Effect of Postmortem Conditions on Certain Chemical, Morphological and Organoleptic Properties of Bovine Muscle

Abstract

Paired sides from U.S. Choice grade beef were aged immediately after slaughter at 2 and 16°C. Samples were removed from longissimus and semitendinosus at slaughter and at 1, 3 and 7 days postmortem for ATPase assay, phase microscopy, shear and organoleptic evaluation. Rib steaks from sides aged at 16°C for 1‐day postmortem were as tender as steaks from sides aged at 2°C for 7 days postmortem. Flavor development of rib steaks also was more rapid at 16°C than at 2°C. Tenderness of semitendinosus steaks was improved by aging sides at 16°C; the difference in improvement of tenderness of semitendinosus, however, was not as great between 2°nd 16° as it was for rib steaks. Ca++, Mg++ and EGTA‐modified ATPase activity of myofibrils from both muscles increased with postmortem time, with myofibrils from muscles held at 16°C having slightly higher ATPase activity than myofibrils from muscles held at 2° Increased EGTA‐modified ATPase activity was indicative of loss of calcium sensitivity of the myofibril. Sarcomeres of myofibrils from longissimus were longer at 1‐day postmortem than those from at‐death longissimus and they remained essentially unchanged during the remainder of postmortem aging; however, tenderness improved at 16°C for 1 day and at 2°C for 3 days. Also greater fragmentation of myofibrils from longissimus postmortem aged at 16°C for 1 day and at 2°C for 3 days was observed, suggesting that the rate of myofibril fragmentation is an important factor in tenderization.

Características e potencial tecnológico da carne da capivara

“…Embora indesejável sob o ponto de vista sanitário, um pH elevado traz vantagens tecnológicas, aumentando a capacidade de retenção de água da carne e permitindo a elaboração de produtos mais nobres, como presunto cozido (HONIKEL, 1988;JUDGE, 1989;TERRA, 1998). Quando os músculos vermelhos são expostos ao frio em estágios anteriores ao estabelecimento do rigor mortis, há um aumento da força de contração tecidual (diminuição do comprimento do sarcômero), com conseqüente prejuízo da maciez da carne, fenômeno conhecido como encurtamento pelo frio (PARRISH et al, 1973;MARSH 1977;LOCHNER et al, 1980;JUDGE et al, 1989), o qual pode ser minimizado em carcaças grandes e pesadas, com adequada gordura de cobertura, pois a velocidade de resfriamento será menor (LOCHNER et al, 1980;MARSHALL, 1994). A carcaça da capivara é pequena e leve, se comparada a uma carcaça bovina.…”

Encurtamento pelo frio de fibras musculares oxidativas de bovinos pela técnica de NADH-TR

“…Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS, Brasil. fenômeno conhecido como cold shortening ou encurtamento pelo frio (PARRISH et al, 1973). O tecido muscular sofre maior encurtamento quando está em pré-rigor e na temperatura entre 2 e 37 o C, exceto na faixa de temperatura entre 14 e 19 o C, onde o encurtamento é mínimo (LOCKER & HAGYARD, 1963).…”

Effects of Aging Period Prior to Freezing on Meat Quality of Hanwoo Muscle (Longissimus dorsi)

“…Similarly, Wheeler and Koohmaraie (1994) reported that the sarcomere length of ovine longissimus muscle decreased up to 24 h postmortem and then increased up to 14 d postmortem at 1 o C in a chill cooler. The myofibrillar fragmentation index (MFI) is a good indicator of the extent of proteolysis due to the vicinity of the Z-disc, and this parameter is affected by the storage periods and temperature Parrish et al, 1973). In many previous studies, MFI was used to evaluate and predict meat tenderness (Han et al, 1996), and a high positive correlation between MFI and shear force (p<0.0001, r= -0.53) in aged muscle was observed by Kim et al (2007).…”