bluuebunny/crossref_metadata_2025_split huggingface dataset:
The removal of fission products from milk: The use of the baby monkey (Macaca irus) for the nutritional evaluation of milk treated by 2 processes
Authors: Cohen B. , Ashworth Margaret , Glascock R. F. , Bryant D. T. W. 
Published: June 2009

SummaryThe nutritional quality of milk treated by 2 previously described processes for the removal of cationic fission products has been evaluated by the use of the baby monkey (Macaca irus).The first process involves acidification of the milk to pH 5·2–5·3 and, when the treated milk was tested on baby monkeys, it was found to be nutritionally unsatisfactory. This result confirmed those previously obtained with baby pigs, from which it was concluded that the process cannot be recommended for the treatment of milk intended for young babies.Two resin beds are used in the second process and no acidification is involved. Milk treated by this process was first tested on baby rats and pigs and then on baby monkeys. No change in the nutritional value of the milk was detected and it was concluded that this is the process which should be used if it should ever become necessary to remove fission products from milk intended for young babies.
An electron-microscope study of the structure of Domiati cheese
Authors: Abd El-Salam M. H. , El-Shibiny Safinaz 
Published: June 2009

SummaryA technique is described for preparing ultrathin sections from cheese for electron-microscopic examination. The internal structure of fresh Domiati cheese was found to be composed of a framework of large, spherical casein aggregates held by bridges and enclosing fat.After pickling, the casein aggregates were partly disintegrated into small spherical particles forming a loose structure.
The influence of some physical characteristics of the milking machine on the rate of new mastitis infections
Authors: Thiel C. C. , Cousins Carol L. , Westgarth D. R. , Neave F. K. 
Published: June 2009

SummaryLarge differences in new infection rates occurred with half-udder milking machines in which one half of the cluster operated substantially free from vacuum fluctuations while the other half was subjected to various combinations of different types of fluctuation in vacuum. To increase the rate of new infection all teats were contaminated before and after each milking by immersion in a suspension of Streptococcus agalactiae and Str. dysgalactiae. A series of short-duration trials indicated that neither irregular nor cyclic fluctuations in vacuum acting alone were able to increase new infection rate. However, either the Nyhan and Cowhig irregular fluctuation, or a variant of it in combination with cyclic fluctuations in vacuum, was able to do so under the particular experimental conditions used.
Seasonal variations in the composition and thermal properties of New Zealand milk fat: I. Fatty-acid composition
Authors: Gray I. K. 
Published: June 2009

SummaryThe fatty-acid composition of 17 samples of New Zealand milk fat obtained throughout one dairy season is reported.The weight percentage of butyric (C4:0) acid was significantly correlated with that of caproic (C6:0) acid and that of caprylic (C8:0) acid. Percentages of C6:0and C8:0showed a highly significant correlation with each other and with weight percentages of capric (C10:0) and lauric (C12:0) acids.There was a highly significant negative correlation between palmitic (C16:0) and stearic (C18:0) acids and between C4:0and C16:0acids. Oleic (C18:1) acid showed significant negative correlations with C8:0, C10:0, C12:0, myristic (C14:0) and C16:0acids.
A rennin-sensitive bond in αs1Β-casein
Authors: Hill R. D. , Lahav E. , Givol D. 
Published: June 2009

SummaryRennin acts on a specially sensitive bond in αs1B-casein to produce a basic peptide containing residues 1–23 of the original protein. At pH 6·4 and 30°C, the action is specific and rapid, the kinetic constants beingKm4·5×10−4M,Kcat3·8 s−1, andkcat/Km0·85×104s−1M−1. Pepsin, and a protease impurity in the acid phosphatase from wheat germ, have a similar action.
Influence of sympathomimetic drugs on the motility of bovine teat muscles
Authors: Peeters G. , de Bruycker Regina 
Published: June 2009

SummarySpontaneous rhythmical contractions of the teats of living cows were recorded by a plethysmographical method. These contractions were inhibited by isoproterenol, adrenaline, isoxsuprine and phentolamine, but were activated by phenylephrine. Noradrenaline induced activation which was often followed by inhibition.These results obtained in vivo were in agreement with responses obtained in vitro. Apparently beta sympathomimetic effects are evoked easily under in vivo conditions.
Heat stability of milk: influence of colloidal calcium phosphate and β-lactoglobulin
Authors: Fox P. F. , Hoynes M. C. T. 
Published: June 2009

SummaryReduction of the level of colloidal calcium phosphate (CCP) progressively increased the heat stability of milk at pH values <~7·0 and increased the pH of maximum stability. Removal of 40% CCP also stabilized the system at the pH of minimum stability, but removal of ≥60% CCP rendered milk very unstable at pH values >7·2, an effect not offset by a 4-fold increase in κ-casein concentration. Doubling CCP had a slight destabilizing effect in the pH range 6·5–7·5.Addition of β-lactoglobulin to serum protein-free casein micelles had a marked destabilizing effect at pH values > ~6·8, but increased stability in the pH range 6·4–6·8. β-Lactoglobulin had a similar and more apparent effect on the heat stability of Na caseinate dissolved in milk diffusate.It is suggested that rather than being a stabilizing factor responsible for the maximum in the heat stability-pH curve, the true effect of β-lactoglobulin is to shift the curve to more acid pH values (reason unknown) and to sensitize the caseinate system to heat-induced Ca phosphate precipitation at pH values > ~7·0. Low stability at ~pH 7·0 introduces an apparent maximum in the heat stability-pH curve at ~pH 6·8, but this has no independent existence. At pH values >7·2, increased protein charge more than off-sets the influence of heat-precipitated CCP and stability again increases in micellar but not in soluble casein systems.
Milk-gel structure. IV. Microstructure of yoghurts in relation to the presence of thickening agents
Authors: Kalab Miloslav , Emmons D. B. , Sargant A. G. 
Published: June 2009

SummaryThe effects of 3 different thickening agents on the microstructure of yoghurt were examined by scanning and transmission electron microscopy. Unsupplemented yoghurt consisted of casein micelles fused together and linked in long chains; they seldom appeared in clusters. The addition of 0·5% gelatin caused no observable change in the yoghurt structure. Carrageenan (0·4%) formed a markedly fibrillar microstructure which connected large clusters of casein micelles. The fibres were thin and long and no free terminations were observed. Pregelatinized waxy maize starch (2%) appeared under scanning electron microscopy in the form of short fibres and sheets. The fibres frequently had free terminations and only some of them were connected with small clusters of casein micelles. Transmission-electron microscopy did not distinguish between pregelatinized starch and carrageenan additives.
Variations in the susceptibility of lactating and non-lactating bovine udders to infection when infused with Escherichia coli
Authors: Bramley A. J. 
Published: June 2009

SummarySmall numbers of Escherichia coli were infused into both lactating and non-lactating udders. Twelve of the 17 lactating quarters infused became infected, and all 12 showed clinical symptoms of udder disease. The 5 lactating quarters which did not become infected all had pre-infusion somatic cell counts > 300000 cells/ml milk, whilst all the quarters which became infected had cell counts < 300000 cells/ml milk. E. coli was subsequently recovered from only 6 of the 16 non-lactating quarters infused. In only 2 of these quarters did clinical infection follow, both quarters being in a cow infused 2 d before calving. The remaining 4 quarters from which E. coli was recovered were all negative within 5 d of infusion. These differences in susceptibility are discussed, particularly with reference to the frequent occurrence of coliform mastitis at and shortly after calving.
Heat stability characteristics of ovine, caprine and equine milks
Authors: Fox P. F. , Hoynes M. C. T. 
Published: June 2009

SummaryOvine and caprine milks showed a marked stability maximum at ~ pH7 in their heat-stability/pH curves, but became very unstable at higher pH values. A low level of κ-casein appears to be responsible for this low stability of ovine milk; β-lactoglobulin offsets the stabilizing influence of κ-casein at lower pH values. Removal of colloidal calcium phosphate from ovine or caprine milks had very little influence on their heat stabilities and it was necessary to reduce the concentration of soluble salts to a very low level before an effect was observed. At the pH of maximum stability ovine and caprine milks, although quite variable, had stabilities in the same range as bovine milks. Equine milk was very unstable to heat and the shape of the heat-stability/pH curve of most individual samples was similar to ovine and caprine milks.
Inhibitory effect of adrenaline on oxytocin release in the ewe during the milk-ejection reflex
Authors: Barowicz Tadeusz 
Published: June 2009

SUMMARYMilk-ejection activity was determined in the blood plasma of ewes during normal milking and during milking when adrenaline was injected intravenously before or after udder stimulation. It was found that administration of adrenaline either before or after udder washing, decreased the oxytocin concentration and milk yield but increased the yield by hand-stripping. Adrenaline also retards the average time for peak oxytocin concentration. These results and the use of a β-receptor blocker to inhibit the effect of adrenaline at the myoepithelial cell level indicate that in ewes adrenaline can prevent the release of oxytocin from neurohypophysis.
Thermal denaturation of α-lactalbumin and β-lactoglobulin in cheese whey: effect of total solids concentration and pH
Authors: Hillier Robyn M. , Lyster Richard L. J. , Cheeseman Gordon C. 
Published: June 2009

SUMMARYMeasurements of residual native protein remaining after heat treatment of cheese whey have been made using quantitative polyacrylamide gel electrophoresis. The results have been expressed in terms of kinetic constants. The effect of concentration was investigated up to 3 times the normal total solids content, dialysis treatments were used to study the effect of non-protein constituents, and the effect of pH was studied at pH 4, 6 and 9. The results indicated that increased total solids (TS) concentration slowed the denaturation of β-lactoglobulin A and B (β-lg A, β-lg B) but hastened the denaturation of α-lactalbumin (α-la). However, increased lactose concentration slowed the denaturation of both α-la and β-lg, perhaps by preventing formation of heat-induced complexes. Increased Ca concentration, up to 0.4 mg/ml, tended to slow the denaturation of both proteins, but further increase in Ca up to 0.9 mg/;ml produced little effect. The rate of denaturation of both α-la and β-lg was slower at pH 4 than at pH 6 or 9, and was probably slowest at the isoelectric point. However, not all the changes associated with pH could be explained in terms of net molecular electrostatic charge. The genetic variants of ′β-lg showed different heat stabilities – below 90 °C β-lgA was more stable than β-lgB, but above 90 °C the situation was reversed at all TS concentrations, and pH 6. However, at pH 4 and 9, °-lgA was less stable than °-lgB over the entire temperature range at normal concentration.
The carbohydrate portions of milk glycoproteins
Authors: Jollès Pierre 
Published: June 2009

SUMMARYk-Casein is the main glycoprotein of cow's milk. Its polysaccharide part is O-glycosidically linked to threonine residue 133. It contains only 3 different sugars (Gal, GalNAc, NeuNAc), but a microheterogeneity has been detected at the sugar level. Two main polysaccharides have so far been characterized. The structure of the trisaccharide is NeuNAc α → 3 Gal β1 →3 GalNAc; the tetrasaccharide contains one additional sialic acid. The polysaccharide part of ovine k-casein resembles that of bovine k-casein, but contains also N-glycolyl neuraminic acid. Human k-casein contains 3 times more carbohydrate than bovine k-casein with 2 additional sugars, GlcNAc and Fuc. The various polysaccharide parts isolated from bovine colostrum k-caseinoglycopeptide are much more complex than those obtained from the normal glycopeptide, indicating an evolution of the sugar part as a function of time after parturition. Some aspects of the secondary structure of k-casein and the role of the sugar part are discussed. The carbohydrate moiety of another milk protein, human lactotransferrin, is also discussed briefly. It is comprised of 2 identical glycan groups, N-glycosidically linked to the protein, and quite different from the k-casein carbohydrate moiety.
The binding of β-casein to hydroxyapatite: the effect of phosphate content and location
Authors: Sleigh Robert W. , Sculley Thomas B. , Mackinlay Antony G. 
Published: June 2009

SUMMARYThe elution behaviour of β-casein from columns of hydroxyapatite has been studied and the effect examined of the enzymic addition of an extra phosphate residue. When the additional phosphate is located near pre-existing phosphate residues stronger binding to hydroxyapatite is observed. When the additional phosphate is remote from the pre-existing phosphates no increase in strength of binding is observed. It is suggested that the clustering of phosphate residues which characterizes αs- and β-caseins can be rationalized on the basis that it facilitates cooperative interactions between these phosphates and the Ca phosphate of the casein micelle and/or basic residues within casein polypeptide chains.
Effect of stage and number of lactation on the yield and composition of cow's milk
Authors: Rook J. A. F. , Campling R. C. 
Published: June 2009

SummaryThe effects of stage of lactation and of age on milk and composition yield of cows kept under controlled conditions of feeding and management were investigated. Two groups each of 3 Friesian heifers were used: one group (A) was given a daily diet of 18 lb hay and concentrates at the rate of 3·8 lb/10 lb of milk and kept on experiment throughout the first 3 lactations; a second group (B) was given the same amount of hay and a constant daily amount of concentrates of 10·7 lb and was kept on experiment throughout the 1st lactation only.The total yields of milk and peak yields for the 1st lactation were similar in both groups. In all the cows, fat content was high early and late in lactation and varied little throughout the mid-lactation period. With cows of group A, the content of solids-not-fat declined until about the 5th week of lactation and then remained steady until a marked rise occurred late in lactation. With cows of group B, however, the content of solids-not-fat was at a minimum between the 5th and 10th weeks of lactation and then increased progressively until late lactation when a more marked rise occurred. Lactose content increased rapidly in the first few days of lactation and then remained constant for several months, eventually declining late in lactation. Characteristic changes were also observed in the contents of total protein, and of the various protein fractions, and of the major minerals of milk.The concentrations of all major constituents in milk secreted from the 2nd–5th months of lactation tended to decrease from lactation to lactation.The results are discussed in relation to the development of knowledge of the changes in milk composition throughout lactation.
Steam distillation of taints from cream. XI. The use of benzyl mercaptan (35S) in a study of its vapour/liquid equilibrium relationships
Authors: Walker N. J. 
Published: June 2009

SummarySolutions of labelled benzyl mercaptan-(35S) in water and cream were subjected to steam distillation in a continuous vaporization equilibrium still, and the concentrations of mercaptan in distillates and residues were obtained by measurement of the radioactivity in toluene extracts.In the steam distillation from aqueous solution the vapour/liquid equilibrium relationship was not linear. The vapour/liquid equilibrium coefficient increased from 73 to 108 over the range of concentrations 0·01–0·05 ppm. in the liquid fraction at the time of partition.In the steam distillation from cream containing 30% fat the relationship was linear, with an equilibrium coefficient of 1·35 over the range 0·1–0·6 ppm. in the cream at the time of partition.The values of the vapour /liquid equilibrium coefficients are of the same order as those reported previously, 105 and 1·30, respectively, for which estimations were made by an absorption method.The butterfat/water partition coefficient for benzyl mercaptan was found to be 160, which is consistent with the large difference found between the steam volatilities of the substance from water and from cream.
Seasonal variation in the viscosity index and adhesive strength of casein from the milk of individual cows
Authors: Southward C. R. , Dolby R. M. 
Published: June 2009

SummaryThe viscosity index and adhesive strength of casein from the milk of 6 individual cows were determined on samples collected regularly throughout the 9-month dairying season. The viscosity index of the casein from each cow showed a seasonal decline while the adhesive strength showed a general increase during this time. Casein from one cow had a consistently low viscosity index attributed to the presence in it of a rare genetic variant of α-casein. It is suggested that the variations in viscosity index and adhesive strength are lactational rather than seasonal.
Factors affecting the viscosity of caseinates in dispersions of high concentrations
Authors: Hayes J. F. , Southby Pamela M. , Muller L. L. 
Published: June 2009

SummaryThe physical effects of various cations in caseinate dispersions of high concentrations were investigated over a range of temperature and pH.With calcium and strontium the temperature-viscosity relationships of the caseinates were abnormal in that the viscosity decreased rapidly from 30 to about 40 °C and a gel formed at temperatures in the region of 50–60 °C. On cooling, the gel reliquefied. No gel formed with barium, aluminium or magnesium. On cooling, magnesium preparations separated into 2 phases.The supernatant phase from the magnesium caseinate and a corresponding phase prepared by centrifuging the calcium caseinate showed depletion ofα-casein and enrichment ofκ-casein andβ-casein. The supernatant phase from the calcium caseinate showed the reversible gel formation on heating. The magnesium supernatant phase did not.κ-Casein and a mixture ofκ- andβ-caseins gave reversible gels at similar levels of calcium and pH.For reversible gel formation to occur, calcium caseinate was required to be in fairly high concentration, to have a calcium content of about 1·0% of the protein and to be within the pH limits 5·2–6·0. The temperature at which gelation occurred was affected by the concentration of calcium and protein and by pH.The behaviour of the material was compared with that of methyl cellulose with and without addition of urea.Some potential commercial applications of the findings on viscosity relationships are outlined.
The folic acid activity of some milk foods for babies
Authors: Ford J. E. , Scott K. J. 
Published: June 2009

SummaryFolic acid activity was determined for National Dried Milk and for 5 proprietary dried milk foods for babies, for a proprietary liquid milk baby food and for 8 brands of tinned evaporated milk. For comparison, values were determined for mature breast milk, for raw bulk cow's milk, for bottled pasteurized cow's milk and for goat's milk.Human milk and raw and pasteurized cow's milk all had much the same folate activity, equivalent to about 54 µg folic acid/1. Values for goat's milk were much lower, around 6 µg/1.Values for the reconstituted baby milks ranged from 9 to 65 µg/1, though only 2 of the products had markedly lower values than breast milk. The question is discussed whether the folic acid requirement in infants can be met by formulas based on cow's milk without having recourse to folic acid supplementation.
Studies on the change in the properties of the fat globule membrane during the concentrating of milk
Authors: Cheeseman G. C. , Mabbitt L. A. 
Published: June 2009

SummaryPrevious work had shown that when milk is boiled in a climbing film evaporator a reaction occurs between the casein micelles and the fat globule membrane, probably at the liquid–gas interface. It now appears that the micelle–globule complex is formed by combination of the κ-casein components of the micelles and the membrane of the fat globule. The reaction is not significantly affected by increases in concentration of individual constituents, or by changes in temperature or pH.The history of the milk before its concentration is an important factor in its subsequent behaviour. Thus, cooling and stirring of the milk during storage, as normally occurs in a bulk collection tank, promotes the reaction in the evaporator and, for some milks, is essential for starting the reaction.A high retention of whey by curds made from the concentrated milks, diluted with water to their original volume before renneting, indicates that curd properties other than fat retention are also altered during concentration.
Errors in fat testing of composite milk samples
Authors: McDowell A. K. R. 
Published: June 2009

SummaryAnalyses were made at the Institute chemistry laboratory over 2 dairy seasons of 900 composite milk samples prepared for routine fat testing at 2 dairy factories and held at ambient temperature. The composites, which were preserved with mercuric chloride, frequently had high free fat acidities and high bacterial and mould counts.At one factory, where the composites were sampled at 85−90 °F, the samples contained incompletely dispersed fat. Werner Schmid fat values for 83 milks pipetted immediately after factory sampling were lower on average by 0·084±0·089% than values obtained for the same samples after high-speed mixing at 115°F. At the other factory, where the samples were mixed at 98–103°F, Werner Schmid tests on 56 milks showed a corresponding difference of only 0·033±0·047%.For 273 factory composites, mixed at high speed, results by the Babcock test and by the Gerber test averaged, respectively, 0·015±0·019% and 0·059±0·054% higher than those by the Werner Schmid test.High bacterial and mould counts in factory composites were attributed to contamination from unsterilized bottles and stoppers and to failure of factory staff to mix the contents of each bottle after the daily addition of milk. Low bacterial and mould counts and negligible increases in free fat acidity were found in composites made up from factory milk in the Institute laboratory in sterilized bottles, kept at ambient temperature and swirled daily. Composites made up from fresh farm milks and held at 38–40°F remained in good condition for sampling after warming to 98–103°F but showed wide variation in free fat acidity.Rises in free fat acidity occurred only in composites preserved with mercuric chloride. Other preservatives, however, were less effective in preventing bacterial growth at ambient temperatures.Increases in free fat acidity up to 10 (ml N alkali/100 g fat) had no effect on results in the Babcock tests but caused a slight rise with the Gerber tests. Acidities over 20 caused a decrease in Babcock and a further rise in Gerber values.It is suggested that fat destabilization in composite samples could be minimized by avoiding rises in temperature during transport of fresh daily samples from farm to factory, by holding composites at 55–60°F and by mixing after each daily addition of milk.