bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polarographic Studies on Storage of Meats.
Authors: OBARA TETSUJIRO , OGASAWARA YASOKICHI 
Published: August 2006

SUMMARYInvestigation was made of the influence of pepsin, irradiated pepsin, trypsin, and papain on the polarographic wave of native and denatured beef protein solutions. Beef protein solutions incubated with pepsin or irradiated pepsin show a characteristic change in the second waves of their polarograms. This change is quite similar to that observed with a water extract from stored irradiated beef. Pepsin subjected to low‐level irradiation causes a more pronounced polarographic change in beef protein solutions than does unirradiated pepsin, and has a greater proteolytic action. Beef protein solutions incubated with trypsin or papain show less significant polarographic changes than those incubated with pepsin.
Direct Chromatographic Analysis of Milka
Authors: BASSETTE R. , OZERIS S. , WHITNAH C. H. 
Published: August 2006

SUMMARYSome organic chemical compounds were detected in milk by a simple, direct chromatographic analysis of head‐space vapors. After modifying the head‐space gas‐sampling technique by saturating the aqueous solution with sodium sulfate and increasing the amplification of the chromatographic hydrogen flame detector electrometer, some organic compounds were detected at less than 0.1 ppm concentration in milk. Samples of fresh and stored raw milk, with and without off‐flavors, were analyzed successfully. Some volatile chemical compounds developed during storage at 2°C. Off‐flavors were characterized by the development of certain chromatographic peaks. Chromatograms were recorded for analyses of rancid, oxidized, sunlight‐oxidized, and high‐acid milks. A number of chromatographic peaks were characterized as carbonyl from their reaction with hydroxylamine. Acetaldehyde, propionaldehyde, acetone, and 2‐butanone were identified. An indication of the concentration of some of these peaks was obtained by analyzing solutions of 0.1 ppm acetaldebyde, propionaldehyde, and 2‐hexanone added to water and to milk.
Toxin Production in Naturally Separated Liquid and Solid Components in Preparations of Heated Surface‐Ripened Cheese Inoculated with Clostridium botulinum
Authors: GRECZ NICHOLAS , DACK GAIL M. 
Published: August 2006

SUMMARYOccasional solid‐liquid separation of soft surface‐ripened cheese packed into test tubes was examined for differences between the components with regard to growth and toxin production of Clostridium botulinum. Botulinum toxin was found in three tubes showing liquid‐solid separation; in each case the toxin was present in the solid but absent from the liquid cheese portion. Two mechanisms were found to be responsible for the peculiar distribution of toxin in liquid‐solid separated cheese: 1) the liquid portion possessed antimicrobial activity preventing the growth of C. botulinum whereas the solid component was antimicrobially inactive; 2) the particles in the solid cheese were able to adsorb botulinum toxin, thus preventing diffusion of preformed toxin into the liquid layer. Separation into a solid and liquid layer could be achieved deliberately by increase of the moisture content of the cheese preparation, or by mixing of thoroughly ripened cheese with relatively fresh cheese. However, in these tubes the toxin—when present—was distributed in essentially equal quantities in the adjacent solid and liquid components.
Alteration of Post‐Mortem Changes in Porcine Muscle by Preslaughter Heat Treatment and Diet Modificationa,b
Authors: SAYRE R. N. , BRISKEY E. J. , HOEKSTRA W.G. 
Published: August 2006

SUMMARYSubjecting animals to elevated environmental temperatures immediately before slaughter resulted in increased muscle temperature and a rapid rate of post‐mortem glycolysis as indicated by a rapid pH decline and decreased color intensity. A high‐fat high‐protein low carbohydrate ration improved the water‐binding, color, and texture characteristics of the muscle. The detrimental influence of sugar feeding was less marked than in previous experiments, but muscle from animals receiving the high sucrose ration had the lowest pH and (except for the heat‐treated lot) the highest percent reflectance of all lots at 24 hr post‐mortem. Phosphofructokinase activity was not affected by ante‐mortem treatments and did not appear to be related to glycolytic rate or physical properties of the muscle at 24 hr post‐mortem. The time course of rigor mortis was markedly accelerated by heat treatment.
An Examination of the Free Amino Acids of the Common Onion (Allium cepa)a
Authors: KUON JORGE , BERNHARD RICHARD A. 
Published: August 2006

SUMMARYFree amino acids in four onion cultivars were studied by two‐dimensional ascending paper chromatography with the following solvents: 1) phenol‐water, 8:2 (v/v), 2) n‐butanol‐acetic acid‐water, 4:1:5 (v/v) (upper layer); and 1) sec butanol–tert butanol‐methylethyl ketone–water, 4:4:8:5 (v/v), 2) n‐butanol–acetic acid‐water, 4:1:5 (v/v) (upper layer).The amino compounds identified in the extracts were: glutathione, aspartic acid, cysteine, cystine, glutamic acid, serine, canavanine, asparagine, glycine, arginine, lysine, threonine, tyrosine, methionine sulfoxide, alanine, dihydro‐alliine, S‐methyl cysteine, tryptophan, methionine, valine, phenylalanine, and mixed leuycines. Suspected as present was α‐L‐glutamyl‐S‐[β‐carboxy‐n‐propyI]‐L‐cysteinyl glycine.Densitometry and colorimetry were used to determine the relative approximate amounts of alanine, aspartic acid, arginine, glutamic acid, glycine, leucines, lysine, methionine sulfoxide, phenylalanine, serine, S‐methyl cysteine, threonine, tyrosine, and valine. The more abundant amino acids were: arginine, glutamic acid, phenylalanine, leucines, tyrosine, lysine, and methionine sulfoxide.
Autoxidation of Fish Oils. II. Changes in the Carbonyl Distribution of Autoxidizing Salmon Oilsa,b
Authors: WYATT C. JANE , DAY E. A. 
Published: August 2006

SUMMARYThe carbonyl compounds of autoxidizing salmon oil were qualitatively and quantitatively analyzed at predetermined levels of oxidation. The 2‐thio‐barbituric acid (TBA) number, peroxide values, and total carbonyls were determined in addition to the individual volatile and Girard‐T‐isolable carbonyls. The C1‐C12 alkanals, C4C12 alk‐2‐enals, and the C6‐C10 alk‐2,4‐dienals composed the major part of the monocarbonyl fractions. The shorter‐chain carbonyls were predominant, with methanal and propanal in the highest concentration. It appears that the Girard T reagent, as employed in the investigation, degrades the precursors of the volatile carbonyl fraction.The hydroperoxides were readily destroyed in unpolymerized oil by the Girard T reaction conditions, but as polymerization proceeded the yield of hydroperoxides increased and that of the Girard‐isolable monocarbonyls and malonaldehyde decreased. Polymerization of the salmon oil stabilized a large portion of the measurable hydroperoxides toward the degradative effects of the Girard and TBA reactions.
A Technique for the Study of Lipid‐Soluble Food Flavor Volatilesa,b
Authors: LIBBEY L. M. , BILLS D. D. , DAY E. A. 
Published: August 2006

SUMMARYA low‐temperature high‐vacuum distillation technique utilizing a molecular still is described. The flavor volatiles are distilled into liquid N2 traps, transferred to a stainless‐steel helical trap of special design, and then blown into a gas chromatograph. Identification of the flavor volatiles is based on relative specific retention volume and collection of the fractions for analysis by techniques such as mass spectrometry. Results are given for application of the described techniques to study of the lipid‐soluble flavor volatiles of Cheddar cheese.
Gas Chromatography of Chicken and Turkey Volatiles: The Effect of Temperature, Oxygen, and Type of Tissue on Composition of the Volatile Fraction
Authors: PIPPEN E. L. , NONAKA M. 
Published: August 2006

SUMMARYConcentrated poultry volatiles were prepared by distilling water from chicken and turkey, extracting volatile components from the distillate with isopentane, and concentrating the dried isopentane extract. These volatiles were investigated by gas chromatography on an apparatus equipped with thermal conductivity detectors. Essentially all volatiles were heat‐produced. Cooking in air, as contrasted to cooking in nitrogen, resulted in a much larger and more complex volatile fraction. Rancid chicken yielded a greater amount of volatiles than did fresh chicken, but qualitatively they were similar. The overall yield of volatile material was greater and of a more complex nature from skin and skin fat than from lean leg and breast muscle. Chromatograms of chicken and turkey volatiles indicated differences in their composition. It was not determined, however, whether the difference in composition was responsible for the different and distinctive flavor of chicken and turkey broths determined by sensory methods. n‐Hexanal and n‐2,4‐decadienal were identified as two of the larger volatile fractions of fresh chicken and turkey and rancid chicken. Information on the nature of chicken and turkey volatiles can also be obtained by directly sampling vapors over the product and subjecting them to dual hydrogen flame chromatography.
Classification of Textural Characteristicsa
Authors: SZCZESNIAK ALINA SURMACKA 
Published: August 2006

SUMMARYDefinition of texture is reviewed, and a system for classification of textural characteristics of foods is described. The system is based on fundamental rheological principles, and at the same time is suitable for routine use. Textural characteristics are defined and classified into mechanical and geometrical qualities as well as those related to the moisture and fat content of a product. The mechanical characteristics are subdivided into the primary parameters of hardness, cohesiveness, viscosity, elasticity, and adhesiveness, and into the secondary parameters of brittleness, chewiness, and gumminess. It is pointed out that popular terms used to describe texture often denote degrees of intensity of these characteristics. The proposed classification lends itself to use with both objective and subjective methods of texture characterization.
Determination of Chlorophylls, Chlorophyllides, Pheophytins, and Pheophorbides in Plant Materiala
Authors: WHITE R. C. , JONES I. D. , GIBBS ELEANOR 
Published: August 2006

SUMMARYEquations have been developed for calculation of the total quantity of pigments consisting of chlorophyll a and its derivatives (chlorophyllide a, pheophytin a, and pheophorbide a) and of chlorophyll b and its derivatives (chlorophyllide b, pheophytin b, and pheophorbide b) in a mixture of these pigments in diethyl ether. Calculations are based on conversion of the chlorophylls and chlorophyllides into the pheophytins and pheophorbides, respectively, by the addition of hydrochloric acid and reading absorbances at two wavelengths. After removal of chlorophyllides a and b and pheophorbides a and b from the diethyl ether solution of the pigment mixture by 0.01N KOH, the quantity of each of the eight components listed above is estimated by indicated experimental and mathematical procedures.
Reaction of Sugar Alcohols with the Anthrone Reagent
Authors: GRAHAM HORACE D. 
Published: August 2006

SUMMARYUnder appropriate conditions of acid concentration, heating time and temperature of heating, the sugar alcohols react with the anthrone reagent in a quantitative manner. Suitable conditions for reproducible quantitative results are: 0.15% anthrone in concentrated sulfuric acid and a heating time of 60 min at 99°C (in a boiling‐water bath). Color measurement should be made 30 minutes after cooling the reaction tubes in an ice water bath, since the intensity of the colors increased with time. Of the various sugar alcohols tested, the order of reactivity is: Glycerol > sorbitol > mannitol > dulcitol > erythri‐tol > arabitol > ribitol > xylitol. Absorption maxima occurred at 720 mμ, for mannitol, sorbitol, and dulcitol, and at 740 mμ for erythritol. Glycerol and the other sugar alcohols exhibited no sharp absorption maxima.
Age‐Associated Changes in Muscle Composition. The Isolation and Properties of a Collagenous Residue from Bovine Musclea
Authors: GOLL DARREL E. , BRAY R. W. , HOEKSTRA W. G. 
Published: August 2006

SUMMARYAge‐associated changes in the chemical composition of bovine biceps femoris muscle were studied. Veal muscle had significantly lower Kjeldahl nitrogen and higher moisture contents than muscle from the three older age groups studied. Muscle from veal and from the oldest group (cows, 10 years) possessed less fat than muscle from the two intermediate groups (steers, 1–2 years, and cows, 5 years). A modified procedure for determination of hydroxyproline and its use directly on mean hydrolysates are described. Use of this technique failed to reveal any significant differences in the hydroxyproline content, and presumably the connective‐tissue content, of muscle from the four groups. Warner‐Bratzler shear‐force values of cores from biceps femoris steaks from the three oldest groups indicated that tenderness decreased with age. A method is given for isolation of large quantities of connective tissue from biceps femoris. Chemical analyses of these connective‐tissue residues are presented, and the possibility is discussed that the veal connective tissue contains large amounts of reticulin.
Nitrogen Balance of Dogs Fed Lime‐Treated Corn Supplemented with Proteins and Amino Acidsa,b
Authors: BRESSANI RICARDO , de VILLARREAL EMELINA M. 
Published: August 2006

SUMMARYThe effect on the nitrogen balance of young dogs of supplementing lime‐treated corn with small amounts of black bean flour, skim milk, fish flour, and torula yeast was investigated. Although the diets were kept isonitrogenous, all supplements increased nitrogen retention significantly, as did supplementing with lysine and tryptophan. The gain was most marked for skim milk, fish flour, and torula yeast plus lysine, and of sufficient magnitude to be of practical significance for human feeding. The better the protein quality of the supplement, the greater the decrease in nitrogen retention after its removal.
Determination of Malonaldehyde by Ultraviolet Spectrophotometrya
Authors: KWON TAI‐WAN , WATTS BETTY M. 
Published: August 2006

SUMMARYMalonaldehyde occurs mainly as the enol form (CHOH = CHCHO) in aqueous solution. The UV absorption spectrum of the compound is pH‐de‐pendent. Below pH 3.0, the compound is s‐cis, planar, having an intramolecular H bond, with absorption maximum at 245 mμ and molar absorptivity (ε) = 1.34 × 104. Above pH 7.0, the compound is completely dissociated and the maximum absorption of the enolate anion occurs at 267 mμ with e = 3.18 × 104. The absorbance difference between acidified and basified malonaldehyde solutions at 267 mμ can be used as a measure of malonaldehyde even in the presence of other compounds that absorb in this spectral region, provided their absorption is not pH‐dependent. This difference is directly proportional to malonaldehyde concentrations from 5 × 10‐6M to 3 × 10‐5M. The method has been successfully applied to the assay of malonaldehyde in distillates from rancid foods. Its sensitivity is only about 40% of the 2‐thiobarhituric acid (TBA) test, but is sufficient to detect threshold levels of rancidity. The test is simpler, much more rapid, and more specific than the TBA test.
Histological Analysis of Wound Healing in Potatoes Treated to Inhibit Sprouting 1. CIPC (Isopropyl‐N‐3‐Chlorophenyl Carbamate) Treatments
Authors: REEVE R. M. , FORRESTER L. JANET , HENDEL C.E. 
Published: August 2006

SUMMARYBoth wound periderm and sprouting were completely inhibited in freshly harvested cut potatoes treated by evaporation of CIPC (isopropyl‐N‐3‐chlorophenyl carbamate) at 10 ppm and 100 ppm (based on tuber weight) and then incubated at 70–75°F and 88% relative humidity. At 1 ppm CIPC, sprouting at room temperature was only slightly retarded. Wound periderm was completely inhibited in the central tissues and markedly retarded in the cortex of the tubers.Application of CIPC did not prevent suberization at the wound surface, but the walls of intact cells immediately subjacent were less suberized than those of the cut cells. Concomitant with inhibition of wound periderm, there was a marked enlargement of those cells that would normally have given rise to the wound periderm.Variability of wound healing rates within different tissue zones of single tubers, and other variation between tubers, are considered significant to problems of sprout control and storage.
Relative Taste Intensities of Selected Sugars and Organic Acidsa
Authors: PANGBORN ROSE MARIE 
Published: August 2006

SUMMARYA highly trained taste panel was used to establish the concentrations of fructose, glucose, and lactose equivalent in sweetness to sucrose at threshold and suprathreshold concentrations. The same panel established the sourness of lactic, tartaric, and acetic acids equivalent to that of citric acid at threshold and suprathreshold concentrations. There was no relation between pH, total acidity, and relative sourness. Results obtained from determinations made in water solutions agreed favorably with values reported in the literature. The threshold measurements are considered to be of limited value since the relative taste intensity of these compounds is not a constant but is materially affected by the absolute concentration chosen for comparison. The presence of a slight bitterness in glucose, and a slight, unidentifiable flavor in lactose, appeared to influence the threshold determinations. When the sweetness of sucrose and fructose were compared in pear nectar, fructose was less sweet than sucrose at all concentrations (1.0–20.0% sucrose). Increasing the total acidity of the pear nectar had little or no effect on the relative sweetness of these two sugars.
Measurement of Discoloration in Fresh Beefa
Authors: SNYDER HARRY E. 
Published: August 2006

SUMMARYA method is described whereby precise measurement of discoloration in fresh red meats can be achieved. The method utilizes α values obtained from Gardner automatic color‐difference meter readings and depends upon careful control of storage temperature, control of sample area from which readings are taken, and consistent orientation of sample during subsequent readings.Results obtained with the method indicate considerable variation in discoloration of samples from the same slice of beef round stored at 6°C; a substantial decrease in discoloration with lowered storage temperature; a decrease in discoloration resulting from increased exposure of the sample to air; and the probable importance of respiration by the meat rather than bacterial contamination in determining discoloration at low temperatures (‐2°C).
Sesquiterpenes. I. Nootkatone, A New Grapefruit Flavor Constituent
Authors: MacLEOD WILLIAM D. , BUIGUES NELIDA M. 
Published: August 2006

SUMMARYThe bicyclic conjugated sesquiterpene ketone, nootkatone, has been found in grapefruit peel oil and in peel‐oil‐free grapefruit juice. The flavor intensity of grapefruit oil appears to be related to the relative abundance of nootkatone. A combination of gas‐liquid chromatography and thin‐layer chromatography revealed the presence of this ketone, which was identified by its infrared spectrum and the melting point of its 2,4‐dinitrophenylhydrazone derivative. Traces of nootkatone were found also in bergamot, lemon, lime, orange, and tangerine oils.
Cheddar Cheese Flavor: Gas Chromatographic and Mass Spectral Analyses of the Neutral Components of the Aroma Fractiona
Authors: DAY E. A. , LIBBEY L. M. 
Published: August 2006

SUMMARYThe aroma fraction from the fat of high‐quality raw‐milk Cheddar cheese was isolated by centrifugation of the intact cheese and passing the recovered fat through a molecular still at 40°C. The aroma fraction was separated by gas chromatography on packed columns containing polar and nonpolar phases and by programmed‐temperature capillary‐column gas chromatography. The effluent from the latter column was admitted directly to the inlet of a rapid‐scan mass spectrometer enabling concurrent recordings of mass spectra for each chromatographic peak. The aroma fraction was separated into approximately 130 components by the capillary column. By correlation of gas chromatography and mass spectral data, most of the major neutral components were characterized. These included aldehydes, methyl ketones, primary and secondary alcohols, esters of the primary and secondary alcohols and fatty acids, γ‐lactones, and the isomeric lactides of lactic acid.
Post‐Mortem Changes in Physical and Chemical Properties of Bovine Musclea
Authors: GOLL DARREL E. , HENDERSON D. W. , KLINE E. A. 
Published: August 2006

SUMMARYPost‐mortem changes in tenderness and protein solubility were studied in bovine semitendinosus muscles. Muscles excised immediately post‐mortem were compared with muscles left attached to the skeleton. Post‐mortem times of 0, 6, 12, 24, 72, and 312 hr were studied. Sarcoplasmic protein solubility was highest immediately after slaughter and lowest in muscles left attached to the skeleton. Myofibrillar protein solubility was decreased in muscles left attached. Protein solubility changed during the first 6 hr post‐mortem but not during the 6‐ to 312‐hr aging period. Muscles left attached to the skeleton were least tender immediately after death and gradually increased in tenderness during post‐mortem aging. Excised muscles were least tender 6–12 hr post‐mortem and became progressively more tender thereafter. Even after 312 hr of aging, excised muscles were less tender than muscles still attached to the skeleton. Protein solubility did not appear to be related to tenderness. Possible relationships of muscle contraction to tenderness were discussed.
Age‐Associated Changes in Bovine Muscle Connective Tissue. I. Rate of Hydrolysis by Collagenasea
Authors: GOLL DARREL E. , HOEKSTRA W. G. , BRAY R. W. 
Published: August 2006

SUMMARYAge‐associated structural changes in collagenous residues isolated from the loose connective‐tissue network found within bovine biceps femoris muscle were studied with collagenase used as a structural probe. Rate of enzymatic digestion was measured by following the release of soluble protein, hydroxyproline, and ninhydrin‐positive material into the medium surrounding the fibrous residues. Under the conditions of the experiment, 8–11% of the protein and 8–21% of the hydroxyproline in the residues were solubilized after 12 hr of incubation with collagenase. Samples from four age groups were studied: Group I, veal, 40–49 days old; Group II, steers, 403–495 days old; Group III, cows, 4 years, 8 months to 5 years, 5 months old; Group IV, aged cows, 10 years, 2 months and 10 years, 5 months old. The groups ranked I, III, IV, and II, from fastest to slowest, in rate of hydrolysis by collagenase. However, it was postulated that the larger amounts of lipid associated with the Group II samples acted to shield collagenase‐labile bonds and cause a slow rate of hydrolysis. Making this assumption, it appears that susceptibility to collagenase digestion of loose connective tissue follows an age pattern similar to that reported for skin and tendon collagen.