the RCR represented by the 4th through 6th rib locations had steaks with higher weighted-average shear force (average shear force of each steak, weighted for surface area of each muscle) values as compared to the remainder of the RCR (P < 0.05). Animal-to-animal variation in shear force was 36% greater than rib-to-rib variation in shear force; thus, statistically significant differences in tenderness among rib locations may be undetectable by consumers. Steaks (n = 330) were offered for sale at a retail supermarket and case time was monitored on each steak to determine consumer purchase preference. Steaks from the 2nd through 4th rib locations required more time to sell (P < 0.01) than steaks from the 5th through 12th rib locations. Two alternative locations for the rib/chuck point of separation could be: between the 6th and 7th ribs yielding a ribeye subprimal useful in marketing a "premium quality'' product or between the 4th and 5th ribs which would yield four more 2.5-cm ribeye steaks per carcass. Intramusclular tenderness variation was also evaluated in four muscles in the beef wholesale round including: biceps femoris (BF), semitendinosus (ST), semimembranosus (SM), and adductor (AD). At 48 h postmortem, the BF, ST, SM, and AD were dissected from either the left or right side of ten carcasses, vacuum packaged, and aged for an additional 8 d. Each muscle was then frozen and cut into 2.54-cm-thick steaks perpendicular to the long axis of the muscle. Steaks were broiled on electric broilers to an internal temperature of 71 ° C. Location specific cores were obtained from each cooked stea~ and Wamer-Bratzler shear force was evaluated. Definable intramuscular tenderness variation (SD = 0.56 kg) was almost twice as large as between-animal tenderness variation (SD= 0.29 kg) and 2.8 times as large as between-muscle variation (SD = 0.20 kg). The ranking of muscles from greatest to least definable intramuscular tenderness variation was BF, SM, ST, and AD (SD=1.09, 0.72, 0.29, and 0.15 kg respectively). The BF had its lowest shear force values at the origin (sirloin end), intermediate shear force values at the insertion, and its highest shear force values in a middle region 7 to 10 cm posterior to the sirloin-round separation point (P < 0.05). The BF had lower shear force values towards the ST side than towards the vastus lateralis side (P < 0.05). The ST had its lowest shear force values in a 10 cm region in the middle, and its highest shear force values towards each end (P < 0.05). The SM had its lowest shear force values in the first 10 cm from the ischial end ( origin), and its highest shear force values in a 13 cm region at the insertion end (P < 0.05). Generally, shear force was lower towards the superficial (medial) side than towards the deep side of the SM (P < 0.05). There were no intramuscular differences in shear force values within the AD (P > 0.05). These data indicate that definable intramuscular tenderness variation is substantial and could be used to develop alternative fabrication and (or) merchandising methods for beef round muscles.

Library of Congress Subject Headings

Beef -- Quality
Meat cuts

Format

application/pdf

Number of Pages

64

Publisher

South Dakota State University

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