Evaluation of Muscle Fiber Characteristics Based on Muscle Fiber Volume in Porcine Longissimus Muscle in Relation to Pork Quality

G D Kim,D D Boler,A C Dilger,B J Klehm,J E Lowell,M F Overholt,B N Harsh

doi:10.22175/mmb2018.07.0018

G D Kim, D D Boler + Show 5 more

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https://doi.org/10.22175/mmb2018.07.0018

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Abstract

In livestock science and meat science, muscle fiber characteristics have been evaluated based on a cross-sectional area (CSA) of muscle fiber. However, muscle fiber is not planar but cylindrical. Thus, muscle fiber volume and volume-based characteristics were evaluated in this study. In addition, their relationships to pork loin quality was assessed and compared with that of CSA-based muscle fiber characteristics. Muscle fiber type IIB was underestimated by CSA-based evaluations with 1.6 times in fiber size and 2.6 times in relative composition. The pennation angle, which ranged from 48.00° to 83.33°, determined the real CSA and total number of fibers (TNF) on the surface of a loin chop. Significant (P < 0.05) correlation coefficients were found: fiber volume (r = –0.37) and volume % (r = –0.37) of type IIX with loin length; volume % of type IIX with CIE L* (r = 0.40); volume % of types IIX (r = 0.39) and IIB (r = –0.39) with Warner-Bratzler shear force. Although those correlations to loin quality differed from those of CSA-based characteristics, the Z-scores did not show any significance between the 2 correlation coefficients, except for TNF. Therefore, the conventional methodology for muscle fiber characteristics can be used for evaluating the relationship to pork quality; however, the new methodology is more useful in estimating the characteristics of muscle fiber, which is elongated and cylindrical and to correct the underestimated fiber size and composition of type IIB.

Highlights

Studies on muscle fiber characteristics and their relationships to meat quality have been conducted frequently in the field of meat science over the last few decades
The influences of breed, genotype, sex, age, diet, exercise, and growth promotors on intramuscular fat (IMF) accumulation in the body, growth performance, and development of muscles can be estimated by the muscle fiber characteristics (Lebret et al, 1999; Wegner et al, 2000; Gentry et al, 2002; Bee et al, 2007; Ebarb et al, 2017)
Loin volume, which was derived from Loineye area (LEA) and loin length, ranged from 2,598.99 to 4,047.59 cm3

Summary

Introduction

Studies on muscle fiber characteristics and their relationships to meat quality have been conducted frequently in the field of meat science over the last few decades. Regardless of animal species, muscle fiber characteristics Ber size and relative composition) were considered important factors or criteria for assessment of the postmortem metabolic properties and meat quality characteristics, such as color, water-holding capacity, tenderness, and sensory property (Ozawa et al, 2000; Chang et al, 2003; Ryu and Kim, 2006; Jeong et al, 2010). Most of the previous studies on meat and livestock science were based on. The influences of breed, genotype, sex, age, diet, exercise, and growth promotors on intramuscular fat (IMF) accumulation in the body, growth performance, and development of muscles can be estimated by the muscle fiber characteristics (Lebret et al, 1999; Wegner et al, 2000; Gentry et al, 2002; Bee et al, 2007; Ebarb et al, 2017).

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