bluuebunny/crossref_metadata_2025_split huggingface dataset:
257. The influence of various factors on the fermentation end-products of the heterofermentative lactobacilli
Authors: Thiel C. C. 
Published: June 2009

1. The influence of temperature, oxygen tension, yeast autolysate and chalk on the production of by-products and the ratios of by-products formed to sugar utilized and lactic acid produced in milk by the lactobacilli has been investigated.2. The total production of lactic acid is increased by the presence of chalk and “growth factors” but is not affected by temperature or oxygen tension. The ratio of lactic acid produced to sugar utilized is decreased at lower temperatures and increased by chalk but yeast autolysate and variation in oxygen tension give variable results.3. The total production of acetic acid is increased by the presence of chalk, and “growth factors” and by anaerobic conditions. The ratios of acetic acid produced to sugar utilized and lactic acid formed are decreased by chalk and anaerobic conditions and there is a tendency for the ratios to be decreased by the presence of yeast and increased at lower temperatures.4. The total production of alcohol is increased by anaerobiosis and also by the presence of chalk and yeast in the medium. The ratios of alcohol formed to sugar utilized and lactic acid produced is increased by anaerobic conditions, and chalk also tends to increase the relative amount of alcohol. Temperature and yeast autolysate have little effect.5. Chalk is effective in maintaining thepH at a higher level during growth, but the influence of chalk on the ratios of by-products formed to sugar utilized is probably not entirely a pS. effect since the addition of talc to the medium has an equally strong influence in altering the relative production of lactic acid and alcohol.6. It was previously shown for the heterofermentative streptococci that the Pasteur effect (suppression of alcoholic fermentation by respiration) is slight; similar results have been obtained with the heterofermentative lactobacilli.
Nutritive properties of freshly prepared and stored evaporated milks manufactured by a normal commercial procedure or by reduced thermal processes in the presence of nisin
Authors: Gregory Margaret E. , Henry Kathleen M. , Kon S. K. 
Published: June 2009

SummaryFrom a batch of raw milk, evaporated milk was prepared commercially by 3 procedures:A, a normal commercial procedure involving holding the filled cans at a maximum temperature of 113 °C for 15 min;B, with nisin added and holding at a maximum temperature of 105 °C for 15 min;C, with nisin added and holding at a maximum temperature of 113 °C for 3 min. The content ofBvitamins in the raw and evaporated milks was measured microbiologically; the nutritive value of the proteins was determined in rat tests.In milkA, 83% of the vitamin B12, 38% of the vitamin B6and 20% of the thiamine were destroyed during processing. In milkB, the losses were 67, 30 and 19%, respectively, only the loss of vitamin B12being significantly lower than in milkA. In milkC, the losses were 67, 23 and 14%, respectively, each of them being significantly lower than in milkA. There was no further loss of thiamine on storage of the milks for 12 months at 4 °C, but at room temperature and at 37 °C further losses occurred in all the milks. Similarly, the vitamin B6activity of the milks decreased on storage, the loss being greatest at 37 °C, but also detectable at 4 °C. No change in the vitamin B12content occurred on storage, and no losses of biotin, nicotinic acid, pantothenic acid or riboflavin were detected during manufacture or storage of the evaporated milks.The biological value and true digestibility of the proteins of the evaporated milks were slightly lower than for the raw milk. Neither nisin treatment nor storage at room temperature for a year affected these characteristics.
An electron microscope study of the internal structure of casein micelles
Authors: Shimmin P. D. , Hill R. D. 
Published: June 2009

SummaryA study of casein micelles was made with the electron microscope, using very thin sections cut from micelles embedded in Araldite. The micelles appear to be built up of units that are approximately spherical, about 100 Å in diameter and of about 300000 molecular weight.
Some factors influencing stickiness of butter
Authors: Thomasos F. I. , Wood F. W. 
Published: June 2009

SummaryThe term stickiness, as used in the butter industry, refers to that property of butter which permits it to remain attached to solid surfaces. It is a phenomenon in which the components of force caused by adhesion and cohesion are inseparably involved and have been described by the term ‘hesion’. Hesion measurements of commercial samples of conventionally-made butter were much higher than those of continuously-made butter. The results of experiments on conventional and laboratory continuously-made butter from the same butterfat source indicated that the characteristic crystal structure influenced the hesion values. Homogenization of Gold'n Flow and conventional commercial butters markedly increased hesion readings. When nitrogen gas was added to pre-crystallized continuously-made butter the hesion values decreased with increasing gas content. However, there was an increase in the amount of butter which remained on the adherend when it became detached from the butter surface. Limited experiments on the effect of gas content in conventional butter also indicated that an increase in gas content resulted in a decrease in hesion values with more butter remaining on the adherend. The results of this investigation indicated that the crystal structure was responsible for the adhesive property of butter and the gas content influenced the cohesive property. It would appear, then, that both the crystal structure and the gas content play an important part in causing stickiness of butter.
A method for studying the factors in milk which influence the deposition of milk solids on a heated surface
Authors: Burton H. 
Published: June 2009

SummaryA laboratory method is described which it is hoped will be of value in the search for some of the chemical factors in milk which control the formation of deposits on heated surfaces during commercial processing. The method uses an electrically heated platinum wire as the surface on which deposits are formed under controlled heat transfer conditions. Preliminary results are given on the effect of milk pH on deposit formation, differences in the sensitivity to deposit formation of different bulk milk supplies, and the effect of forewarming on the reduction of deposition.
The influence of liveweight at calving on milk production in Friesian heifers
Authors: Ridler B. , Broster W. H. , Westgarth D. R. 
Published: June 2009

SummaryRecords of 81 heifers, daughters of 6 bulls, were examined to determine the regressions of milk yield, corrected for lactation length, on initial liveweight and age at calving.Age was found to have no significant effect and was discarded in the final analysis.The regression equations were similar for the different groups of half-sibs, except for one group whose members had not been fed according to milk yield. After removal of this group, a highly significant positive relationship between lactation yield and liveweight at calving was found ‘within bull groups’. The mean values of groups of halfsibs did not show this relationship, and significant differences in milk yield still persisted between groups after adjustment for liveweight differences.It was concluded that herd improvement by choosing heifers solely on the basis of liveweight shortly after calving appears unlikely to be effective unless the sire's potential is known and the feeding during lactation takes into account the greater maintenance requirements of heavier animals.
Steam distillation of taints from cream: X. Vapour liquid equilibrium relationships for benzyl mercaptan
Authors: McDowall F. H. 
Published: June 2009

SummaryThe vapour/liquid equilibrium coefficient for benzyl mercaptan, which is the substance causing ‘landcress’ taint in butter from the milk of cows grazing pastures infested with the cruciferous weed Coronopus didymus, was found by use of a continuous vaporization equilibrium still to be 105 from solution in water and 1·30 from solution in cream of 30% fat content. It was concluded that complete removal of heatdeveloped landcress taint from cream would not be commercially practicable.
The labelling of certain milk proteins with iodine131
Authors: Veringa H. A. , Mogot M. F. Kerkhof 
Published: June 2009

SummaryWhole casein, β-casein, β-lactoglobulin and euglobulin were labelled with131I. The conditions under which iodination was carried out were chosen so as to avoid any modification of the original characteristics of the proteins. This was checked by starch-gel electrophoresis and determination of sedimentation constants, apparent molecular weights and, for euglobulin, the clustering effect on fat globules.As was shown by autoradiograms of the starch-gel plates, the radioactivity was incorporated in all zones of the electrophoresis pattern.
β-Lactoglobulin variation in milk from individual cows
Authors: Kiddy C. A. , Townend R. E. , Thatcher W. W. , Timasheff S. N. 
Published: June 2009

SummaryThe β-lactoglobulin types of 812 individual cows of various breeds were determined by paper and polyacrylamide gel electrophoresis. The results support the hypothesis that β-lactoglobulins A and B are controlled genetically by codominant autosomal alleles (LgAand LgB).Milks from 5 heterozygous cows (LgA/LgB) were examined by free electrophoresis and column chromatography to estimate the relative quantities of β-A and β-B produced by these animals. The results indicate that β-A and β-B are produced in approximately equal amounts, with β-A being slightly in excess of β-B.Lacteal secretions were obtained from 2 castrated males and typed for β-lactoglobulin by means of paper electrophoresis. These animals were found to produce β-lactoglobulins (B and AB) consistent with their expected genotypes as deduced from pedigree analysis.
The effect of intravenous injections of oxytocin during milking and the removal of residual milk on the composition of cow's milk
Authors: Wheelock J. V. , Rook J. A. F. , Dodd F. H. 
Published: June 2009

SummaryAfter an injection of oxytocin and the removal of residual milk, the milk obtained at the next milking had an increased content of sodium, chloride and whey proteins and a decreased content of lactose. The effect persisted for several milkings. It is suggested that this was due to a direct effect of oxytocin on the permeability of the mammary epithelium and that oxytocin should be used with caution in certain types of milk secretion experiment.
The effect of intramammary infection during the dry period on the milk production of the affected quarter at the start of the succeeding lactation
Authors: Smith A. , Dodd F. H. , Neave F. K. 
Published: June 2009

SummaryIntramammary infection present in quarters of dairy cows, either throughout the dry period or originating in the dry period, reduces the milk yield after calving. Relative to the milk yield of equivalent non-infected quarters of the same udder the reduction was found in this work to be about 35%. The relative milk yield of quarters found infected in late lactation was depressed by 48% but if the infection was eliminated during the dry period, the depression in milk yield was only 11% after parturition.
The effect of regular intravenous injections of oxytocin at milking time on the proportion of the yield obtained as residual milk in the ewe
Authors: Morag M. 
Published: June 2009

SummaryThe changes in the size of the milking and residual fractions following milking intervals of 4, 8, 12, 16, 20 and 24 h were investigated in 18 ewes receiving regular injections of oxytocin at each milking. The observations were carried out using a 6×6 Latin square design in which each treatment interval was repeated 4 times. The milking and the residual fractions were found to increase significantly with the lengthening of the interval. The amount of hand strippings was also related to interval length. When a given interval was repeated there were no changes in the relative sizes of the fractions. A change in the milking interval, however, caused significant changes in the various fractions. It is suggested that in the present experiment the milking fractions consisted in the main of milk that was present in the sinuses prior to milking.
The quantitative partition of the albumin fraction of milk serum proteins by gel chromatography
Authors: Davies D. T. 
Published: June 2009

SummaryA method for the quantitative partition of the albumin fraction of milk serum proteins is described. The partition, which is carried out by chromatography on a column of Sephadex G-100 (2·5×90cm) at 4°C in the presence of 0·02 m-sodium phosphate buffer (pH 6·7) containing 0·1 m-NaCl, yields 4 fractions. By gel electrophoresis it was shown that the fractions represent, in order of elution from the Sephadex, the following: fraction 1, a mixture of the largest proteins present, probably comprising γ-globulins, proteose-peptones and lactoferrin; fraction 2, bovine serum albumin and bovine serum transferrins; fraction 3, β-lactoglobulins; and fraction 4, α-lactalbumins. The protein contents of the various fractions were determined by nitrogen analysis and the results showed that good agreement was obtained between values from duplicate fractionations, and also that the recovery of material was satisfactory. The partition of the albumin fraction was not complete, but at least 90% of the material was found in fractions which represent essentially single proteins. The influences of some aspects of the pretreatment of samples, buffer composition and column preparation are described.
Electron microscope studies of the development of structure in Cheddar cheese
Authors: Kimber Alwyn M. , Brooker B. E. , Hobbs D. G. , Prentice J. H. 
Published: June 2009

SummaryThe development of structure in Cheddar cheese was followed using electron microscopy, of both thin sections and freeze-etched preparations. The casein micelles, at first separate, were seen to aggregate into a network, coalesce and finally form a granular mass. The fat globules, also separate at first, were gradually forced into clumps as a result of shrinkage of the casein network and incomplete fusion took place during ripening. Starter bacteria were seen trapped in the casein near the fat–casein interface, which was shown to be the region of highest water content in the mature cheese.
Disinfection properties of some bovine teat dips
Authors: King J. S. , Neave F. K. , Westgarth D. R. 
Published: June 2009

SummaryThe efficacy of 18 disinfectant teat dips was tested on teats artificially contaminated with a milk suspension of Staphylococcus aureus. A solution of Na hypochlorite with 40 g/l available chlorine was significantly more bactericidal than one containing 1 g/l available chlorine and than most other disinfectants tested. The method was not able to distinguish differences in efficacy between solutions containing 40 g/l and 10 g/l available chlorine nor between these and some of the iodophors containing 5 g/l available iodine. The addition of 190–416 g/l (15–33 % v/v) glycerol significantly reduced the bactericidal properties of 3 iodophors (5 g/l available iodine), but soluble lanolin at approximately 20 g/l did not appear to lower the efficiency of NaOCl (45 g/l available chlorine) or of an iodophor (5 g/l available iodine).
Isoelectric focusing of milk-clotting enzymes
Authors: Righetti P. G. , Molinari Bruna M. , Molinari G. 
Published: June 2009

SummaryIsoelectric focusing in thin-layer polyacrylamide gel has been applied successfully to the characterization and identification of calf rennet and its substitutes. The use of acidic pH gradients (pH range 2·5–6) allows the identification of calf and microbial rennets and bovine and pig pepsins.A new, very rapid and sensitive zymogram technique has been developed by overlaying the gel with a highly porous, transparent cellulose acetate film impregnated with casein.
Kinetics of the heat-induced aggregation of milk protein
Authors: White J. C. D. , Sweetsur A. W. M. 
Published: June 2009

SummaryThis investigation was a first attempt to characterize the kinetics of the heat aggregation of the caseinate micelles in milk. The aggregation reaction subsequent to the beginning of visible aggregation in milk heated at temperatures in the range 110–140 °C appeared to be second order, with an activation energy of about 30 kcal/mol (124 kJ/mol). The kinetic parameters of the aggregation reaction were not significantly altered by the removal of serum proteins or of colloidal calcium phosphate, or by the inactivation of β-lactoglobulin.
Mammary blood flow during experimental Escherichia coli endotoxin induced mastitis in goats and cows
Authors: Dhondt G. , Burvenich C. , Peeters G. 
Published: June 2009

SummaryThe effect of intramammary infusion of Escherichia coli endotoxin upon mammary blood flow was studied in lactating goats and cows. Blood flow was recorded by means of an electromagnetic flow probe chronically implanted around one mammary artery.Endotoxin mastitis was always accompanied by a significant increase in mammary blood flow, characterized by 2 conspicuous peaks. The flow returned to control values by the thirteenth hour after infusion. Other symptoms of acute mastitis were: fever, increased heart rate, swelling, heat and pain of the gland, increased chloride and total cell count in milk.
Resistance of 17 mesophilic lacticStreptococcusbacteriophages to pasteurization and spray-drying
Authors: Chopin Marie-Christine 
Published: June 2009

SummaryFor 17 phages active againstStreptococcus cremoris, Str. lactisandStr. lactissubsp.diacetylactis, the killing efficiency of pasteurization (logNo/N) at 72°C for 15 s in skim-milk showed large variations from > 6 to 0; the efficienty of killing during spray-drying ranged from 3.7 to 0.2 and phages survived well storage of milk powder at room temperature. Destruction in a heat exchanger was found to be greater than that calculated from biphasic curves obtained by heating phages in sealed ampoules. No relationship was established between lytic classification of phages and their heat resistance.
Heat stability of milk
Authors: Darling Donald F. 
Published: June 2009

SummaryThe heat stability of a standard reconstituted skim-milk preparation has been investigated as a function of pH, temperature of coagulation, and forewarming treatment. Apparent activation energies have been calculated from the temperature dependence of coagulation time, and a constant value of 144 kJ/mole has been found for milks between pH 6·6 and 6·9. The effect of forewarming resulted in a decrease in stability at the most acid pH values, a slight increase at higher pH but below the pH maximum, and a decrease in the region of the pH minimum. A working hypothesis is proposed for the mechanisms leading to the coagulation of milk at elevated temperatures, based upon Ca induced precipitation of casein, protein polymerization, β-lactoglobulin: κ-casein interaction, and precipitation of insoluble Ca phosphates.
Binding of calcium ions to bovine β-casein
Authors: Parker Thomas G. , Dalgleish Douglas G. 
Published: June 2009

SummaryThe isotherms for Ca2+ binding to bovine β-casein have been measured at 5 temperatures in the range 4–40 °C and at 4 different ionic strengths. The results are interpreted by an interactive-site binding model, and are compared with results previously obtained on αs1-casein. The affinity of β-cesein for the first Ca2+ to bind is similar to the affinity of αsl-casein for the same binding event: however, binding of subsequent Ca2+ to β-casein is weaker than the binding to αs1-casein. The results are discussed in terms of precipitability of the 2 caseins caused by the binding of Ca2+.
Heat stability of milk: interrelationship between assay temperature, pH and agitation
Authors: Hyslop Douglas B. , Fox Patrick F. 
Published: June 2009

SummaryAs determined by the standard subjective assay procedure, the minimum in the heat stability–pH curve of milk persisted down to at least 116 °C. However when samples were not agitated during heating the minimum became progressively less pronounced as the assay temperature was lowered and it disappeared at approximately 116 °C. Activation energies (Ea) for unagitated samples were approximately 30 Kcal/mole at pH 6·87 (maximum) and at pH 7·18, throughout the temperature range 116–145 °C and for the pH 6·95 (minimum) sample at 116–125 °C; however Eα for the pH 6.95 sample increased to approximately 100 Kcal/mole in the range 127–135 °C suggesting that some highly temperature-dependent reaction had occurred and caused premature coagulation at certain pH values, i.e. to a heat stability minimum. The stability of concentrated milk (20% total solids) was very low at pH values above 6·9, regardless of whether the samples were agitated or not during heating and the maximum/minimum in the heat stability–pH curve persisted down to at least 90 °C in both agitated and quiescent samples.
Leucocytes of sheep colostrum, milk and involution secretion, with particular reference to ultrastructure and lymphocyte sub-populations
Authors: Lee Chee-Seong , Outteridge Peter M. 
Published: June 2009

SummaryThe leucocytes in sheep colostrum, milk and involution secretion were studied using the electron microscope. The predominant cell type in colostrum was the polymorphonuclear leucocyte (PMNL) (41–84%), followed by the macrophage (8–49%), and the lymphocyte (6–11 %). Plasma cells were present in low numbers (1–2%) while no secretory epithelial cells were observed. In mid-lactation the cell components changed so that the macrophage was the predominant cell (83–86%) followed by the lymphocyte (10–17%). In early involution secretion, PMNL reappeared but declined in secretion obtained 21 d after weaning, when the macrophage was again the predominant cell. Associated with the whole cells were membranous extracellular materials and ‘sunburst’ fragments of the secretory epithelial cells. These were phagocytosed by both PMNL and macrophages, which also engulfed fat droplets from the milk. The lymphocytes were examined for plasma membrane markers and the T-cell percentage (E+ rosettes) fluctuated within wide limits, (0–80 %). However, there was no discernible trend associated with stage of lactation. The B-cell markers (C1 and Fcγ) also fluctuated widely and it was evident that contaminating monocytes reduced the accuracy of the count. However, it appeared that more B-cells were present in milk than in blood.
Goat's milk yoghurt made from non-homogenized and homogenized milks, concentrated by different methods
Authors: Abrahamsen Roger K. , Holmen Tove Blytt 
Published: June 2009

SummaryQuality characteristics of goat's milk yoghurt made from homogenized and non-homogenized concentrates prepared by vacuum evaporation, addition of dried skimmed goat's milk, reverse osmosis or ultrafiltration were observed. Yoghurts made from ultrafiltered milk gave the best flavour and viscosity, whilst homogenization of the concentrates also increased these qualities. Cow's milk yoghurts prepared in the same way were improved to an even greater extent by homogenization. Stirred goat's milk yoghurt had too low a viscosity to be acceptable, unless made from homogenized ultrafiltered milk.