bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steam distillation of taints from cream: IX. Vapour/liquid equilibrium relationships for indole and skatole in water and cream
Authors: McDowall F. H. 
Published: June 2009

SummaryThe vapour/liquid equilibrium coefficients for the steam distillation of indole and skatole from water solution over the range of concentrations 0·1 to 20–30 ppm. were found to be 2·4 and 4·7, respectively. The coefficient for indole in a cream containing 30% fat was found to be 0·31, and for skatole, in a cream containing 40% fat, 0·14. It is concluded that complete removal of indole and skatole contaminations from cream by use of steam distillation equipment is not commercially practicable.
Factors affecting the fat globule sizes during the homogenization of milk and cream
Authors: Goulden J. D. S. , Phipps L. W. 
Published: June 2009

SummaryThe homogenization of milk and cream with a piston-type homogenizer has been studied. An examination has been made of the influences upon the mean fat globule diameters of changes in milk fat content, flow rate and homogenization temperature. The results are discussed in terms of the variations in the parameters q and P0 of the empirical equation d = (P0/P)q relating the globule diameter d to applied pressure P.
Attempts to relate the selenium content of heat-treated milks with their nutritive properties
Authors: Henry Kathleen M. 
Published: June 2009

SummaryFink (1954) and Fink & Schlie (1955a) fed rats on a diet intentionally marginal in vitamin E and the sulphur-amino acids, in which dried milk supplied the protein (10%). They were able to relate the development of fatal liver necrosis in rats to heat damage of dried milks. Using their method, no liver necrosis developed in our rats with 2 spray-dried skim-milks, evaporated milk and milk subjected to ultrahigh temperature treatment, with or without subsequent in-bottle sterilization. With a roller-dried skim-milk sent to us from Germany by Fink and found by him to be of ‘middle degree necrogenity’, no liver necrosis occurred in hooded or albino rats bred in our laboratory, but the lesion developed in albino rats from an outside source. It was found that this milk had a lower selenium content than 2 British spray-dried milks. With rats given a necrogenic diet, differences were observed between and within strains in their susceptibility to liver necrosis and in their ability to utilize dietary selenium.
The action of rennin on casein: the effect of modifying functional groups on the casein
Authors: Hill R. D. , Laing Raione R. 
Published: June 2009

Summaryk-Casein and whole casein when photo-oxidized in the presence of methylene blue lose the ability to clot when treated with rennin. Two effects are involved—first the photo-oxidation alters the k-casein fraction so that the rennin is unable to split off the glycopeptide fragment, and secondly, in whole casein the photo-oxidation interferes with the aggregation in the presence of Ca++that normally follows rennin action. As a result of amino acid analysis and specific treatments which affect other photo-oxidizable side chains, it is concluded that both of these effects are caused by the alteration of histidines.
A modification of the acid degree value test for lipolytic rancidity in milk
Authors: Hunter A. C. , Wilson Judith M. , Barclay Grace W. 
Published: June 2009

SummaryWhile using an acid degree value test during work on lipolysis in milk, difficulty was encountered in extracting the fat from the milk of certain cows, especially milk of high butterfat content and milk from newly calved cows. This difficulty was overcome by increasing the quantity of reagent used. A study was made of the quantities of reagent required for milks of different butterfat content and for colostrum. No effect on the acid degree value occurred as a result of increasing the quantity of reagent. A modification of the test is recommended, using an increased quantity of reagent.
The effects of dietary tallow and cottonseed oil on milk fat secretion in the cow
Authors: Steele W. , Moore J. H. 
Published: June 2009

SummaryThe effects of the isocaloric replacement of part of the dietary concentrate mixture by either tallow or cottonseed oil on the yield and composition of the milk fat was investigated in 2 feeding experiments with a total of 26 cows in midlactation. The concentrates were given with high- or low-roughage diets that supplied either 9·1–9·5 or 1·8–3·2kg hay/day.In expt 1, the addition of cottonseed oil to the high-roughage diet increased the yield of milk fat during the first 8 days but decreased it during the last 4 days of a 28-day feeding period. In contrast, the inclusion of tallow in the high-roughage diet resulted in an increased yield of milk fat that was sustained throughout the period of 28 days. In expt 2, the intake of dietary fat was less than it was in expt 1 and the inclusion of tallow or cottonseed oil in either the high- or low-roughage diets had little effect on the yield of milk fat.The inclusion of either fat in the diet increased the yields and percentages of stearic and oleic acids and, in general, decreased the yields and percentages of the medium-chain fatty acids (10:0, 12:0 and 14:0) in the milk fat. The addition of tallow to the diet did not appear to alter the yields of the short-chain fatty acids (C4–C8, 4:0, 6:0 and 8:0) in the milk fat. When the low-roughage diets resulted in a decreased yield of milk fat, the secretion of all the fatty acids in the milk fat was reduced, but the reduction in the secretion of oleic acid was less than the reductions in the secretions of the other constituent fatty acids.
A preliminary study by gel filtration and ultracentrifugation of the interaction of bovine milk caseins with detergents
Authors: Cheeseman G. C. 
Published: June 2009

SummaryThe detergents sodium dodecyl sulphate and octyl phenoxy polyethoxyethanol interact with casein and cause dissociation of the high-molecular-weight casein aggregates. It is presumed that the detergent binds with hydrophobic regions in the casein molecule. The size of the complexes formed between detergents and αs1-casein, β-casein and κ-casein, as estimated by gel filtration and sedimentation velocity experiments, suggests that the caseins were complexed as monomers.During gel filtration under non-reducing conditions, detergent-κ-casein complexes were separated from other major components because of their conversion through formation of disulphide bonds into high-molecular-weight aggregates. This reaction, which did not occur in sedimentation velocity experiments, was presumably facilitated by the changes in the equilibrium between the individual caseins during gel filtration.Sedimentation velocity experiments showed that a ratio of about 40 detergent molecules to 1 casein molecule was required to give the smallest casein-detergent complex.
The effect of nitrogen source in the diet on milk production and amino-acid uptake by the udder
Authors: Kellaway R. C. , Ranawana S. S. E. , Buchanan J. H. , Smart L. D. 
Published: June 2009

SummaryTwo experiments were carried out with Friesian cows grazing improved winter pastures. In expt 1, 12 cows were fed 6·6kg/d of a barley-based concentrate containing either no N supplement, or supplements of casein, formaldehydeprotected casein or urea which provided 48 g N/d. In expt 2, 12 cows were fed 2·6kg/d of a barley-based concentrate containing either casein, formaldehyde-protected casein or equal mixtures of both, all of which provided 96g N/d.In expt 1, although the production of fat-corrected milk was 7·1% higher and that of total solids 6·1% higher on the protected casein than on the casein diet, production of milk and milk constituents on the control and urea diets were similar to values obtained for cows fed protected casein. In expt 2, milk production and composition were unaffected by treatments.The concentrations of amino acids in jugular plasma and mammary uptake per litre of plasma were not affected by the experimental diets in expt 1, and were unrelated to milk yield in either experiment. In expt 2 the concentrations of glycine, serine and threonine in jugular plasma were significantly higher in the diet in which none of the casein was protected. Mobilization of muscle protein may have been responsible for the elevated levels of glycine in cows fed this diet. Mammary uptakes of essential amino acids in expts 1 and 2 were respectively 47 and 42% of those available, whereas the uptakes of non-essential amino acids were respectively 24 and 17% of those available.An attempt was made to determine the amino acids most likely to limit milk production. Milk:uptake concentration ratios were obtained using our values for amino-acid uptakes and values published previously for the concentration of amino acids in milk. The results of these calculations suggest that the amino acids most likely to limit milk production are threonine, phenylalanine and methionine.
The Role of β-lactoglobulin in the primary phase of rennin action on heated casein micelles and heated milk
Authors: Wheelock J. V. , Kirk A. 
Published: June 2009

SummaryIt has been shown that the inhibition caused by heat treatment, of the primary phase of rennin action on casein micelles, is dependent on the presence of β-lactoglobulin. The degree of inhibition increased with increasing amounts of added β-lactoglobulin for both heated casein micelles and heated skim-milk to a constant value. The results are fully consistent with the hypothesis that the inhibition is caused by complex formation between β-lactoglobulin and κ-casein when milk is heated.
Relationships between blood composition and fertility in dairy cows – a field study
Authors: Rowlands G. J. , Little W. , Kitchenham B. A. 
Published: June 2009

SummaryThree hundred and fifty-one lactating dairy cows, which were between 40 and 100 d post-calving, were selected from cows sampled during metabolic profile testing of 21 herds. Blood samples were analysed for packed cell volume (PCV), blood glucose and haemoglobin, and serum urea-N, albumin, total protein, inorganic phosphate, Ca, Mg, Na, K, Cu and Fe. After adjusting for herd and date of sampling and each cow's age, stage of lactation, milk yield and interval from calving to first service, concentrations of albumin and K (P < 0·01) and PCV (P < 0·05) were inversely related and concentrations of globulin (derived as the difference between total protein and albumin) directly related (P < 0·05) to the number of services required for conception. Conception rates to first service were inversely related to lactation number but not to milk yield on day of sampling.
Influence of age, dietary protein and weaning on calf abomasal enzymic secretion
Authors: Garnot P. , Toullec R. , Thapon J.-L. , Martin P. , Hoang Minh-Thu , Mathieu C.-M. , Dumas B. Ribadeau 
Published: June 2009

SummaryUsing fistulated calves, the influence of the age, type of dietary protein and weaning on the secretion of chymosin and pepsin by the abomasum were studied. The abomasum secreted both chymosin and pepsin when the animals were fed milk. Chymosin secretion appeared to be independent of the age of the animals, whereas a slow increase in pepsin secretion was observed as the calves aged. Several preruminant animals were fed either a skim-milk diet or a milt substitute in which proteins were provided by fish, soya or whey concentrates. Each of these 3 milk substitutes led to a decrease in chymosin secretion without modification of pepsin secretion. Chymosin secretion was partly restored when the calves were again given a skim-milk diet. At weaning, chymosin secretion dropped abruptly, but the pepsin level was not affected. These results indicate that milk (most probably its casein fraction) is responsible for the activation of chymosin secretion.
Fractionation of whole casein on hydroxyapatite. Application to a study of buffalo κ-casein
Authors: Addeo F. , Chobert J.-M. , Ribadeau-Dumas B. 
Published: June 2009

SummaryWhen whole caseins from cow and Italian buffalo (Bubalus arnee) were fractionated by chromatography on a column of hydroxyapatite they behaved in a similar manner. κ-Casein was eluted with 5 mM phosphate buffer, pH 6·8, containing 0·2 M-KCI, 4·5 M-urea and 2 mM-2-mercaptoethanol, but β- and αs-caseins were retained and could be eluted successively by a linear gradient from 5 mM to 250 mMphosphate buffer. Buffalo κ-casein preparations, obtained from bulk milk or from milks of individual animals by chromatography on hydroxyapatite, produced identical electrophoretic patterns at pH 8·6. By further fractionation of these κ-caseins on DEAE-cellulose, in each case, at least 7 components were purified; they had different electrophoretic mobilities but were all sensitive towards chymosin. The major fraction migrated like component 1 of bovine κ-casein B.
Autotransplantation of the goat mammary gland
Authors: Peaker Malcolm , Fleet Ivan R. 
Published: June 2009

SummaryThe modified technique for transplanting one mammary gland of a lactating goat to the neck, with the mammary (pudic) artery and vein anastomosed to the carotid artery and jugular vein respectively, is described. This technique was successful in 6 operations and there were no significant differences between the milk yield of the transplanted and control (in situ) glands at any stage after operation. These results are compared with those from an earlier series in which no special provision was made for lymphatic drainage and in which anticoagulant therapy and treatment of the gland prior to attachment were not standardized.
Proteolysis and aggregation of casein micelles treated with immobilized or soluble chymosin
Authors: Dalgleish Douglas G. 
Published: June 2009

SummaryThe relationship between extent of κ-casein proteolysis and aggregatability of milk casein micelles has been studied using chymosin either bound to porous glass supports or free in solution. Both enzyme preparations demonstrated that, overall, 86–90 % of the κ-casein had to be destroyed before any aggregation could occur. Based on these results, a mathematical model of chymosin action on casein is described involving (i) the attack on κ-casein by chymosin, via a Michaelis–Menten mechanism (ii) the probability that sufficient κ-casein on any micelle is destroyed to allow aggregation, and (iii) the aggregation of para-casein micelles by a von Smoluchowski mechanism.
Analysis of somatic cell volume distribution as an aid to the diagnosis of mastitis
Authors: Hoare Roderic J. T. , Sheldrake Richard F. , Nicholls Paul J. , McGregor Gavin D. , Woodhouse Victoria E. 
Published: June 2009

SummaryElectronic somatic cell counts (ESCC) and relative cell volume distributions (RCVD) in milk samples were obtained simultaneously on a Coulter Counter Model TA and their potential assessed, either singly or in combination, for identifying mastitic quarters and cows in 2 herds. Using log (ESCC) alone the probability Pm of misclassifying quarters infected with major pathogens was 6–7 % for herd 1 and 18–1% for herd 2. The inclusion of RCVD variables with log (ESCC) did not substantially improve the chance of detecting quarters infected with major pathogens. However, the RCVD variables did improve the chance of identifying quarters infected by major and minor pathogens compared to the use of log (ESCC) alone, the Pm figures being reduced by about one third.When testing composite quarter samples, where milk from infected quarters was diluted with that from uninfected quarters, the inclusion of RCVD variables decreased the Pm compared to the use of log (ESCC) alone. In herd 1 the improvement was from 26–1 to 3·0 %, while in herd 2 the effect was less marked, the Pm being reduced from 28–6 to 21–6%. However, as the RCVD assessment is provided simultaneously with ESCC, the additional information is obtained at minimal cost.
Light scattering investigation of the stability of bovine casein micelles to dilution
Authors: Parker Thomas G. , Horne David S. 
Published: June 2009

SUMMARYDialysed whey and dialysed ultracentrifugate from skim-milk were found to be satisfactory dilution media for light scattering studies on bovine casein micelles at 20 °C. Both milk dialysate and milk ultracentrifugate were only useful at fairly low levels of dilution and even then only for short periods of time. Whey, pH-adjusted to that of the original milk, was found to be an unsuitable diluent medium. Most of the instability of casein micelles to dilution could be attributed to some form of Ca phosphate precipitation or Ca phosphate–casein micelle aggregation.
Biological responses of the bovine teat to milking: information from measurements of milk flow-rate within single pulsation cycles
Authors: Williams David M. , Mein Graeme A. , Brown Murray R. 
Published: June 2009

SummaryThe mass flow-rate (FR) of milk from the bovine teat within individual pulsation cycles was measured by continuous computation of the average optical density of the milk–air mixture within a teatcup. Measurements during milking were made on both live and excised teats using a range of teatcup liners, vacuum levels and pulsation characteristics. During a typical pulsation cycle, soon after the start of milking, milk FR from live teats reached a peak within 100 ms of the start of the flow period and fell to about 60% of the maximum value between 0·5 and 1·5 s of flow. If the liner was held open for longer than 1·5 s, the FR typically declined a further 10% over the next 10–15 s. After 10–15 s little or no further change occurred in milk FR at normal milking vacuum levels. Milk flow from excised teats reached a steady value within 100 ms of the start of the flow period and showed no subsequent fall in FR.Within individual pulsation cycles the changes in FR from live teats are affected by: (i) the degree of compressive load applied by the collapsed liner to the teat in the preceding cycle; and (ii) the duration of application of the compressive load. Increasing the degree of compressive load or the length of time of loading increases the peak milk FR of the next cycle by reducing the degree of congestion in the tissues of the teat surrounding the teat canal. Muscular effects are of secondary importance. The relatively small changes in milk FR associated with muscle contractions of the teat can be seen most clearly at low milking vacuum levels (below about 30 kPa) or with an unsupported teat (e.g. using a very distensible, thin-walled liner).
Effects of adding potassium iodate to milk before UHT treatment: I. Reduction in the amount of deposit on the heated surfaces
Authors: Skudder Paul J. , Thomas Elmer L. , Pavey John A. , Perkin Allen G. 
Published: June 2009

SummaryAdditions of potassium iodate to milk at 0·05 and 0·1 mM (10 and 20 ppm) before UHT treatment markedly reduced the rate at which pressure built up during processing. This permitted the use of longer processing times before unacceptable pressures were reached in the heat exchangers. Iodate reduced the amount of protein deposited, particularly in the higher temperature sections of the plant, but had no effect on the deposition of minerals. The more compact nature of the highly mineral deposits offered less resistance to the flow path. Reduction in the amount of protein deposited is likely to be caused by increased denaturation of β-lactoglobulin and oxidation of heat activated sulphydryl groups by the iodate, thus reducing the formation of high molecular weight polymers of sulphur-containing proteins at the heated surfaces. Increasing the level of sulphydryl groups in the milk through the addition of L-cysteine-HCl caused an increase in the amount of deposit formed during UHT treatment. Whilst little detrimental effect on the quality of the milk resulted from additions of iodate at 0·05 mM, milks with 01 mM-iodate became bitter during subsequent aseptic storage. Bitterness was a result of iodate-induced proteolysis of casein.
Pickled soft cheese-making from recombined milk with added dried buttermilk
Authors: El-Salam Mohamed H. Abd , El-Shibiny Safinaz , Moneib Ahmed , El-Heiba A. Abo , Al-Khamy Ahmed 
Published: June 2009

SummaryPickled soft cheese was made from recombined milk (30 % total solids, 8 % fat) containing buttermilk powder (0–4%) and stored in the pickle at room temperature (25±5 °C) for 135 d. The yield, quality and composition of cheese were followed periodically during storage. The addition of buttermilk slightly increased the yield and improved the flavour intensity of the cheese, whilst only slightly affecting its chemical composition.
Isolation of κ-casein-like fractions from human whole casein by chromatography on thiol-Sepharose, hydroxyapatite and DEAE-cellulose
Authors: Chobert Jean-Marc , Addeo Francesco , Dumas Bruno Ribadeau 
Published: June 2009

SummaryDifferent fractions of human κ-casein characterized by their sensitivity to chymosin were separated, after reduction, by affinity chromatography on thiol-Sepharose in a 0·1 m-Tris-HCl buffer, pH 7·0, containing 7 M-urea, 0·3 m-NaCl and 1 mm-EDTA. The fraction retained on the column and bearing the SH-groups was then chromatographed on hydroxyapatite in a 5 mm-phosphate buffer, pH 6·8, containing 0·2 m-KC1, 4·5 m-urea and 2 mm 2-mercaptoethanol. The fraction not retained on this column was purified by chromatography on DEAE-cellulose in a 6·6 m-urea, 0·02 m-imidazole, 0·02 m 2-mercaptoethanol buffer, pH 7·0. Two chymosinsensitive fractions were identified by starch-gel electrophoresis at pH 8·6; one of low electrophoretic mobility, the other a smeared band covering the whole distance of migration, in which several bands with mobilities greater than those of β-caseins could be detected.
Factors affecting the distribution of lipoprotein lipase activity between serum and casein micelles in bovine milk
Authors: Anderson Malcolm 
Published: June 2009

SUMMARYThe influence of mastitis and early lactation, and the effect of treating milk with heparin, blood serum and trypsin, on the proportion of lipoprotein lipase (LPL) activity in milk serum was investigated. The relative importance of milk serum LPL and LPL bound to micellar casein in promoting lipolysis was also examined. Colostrum contained LPL activity, 45% of which was found in the serum phase in samples obtained from the first milking post partum, but this value fell to 34% in samples taken 24 h later. The proportion of serum LPL was also increased in milks from quarters infected with Staphylococcus aureus, but not after overnight treatment of normal milk at 4 °C with 5% (w/v) blood serum or 2 µg/ml trypsin. The addition of 5 µg/ml heparin resulted in a consistent increase in serum LPL which varied between 14 and 50% of total milk LPL. Heparin did not release all the enzyme bound to casein micelles even after a second heparin treatment of resuspended micelles. Serum LPL was more effective in promoting lipolysis and was more responsive to blood serum activation than LPL bound to casein micelles. Lipolysis increased after heparin treatment but the increase was not related to serum LPL activity.
Triacylglycerol composition of buffalo milk fat
Authors: Arumughan C. , Narayanan K. M. 
Published: June 2009

SUMMARYBuffalo milk fat was first separated by thin layer chromatography (t.l.c.) into high (HMT), medium (MMT) and low (LMT) molecular weight triacylglycerols. The triacylglycerol (TG) fractions thus obtained were further resolved by argentation t.l.c. into saturated,trans-monoene,cis-monoene, diene and polyene TG species. Whereas 18:1 was concentrated in HMT, 6:0, 8:0 and 10:0 tended to be located in MMT. LMT was unique in containing almost all 4:0. HMT, MMT and LMT showed great variations in their levels of different TG species. The distribution of fatty acids among the TG species was found to be characteristic of each TG species.