bluuebunny/crossref_metadata_2025_split huggingface dataset:
A pilot plant for the removal of cationic fission products from milk: I. Design and construction
Authors: Glascock R. F. , Hall H. S. , Suffolk S. F. , Bryant D. T. W. 
Published: June 2009

SummaryA pilot plant with a capacity of 2300 1./5 h day for the removal of cationic fission products from milk is described. The process involves the acidification of the milk with citric acid to pH 5.25 and its passage through an ion exchange resin charged with the ions of Ca, K, Na and Mg in the same proportions as those in which they occur in milk. The effluent milk is neutralized with potassium hydroxide. At the end of the day the plant and resin bed are washed and sterilized.Two resin beds are provided and are used on alternate days, one being washed and regenerated while the other is in use. Regeneration is carried out with a solution which removes radioactive cations and restores the resin bed to its original ionic composition.Bacteriological tests show that the method of cleaning both plant and resin bed is satisfactory.Conclusions are drawn as to a suitable design for a larger scale plant.
Further studies on the effects of dietary 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 cottonseed oil on the yield and composition of the milk fat and on the pattern of rumen fermentation was investigated in 2 feeding experiments with a total of 8 cows in mid-lactation. The concentrate mixtures were given with high- or low-roughage diets that supplied 9·1 or 1·8 kg of hay/day.In expt 1 the yield of milk fat was not altered by the addition of 10% cottonseed oil to the concentrate mixtures given either with the high- or with the low-levels of dietary roughage. On the low-roughage treatment, dietary cottonseed oil increased milk yield but reduced the fat content of the milk. The change from the high- to the low-roughage diets containing no cottonseed oil resulted in reductions in the yield and percentage of fat in the milk. In expt 2 the yields of milk and milk fat were similar irrespective of whether the concentrate mixture contained 5 or 10% cottonseed oil.In expt 1 the inclusion of 10% cottonseed oil in the concentrate mixture reduced the yields and percentages of the medium-chain fatty acids (12:0, 14:0 and 16:0) and increased the yields and percentages of the C18 fatty acids in the milk fat. In expt 2, when the concentrate mixture contained 5% cottonseed oil, the yields and percentages of all the fatty acids in the milk fat were similar to the values obtained when the concentrates contained 10% cottonseed oil. For any given concentrate mixture, the change from the high- to the low-roughage treatments in both expts 1 and 2 resulted in increases in the percentage of oleic acid in the milk fat. The highest concentration of trans-octadecenoic acid was observed in the milk fat of the cows when they were given the high-roughage diet with the concentrate mixture containing 10% cottonseed oil.In expt 2 the level of cottonseed oil in the concentrate mixture did not influence the pattern of rumen fermentation as measured by the concentrations of the various volatile fatty acids in the rumen liquor. However, the change from the high- to the low-roughage diets reduced the proportion of acetic and increased the proportions of propionic and n-valeric acids in the total volatile fatty acids in the rumen liquor.
The effect of ageing on heat-sterilized milk
Authors: Wheelock J. V. , Hindle E. J. 
Published: June 2009

SummaryDuring 7 months' storage of heat-sterilized milk there were changes in the glycopeptides released by rennin (E.C. 3.4.4.3) action and soluble in 12% (w/v) trichloroacetic acid (TCA). The results showed a progressive decrease in the amount of carbohydrates attached to κ-casein. As these carbohydrates may contribute to the micelle-stabilizing power of κ-casein it was concluded that the loss of carbohydrates could be one factor in the development of gelation in heat-sterilized milks during storage.
The structure of a bitter peptide derived from casein by digestion with papain
Authors: Clegg K. Mary , Lim C. L. , Manson W. 
Published: June 2009

SummaryTreatment of unfractionated bovine casein with papain produced a digest which was bitter in taste. The bitterness was shown to be a property of a peptide originating only in β-casein and having an amino-acid composition consistent with its derivation from residues 53–79 inclusive of β-casein. The relationship existing between flavour and primary structure in this peptide is discussed briefly.
Measurements in vivo of the rate of production of protozoa in the rumen
Authors: Singh U. B. , Varma A. , Verma D. N. , Ranjhan S. K. 
Published: June 2009

SummaryThe rates of production of protozoa in the rumen of buffalo calves have been estimated using a single-injection isotope dilution technique. The calves were fed at 2 levels of crude protein, namely, 13% lower and 19% higher than that recommended by the National Research Council. The animals were given their rations at 2-h intervals for 3 weeks. Thereafter 14C-labelled rumen protozoa were injected into the rumen of each calf in a single injection. Samples of the rumen liquor were drawn at various time-intervals for 10 h and were analysed for the concentration of protozoa and radioactivity. The decline in the specific radioactivity of protozoa cells in the rumen as a function of time was used for calculating half life (t½). A mathematical equation was used to calculate the rate of production of protozoa. The average t½ was 1077 min for both groups and the rates of production of protozoa were 73·9 and 92·1mg/min in groups fed on low and high planes of crude protein respectively, showing that the production of protozoa is significantly (P < 0·01) higher in animals consuming a ration high in crude protein.
The nature of casein aggregates in heated and stored milk
Authors: Cheeseman G. C. , Knight Dorothy 
Published: June 2009

SummaryGel filtration on Sepharose 6-B was used to study the size distribution of sub-micellar casein aggregates in colloidal phosphate-free milk, and comparisons were made between the elution profiles obtained for fresh, heated, ultra-hightemperature (UHT) treated and stored UHT milks. Increase in length of storage of UHT milk gave rise to an increase in proportion of casein aggregates excluded from Sepharose 6-B, but no corresponding increase in size of included casein aggregates was observed.
Effect of urea on the heat coagulation of the caseinate complex in skim-milk
Authors: Muir D. D. , Sweetsur A. W. M. 
Published: June 2009

SummaryAdditions of urea progressively increased the heat stability of milk outside of its coagulation time (CT)–pH minimum. In the region of the CT–pH minimum larger amounts of urea were required before an increase in heat stability occurred. The effect of urea was observed over the temperature range 125–140 °Cfornaturalmilk, milk which had been dialysed against synthetic sera, and milk to which a sulphydrylblocking agent had been added. Urea additions did not affect the activation energy of the heat coagulation reaction or the stability of milk to rennet or ethanol.
The role of various milk fractions and the importance of somatic cells in the formation of germinant(s) for Bacillus cereus when milk is pasteurized
Authors: Davies F. L. 
Published: June 2009

SummaryConfirmation was obtained for the occurrence of an interaction between high and low molecular weight fractions of milk during its pasteurization, resulting in the formation of germinant(s) for Bacillus cereus. Various milk fractions were added to supernatants or dialysates of raw skim-milk, pasteurized and assayed for germinant. Micellar casein obtained by high speed centrifugation of raw milk stimulated germinant formation, but whole casein obtained by acid precipitation was less stimulatory and individual casein fractions showed no stimulation. A membrane rich ‘fluff’ layer obtained by high speed centrifugation of raw milk was highly stimulatory and suggested the possibility that the somatic cell count of milk may be related to germinant production.Using milk from endotoxin infused and infected quarters of individual cows, a correlation between cell count and germinant formation was clearly demonstrated. Adjustment of the cell counts of individual milk samples was generally accompanied by corresponding changes in germinant formation, though removal of cells by filtration did not have this effect, possibly since germinant precursor had leached from the cells and remained in the milk. Pasteurization was necessary, not simply to express germinant from cells but to effect an interaction of germinant precursors. It is not clear whether the cell associated germinant precursor is derived from the cells themselves or from a related component. Addition of blood serum proteins was without stimulatory effect.Since low cell count milks sometimes supported appreciable germination after pasteurization, but showed still higher levels when the cell count was raised, germinant may be formed via 2 pasteurization dependent processes, one between milk constituents alone and the other involving both milk constituents and somatic cells.
Effect of vacuum fluctuation during milking on the development of intramammary infection from teat duct colonization by Staphylococcus aureus
Authors: King Joseph S. , Neave Frank K. , Williams Raymond L. 
Published: June 2009

SummaryTwelve of twenty-one udder quarters with colonized teat ducts became infected within 13 d when milked with a machine producing large cyclic and irregular vacuum fluctuations in the teatcup; of 23 quarters milked under the same conditions, but with metal shields fitted inside the liners to protect the teat apex (Thiel, 1974), only 2 quarters became infected in the same period. The introduction of a post-milking teat disinfectant teat dip resulted in the elimination of orifice colonization from 15 teats dipped in Na hypochlorite solution (40 g/l available chlorine) and from all but 2 of 15 teats dipped in an iodophor solution (5 g/l available iodine).
Relationship between trisaturated glyceride composition and the softening point of milk fat
Authors: Parodi Peter W. 
Published: June 2009

SummaryNo relationship was found between the trisaturated glyceride content and the softening point (SP) of milk fat. Inter-esterification of milk fat increased its SP, but did not change the trisaturated glyceride content or the fatty acid composition of the trisaturated glyceride fraction. Inter-esterification increased the amount of both low and high and decreased the amount of medium molecular weight triglyceride species in the trisaturated glyceride fraction. The increase in the amount of high molecular weight triglyceride species was up to 3 times greater than the increase in the amount of low molecular weight triglycerides.The triglyceride species composition of the trisaturated glyceride fraction of milk fat was found to vary seasonally. Excellent correlation was found between SP and groups of low molecular weight triglycerides, groups of high molecular weight triglycerides and some individual triglyceride species. Correlation coefficients were higher than those previously reported between groups of fatty acids and SP.
Susceptibility of the bovine udder to bacterial infection in the dry period
Authors: Cousins Carol L. , Higgs Trevor M. , Jackson Eric R. , Neave Frank K. , Dodd Frank H. 
Published: June 2009

SummaryThe teats of 18 cows were externally exposed to infection with mastitis organisms by dipping them daily for 1 or 2 weeks in a mixed suspension of Streptococcus dysgalactiae and Str. uberis at the start, the middle or the end of the dry period. The teat sinuses of quarters which remained uninfected after external exposure at the beginning or the middle of the dry period were then infused with the same strains of streptococci. Of the 9 quarters infected following external exposure 8 occurred in animals exposed at the start and one in the middle of the dry period. Thirty-six new infections occurred after infusion of bacteria into the teat sinuses of 38 quarters. In a further trial with 10 cows, Staphylococcus aureus and Str. zooepidemicus were inoculated into the distal 3 mm of the streak canals of 5 cows immediately after drying-off and into those of 5 cows which had been dry for 28 weeks. Animals were slaughtered 48 h later and infection determined by teat puncture. Five infections occurred in cows which were at the start of the dry period and only one in the cows dry for 28 weeks. It is suggested that these differences in the rates of new infection between the early dry period and a very extended dry period are due to differences in the ease with which bacteria can penetrate the teat canal. At the later stage bacterial growth through the teat canal appeared to be inhibited.
Post-milking iodine teat skin disinfectants: 3. Residues
Authors: Sheldrake Richard F. , Hoare Roderic J. T. , Chen Stanley C. , McPhillips John 
Published: June 2009

SummaryTeat dipping of lactating cows with either 1000 or 5000 mg available iodine/; (mg avI/;) solution and thoroughly washing and drying of the teats before sampling resulted in levels of 70 and 99 µg avI per quarter per milking respectively. Without any pre-milking udder preparation prior to sampling the levels of iodine recorded were 143 and 291 µg avI per quarter per milking respectively. Some systemic transfer of iodine from the teat skin to the milk was observed, but the bulk of iodine residue in milk was of direct teat skin origin.
Casein compositional studies: 1. The composition of casein from Friesian herd milks
Authors: Barry J. Gerard , Donnelly William J. 
Published: June 2009

SummaryCasein composition in Friesian herd milks was examined by quantitative column chromatography on hydroxyapatite. Whole casein was resolved into 5 fractions: (1) γ-casein + para-κ-casein; (2) κ-casein + unidentified chymosin-resistant components; (3) unidentified minor protein; (4) β-casein; (5) αs1,0- + minor αs-caseins. Protein in fractions 1, 2, 4, 5 was measured by ultraviolet spectrometry, using appropriate specific absorption coefficients. The quantitative contribution of chymosin-resistant components to the κ-casein fraction was measured by a method involving hydroxyapatite chromatography of chymosin-treated whole casein. Compositional analysis was carried out throughout a lactation cycle on a total of 24 casein samples from the milks of a winter/spring calving and autumn-calving herd. Average composition (expressed as % total casein), which was similar for both herds, was 48·7% αs-, 33·8% β-, 4·9% γ-, 9·5% κ- and 3·2% unidentified components. Lactational effects on composition were also similar for both herds and were most pronounced in late lactation where increases were recorded in γ-casein and unidentified components, and decreases in β- and αs-caseins. Fluctuations in κ-casein proportions were small and slightly higher values were obtained in early and late lactation. Casein composition also appeared to be affected to some extent by season, as shown by differences in the proportions of αs-caseins and unidentified components between mid-lactation milks from the 2 herds. Compositional variations resulted partly from the action of milk proteinase on β-casein and also, apparently, from differences in relative rates of protein biosynthesis.
Effect of concentration by ultrafiltration on the heat stability of skim-milk
Authors: Sweetsur A. W. Maurice , Muir D. Donald 
Published: June 2009

SUMMARYAn examination has been made of the heat stability characteristics of skim-milk concentrate prepared by ultrafiltration (UF). Concentrate prepared by UF was found to be more stable than that prepared by conventional evaporation. In contrast to conventional concentrate, the heat stability of UF concentrate was not appreciably affected by forewarming or addition of permitted stabilizers, but the effect of addition of urea was generally the same for both UF and conventional concentrates; an increase in heat stability was obtained if the milk total solids level was less than 14%. As with conventional concentrate, addition of simple aldehydes induced large increases in the heat stability of UF concentrate. It is suggested that a novel range of sterile milk products could be prepared from UF concentrates. Because of the high protein and low lactose contents of these concentrates, the products might be nutritionally more attractive than those prepared from conventional concentrates.
Occurrence of γ-caseins in buffalo milk
Authors: Trieu-Cuot Patrick , Addeo Francesco 
Published: June 2009

SummaryUsing polyacrylamide gel electrophoresis, 2-dimensional gel electrophoresis and electrofocusing, it has been shown that 4 basic fragments were produced by action of plasmin on buffalo β-casein. These fragments were present in whole buffalo casein prepared from bulk milk. Their mol. wts, 20000, 16000 and 11000 (2 components) were determined by SDS-gradient polyacrylamide gel electrophoresis. It is suggested that 3 of them are homologous to bovine γ1-, γ2- and γ3-caseins respectively, while the last one (mol. wt 16000), which has no counterpart in plasmin digest of bovine β-casein, could arise from a cleavage at bond 68–69.
Constitutive nature of the enzymes of citrate metabolism inStreptococcus lactissubsp.diacetylactis
Authors: Cogan Timothy M. 
Published: June 2009

SummaryFour enzymes of citrate metabolism (viz. citrate lyase, acetolactate synthase, diacetyl reductase and acetoin reductase) were constitutively present in cells of several strains ofStreptococcus lactissubsp.diacetylactis. In strain DRC1, which was studied in detail, diacetyl reductase and acetoin reductase were partly repressed and acetolactate synthase partly induced by growth on citrate. The stage of growth also affected the formation of each enzyme. The buffer species affected the activity of acetolactate synthase, diacetyl reductase and acetoin reductase.
A new method for the detection of microbial proteolytic enzymes in milk
Authors: Cliffe Allan J. , Law Barry A. 
Published: June 2009

SUMMARYOptimum conditions have been determined for the use of Hide Powder Azure (HPA) to estimate extracellular proteinases produced by psychrotrophic Gram-negative bacteria. This assay is quicker, more precise and 3·2 times more sensitive than assays of soluble N released from casein. It provides a simple alternative method for monitoring proteinase purification schemes. With the modification described it is now possible to determine proteinase activities directly in milk. In its simplest form the HPA assay is sufficiently sensitive to detect proteinases produced by as few as 1·5 x 106c.f.u. ml-1psychrobtrophs without the necessity for any sample processing.
Effects of thermal industrial processing on acid-soluble nucleotides of milk
Authors: Gil Angel , Sanchez-Medina Fermin 
Published: June 2009

SUMMARYCommercial bulk milk contained, in its acid-soluble nucleotide fraction, small quantities of CMP and AMP as well as a high proportion of orotate (503±16 μg/g of total solids). These components were altered by thermal treatment during processing. Standard sterilization and spray drying of milk lowered significantly the CMP, AMP, and orotate concentrations. HTST pasteurization caused a slight decrease in CMP and AMP concentrations, but the orotate content remained unchanged. The UHT sterilization seemed to be the thermal treatment in which the acid-soluble nucleotides of milk underwent least change. It is therefore concluded that the decrease in concentration of the nucleotides of milk is more directly related to the time for which the milk remains at the processing temperature than to the temperature itself.
Determination of oxidative deterioration of milk powder and reconstitute milk by measurement of chemiluminescence
Authors: Timms Ralph E. , Roupas Peter , Rogers William P. 
Published: June 2009

SUMMARYA scintillation counter was used to measure chemiluminescence (CL) from milk powder and reconstituted milk. Only a small amount of CL, just above the background level, was observed from powders, but reconstituted milks emitted easily measurable CL. CL from milk was stimulated by exposure to light and found to decline gradually but non-exponentially after the exposure ceased. CL was at a maximum immediately after the milk was reconstituted from milk powder. Without light exposure, CL then declined gradually but non-exponentially over several hours to reach a constant value related to the level of oxidation of the powder. When determined under standard conditions 60 min after reconstitution, CL of milk reconstituted from stored milk powders correlated well with peroxide values and oxidized flavour as assessed by a taste panel.
Chemical composition and coagulating properties of renneted milks from different breeds and species of ruminant
Authors: Storry John E. , Grandison Alistair S. , Millard David , Owen A. Jane , Ford Graeme D. 
Published: June 2009

SummaryThe detailed chemical composition of 25 milks from different breeds of cow, sheep and goat were related to their properties of rennet clotting, coagulum development and syneresis at pH 6·4. Experiments in which concentrations of fat and whey proteins in milk were manipulated, and in which milks were homogenized at different pressures, were also carried out and the effects observed were related to the above processes.The composition of milks varied widely and many relations between concentrations of components could be related to their known modes of secretion from the alveolus or to their structural functions in the colloidal phase of milk. Rennet clotting was related to total Ca concentration and also to the proportions of αs- and β-caseins present. Coagulum strength was strongly related to total casein concentration in milk but was unaffected by total fat content or by casein/fat ratios. Syneresis was inversely related to fat content of milk and little affected by coagulum strength. Homogenization retarded syneresis, probably by altering coagulum structure and modifying entrapment of fat globules within the coagulum.
Domiati cheese made with ultrafiltered reconstituted milk and lipolysed recombined cream
Authors: Abd El-Salam Mohamed E. , El-Shibiny Safinaz , El-Koussey Laila A. , Haggag Hamdy F. 
Published: June 2009

SummaryA new method was developed for making Domiati cheese, based on blending ultrafiltered reconstituted milk and lipolysed recombined cream. The chemical composition of the new product was similar to the traditional cheese. The flavour intensity increased with the amount of lipase used in the cream hydrolysis. During storage the acidity and tyrosine content of cheese from different treatments increased at nearly similar rates. The level of total volatile fatty acids was affected by the level of lipase used. Organoleptic scoring showed that cheese made with cream treated with the intermediate levels of lipase (2 or 5 g/500 g cream) ranked the highest, after 1 and 4 months of storage respectively.
Influence of sulphydryl group interactions on the heat stability of homogenized concentrated milk
Authors: Sweetsur A. W. Maurice , Muir D. Donald 
Published: June 2009

SUMMABYThe heat stability of homogenized concentrated milk was found to be more susceptible than that of unhomogenized concentrated milk to changes in the ratio of β-lactoglobulin to κ-casein which were deliberately designed to alter the extent of disulphide-linked complex formation during heating. When sulphydryl group interactions were prevented by the addition to the milk before homogenization of blocking or oxidizing agents, homogenization did not change the heat stability of subsequently concentrated milk.