摘要:

SUMMARY—Methods were developed for the extraction and characterization of residual lipids of fish protein concentrate (FPC). Isopropanol‐extracted samples had 0.1–0.2% residual lipid and an ethylene dichloride‐extracted sample had approximately 0.5% residual lipid. The lipids contained 50–60% neutral lipid, 20–25% phospholipids, 5–10% acidic lipids, and the remainder uncharacterized. Fatty acid analysis of the total lipids showed that the saturated fatty acids were mainly palmitic and stearic and the unsaturated fatty acids were mainly oleic and palmitoleic. The observed low content of polyenoic fatty acids may account in part for the high stability of the lipid extracts

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09684.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Progress in an investigation of the chemistry of flavor in fish protein concentrate (FPC) prepared by extraction of red hake (Urophycis chuss) withiso‐propanol is described. Lyophilization of slurries of FPC yielded condensates from which a neutral fraction and a mixture of amine hydrochlorides were isolated. The quantity of amine mixture present was dependent on processing conditions used in the FPC preparation and was related to the flavor intensity observed. The contribution of neutral components to flavor was not determined. Based on chromatographic separations and direct investigation of components by mass spectrometry, dimethylamine, trimethylamine, ammonia, ethylamine, diethylamine,n‐propyl‐amine and a butylamine were identified. The probable presence of methylamine, methylethylamine andiso‐propylamine was

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09685.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Beef irradiated at levels from 0.3 to 2.4 Mrads with cobalt‐60 showed much greater changes in extract‐release volume than water‐holding capacity measured by the filter paper press method. The difference was even greater after storage at 5°C for 30 days. This difference appears to be a consequence of the greater amount of meat shrinkage after irradiation. Meat shrinkage increased both with increased levels of radiation and time of

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09686.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—2‐Pentyl furan is identified as a component of the volatile decomposition products of slightly autoxidized soybean and cottonseed oils and those of thermal oxidation of corn oil and hydrogenated cottonseed oil. The flavor threshold of this compound in oil at room temperature is 1 ppm. At concentrations of 1‐10 ppm, it imparts to the oil a characteristic beany odor and flavor reminiscent of those of a reverted soybean oil. Expert organoleptic panels consistently identified a deodorized cottonseed oil containing 5 ppm of 2.pentyl furan as a reverted soybean oil. It is proposed that this compound is formed by autoxidation of linoleic

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09687.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—The dominant wavelength of muscle color depended almost exclusively on pH. A high pH was associated with a high dominant wavelength. Muscle color saturation was associated with moisture content, pH, water‐holding capacity, and myoglobin content. The color exhibited the highest degree of purity in muscles that were high in myoglobin content and low in pH, water‐holding capacity, and water content. Color lightness was negatively associated with pH, water‐holding capacity, and muscle p

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09688.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Ontario potatoes, representing a variety that is very susceptible to precooking blackening, were grown in each of two consecutive years at different levels of potassium fertilization. In each of the two years of the study, the discoloration and total phenolic content of tubers decreased as potash applications were increased from 140 to 400 or 540 lb. per acre. The differences in discoloration were significant at the 1% level and the differences in phenolic content at the 5% level. Potatoes grown at high levels of potassium fertilization had higher cytochrome oxidase activity than those grown at lower levels. Potassium fertilization had no significant effect on polyphenol oxidase activity. A positive correlation (0.830) was found between the phenolic content and discoloration of potatoes as affected by potassium fertilize

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09689.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—The level of phosphoglucomutase in potato tubers has been found to be about 400 times higher than previously reported. This enzyme has been purified 40‐fold over the dialyzed crude extract by a procedure consisting of fractionation with ethanol and acetone, fractionation with ammonium sulfate, and filtration through Sephadex G‐100. The potato enzyme is similar to phosphoglucomutases obtained from other sources, but most closely resembles the rabbit muscle enzyme. It requires Mg2+and cysteine for activity, is activated by preincubation with Mg2+and cysteine, possesses a molecular weight of 63,000, exhibits optimal activity at pH 7.6, and is inhibited by a

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09690.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—A study was made of the fine structure of myofibril suspensions prepared from seven heifers immediately after death and after various times post‐mortem. Studies on myofibrils sampled immediately after death showed that sucrose isolation gave the best structural preservation as indicated by maintenance of Z‐line structure. Although the appearance of resting muscle was maintained in both sucrose and KCI preparations, several myofibrils from the KCI‐treated preparations showed stretched sarcomeres. Glycerol‐treated myofibrils usually had shorter sarcomere lengths than myofibrils prepared with the other two solvents. Although fibrillar preservation seemed adequate when glycerol was used, Z‐line structurewas seldomwell‐preserved with glycerol.Myofibrils from muscle sampled 24 hr post‐mortem at 2°C were supercontracted with thick filaments pushed against or through the Z‐line, and no trace of l‐bands remained. Myofibrils from muscle sampled 24 hr post‐mortem at 16°C were contracted, but to a much lesser extent than 2°C‐24 hr myofibrils. Storage at 2°C for 312 hr after death resulted in myofibrils that were contracted and that were structurally in a much poorer state of preservation than their 16°C counterparts. The 16°C‐312 hr myofibrils were slightly contracted as indicated by the absence of H‐zones and the presence of prominent, although narrowed, I‐bands. All observations showed that shortening accompanying rigor mortis caused changes in banding patterns similar, and probably identical, to those predicted by Huxley's sliding fi

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09691.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY–Investigations were conducted on the effect of three storage temperatures, 2°, 16°, and 37°, on the changes and relationships of certain chemical and physical properties of post‐mortem bovine semitendinosus and psoas muscle. Post‐mortem muscle shortening was measured with the isometer. Isometric tension development was maximal at 2°, minimal at 16°, and at 37° tension was approximately one‐half that developed at 2°. The large tension development at 2° very likely originates from the same events as those in “cold shortening.” Differences in isometric tension parameters were noted between muscles in that psoas muscle developed tension and lost the ability to maintain tension more quickly than did the semitendinosus. Loss of ability to maintain tension was observed only at 2°, and this could correspond to a “resolution” ofrigor mortis.Adenosine triphosphate (ATP) degradation was measured by two methods, ammonia production and bioluminescent enzymic method; the bioluminescent method proved to be the more satisfactory. A common relationship was observed between pH and ATP for both muscles and the three temperatures studied. No direct relationship was found between ATP degradation and shear resistance with the possible exception of muscle stored at 37°. Isometric tension parameters and shear resistance were related somewhat at 2° in semitendinosus muscle, but no relationship existed at 16° and 37°. Although considerable tension developed in psoas and semitendinosus muscle at 37°, shear resistance values decreased continuously, indicating that factors other than shortening are more important at high temperature and that these factors are temperature‐dependent.The role of ATP degradation in tension development was difficult to interpret, since at 2°, only a small change occurred in ATP level during large tension development, and the level of ATP at 2° did not differ from ATP level in muscle stored at 16° which developed little tension.Differences in post‐mortem muscle

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09692.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARY—Amino acids are produced during the fermentation of cocoa beans at a rate which is in agreement with the already established rapid rate of flavour and aroma development. The role of these compounds as aroma precursors receives further confirmation as a result of these studies, and an objective method of assessing the “degree of fermentation” of cocoa beans has been described and tested on a number of different commercial varieties of

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1967.tb09693.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY