Effect of High Hydrostatic Pressure on Meat Microstructure

Bovine longissimus muscle was prerigor pressure treated at 103.5 MNm- 2 at 37 °C for 2 min and immediately sampled, fixed and examined by light microscopy, scanning and transmission electron microscopy. Parameters like pH, Warner-Bratzler shear force values and sarcomere length were measured and related to the microscopic observations. Pressure treated samples have shorter sarcomere length, lower pH and W-B values. Physical changes include separation of sarcolemmal and endomysial sheath, contraction bands, disruption of myofibrillar structure and increased interfibrillar and intermyofibrillar spaces. At the subcellular levels, disappearance of glycogen granules, appearance of swollen mitochondria, sarcoplasmic reticulum and in some cases ruptured mitochondria were observed . These morphological changes in mitochondria and sarcoplasmic reticulum should furnish the additional Ca 2+ to account for the pressure induced contraction. The interactions between the chemical and physical effects should account for the tenderizing effect of pressure treatment

The Combined Effects of the Calcium Activated Factor and Cathepsin D on Skeletal Muscle

Myofibrils were isolated from atdeath ovin elongissimus muscles and incubated with crude calcium activated factor prepared from the same muscle and with purified cathepsin D. Myofibrils we reincubated with these enzymes separately (first incubation) and successively (second incubation). The major changes induced by cathepsin D first incubation include degradation of myofibrillar proteins with molecular weight \u3e 200 K, myosin, actin, troponin- T and troponin 1. Also new bands appeared at the 140- 160 K, 80 K, 68 K and 30 K regions. Similar changes were obtained 1v hen myofibrils were incubated first with CAF then with cathepsin D (second incubation). On the other h and CAF first incubation resulted in the degradation of the high molecular weight proteins ( \u3e 200 K), desmin, troponin T , troponin I and it released a -actinin. Also new bands appeared immediately below C-protein (140 K) , 95 K and 30 K. Unlike cathepsin D, CAF did not affect myosin or actin. However, when myofibrils were first incubated with cathepsin D then wit h CAF (second incubation) the latter was able to degrade actin to a much greater degree than cathepsin D. Both enzymes were able to affect the Z-lines of the myofibrils

Malheur feeders day

Published April 1962. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Effect of Prerigor Pressurization on Bovine Lysomal Enzyme Activity

Longissimus muscle from 8 dairy cows was prerigor pressure (PRP) treated at different pres sure levels (0, 34.5, 68.9 and 103.5 I·INm- \u27 ). a-Glucuronidase (indicator of lysosomal enzymes) activity in the unsedimentable (U) and sedimentable (S) fractions was fluorometrically assayed at ! ~ , 24 and 168 hr postmortem. At I ~ and 24 hr postmortem, the specific activity of a-Glucuronidase in the U-fraction from PRP treated samples was significantly (

Summary of reports : sheep and wool day, November 3, 1961

Published November 1961. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo