The Effect of Quality Grade and Muscle on Collagen Contents and Tenderness of Intramuscular Connective Tissue and Myofibrillar Protein for Hanwoo Beef

S S Moon

doi:10.5713/ajas.2006.1059

Abstract

Six muscles were seamed out randomly from Hanwoo carcasses (n = 12) of each quality grade (quality grades 1, 2 and 3). Samples were analysed for their total and soluble collagen contents, IMCT (intramuscular connective tissue) and Warner-Bratzler shear force (WBSF). Simple correlation (n = 21) was determined for WBSF among major muscles. For LT (longissimus thoracis), total collagen content was significantly higher (p<0.05) for quality grade 3 than those for quality grades 1 and 2. For semitendinosus (ST), semimembranosus (SM), psoas major (PM) and serratus ventralis (SV), total collagen content of quality grade 1 was lowest (p<0.05) of all quality grades. IMCT shear force for gluteus medius (GM) decreased (p<0.05) with better quality grade, and those for other muscles, with the exception of GM, were higher (p<0.05) for quality grade 3 than for quality grades 1 and 2. WBSF values showed GM and LT to be decreased (p<0.05) with better quality grade, and PM to be higher (p<0.05) for quality grade 3 than those for quality grades 1 and 2. SM, ST and SV from quality grade 1 had lower (p<0.05) WBSF value than those from quality grades 2 and 3. Total collagen content of ST was highest (p<0.05) of all muscles, whereas that of PM was lowest (p<0.05). Soluble collagen contents of LT and SV from quality grades 1 and 2 were, in general, higher (p<0.05) than other muscles, but that of SM was lowest (p<0.05). ST and SM had higher (p<0.05) WBSF values for three quality grades when compared to other muscles, whereas PM was lowest (p<0.05). LT had the strongest simple correlation with SV (r = 0.78) and GM (r = 0.77), and SM had the strongest correlation with ST (r = 0.73) and LT (r = 0.73). Also, PM had the strongest correlation with SV (r = 0.62).

Highlights

The quality grade is primarily determined by the marbling score and adjusted by other carcass traits such as meat colour, fat colour, texture and maturity when there is a particular defect in these traits (USDA, 1989; APGS, 1995)
Carcass and retail cut price are largely determined by the quality grade, so breeders and producers have forced the improvement of the quality grade (Savell et al, 1989; Park et al, 2002; Moon et al, 2003)
Much research has been focused on the prediction of longissimus tenderness, because the longissimus comprises a higher proportion of total carcass value as compared to any other muscles (Shackelford et al, 1995, 1997)

Summary

Introduction

The quality grade is primarily determined by the marbling score and adjusted by other carcass traits such as meat colour, fat colour, texture and maturity when there is a particular defect in these traits (USDA, 1989; APGS, 1995). Better quality grades have a heavier carcass weight with a higher marbling score, redder meat colour and whiter fat colour (Lorenzen et al, 1993; Vergara et al, 1999; Moon et al, 2003). Under the circumstances of the Korean meat market, longissimus within the same quality grade is estimated at the highest price compared with other muscles (APGS, 2003). It might be desirable if longissimus could be

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