Biochemical and Structural Effects of Rigor Mortis-Accelerating Treatments in Broiler Pectoralis

Abstract

This study was conducted to elucidate the mechanism of action of two selected rigor mortis-accelerating treatment systems employed in the prevention of the toughness associated with early-harvested (1 h post-mortem) broiler Pectoralis muscle. The treatments included 14 min of low voltage electrical stimulation (110 V, 1 A, pulsing 1 s on and 1 s off) combined with high temperature conditioning (39 C) and muscle tensioning (LV + HTC + MT); a 15-s high voltage stimulation (440 V, 1 A pulsing 2 s on and 1 s off) combined with muscle tensioning (HV + MT); and a control simulating commercial broiler processing practices. The rigor-accelerating treatments reduced pH and increased R-value (inosine:adenosine ratio) at 1 h post-mortem, but only the LV + HTC + MT treatment reduced sarcomere shortening. Both rigor treatments reduced the amount of measurable myofibrillar fragmentation. Cathepsin B and B + L activities were not affected by the rigor treatments. Calpain I activity was not detectable in any 24-h post-mortem sample. Calpain II activity at 24 h post-mortem was greater in muscles receiving HV + MT than from the LV + HTC + MT or control carcasses, but was reduced in all muscles by 24 h postmortem. An SDS-PAGE indicated a 30-kDa polypeptide that was absent at death and appeared in control and LV + HTC + MT muscles but to a lesser extent in HV + MT muscles. These results suggested that the LV + HTC + MT treatment has a greater tenderizing effect than the HV + MT treatment because the former achieves a better balance between reduced sarcomere shortening and myofibrillar fragmentation.

Physical and Biochemical Effects of Broiler Breast Tenderization by Aging after Pre‐rigor Deboning

“…As a result, Etherington et al (1987) postulated that the rapid rate of conditioning in the avian species may account for differences in proteolytic activity from mammalian muscle. Walker et al (1995) found that residual µ-calpain activity in Pectoralis was absent at 24 hr post-mortem suggesting complete autolysis by this time.…”

“…The activities of µand m-calpain were determined using the extraction and caseinolytic methods described by Wheeler and Koohmaraie (1990). Myofibrillar protein extraction using modified procedures described by Walker et al (1995) enabled the detection of the 30 kDa protein. The procedure was modified in order to concentrate myofibrillar proteins by homogenizing muscle samples in 2.5 volumes of extraction buffer instead of the 6 volume.…”

“…A set of molecular weight markers (Sigma Chemical Company, St. Louis, MO) provided identification of protein and polypeptide components of the myofibrillar extract. The 30 kDa protein was quantified at 0, 47, and 71 hr post-deboning aging using a video densitometeric (Interactive Technologies International, L.C., St. Petersburg, FL) scan of the gel allowing for estimation of the amount of protein in each band relative to the total protein in each lane (Walker et al, 1995). Sarcomere lengths were measured using a neon laser diffraction method of Cross et al (1980) as modified (Sams and Janky, 1986).…”

Impact of the electric shock on the embryonic development and physiological traits in chicks embryo

“…While broilers have a high-voltage ES decreased at least m-calpain activity "p-calpain was completely autolysis in both ES and control muscles" (Walker et al 1995). ES, on the other hand, enhanced calpain activity but had no impact on m-calpain (Alvarado and Sams 2000).…”