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Notes: The epimysial connective tissues from normal and PSE longissimus dorsi muscles were subjected to physical characterization. No differences in conventionally determined shrinkage temperatures were observed. However, differential thermal analysis (DTA) studies revealed that epimysium from PSE tissues had lower onset and recovery temperatures and contained a higher percentage of components melting at low temperatures than that from normal tissues. The epimysium from PSE muscles also had a higher initial moisture and lower dry matter content. Epimysial connective tissues underwent osmotic swelling in neutral solutions, with those from PSE muscles imbibing significantly more water than that from normal muscles. Dry matter content decreased during neutral swelling, probably due to a loss of ground substance. Collagen from PSE muscles had a molecular weight between cross-links (Mc) of 6.37 ± 104 and a resultant cross-link density of 5.23/ molecule, while normal tissues had corresponding values of 4.67 ± 104 and 7.73. These differences were only significant at the 10% level.

Notes: Meat and water slurries of both leg and breast muscle from heavy hens were cooked in a nitrogen atmosphere. Some of the chemical components in the volatile fraction were identified by solubility classification, derivative preparation, and/or functional group analysis in combination with gas chromatography and/or qualitative chemical analyses and odor evaluation. Twenty-nine compounds in the volatiles from leg muscle and 25 compounds from breast muscle were identified by the functional-group trapping technique followed by gas chromatography of the effluent fractions. Qualitative chemical tests revealed 19 major classes of compounds and a few specific compounds.Removal of sulfur compounds resulted in an almost complete loss of “meaty odor” in both dark and light meat. Removal of the carbonyls from the volatile fraction resulted in a loss of “chickeny-flavor” and intensification of the “meaty or beef-like odor.”

Notes: SUMMARY– The epimysial connective tissue from normal and PSE (pale, soft and exudative) porcine muscle was chemically characterized. Samples from PSE muscles exhibited markedly lower turbidity values (P 〈 0.01) than those from normal muscles. No significant differences were found in ultimate pH values. The epimysium from PSE muscles contained significantly higher (P 〈 0.05) quantities of salt soluble tropocollagen and a greater amount of heat labile collagen (P 〈 0.01) than that from normal tissues. No significant differences in α- and β-subunit composition, plasma hydroxy-proline levels or amino acid composition were evident between the two sources of epimysial connective tissues.

Notes: The activity of 17 or 18 specific enzymes in the longissimus dorsi muscle of five beef and 18 pork carcasses was followed by histochemical procedures. Beef samples were removed from carcasses within 10 min up to 20 days port-mortem, and pork samples within 16 min up to 24 and/or 48 hr post-mortem. The beef carcasses were submitted to so-called normal cooling procedures. However, one side of each of 13 pork carcasses was placed at –29°C, while the other side was subjected to 37°C for the first 41/2–5 hr post-mortem.In beef muscle, the histochemical activity of lactate dehydrogenase, alpha-glycerophosphate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, TPN diaphorase, and DPN diaphorase showed a steady decrease with increasing time post-mortem. Reactions for both alcohol dehydrogenase and glutamate dehydrogenase were very weak or entirely absent at 48 hr post-mortem and all subsequent sampling periods. Positive reactions for glucose-6-phosphate dehydrogenase and beta-hydroxybutyrate dehydrogenase were observed in the initial samples only. No acid phosphatase, leucine amino peptidase, or 6-phosphogluconate dehydrogenase activity was detected in any of the samples.In pork muscle, the activity of lactate dehydrogenase, alpha-glycerophosphate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, and DPN diaphorase was slightly weaker at both 0 and 24 hr post-mortem than similar activity in beef muscle. Alcohol dehydrogenase activity was weaker than that observed for the above enzymes, while the activity of glutamate dehydrogenase was of intermediate intensity. Traces of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activity were observed in only a portion of the initial samples. Similarly, weak reactions for beta-hydroxybutyrate dehydrogenase were observed only at 0 hr post-mortem. None or only weak activity was observed for malic dehydrogenase, and TPN diaphorase activity was unexplainably absent from all samples. Moderate levels of cytochrome oxidase activity were observed at both 0 and 24 hr post-mortem. LTDPG-glycogen transferase was completely inactivated by the 37°C treatment post-mortem, but the treatment had a less marked effect upon phosphorylase and branching enzyme. The presence of acid and alkaline phosphatase activity in muscles of 7 carcasses suggested that a degenerative condition existed in these muscles.

Notes: SUMMARY— Beef adipose tissue was separated into the water soluble, salt soluble and insoluble (water-salt-ether) fractions, and the amount of H, S evolved upon heating each of the fractions was determined. The yield of H, S per 100 g of adipose tissue was 17.6, 1.7 and 5.5 μM for the water soluble, salt soluble and insoluble fractions, respectively. Thus, the water soluble fraction contributed about 71% of the H, S, while the corresponding contributions from the salt soluble and the insoluble fractions amounted to approximately 7 and 22%, respectively.