摘要:

SUMMARYMuscle from stress‐susceptible and stress‐resistant pigs was studied for capillary distribution and fiber characteristics. More capillaries were associated with red fibers than white fibers and there was a greater capillary to fiber ratio in red than white muscle. There was no difference in capillary fiber ratio between normal (from stress‐resistant pigs) and PSE (from stress‐susceptible pigs) muscle. Muscle from stress‐susceptible animals had more intermediate fibers than did muscle from stress‐resistant animals. Certain intermediate fibers from stress‐susceptible animals had a high amylophosphorylase and ATPase activity. It was postulated that such fibers are important in the drastic post‐mortem muscle behavior in stress‐susceptible animals and may represent the characteristic which causes mus

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10348.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYResults suggest that actomyosin from muscle in rigor is more easily dissociated than actomyosin from prerigor muscle. The addition of MgCl2decreased the rate of ATP hydrolysis and extended the clear phase of the fibrillar protein extract. Pyrophosphate in the presence of magnesium was as effective as ATP in clearing actomyosin. As the ATP was hydrolyzed, the viscosity of the solution returned to values greater than those obtained before the addition of ATP. However, samples cleared with pyrophosphate retained their low viscosity characteristics indefinitely.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10349.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYThe 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 ± 104and a resultant cross‐link density of 5.23/ molecule, while normal tissues had corresponding values of 4.67 ± 104and 7.73. These differences were only significant at the 10%

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10350.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Natural actomyosin was prepared from the longissimus dorsi of both bovine and rabbit. Rabbit actomyosin had about two times the ATPase activity of bovine muscle actomyosin. However, both types of natural actomyosin behaved in a similar manner with respect to ionic conditions. They were activated by Mg++at low KCI (20–50 mM), inhibited by Mg++at high KCI (100 mM) and activated by Ca++at high KCI (100 mM). Bovine actomyosin, in contrast to rabbit actomyosin, did not show activation at low Mg++(0.01 mM) in the alkaline pH range. Maleate, when used as Tris‐Maleate buffer, inhibited superprecipitation of natural actomyosin from rabbit and bovine muscle. It was hypothesized that the low ATPase activity and the non‐activation at low Mg++in the alkaline pH range of bovine compared to rabbit actomyosin was a species dif

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10351.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Laying pullets were fed a low fat semipurified diet or the low fat diet supplement with 10% vegetable oil (corn, soybean, olive, safflower or hydrogenated coconut oil). The eggs were analyzed for change in the fatty acid composition of the total yolk lipids with time on the diet and for fatty acid composition of the triglyceride, cephalin and lecithin fractions of lipovitellin and lipovitellenin. Determinations were made for volume of sponge cakes, emulsification, and lipid content of stored eggs. A taste panel was used to assess any difference in flavor and mouth feel of yolk from stored eggs. The fatty acid composition of the total yolk lipids was influenced by all dietary fats. The major change was in the linoleic acid at the expense of oleic acid with corn, soybean and safflower oil. Olive oil increased the oleic acid and hydogenated coconut oil increased lauric, myristic and myristoleic acids. The fatty acid composition of the fractions of the lipoproteins was influenced by the dietary fats and varied between fractions. Differences were noted between sponge cake volume with eggs of low fat, corn oil, soybean oil and hydrogenated coconut oil diets. The dietary fats did not appear to affect emulsification capacity or migration of the yolk. A taste panel was unable to differentiate on the basis of flavor or mouth feel the egg yolk from the several treatment

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10352.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—A method employing the fluoride ion‐selective solid‐state membrane electrode has been developed to determine the presence and amount of free fluoride ion in carbonated and noncarbonated beverages. Representative carbonated and non‐carbonated beverages containing known amounts of added fluoride were used to relate electrode activity measurements to fluoride concentration in parts per million. Calibration curves were constructed for each system wherein fluoride concentration (ppm), was plotted as a function of potentiometric measurements (millivolts); using the fluorideion‐activity‐electrode as the indicator electrode and a saturated calomel electrode (SCE), as the reference electrode. Beverages studied were selected to represent a range of pH values and complexity of organic and inorganic constituents present in order to demonstrate the ability of the fluoride‐ion‐electrode to selectively determine fr

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10353.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARYThis work was done to determine if 60 mc/sec R‐F energy has a selective killing effect on microorganisms other than that attributable to heat. The organisms studied were Saccharomyces cerevisiae, Escherichia coli, and Bacillus subtilis, An aqueous buffer medium was used to suspend the microorganisms for the irradiation treatments. No killing effect of the R‐F energy per se on the organisms was observed at any of the various buffer pH values, nor was there an obsevable synergistic killing effect of R‐F energy and heat on the microorganisms in any of the buffer. However, a synergistic killing effect of ethanol and heat at 48.8°C was demonstrated on S. cerevisiae. Irradiating S. cerevisiae and E. coli in several liquid foods also failed to show a selective killing effect of R‐

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10354.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—To enable development of a model describing reaction kinetics in dehydrated foods, we studied sucrose hydrolysis at limited water concentration. Saturated sucrose solutions containing various acids and inert solid materials gave identical rate constants and energy of activation as predicted from dilute solutions. Reaction rates in freeze‐dried systems humidified to low moisture contents indicated that any equation describing the rate of hydrolysis must include a term for the velocity of dissolution of solid sucrose into the surface water. The rate of hydrolysis was a pseudo first‐order reaction obeying the same kinetics as in dilute solution; the rate of dissolution became rate‐limiting when the initial supply of dissolved sucrose was ex

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10355.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Free amino acid (FAA) analyses were conducted on 87 I. dorsi and 58 b. femoris samples from cattle varying in sex, breeding and age to study the relationships between these muscle constituents and Warner‐Bratzler Shear values. The b. femoris contained greater amounts of FAA than the I. dorsi and was significantly tougher. Muscles from a line of cattle that tended to be more tender possessed greater amounts of FAA. With few exceptions the I. dorsi of steers contained greater amounts of FAA than the same muscle from bulls. Differences in bull muscles due to age were not significant for any FAA. Steer muscle with low shear values tended to possess greater amounts of FAA than steers with high shear values. Although not significantly correlated individual and total FAA increased slightly with increasing tenderness within beef musc

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10356.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SUMMARY—Homestead tomato fruit were irradiated with 300 Krad of60Co gamma rays at three stages of maturity–mature‐green, 2 and 6 days from color break. Though oxygen consumption by mitochondrial preparations was greatly suppressed immediately after irradiation it increased to a maximum during the following 2 days and then declined similarily to nonirradiated fruit. Oxygen consumption was reduced considerably during ripening of the nonirradiated and irradiated 6 day breakers. Mitochondria from irradiated fruit exhibited lower P/O ratios than from nonirradiated fruit. A considerable reduction was less pronounced with the 2 and 6 day breakers. In vitro irradiation of mitochondrial preparations indicated no differences in activity with doses up to 100 Krad, but at 150 and 300 Krad, the activity decreased by 50 and 90%, respect

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1969.tb10357.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY