bluuebunny/crossref_metadata_2025_split huggingface dataset:
The composition of milk deposits in an ultra-high-temperature plant
Authors: Lyster R. L. J. 
Published: June 2009

SummaryMilk deposits from an ultra-high-temperature (UHT) plant were analysed for protein, fat and minerals. The physical appearance and composition of the deposits was found to vary with modifications of the plant. For each particular arrangement of the plant, a characteristic pattern of deposits occurred. Possible mechanisms involved in the formation of the deposits are discussed.
A pilot plant for the removal of cationic fission products from milk: II. Efficiency of the process and composition of the product
Authors: Glascock R. F. , Bryant D. T. W. 
Published: June 2009

SummaryAS previously described, the process consists essentially of the passage of milk at pH 5·2–5·25 through an ion exchange resin charged with a suitable mixture of the ions of Ca, K, Na and Mg.When citric acid was used for reduction of the pH and 30 resin bed volumes (r.b.v.) were treated, the concentration of residual85Sr was reduced to 2–4% whether it had been introducedin vivo or in vitro. There was no evidence that repeated use of the resin bed resulted in diminished radiochemical efficiency.About the same efficiency of removal of133Ba was obtained but this efficiency was achieved with137Cs only if not more than 15 r.b.v. were treated. If 30 r.b.v. were treated the concentration of residual137Cs was as much as 30%.When hydrochloric acid was substituted for citric acid the residual concentration of85Sr was 11%. Analyses of milks processed after adjustment of pH with either citric or hydrochloric acid showed the products to be satisfactory. The only important constituent lost was thiamine. Concentrations of heavy metals remained well below maximum values. Although the flavour of milk was detectably changed by the treatment it was still acceptable.The results are discussed in relation to the problem of achieving maximum decontamination and to the design of a large scale plant.
A kinetic model of the clotting of casein by rennet
Authors: Tuszyński W. B. 
Published: June 2009

SummaryA kinetic model of casein clotting caused in milk by rennet was defined by measuring changes in viscosity and in the complex modulus of rigidity. Three separate stages of the process were distinguished: the enzymic, the flocculation and the gelification. The kinetic equations and the main activation parameters were defined for each stage.
The chemical composition and physical properties of fractions of milk fat obtained by a commercial fractionation process
Authors: Norris R. , Gray I. K. , McDowell A. K. R. , Dolby R. M. 
Published: June 2009

SummarySamples of liquid and solid fractions obtained by a commercial process from anhydrous milk fat of softening point (S.P.) 33·5–34°C had S.P. values of 22–23°C and 36–38°C respectively.Determinations of fatty acid composition by GLC showed that unsaturated and short chain fatty acids were present in increased concentration in the liquid fraction (average 37·8 and 12·4% as compared with 35·1 and 10·8% in the original milk fat) and long chain saturated acids in the solid fraction (average 57·8 as compared with 53·8%). There was some concentration of carotene and vitamin A, and to a lesser extent of cholesterol, in the liquid fraction.Crystallization and melting curves determined by a differential scanning calorimeter (DSC) showed that while the liquid fraction was completely melted at 25°C, the solid fraction contained an increased proportion of fat melting between 30 and 40°C. In addition to these high melting triglycerides the solid fraction also contained some 65% of fat in the liquid phase at the original crystallization temperature of 25°C.
Factors affecting the concentration of vitamins in milk: III. Effect of season and solar radiation on the vitamin D potency of butter
Authors: Henry Kathleen M. , Hosking Zena D. , Thompson S. Y. , Toothill Joyce , Edwards-Webb J. D. , Smith L. P. 
Published: June 2009

SummaryBetween August and May-the butter-making season in New Zealand-the average vitamin Dcontent of the butterfat varied between 10 and 64 i.u./100g and during the corresponding months in Great Britain (February-November) the values were between 15 and 39 i.u./100g. At the beginning and end of the season the values in both countries were similarly low but in mid-season New Zealand values were up to twice those for Great Britain. Within each country the vitamin D values were highly correlated with hours of sunshine and, for both countries, with total radiation, which includes the diffuse radiation in ‘skyshine’ and also allows for variation in sunshine intensity. The higher content of vitamin D in New Zealand butter in mid-season was attributed to a higher level of total radiation.
A double-bed process for the removal of cationic fission products from milk
Authors: Glascock R. F. , Bryant D. T. W. 
Published: June 2009

SummaryA process for the removal of cationic fission products from milk is described in which no prior acidification is necessary. The milk is treated at 40°C by 2 beds of suitably charged cation exchange resins, one of which is of the carboxylic acid type and the other of the sulphonic acid type. On the first bed all the metallic cations of the milk are replaced by K+and H+, and on the second the ioniccomposition is restored. During processing the pH is reduced from 6·8 to approximately 6·2 and is restored to 6·8 by the addition of alkali metal carbonates to the milk after treatment.On a pilot plant of capacity 1600 1 (30 resin bed volumes) per 5-h day it was found that the radiochemical efficiency was approximately 80% for85Sr and 97% for137Cs.The process caused some losses of vitamins, especially of thiamine, and an increase in the lead, copper and iron contents all of which, however, were at an acceptable level. Other changes in chemical composition were negligible and enzymic clotting time remained unchanged. Flavour and appearance of the product were satisfactory and it was satisfactorily both roller- and spray-dried. The process is discussed with reference to an earlier method in which prior acidification is necessary. It is concluded that the double-bed process is somewhat more efficient for the removal of fission products and that a full-scale plant would be little or no more expensive to erect and only slightly more expensive to operate.
The determination of acetic, propionic and butyric acids in cheese
Authors: Keen A. R. , Walker N. J. 
Published: June 2009

SummaryA method has been developed for the routine determination of acetic, propionic and butyric acids in cheese. The cheese sample is homogenized with water (1:2) at 40°C for 15 min and the slurry centrifuged at −5°C and 12000 g for 10 min. The free fatty acids in a portion of the aqueous centrifugate are adsorbed on to a column of anion-exchange resin in the hydroxide form. After washing the column with water to remove extraneous material the acids are eluted from the resin with aqueous formic acid. Amino acids in the acidic eluate which interfere with subsequent analyses are removed by a cation-exchange resin column in the hydrogen ion form. The concentrations of acetic, propionic and butyric acids in the cation-exchange resin eluate are determined by isothermal gas chromatography using a glass column (1·8m×2mm i.d.) packed with Chromosorb 101 (100/120mesh). Cheese oil-water partition coefficients are then used to calculate the concentrations of acetic, propionic and butyric acids in the cheese sample.
Denaturation of porcine pepsin during Cheddar cheese manufacture
Authors: O'Keeffe A. M. , Fox P. F. , Daly C. 
Published: June 2009

SummaryPorcine pepsin was rapidly denatured in phosphate buffers, pH 6·4–6·7, in the temperature range 31–39 °C and was only slightly more stable in milk under similar conditions. However, the enzyme was considerably more stable in Cheddar cheese curd in which the extent of denaturation was very markedly influenced by the pH of the milk at setting. Under normal cheese-making conditions, porcine pepsin was about equally stable with chymosin. Two modifications of the cheesemanufacturing procedure were developed which permit the manufacture of cheese almost free of coagulant and suitable for the assessment of the contribution of starter proteinases to proteolysis during cheese ripening.
The caseins of buffalo milk
Authors: Addeo F. , Mercier J.-C. , Ribadeau-Dumas B. 
Published: June 2009

SummaryThe components of whole casein from water buffalo (Bubalis L.) have been re-investigated in the light of recent studies elucidating the primary structure of all the bovine caseins (αs1, αs2, β & κ). Whole casein samples obtained from individual Italian buffaloes all contained 2 αs1- and 2αs2-casein fractions. These 4 components were isolated and identified by their amino acid compositions and terminal amino acid sequences. The 2 αs1-casein fractions seem to have identical peptide chains as do the 2 αs2fractions, with the individual fractions within each group differing only in their phosphate content. Buffalo β-casein was also isolated and characterized by its amino acid composition and terminal sequences. The isolation of different buffalo κ-casein fractions was reported earlier (Addeo, Chobert & Ribadeau-Dumas, 1977). These fractions were purified and analysed. They were found to have the same amino acid compositions and C-terminal sequences, but to differ in their carbohydrate content. The prominent component, κ1, was treated with chymosin; the caseinomacropeptide and para κ-casein were separated from the digest and analysed. Starchgel electrophoresis at alkaline pH showed no polymorphism of αs1-, β- and κ-caseins in 170 individual buffalo whole casein samples. On 5 occasions the electrophoretic pattern of αs2-casein suggested genetic polymorphism. The behaviour of buffalo αs1−and αs2-caseins in the presence of Ca2+was also studied.
Effect of deflector shields fitted in the milking machine teatcup liner on bovine udder disease
Authors: Griffin Tony K. , Mein Graeme A. , Westgrath David R. , Neave Frank K. , Thompson William H. , Maguire Peter D. 
Published: June 2009

SummaryDeflector shields were inserted in the teatcup to prevent ‘impacts’ against the teat end, and their effect on the rate of new udder infections was studied on 15 commercial dairy farms in Britain and 16 in Australia. Small metal shields were fitted between the liner barrel and short milk tube of 2 teatcups in each cluster in a milking installation so that all cows in a herd always had the same 2 quarters shielded. Half-udder comparisons were made using 1039 cows in the British herds and 1268 in the Australian herds. Herds were quarter-sampled for cytological and bacteriological examination when shields were fitted at the start of the experiment and again after 6 months. The shield effects were similar in the 2 experiments. The combined results from the 31 farms showed that 10·5% fewer quarters became infected when protected by shields (P < 0·05). In the 1287 cows that had no infected quarters at the start of the trial, 15% fewer quarters became infected when protected by shields (P < 0·01). The shield effect was mainly confined to hind quarters in which 23% fewer shielded quarters became infected (P < 0·001). The small reduction of 2% in forequarters was not significant. In the 16 herds in which post-milking disinfection of teats was practised, shielded quarters had 23·5% fewer new infections than unshielded quarters (P < 0·01). In 6 British herds milked in installations classed as non-standard, shielded quarters had almost 50% fewer new infections than the unshielded quarters (0·05 < P < 0·10). The results provide evidence of a milking machine effect, at varying levels of intensity, to increase new infection rates on all or most farms. Control of this machine effect could lead to substantial reduction in new infections in some herds and a modest reduction in most.
Effect of oil-enriched diets on the milk yield and composition, and on the composition and physical properties of the milk fat, of dairy cows receiving a basal ration of grass silage
Authors: Banks William , Clapperton John L. , Kelly Morag E. 
Published: June 2009

SummaryThe effects of supplementing a basal diet of grass silage with various oil-enriched mixtures on milk yield and composition, fatty acid composition and the melting characteristics of the milk fats are reported. In the first experiment, various dietary fats (soya oil, tallow and a palm oil/palmitic acid mixture) were fed at a fixed level (10% by weight of the concentrate ration). Soya oil had no effect on the proportion or yield of milk fat, and increased the proportion of low melting material in the milk fat; tallow increased the proportion of milk fat, and had little effect on the melting characteristics of the milk fat; the palm oil/palmitic acid mixture increased both the content and the yield of milk fat, and increased the proportion of high-melting material in the milk fat. In the second experiment, soya oil was fed at 3 levels (10, 15 and 20% by weight of the concentrate ration). No statistically significant effect on the yield of milk or of its constituents was observed; the proportion of low-melting material in the milk fat increased progressively with increasing intake of soya oil.
Effect on milk lipolysis of restricted feeding with and without supplementation with protected rape seed oil
Authors: Astrup Harald N. , Bævre Lars , Vik-Mo Lars , Ekern Asmund 
Published: June 2009

SummaryFeeding lactating cows at a reduced level for a 6-d-period caused blood serum and milk free fatty acids (FFA) to rise. Milk lipolysis developed more slowly and lasted longer than elevation of the level of FFA in blood. In a second experiment protected rape seed oil was given to underfed animals and inhibited the development of rancidity in the milk. Since unsaturated fat reduced lipoprotein lipase activity in the underfed cow, this supplement appears to reduce the effect of underfeeding if it is accepted that a normal response to underfeeding is to improve the efficiency of fat metabolism through increased lipoprotein lipase activity.
Factors influencing the stability of milk dialysate
Authors: Parker Thomas G. , Horne David S. 
Published: June 2009

SUMMARYThe turbidity increase on storage of milk dialysate was shown to be due to Ca phosphate precipitation. The rate of precipitation at 40 °C could be decreased by shortening the duration of dialysis or by the addition of small amounts of EDTA. The dialysate was stabilized against Ca phosphate precipitation by the addition of the whey protein fraction of milk. Individual whey proteins varied in their stabilizing ability: α-lactalbumin was found to be more effective than β-lactoglobulin which gave approximately the same effect as an immunoglobulin fraction. BSA and lysozyme had a destabilizing effect and ovalbumin possessed a slight stabilizing ability.
Effect of ripening cream with selected lactic acid bacteria on the quality of ghee
Authors: Joseph Abraham M. , Appachar Srinivasan R. 
Published: June 2009

SummaryThe effect of ripening cow'milk cream (40% fat) with 4 strains of lactic acid bacteria on the quality of ghee, an Indian product resembling clarified butterfat, was studied by measuring changes in titratable acidity, pH, volatile acids and diacetyl content due toStreptococcus lactis, Str. lactissubsp.diacetylactis (Str. diacetylactis), Str. thermophilusandLactobacillus bulgaricusin cream prior to conversion into ghee.L. bulgaricusproduced the maximum titratable acidity (1·25% lactic acid) followed byStr. diacetylactis(0·80 % lactic acid) after 72 h.Str. diacetylactisproduced the highest level of diacetyl (28 ppm), after 48 h.L. bulgaricusproduced no detectable diacetyl. Both of these strains produced the maximum amount of volatile acids (2·2–3·5 ml), after 72 h. The flavour and keeping quality of ghee were improved byStr. diacetylactisandStr. lactiswhilstStr. thermophilusandL. bulgaricushad no effect.
Effect of use of milk concentrated by ultrafiltration on the manufacture and ripening of Cheddar cheese
Authors: Green Margaret L. , Glover Frank A. , Scurlock Elizabeth M. W. , Marshall Richard J. , Hatfield David S. 
Published: June 2009

SummaryMilks were prepared at 1·7- to 4-fold the initial concentration by combining skim-milk concentrated by ultrafiltration with cream, and used for Cheddar cheese-making. Starter growth was unaffected, but the increased buffering capacity in the more concentrated milks resulted in a slower decline in pH and a higher pH value in the cheese. Curd formation was faster despite the use of reduced amounts of rennet. With milk concentrated more than 2-fold, large amounts of fat were lost in the whey, so that the cheeses had less fat than normally. Fat losses may be partly related to the lower degree of aggregation of the casein micelles when the curd was cut. As the concentration factor of the milk increased, the rate of casein breakdown, the intensity of Cheddar flavour, and the levels of H2S and methanethiol in the cheese decreased. These factors may relate to the reduced concentration of active rennet retained in the curd at pressing.
Immunological identification of milk-clotting enzymes
Authors: Collin Jean-Claude , de Retta Graciela Muset , Martin Patrice 
Published: June 2009

SUMMARYThe 6 most widely used milk-clotting enzymes, i.e. chymosin, bovine and porcine pepsins and proteinases from Mucor miehei, M. pusillus and Endothia parasitica, have been purified and used to prepare rabbit antisera against each of them. The antisera were adsorbed with appropriate cross-linked antigens to remove non-specific antibodies. Monospecific antisera thus obtained were used to identify enzymes eventually added to calf or bovine rennets, using the double radial immunodiffusion technique. The threshold of sensitivity was c. 1%, expressed as clotting activity. This qualitative method complements the quantitative procedure recently proposed for determining chymosin and bovine pepsin A in commercial extracts of bovine veils.
Sources of Streptococcus uberis in the dairy herd: II. Evidence of colonization of the bovine intestine by Str. uberis
Authors: Kruze Juan , Bramley A. John 
Published: June 2009

SUMMARYSwabs taken from the rectum and vulva of 14 dairy cows on 7 occasions at approximately weekly intervals revealed a pattern of isolations of Streptococcus uberis which were not random. Two of the 14 cows were responsible for 80 and 40% respectively of the swabs of the rectum and vulva which were found to be positive. It is suggested that these patterns are consistent with these 2 cows being intestinally colonized with Str. uberis. The implications of this work are discussed with reference to the sources of Str. uberis in the dairy herd.
Some aspects of the ethanol stability of caprine milk
Authors: Horne David S. , Parker Thomas G. 
Published: June 2009

SUMMARYCaprine skim-milk exhibits markedly lower ethanol (EtOH) stability than bovine skim-milk but can still be characterized by a sigmoidal pH profile. As with bovine milk, the position of this profile along the pH-axis was found to be sensitive to available Ca levels. Manipulation of salt levels, either by serum interchange, addition or diminution did not result in any significant increase in the EtOH stability high pH asymptote, Smax, and reduction of the colloidal calcium phosphate of caprine milk also had no significant effect. EtOH stability/pH profiles similar to those of bovine milk were achieved only by chemical modification of the caprine milk protein by reaction with aldehydes and anhydrides. It is concluded that the low EtOH stability of caprine milk as compared with bovine milk is due to the different proportions of the individual caseins present, in particular the lack of an αsl-casein homologue in caprine milk.
A study of proteolysis during Camembert cheese ripening using isoelectric focusing and two-dimensional electrophoresis
Authors: Trieu-Cuot Patrick , Gripon Jean-Claude 
Published: June 2009

SUMMABYIsoelectric focusing and 2-dimensional electrophoresis were used to study the development of the pH 4·6-insoluble fraction during Camembert cheese ripening. Modifications of this fraction were due mainly to the action of 5 proteinases: rennet (chymosin + bovine pepsin), plasmin and Penicillium caseicolum aspartyl-and metalloproteinases. Rennet was inactive on β-casein, but acted very early on αs1-casein. However, rennet and P. caseicolum aspartyl-proteinase had a very similar action on the latter substrate, which prevented clear definition of the respective actions of these proteinases on αs1-casein after 7 d of ripening. Plasmin action on β-casein was important from 21 and 35 d of ripening at the surface and in the centre of the cheese respectively, suggesting an important influence of pH changes during maturation. The respective activities of the metallo-and aspartyl-proteinases of P. caseicolum were characterized and followed using β-casein degradation products as markers. The metallo-proteinase activity was detectable immediately after the development of the Penicillium (7 d), while that of the aspartyl-proteinase was observed 3 d later. Thereafter, the amount of β-casein degradation peptides resulting from the metalloproteinase decreased while that resulting from the aspartyl-proteinase increased, suggesting a more important role of the latter enzyme.
Investigations into falsely elevated somatic cell counts of bulked herd milk
Authors: Hoare Roderic J. T. , Nicholls Paul J. , Sheldrake Richard F. 
Published: June 2009

SUMMARYBulk milk cell counts obtained by a Coulter Milk Cell Counter were shown to be falsely elevated because of the formation of non-cellular particles (NCP). The NCP, which were detected by the use of a particle size analyser, were removed if the milk samples were heated to 55 °C for 15 min before the addition of formalin. A survey of bulk milk supplies in New South Wales showed that NCP occurred in milk from 2 % of farms, the counts being falsely elevated by about 200000 cells/ml. Surveys of milking equipment of farms where the bulk milk had shown this phenomenon demonstrated a relationship between the use of centrifugal milk pumps and the presence of NCP with a much lower prevalence in herds where spit chamber releasers were used. These particles were not air bubbles since air was removed from the milk by heating to 60 °C for 5 min, vacuum at 65 mmHg for 15 minor 0·5% v/voctan-2-ol; only the heat treatment removed the NCP.
A yoghurt-like product made by fermenting ultrafiltered milk containing elevated whey proteins withLactobacillus acidophilus
Authors: Marshall Valerie M. , Cole Wendy M. , Vega J. Roberto 
Published: June 2009

SUMMARYA fermented milk with typical yoghurt flavour and aroma was prepared using a human strain ofLactobacillus acidophilus. Growth of the lactobacillus was stimulated when the whey proteins of the ultrafiltered skim-milk substrate were increased by addition of ultrafiltered Cheddar cheese whey. Fermentation, which was carried out at 37 °C, was accelerated by addition of lactase. The resulting product had a smooth consistency, a pH of 4⋅2, acetaldehyde levels up to 15 p.p.m. and no off-flavours.L. acidophilusremained viable at a level of approx. 108colony forming units/ml, with no impairment of quality, for up to 14 d at 4 °C.
Nitrogen content of human milk: limitations of spectrophotometry for the determination of protein in milk
Authors: Hudson Geofrey J. , Lucas Alan 
Published: June 2009

SummaryNakai & Chi Le (1970) have described a rapid method for the determination of the N content of bovine milk based on the close correlation of absorbance at 280 nm with values for total N as determined by the Kjeldahl procedure. The applicability of the method to human milk samples has been investigated. The procedure is limited by: (1) the dependence of the relation between absorbance value and N content on both the mode of collection and the postnatal age of the donor, and (2) variable interference by non-protein components of the milk. In spite of these shortcomings, the method may be of value as a screening test for certain human milk banks.