L. J. BRATZLER’s research while affiliated with Michigan State University and other places

Eleven polycyclic hydrocarbons derived from predominantly hard maple sawdust smoke have been separated and identified. The hydrocarbons were isolated and separated stepwise by a combination of liquid-liquid extraction, chromatography on silicic acid, thin-layer chromatography with acetylated cellulose powder and chromatography on aluminum oxide. They were characterized by ultraviolet and fluorescence studies on the fractions thus obtained from the aluminum oxide column. The polycyclic hydrocarbons found in the hardwood sawdust smoke include naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, pyrene, fluor-anthene, 1,2-benzanthracene, chrysene, 3,4-benzopyrene and 1,2-benzopyrene. Analysis of whole wood smoke and the vapor phase obtained by an electrostatic air filter showed only quantitative differences.

Isolation, separation, and partial identification of 21 carbonyl compounds found in wood smoke are described. Isolation was by precipitation of carbonyls by 2,4-dinitrophenyl-hydrazine. Separation was by gas cbromatography using Carbowax ZOM and diisodecylphthlate as the liquid phase. Tentative identification of the eluted components was based upon retention times of the unknowns compared with those of authentic compounds on the two columns used. Sixteen of the twenty-one components were tentatively identified: formaldehyde, acetaldehyde, propanal, acetone, acrolein, isobutyraldehyde, butanal, 2-butanone, diacetyl, isovaleraldehyde, J-methyl-Z-butanone, crotonaldehyde, pinacolone, 4-methyl-3-pentanone, α-methylvaleraldehyde, and tiglic aldehyde. Trace amounts of 3-hexanone and 2-hexanone were found. Also present were 1-3 five-carbon compounds, but no separation could by. achieved to identify them.

Frozen meat-water extracts stored under lights exhibit a pattern of metmyoglobin formation similar to that in frozen steaks. The spectrophotometric method of analysis was satisfactory for estimating the percent metmyoglobin in the solutions. Fluorescent lights significantly increased the formation of metmyoglobin in the solutions, similar to that reported for frozen steaks. Dialyzing the extract inhibited the increase of metmyoglobin in the frozen solution when stored under light. Addition of copper, manganese, or calcium ions in the form of the chloride salts to the dialyzed solution did not increase rate of metmyoglobin formation appreciably. The addition of chloride salts of magnesium and iron contributed to an increase in the rate of metmyoglobin formation. When the dialysate was concentrated and added to the dialyzed residue there was a significant increase in the rate of metmyoglobin formation.

The longissimus dorsi muscle was taken from 7 beef ribs, 15 beef short-loins, 129 lamb loins, and the semitendinosus muscle from 51 beef rounds and tested for tenderness by panel, press, and shear methods. Results showed that the press and shear methods used on cooked meat gave comparable relations with sensory-panel scores. When raw samples were tested by the press, little relation with panel scores of the cooked meat was found.

SUMMARY–Electrophoresis of 0.6 M KCI extracts of porcine longissimus dorsi muscle revealed little change in the type or number of protein bands found either by starch-urea or disc-urea gel electrophoresis. The 0.6 M KCI extracts of muscle samples inoculated with Pediococcus cerevisiae, Leuconostoc mesenteroides and Micrococcus luteus and stored at 2 and 10°C for 20 days did not differ electrophoretically from control samples. Extracts of samples inoculated with Pseudomonas fragi showed a loss in the number of protein bands on starch-urea gel and disc-urea gel electrophoresis, indicating this organism exhibited some proteolytic effect upon the myofibrillar proteins.

SUMMARYA procedure developed to fractionate the major nitrogen-containing components of muscle was utilized to study the relationship of intracellular muscle proteins to tenderness. The study was performed on a group of 20 yearling bulls from two lines of cattle that had been selected for differences in tenderness. The longissimus dorsi muscle contained more total nitrogen per unit of muscle tissue and almost twice as much sarcoplasmic protein as the infra-spinatus muscle. The longissimus dorsi contained less fibrillar protein and non-protein nitrogen than the infraspinatus. The following factors were correlated with tenderness as measured by shear and panel: sarcoplasmic protein nitrogen/total fibrillar protein nitrogen; soluble fibrillar protein nitrogen/ total fibrillar protein nitrogen; water released/total water. Fibrillar protein solubility was highly correlated with tenderness (r.=−0.69 for shear and r= 0.59 for panel). An r value of 0.49, significant at the 5% level, was found between water-holding capacity and tenderness as measured by the shear.

The emulsifying capacity curves for actin, myosin, actomyosin, and sarcoplasmic proteins were determined under various conditions. The proteins were ranked from greatest emulsifying capacity to least as follows: actin in the absence of salt, myosin, actomyosin, sarcoplasmic proteins (water extracted), and actin in 0.3M salt. Myosin and actomyosin produced emulsions with superior stability; however, at the pH of normal fresh meat (5.6–5.8), the sarcoplasmic fraction produced the most stable emulsions. Actin produced very stable emulsions under all conditions. The amount of protein utilized in the formation of an interface appeared to be related to the stability of au emulsion. NPN compounds were found to have no role in emulsion formation.

SUMMARY–A technique was used to obtain aseptic porcine muscle, portions of which were inoculated with cultures of Pediococcus cerevisiae, Micrococcus luteus, Leuconostoc mesenteroides and Pseudomonas fragi. The inoculated samples were compared with aseptic controls throughout a 20-day storage period at temperatures of 2 and 10°C. All 4 organisms grew at 10°C, but only P. fragi and L. mesenteroides grew at 2°C. The solubilities of the various protein fractions were affected by inoculation treatment. This was exemplified by correlation coefficients ranging from —.37—0.50. The coefficients indicated the interrelationships affected by storage conditions and bacterial growth. Protein solubility studies revealed a loss in the water-soluble fraction during storage of the controls and the M. luteus- and L. mesenteroides-treated samples. Samples inoculated with P. fragi evidenced an initial loss, followed by an increase. The solubility of meat proteins in a salt solution increased during the first 8 days of storage, then decreased or remained relatively constant for all samples. In comparison with controls, samples inoculated with P. fragi increased in salt-soluble protein solubility during the first 8 days, whereas those inoculated with L. mesenteroides decreased during the latter part of storage. Insoluble protein generally increased except for P. fragi-inoculated samples, which decreased. Nonprotein nitrogen (NPN) increased for all treatments and controls during the 20-day storage period. NPN extracted from the samples inoculated with P. fragi increased greatly. The pH increased with growth of M. luteus and P. fragi and decreased with growth of P. cerevisiae and L. mesenteroides. The emulsifying capacity was not influenced by the growth of M. luteus or P. cerevisiae. However, the emulsifying capacity of samples inoculated with L. mesenteroides decreased, whereas that of samples inoculated with P. fragi increased.