摘要:

SUMMARY—The tenderness of beef was improved by aging. Tenderness decreased with increasing maturity for the cattle evaluated in this investigation. During the early stages of aging, samples were more tender from control animals than from ante‐mortem‐stressed cattle, but this difference was eliminated by the end of the aging periods. Water‐holding capacity and juiciness scores were increased by ante‐mortem stress treatments. WHC and juiciness scores decreased during aging. Tenderness scores were correlated significantly with WHC values and juiciness scores at the termination of the low‐temperature aging period. Transfer of moisture and mineral ions during aging appeared to be associated with the changes involved in the development and resolution of rigor mortis and improved tenderization of the meat. AS tenderness improved during aging, extractable sodium, magnesium, and calcium were released from the muscle proteins, while potassium, phosphate, and nitrogen were retained. These components changed radically during the early stages of aging, with movement and transfer more uniform during the latter stages.Magnesium was the only mineral component present in the exudate of the water‐holding‐capacity determination that appeared to be related to tenderness. A relationship existed between physiological cell maturity and the ability of the meat to transfer and bind cellular magnesium. Tenderness decreased as the quantity of magnesium decreased in the exudate from the water‐holding‐capacity determination.The pH of meat was increased by broiling, while the pH of the exudate decreased when meat samples were cooked in the water‐h

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01945.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Pre‐rigor and post‐rigor semitendinosus muscle was examined under the light microscope and in the electron microscope before and after cooking. During cooking, pre‐rigor samples were unrestrained or restrained on stainless‐steel frames at normal length and at 130% normal length. Samples which passed at 0°C into rigor unrestrained, or while restrained to the same degrees of stretch as above, were cooked post‐rigor without mechanical restraint after various periods of storage. The treatments produced differences in tenderness of the muscle pieces which were related to differences seen in the ultrastructure in the micrographs. It was concluded that, provided the effects of gross connective tissue are small, tenderness in beef muscle is produced by disruption of the actin filaments and by a breaking down of the linkages between the actin and myosin filaments in th

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01946.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—pH changes were followed in ox sternomandibularis muscles placed soon after slaughter at temperatures ranging from 1 to 37°C. Over the range 5 to 37°C, the rate at which the pH fell diminished with decrease in temperature, but for the first few hours post‐mortem it was faster at 1 than at 5°C. The ultimate pH attained at 1 or 5°C was significantly higher than that attained at 15, 25,

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01947.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Freezer burn on bovine semitendinosus muscle from animals of good grade stored at ‐10°C and 78% RH was minimized by 24 hr of pre‐storage post‐mortem at 0°C, followed by slow freezing with permitted weight loss. Good‐quality beef was less likely to develop freezer burn of the muscle surface. To induce a definite intensity, muscle tissue from calf or canner‐grade cow required weight losses that were slightly lower, though the difference was statistically significant. Lapse of time after slaughter was examined in relation to total weight lost by the samples when specified intensities of freezer burn first became apparent. For samples frozen before or during the onset of rigor, or shortly after, this loss was almost twice as much as for samples frozen several days later.Histological examination showed that freezer burn in muscle tissue frozen prerigor frequently starts from intracellular cavities left by sublimation of ice crystals during desiccation. Intracellular desiccation produced a form of microburn. The occurrence of microburn was negligibly small in muscle chilled for 24 hr be

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01948.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Four porcine muscle fiber types were determined on the basis of histochemical tests. Lightweight boars had a significantly higher percentage of β‐hydroxybutyric‐dehydro‐genase‐positive fibers in the longissimus dorsi than did gilts. Heavyweight boars had significtanly more esterase‐positive fibers in all muscles sampled (except gluteus medius) and significantly more β‐hydroxybutyric‐dehydrogenase‐positive fibers in the longissimus dorsi than either barrows or gilts. The number of esterase‐positive fibers in all four muscles from boars tended to be higher in the heavyweight than in the lightweight group, with the difference being significant for the dark biceps femoris. The trend between weight groups was opposite for all muscles from barrows and gilts. The quantity of intramuscular lipid in the longissimus dorsi increased with slaughter weight and tended to be lowest in the boars. It was postulated that the tendency for a greater accumulation of intramuscular lipid in the longissimus dorsi muscle of barrows and gilts than in boars could be attributed partially to the smaller percentage of fibers positive for enzymes (esterase and β‐hydroxybutyric dehydrogenase) necessary in removing lipid from muscle. Differences were noted between light and dark muscles in the distribution a

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01949.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—The fatty acid composition of porcine longissimus dorsi muscle lipid was determined for 30 animals slaughtered at two live weights (49.6 and 94.1 kg) and consisting of an equal number of boars, barrows, and gilts. The lipid was separated into the neutral lipid and phospholipid fractions prior to analysis.Odd‐numbered fatty acids Cl1, C13, C15, and Cl7 were significantly higher in the phospholipid fraction. Fatty acid Cl7 was never detected in the neutral lipid fraction.Both weight and sex effects were quite restricted to the neutral lipid fraction. Weight had a significant effect on amount of fatty acids C10, C11, C12, C14, C16, and Cl8 in one or more of the sexes. The most interesting result was the marked increase in fatty acid Cl8 of the heavy (94.1 kg) gilts and barrows over its very constant level in the muscle from boars of both weights. This difference, coupled with significantly lower C18–1 values in heavy barrows and gilts than in boars, resulted in a markedly higher mean ratio of fatty acid C18–1 to Cl8 for heavy boars. Thus these data suggest that much of the increase in saturation of intramuscular lipid that occurs after about 5.5 kg live weight can be attributed to the ratio of fatty acid C18–1 to C18. This change is probably dependent upon sex hormones and is restricted to the neutral lipid

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01950.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—A method was perfected for the precise, accurate measurement of total and free cholesterol in lipid extracts of raw beef and pork muscle and meat products. The average total cholesterol content of beef and pork muscles was estimated to be 58 and 65 mg % (mg per 100 g), respectively. Both beef and pork muscles had an average cholesterol ester concentration of about 6% of the total cholesterol. Regression equations indicated that the total cholesterol content of muscle increased very slightly as the percent lipid value rose. Extramuscular adipose fat from beef and pork carcassess had total cholesterol values between about 43 and 68 mg %. Total cholesterol was estimated for some meat products. During the broiling of ground chuck samples, up to 15% of the total cholesterol in raw meat was lost in the cook dri

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01951.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Fresh chicken muscle contained about 1.1% lipids, of which more than half was made up of phospholipids. Lipids from fresh muscle also contained about 30% triglycerides and small amounts of cholesterol, cholesterol esters, and free fatty acids. During storage at — 10°C, the phospholipid content of the muscle decreased and the free fatty acid and triglyceride contents increased. The decrease in phospholipid content resulted from loss of lecithins and cephalins. The sphingo‐myelin content remained the same, and the lysolecithin content increased. The results suggest that lipolysis occurred during frozen storage, and that lipid hydrolysis and protein denaturation may be interdependent phe

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01952.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—The course and rate of nucleotide degradation in muscle was determined on ice‐stored halibut of different sizes. The distribution of nucleotides and hypoxanthine was also determined. ATP dephosphorylation and AMP deamina‐tion proceeded very rapidly in halibut post‐mortem, but dephosphorylation of IMP was comparatively slow. Approximately 2.0μM IMP per gram was found in halibut stored on ice for 21 days; 0.5μM per g was found in some of the halibut after 41 days. The rate of IMP dephosphorylation and hypoxanthine accumulation varied between fish; size, however, did not correlate with these rates. Both nucleotides and hypoxanthine showed a fairly even distribution throughout halibut muscle. The work indicates that the determination of nucleotides and hypoxanthine can be used to estimate the storage time of halibut on ice, but reliability is poor during the first 21/2 weeks o

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01953.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Lemons, both mature‐green and yellow, yield a complex mixture of carotenoids. The lighter color of the pulp and flavedo of yellow lemons may be attributed to much lower concentrations of carotenoids than in oranges. A comparison of the pigment mixtures shows that, as the lemons ripen and coincident with the disappearance of chlorophyll, alpha‐carotene disappears and zeta‐carotene and an eta‐carotene‐like compound appear in both the pulp and peel. The eta‐carotene‐like compound has not been previously reported in citrus. Furthermore, small but significant amounts of beta‐carotene 5,6‐monoepoxide and its isomeric 5,8‐epoxide, mutatochrome, are present in the

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb01954.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY