bluuebunny/crossref_metadata_2025_split huggingface dataset:
The persistence of penicillin G in the mammary gland when infused immediately after the last milking of lactation
Authors: Smith A. , Neave F. K. , Jones A. 
Published: June 2009

SummaryPenicillin G at a dose level of 1 and 5 million units infused in a quick release base or an aqueous solution into quarters of cows after the last milking of the lactation persisted in infused quarters for about 4 days. From 1 h after infusion penicillin was detected in the venous blood and from 2 h after infusion in non-infused quarters.
Volatile compounds in butter oil: I. Lower boiling compounds
Authors: Forss D. A. , Stark W. , Urbach Gerda 
Published: June 2009

SummaryThe following compounds were isolated from best-quality Australian butter oil by high vacuum degassing, and identified by the combination of gas chromatography and mass spectrometry: the C3,5,7,9 alkan-2-ones, the C2,4,6,8,10,12 n-alkanoic acids, the C6,8,10 5-lactones (or their hydroxyacids), dimethyl sulphone, all isolated in amounts above 1 pt in 108 of butter oil, and butanone, undecan-2-one, 5-dodecalactone, diacetyl, n-nonanoic acid, a decenoic acid, methyl n-decanoate, toluene, o-methoxyphenol, a cresol, phenol, benzaldehyde, methyl benzoate and benzothiazole, all isolated in amounts between 1 pt in 1011 and 1 pt in 108 of butter oil.No compound was isolated in an amount greater than flavour threshold, in fact most compounds were below one-tenth threshold level. However, the distillate obtained by degassing produced a very attractive creamy flavour when added to bland non-cultured butter.
Some effects of process treatment on the body of cream
Authors: Prentice J. H. , Chapman Helen R. 
Published: June 2009

SummaryEffects of age and agitation of milk, temperature of separation, heat treatment and cooling, homogenization and ageing on the body of double cream were studied. Homogenization and temperature of heat treatment gave rise to the greatest effect. The effects of most treatments were inter-related to some extent, but this was most pronounced with cooling and ageing.
The folate-binding protein in milk
Authors: Ford J. E. , Salter D. N. , Scott K. J. 
Published: June 2009

SummaryThe folate in cow's milk was strongly and specifically bound to a minor whey protein (FP), forming a complex of primary M of about 38000, but exhibiting concentration-dependent reversible aggregation. The binding protein was present in excess, and the milk had the capacity to bind about 50μgadded folic acid/l. An enriched concentrate of FP was prepared by ammonium sulphate fractionation—FP was precipitated at between 50 and 60% saturation—and further purified by chromatography in DEAE-cellulose and filtration in Sephadex gel G150. Its identity as a distinct minor whey protein was confirmed by comparative starch gel electrophoresis at various pH values.Some properties of the protein are described, and its physiological significance discussed.
The interaction of bovine milk caseins with the detergent sodium dodecyl sulphate. I. The relationship between the composition and the size of the protein–detergent aggregate
Authors: Cheeseman G. C. , Jeffcoat Joan 
Published: June 2009

SummaryStudy of the dissociation of high-molecular-weight aggregates of preparations of αs1-, β-, κ-, and para-κ-casein by the detergent, sodium dodecyl sulphate (SDS), showed that there are differences in the aggregation properties of the individual caseins. Binding of detergent led first to the dissociation of casein aggregates and then to further interaction with the casein molecules. The amounts of detergent required to give the minimum sized protein-detergent aggregate when expressed as mg/mg casein were similar for κ-, para-κ- and αs1-casein but much less for β-casein. However, expressed as mole/mole the requirement for κ- and αs1-casein was similar but was twice that found for para-κ- and β-casein. The maximum amount of SDS bound was about twice that required for complete dissociation of the aggregates for κ-, para-κ- and αs1-casein but was 13 times greater for β-casein.Complete dissociation of κ-casein aggregates by SDS alone was not possible due to the presence of aggregates formed by disulphide linkages. These aggregates, which consisted of 3±1 protein molecules, accounted for about one-third of the κ-casein in the preparations examined.
Milk enzymes—their distribution and activity
Authors: Kitchen B. J. , Taylor G. C. , White I. C. 
Published: June 2009

SummaryThe distribution and activity of alkaline phosphatase (E.C. 3.1.3.1), acid phosphatase (E.C. 3.1.3.2), catalase (E.C. 1.11.1.6), xanthine oxidase (E.C. 1.2.3.2), aldolase (E.C. 4.1.2.7 and 4.1.2.13), ribonuclease (E.C. 2.7.7.16) and carbonic anhydrase (E.C. 4.2.1.1) were studied in the major components of bovine milk. Fractionation was accomplished by centrifugation of milk, skim-milk and buttermilk, and ammonium sulphate precipitation of skim-milk serum. The range of activities found for the enzymes studied are tabulated together with the activities of some of the enzymes in mastitic milk, and the significance of the results obtained is discussed. No carbonic anhydrase activity was detected in any of the samples tested. The other enzymes studied were found to have a greater proportion of their total activity located in the skim-milk fraction. However, all of these enzymes except ribonuclease had a higher specific activity in the fat fraction.
Comparison of milks processed by the direct and indirect methods of ultra-high-temperature sterilization. IV. The vitamin composition of milks sterilized by different processes
Authors: Burton H. , Ford J. E. , Perkin A. G. , Porter J. W. G. , Scott K. J. , Thompson S. Y. , Toothill Joyce , Edwards-Webb J. D. 
Published: June 2009

SummaryA comparison was made of the effects of direct and of indirect ultra-high-temperature (UHT) processing of milk, under standardized operating conditions giving equal sporicidal effects, on some of the more labile water-soluble vitamins and on vitamin A and carotene. The effects of processing per se were negligibly small, and the method of processing was important only in so far as the presence of residual oxygen in the sterilized milk has been found to cause losses of folic acid and ascorbic acid during storage subsequent to sterilization. The incorporation of a de-aerator vessel, to reduce the oxygen level in the indirectly heated milk and so eliminate the adverse effects of oxygen during storage, had no effect on the vitamin loss occurring during heat treatment. It is concluded that milk produced by indirect heating plant incorporating a de-aerator should be similar in vitamin content to milk produced on a direct heating plant, both immediately after processing and after storage.
Influence of the physical form of a barley grain and barley straw diet on nitrogen metabolism in sheep
Authors: Jackson P. , Rook J. A. F. , Towers K. G. 
Published: June 2009

Summary(1) Two wether sheep fitted with ruminal and duodenal re-entrant cannulas were used to study the influence of the physical form of a barley grain and barley straw diet and intraruminal addition of ammonium salts (mainly acetate) on digestibility of dietary constituents, the flow of digesta to the duodenum and the composition of digesta from the rumen and duodenum.(2). Grinding and pelleting of the diet depressed the digestibility of crude fibre and increased that of the nitrogen-free extract and addition of ammonium salts increased the digestibility of crude fibre. The effects of the physical form of the diet on the composition of the short-chain fatty acids of rumen liquor were not consistent and the addition of ammonium salts produced changes over and above those attributable to the small amounts of acids in the mixture. The extreme values observed for the molar proportion of propionic acid were 12·3 and 38·1% and the corresponding values for η-butyric acid were 28·1 and 9·0%.(3). Variations in the flow of nitrogenous materials to the duodenum were related more to the pattern of fermentation established in the rumen than to the experimental treatments. There was a highly significant relationship between the molar proportion of propionic acid and the abomasal output of nitrogen and also the abomasal output of α-ε-diaminopimelic acid and α-linked glucose polymers. The amino acid composition of duodenal digesta differed from that of the diet—in particular the proportion of glutamic acid was decreased and the proportions of aspartic acid, alanine, lysine and histidine were increased—but differences in composition between treatments and between animals were small.(4). The faecal output of nitrogen differed little between animals and between treatments, but nitrogen retention was significantly increased during the intraruminal infusion of ammonium salts.
Volatile compounds in butter oil: II. Flavour and flavour thresholds of lactones, fatty acids, phenols, indole and skatole in deodorized synthetic butter
Authors: Urbach Gerda , Stark W. , Forss D. A. 
Published: June 2009

SummaryThe flavours of the following compounds were determined in synthetic butter prepared from 84% steam-deodorized butter oil and 16% water: C6, 8, 10, 12, 14 δ-lactones, C12 γ-lactone, C2, 4, 6, 8, 10, 12, 14n-alkanoic acids, phenol, m- and p-cresols, o-methoxyphenol, indole and skatole. C6, 8, 10 δ-lactones, C2, 4, 6, 8, 10, 12, 14n-alkanoic acids, phenol, m- and p-cresols, o-methoxyphenol and volatile fractions from butter oil were also evaluated in bland butter. None of the compounds listed constitute basic butter flavour on their own, but C8, 10 δ-lactones, C10 acid, phenol, p-cresol, indole and skatole contribute to butter flavour.
Influence of temperature and composition on some physical properties of milk and milk concentrates. I. Heat capacity
Authors: Fernández-Martín F. 
Published: June 2009

SummaryAn isothermal jacket calorimeter was set up and apparent heat capacities of skim-milk, half-and-half milk, whole milk, and their concentrates up to about 30 % total solids were measured throughout the 5–70°C temperature range. Above the butterfat melting interval, the heat capacity of every sample was linearly related to temperature and a linear regression equation was found to relate heat capacity and total solids content for each one of the 3 milk sets. By means of an overall approximation, a single expression relating heat capacity, temperature and total solids content was also derived. To facilitate calculations of relative heat content for practical purposes, an average apparent heat capacity was computed for the whole temperature range and a nomogram was constructed for its determination from fat and solids-not-fat contents in any sample.
Influence of temperature and composition on some physical properties of milk and milk concentrates. II. Viscosity
Authors: Fernández-Martín F. 
Published: June 2009

SummaryTen different types of milk, arranged in 3 sets, were observed to be pseudoplastic fluids with linear behaviour at high shear rates in a coaxial cylinder rheometer; at low rates of shear all the samples could be considered sufficiently Newtonian and a Höppler viscometer was used for their study. Dynamic viscosity coefficients of skimmilk, half-and-half milk, whole milk and their concentrates up to about 30% total solids were determined every 5°C between 0 and 80°C. For every milk type a quadratic equation relating t to log η was obtained. At a given temperature the concentration dependence of η for the 3 milk sets was expressed by a single relation of the same mathematical model as in the previous case. A general expression was derived to enable η to be calculated at any temperature (0–80°C), and for any concentration (0–30% total solids) whatever the fat to solids-not-fat ratio (0·01–0·4). A nomogram was also constructed for the immediate computation of η without any practical loss of accuracy.
Growth studies on the lactic streptococci: III. Observations on continuous growth behaviour in reconstituted skim-milk
Authors: Keen A. R. 
Published: June 2009

SummaryThe behaviour ofStreptococcus cremorisAM1and AM2, andStreptococcus lactisML8in continuous growth in reconstituted skim-milk medium under controlled conditions of pH has been investigated.At 20°C under aerobic conditions small quantities of oxygen were found to stimulate the growth rate ofStr. lactisML8between pH 5·05 and 5·45. Growth between pH 5·45 and 6·35 became erratic due to the accumulation of hydrogen peroxide. Above pH 6·35 hydrogen peroxide could not be detected in the continuously growing culture and below pH 5·05 the growth rate of the culture was not affected by small quantities of oxygen. An effect of direct oxygen toxicity on growth, distinct from that of hydrogen peroxide accumulation, was observed over the limited pH range investigated. After 48 h growth in the presence of small concentrations of oxygen the effect disappeared.At 30°C under anaerobic conditions a region in the dilution rate curves was observed withStr. cremorisAM1and AM2andStr. lactisML8which suggested the occurrence of a growth-limiting component. This region of slow growth could be correlated with diminished soluble nitrogen values, and was eliminated by enrichment of the medium with soluble nitrogen.An unusual feature of the investigation was the dilution rates, indicative of extremely fast specific growth rates, experienced forStr. lactisML8. It was thought unlikely that wall growth contributed appreciably to the dilution rate as a similar phenomenon was not observed withStr. cremorisAM1or AM2.
Variations in the concentrations of free amino acids in the plasma of the dairy cow at parturition
Authors: Verbeke R. , Roets E. , Peeters G. 
Published: June 2009

SummaryThe plasma levels of individual amino acids were studied in 6 dairy cows from 4 days before to 3 days after calving. During this sampling period, the concentrations of 13 amino acids showed significant changes. The levels of several amino acids were depressed markedly in the sample collected immediately before calving. Following parturition, the concentration of most amino acids gradually returned to values obtained 3 days before calving. The glutamine and alanine contents of the plasma rose to a peak value 1 day after calving and subsequently decreased. The mean concentrations of glycine and α-aminobutyric acid did not change before parturition but rose significantly thereafter. These observations are discussed in terms of amino-acid utilization for milk protein synthesis and gluconeogenesis at the onset of lactation. The changes in plasma amino acid levels appear to be synchronized with those reported for prolactin and progesterone in the 24 h before parturition. This may indicate an important influence of both hormones on the lactogenic process in the cow. The highly significant correlations obtained between the concentrations of 14 individual amino acids are discussed.
Kinetics of rennin action on casein prepared by ultracentrifugation
Authors: Castle A. V. , Wheelock J. V. 
Published: June 2009

SummaryThe kinetics of the primary phase of rennin action on casein micelles and on total casein prepared by ultracentrifugation have been studied. It was observed that the values of Km and V varied for the different casein samples. Addition of whey proteins to the reaction mixture or variation of the concentrations of Na+ and K+ had no effect on Km and V and V, but there was a consistent increase in the values of both these parameters when κ-casein was added. It was concluded that these changes were due to an increase in the accessibility of the κ-casein resulting from the rearrangement of the casein micelles. These results are in agreement with our earlier conclusion that the Km for rennin action on casein is dependent on the carbohydrate composition of the molecule.
Casein micelle structure: susceptibility of various casein systems to proteolysis
Authors: Fox P. F. , Guiney J. 
Published: June 2009

SummaryThe susceptibility of the components of various caseinate systems (skim-milk, β-casein-depleted milks, colloidal phosphate-free (CPF) milk, sodium caseinate and isolated β-casein) to proteolysis was investigated. Isolated αs1- and β-caseins were quite susceptible to proteolysis, but their susceptibility decreased in heterogeneous soluble systems and even more so in heterogeneous aggregated systems. In skim-milk and β-casein-depleted milks only about 50% of both αs1- and β-casein was hydrolysable by high levels of rennin, and in CPF milk all αs1- and 70% of the β-casein was hydrolysable. It is suggested that about 50% of micellar β-casein is firmly fixed within the micelle and is unavailable for proteolysis, while the remainder can dissociate from the micelle on cooling and is then readily hydrolysable.The compatibility of the data with the various published models of the casein micelle is discussed, and a modification of Rose's (1969) model is proposed.
Periodic omission of dairy cow milkings: II. Effect on the composition and processing properties of herd milk
Authors: Bailey L. F. , Radcliffe J. C. , Hehir A. F. 
Published: June 2009

SummaryForty-five Friesian cows were assigned to one of 3 milking management treatments: (1) cows milked 14 times weekly, (2) cows milked 13 times weekly (Wednesday morning milking omitted) and (3) cows milked 12 times weekly (Tuesday evening and Wednesday morning milkings omitted). The trial continued for 12 months.Milking omission led to compositional changes in herd milk similar to those described for subclinical mastitis, including increases in pH, chloride level and cell count. Alterations in processing properties consistent with these changes were encountered. Heat stability and curd firmness were affected by extending the milking interval, but the magnitude and direction of the effects varied.Where only one milking was omitted weekly, herd milk arriving at cheese or powdered-milk factories would not be expected to cause any serious technical difficulties. Omission of 2 consecutive milkings a week would cause processing difficulties where milk was to be condensed or dried, since the maximum heat stability obtained by pH adjustment was reduced.
Utilization of nutrients by the dairy cow and optimal N:energy ratio in the diet
Authors: Paquay R. , Godeau J. M. , De Baere R. , Lousse A. 
Published: June 2009

SummaryThe dietary and individual animal factors influencing the utilization of digestible nitrogen and of metabolizable energy for milk production were studied and change in the optimal nitrogen:energy ratio during lactation was investigated using 35 different experimental diets and the individual results obtained from 119 Friesian cows whose daily milk production varied from 4 to 30kg.The amount of N secreted in the milk and the daily milk production depended above all on the metabolizable energy intake and on the stage of lactation. They were related to the dietary N: energy ratio.The percentages of digestible N and of metabolizable energy utilized for milk production were also related to the dietary digestible N: metabolizable energy ratio of the diet.The optimal digestible N:metabolizable energy ratio ranged from about 2·2g/MJ during the first 3 months of lactation to about 1·7g/MJ in the sixth and seventh months and 1·3g/MJ from the tenth month. When expressed in g N intake per MJ energy intake, this optimal ratio ranged from 1·6 after calving to 1·1 at the end of lactation.
Separation and estimation of diacetyl and acetoin in milk
Authors: Walsh B. , Cogan T. M. 
Published: June 2009

SummaryTwo methods are described for the separation of diacetyl and acetoin in milk by steam distillation. In the first method, acetoin is measured in the residue remaining in the extraction flask after steam distillation while diacetyl is measured in the first 10 ml of distillate which contains 35% of the acetoin and 100% of the diacetyl. Increases in the volume of residue taken for analysis decreased colour development by acetoin. In the second and preferred method, diacetyl is measured in the first 10 ml of distillate and acetoin in the second 10 ml of distillate which contains about 24% of the added acetoin. Diacetyl in both methods is measured by a modification of the method of Prill & Hammer (Walsh & Cogan, 1974) and acetoin by the Westerfeld (1945) procedure.
Effects of intramammary arterial infusion of essential amino acids in the lactating goat
Authors: Linzell J. L. , Mepham T. B. 
Published: June 2009

SummaryExperiments were performed on 3 lactating goats, in which mammary arterial plasma amino-acid concentrations were elevated by the infusion of a solution of essential amino-acids into the carotid artery supplying a transplanted mammary gland. In 2 experiments there were marked elevations in the arterial concentrations of most essential amino acids, but in one case only did this result in significantly increased uptake of amino acids by the gland, the arterio-venous difference being significantly correlated with arterial concentration for all except one amino acid. In the experiment in which increased amino-acid uptake was observed, infusion also resulted in a significantly increased milk yield and increased milk protein yield. The results are discussed in relation to data from other laboratories and lead to the suggestion that milk protein synthesis may be limited by the availability of either methionine or tryptophan.
Organochlorine content of milks, dairy products and animal feed ingredients: Ireland 1971–1972
Authors: Downey W. K. , Flynn Mary P. , Aherne S. A. 
Published: June 2009

SummaryMilks (bovine and human) and dairy products (butter, cheese, skim and whey powders, calf-replacer, casein, butter-oil and dietetic food) were collected during 1971/2 throughout Ireland together with a more limited sample of the 10 major animal feed ingredients, and analysed for organochlorine insecticide residues using electron-capture gas chromatography. The different materials contained low or negligible levels of chlorinated insecticides. Apart from some of the animal feed ingredients the DDT residues were generally the predominant contaminants detected together with lower levels of γ-BHC (lindane), aldrin/dieldrin and heptachlor/heptachlor epoxide. The maximum levels of these insecticides in the bovine milk and dairy products (511, 100, 62 and 21 μg/kg fat respectively) constitute only 50% or less of the Codex Tolerance Limits. The correspondingly low residue levels in the human milk (maxima of 128, 1, 1, and 5 μg/kg fat respectively) which at most represent insecticidal ingestion by infants equivalent to 13, 0·05, 5 and 5% respectively of the WHO/FAO acceptable daily intake for DDT, γ-BHC, aldrin/dieldrin and heptachlor/heptachlor epoxide again pose no obvious health hazards and are strongly indicative of negligible organochlorine contamination in the general diet. The samples of animal feed ingredients examined also contained trace levels of organochlorines (maxima of 0·9, 0·1, 1·6 and 1·0 μg/kg respectively). More extensive monitoring of the residues in animal feed ingredients (the most probable source of milk contamination) is advocated, and the desirability of tolerance limits for insecticides in animal feeds discussed.
Citrate utilization in milk byLeuconostoc cremorisandStreptococcus diacetilactis
Authors: Cogan T. M. 
Published: June 2009

SummaryCitrate utilization and diacetyl, acetoin and acetaldehyde production by 2 strains each ofLeuconostoc cremorisandStreptococcus diacetilactisin milk were studied. With the leuconostoc bacteria no growth and little citrate utilization occurred unless a stimulant (yeast extract) was present, when complete utilization of citrate without concomitant production of diacetyl or acetoin was obtained. The addition of Mn2+stimulated growth and citrate utilization in the presence of yeast extract. Addition of citric acid after 65-h growth resulted in diacetyl and acetoin production. Destruction of diacetyl and acetoin occurred when the citric acid level fell toc. 1000 and 600 μg/g in the case ofLeuc. cremorisFR8-1 and CAF1, respectively. Only strain FR8-1 produced acetaldehyde. In contrast,Str. diacetilactisproduced diacetyl, acetoin and acetaldehyde concomitant with citrate utilization.