Sorting for beef tenderness using high performance liquid ...

Sorting for beef tenderness using high performance liquid chromatography and capillary electrophoresis: A research note q J.R. Patel, M.B. Solomon * , T. Fahrenholz, E. Paroczay USDA, Agricultural Research Service, Food Technology and Safety Laboratory, 10300 Baltimore Avenue, BARC-East, Bldg. 201, Beltsville, MD 20705-2350, USA Received 4 January 2005; received in revised form 18 July 2005; accepted 18 July 2005 Abstract This study utilized two sampling methods to examine changes in sarcoplasmic proteins during aging of beef and their relation to tenderness. Water-soluble proteins either obtained by manually expressing exudates from the meat (drip) or by an extraction pro-
cedure using homogenization and centrifugation (ext) were analyzed for longissimus lumborum muscle using HPLC and capillary
electrophoresis (CE) on days 2, 7, 10 and 14 postmortem. A peak that consistently increased with aging was identied using HPLC.
Among nine peaks detected in the CE analysis, peak 9 (100 kDa) that increased and peak 4 (30 kDa) that decreased with aging were
correlated (P < 0.05) to tenderness as determined by WarnerBratzler shear force (WBSF). For pooled data of all aging periods, drip
sample explained the most variability (49%) in shear force compared to ext sample (25%) using HPLC analyses. At 2 days postmor-
tem, a multiple linear regression model explained 83% of the variation in WBSF using CE-ext or HPLC-drip samples. Sixty percent
of the variability in shear force was explained by CE-ext samples for day 7 data. The variability in shear force as explained by either
drip or ext sample was less than 51 percent for 10 and 14 days postmortem data. The drip samples were comparable to ext samples in
predicting WBSF values for both tough (>46 N WBSF on day 2) and tender (<46 N WBSF on day 2) strip loins using CE and
HPLC procedure. Results suggest that a simple drip sampling may have a potential for use with either HPLC or CE analyses on
day 2 postmortem for sorting carcasses into tenderness groups.
Published by Elsevier Ltd. Keywords: Tenderness; High performance liquid chromatography; Beef; Aging; Capillary electrophoresis 1. Introduction The eating quality of beef depends on a number of organoleptic properties including tenderness, appear-
ance, color, intramuscular fat content, taste, and tex-
ture. While color and fat content are predominant traits considered when consumers purchase beef, tender-
ness is the most important quality characteristic that
inuences the satisfaction of and decision to repurchase
meat ( Koohmaraie, Wheeler, & Shackelford, 1995; Morgan et al., 1991 ). Achieving consistent tenderness in beef has been dicult despite the eorts to standard-
ize breeding, management, nutrition, age and post har-
vest handling. In order to control the problem of
inconsistent tenderness, it is important to have a better
understanding of the mechanisms that aect meat ten-
derness during postmortem aging. The conversion of muscle to meat and subsequent tenderization typically are a result of the activity of
several pH-dependent enzyme systems ( Hu-Lonergan 0309-1740/$ - see front matter. Published by Elsevier Ltd.
doi:10.1016/j.meatsci.2005.07.011 q The use of trade, rm or corporation names in this publication is for the information and convenience of the reader. Such use does not
constitute an ocial endorsement or approval by the United States
Department of Agriculture or the Agricultural Research Service of any
product or service to the exclusion of others that may be suitable. * Corresponding author. Tel.: +1 301 504 8400; fax: +1 301 504 8438. E-mail address: msolomon@anri.barc.usda.gov (M.B. Solomon). www.elsevier.com/locate/meatsci MEAT SCIENCE Meat Science 72 (2006) 574580 & Lonergan, 1999 ). Most research has pointed to the calpain proteolytic enzyme family as being the major
factor responsible for the protein degradation that
causes meat tenderization ( Koohmaraie, 1996 ). During aging, sarcomeric and cytoskeletal proteins, such as
titin, nebulin ( Taylor, Geesink, Thompson, Koohma- raie, & Goll, 1995 ), desmin ( Rowe, Maddock, Loner- gan, & Hu-Lonergan, 2001 ) and troponin-T (TnT) ( Lonergan, Hu-Lonergan, Wiegand, & Kriese-Ander- son, 2001 ) are degraded. The identication and quantication of aging- induced proteolytic products oer the potential for
predicting beef tenderness. A 110 kDa myobrillar frag-
ment, found to originate from C-protein ( Casserly, Stoeva, Voelter, Healy, & Troy, 1998 ), appears during the aging of beef ( O

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