QUALITY OF PROTEIN IN MILK REPLACERS FOR YOUNG CALVES. III. RENNET COAGULATION AND UNDENATURED WHEY PROTEIN NITROGEN CONTENT OF SKIM MILK POWDERS AND COMMERCIAL MILK REPLACERS

1976 ◽  
Vol 56 (2) ◽  
pp. 335-338
Author(s):  
D. B. EMMONS ◽  
E. E. LISTER ◽  
D. L. CAMPBELL
Keyword(s):  
Whey Protein ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Plant Proteins ◽  
Protein Nitrogen ◽  
Rennet Coagulation ◽  
Powder Samples ◽  
Milk Replacers

Reconstituted commercial skim milk powder samples which produced a firm (> 30 g) rennet curd had high levels (> 4 mg N/g) of undenatured whey protein nitrogen (WPN) as measured by the modified Harland–Ashworth test. However, similar samples which also had high levels of WPN (> 6 mg N/g) had low curd firmness or failed to coagulate. Of 24 commercial samples of milk replacers, 2 formed a soft curd; the rest did not coagulate. Five had high levels of WPN (> 6 mg N/g); one sample contained 17.8 mg N/g, well above normal levels of skim milk powder. Plant proteins may have caused high WPN values and interfered with the Harland–Ashworth test. It was concluded that WPN is neither an acceptable index of rennet coagulability of milk replacers, nor a reliable index for selecting commercially produced skim milk powders with good rennet coagulability.

SOME IN VITRO OBSERVATIONS ON FACTORS AFFECTING RENNET (CHYMOSIN) CLOTTING OF CALF MILK REPLACERS

1981 ◽  
Vol 61 (2) ◽  
pp. 393-401 ◽  
Author(s):  
K. J. JENKINS ◽  
J. R. LESSARD ◽  
D. B. EMMONS
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Total Solid ◽  
Skim Milk Powder ◽  
Factors Affecting ◽  
Total Solids ◽  
Rennet Coagulation ◽  
High Concentrations ◽  
Milk Replacers

The formation of a firm rennet (chymosin) curd in the abomasum appears to have a useful physiological function in the newborn calf. The results of in vitro experiments with calf milk replacers conducted to study the effect of various factors on rennet clot formation demonstrated that low-pressure (L) dispersion of lipid into skim milk powder replacers resulted in markedly higher (P < 0.05) curd firmness values with rennet than homogenization (H) at all total solid (10, 15 and 20%) and lipid (10, 20, 30 and 40% TS) levels tested. At higher total solids levels, curd firmness, clot weight and percentage of replacer lipid in clot were significantly (P < 0.05) increased. The L dispersion method also promoted rennet coagulation and firmer curds than H when skim was partially replaced by mixtures offish protein-whey or Promine D-whey. The results indicate that reconstitution of milk replacers at high total solids levels (e.g., 20%), in conjunction with L dispersion of lipid, would be beneficial for promoting rennet coagulation, curd firmness and high concentrations of protein and lipid in the clot.

scholarly journals Relationship between whey protein nitrogen index of skim milk powder and the heat stability of recombined filled evaporated milk

LWT ◽  
2021 ◽  
pp. 112754
Author(s):  
Jianfeng Wu ◽  
Chunxia Su ◽  
Lorenz de Neve ◽  
Ali Sedaghat Doost ◽  
Karin De Grave ◽  
...  
Keyword(s):  
Whey Protein ◽  
Milk Powder ◽  
Skim Milk ◽  
Heat Stability ◽  
Skim Milk Powder ◽  
Protein Nitrogen

scholarly journals Effect of β-lactoglobulin phenotype on whey protein nitrogen index and sulphydryl content of skim milk powder

1999 ◽  
Vol 79 (2) ◽  
pp. 229-244 ◽  
Author(s):  
E. Antoinette O'Sullivan ◽  
Philip M. Kelly ◽  
Richard J. Fitzgerald ◽  
Kevin O'Farrell ◽  
Matthew F. Murphy ◽  
...  
Keyword(s):  
Whey Protein ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Protein Nitrogen ◽  
Β Lactoglobulin

Concurrent studies of the flow of digesta in the duodenum and of exocrine pancreatic secretion of calves

1974 ◽  
Vol 31 (1) ◽  
pp. 13-26 ◽  
Author(s):  
J. H. Ternouth ◽  
J. H. B. Roy ◽  
R. C. Siddons
Keyword(s):  
Enzyme Activity ◽  
Pancreatic Secretion ◽  
Pancreatic Enzyme ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Protein Nitrogen ◽  
Postprandial Period ◽  
Pancreatic Protease ◽  
Protease Secretion

1. The duodenal flow of digesta and the concurrent pancreatic secretion were compared when six Ayrshire calves, with duodenal re-entrant and pancreatic sac cannulas, were fed on three reconstituted milks. The diets were: reconstituted, ‘mildly’ preheated, spray-dried skim-milk powder (SK); the same skim milk containing 20 g fat/l (SKF); and reconstituted, ‘severely’ preheated skim-milk powder containing 20 g fat/l (HSKF). The calves were fed ad lib. from teats twice daily from 9 to 21 d of age, each diet being offered for 4 d. Collections of duodenal digesta and pancreatic secretions were made for 12 h after the fourth and eighth meals on each diet.2. The calves tended to have the highest liquid intakes when diet SK was given. After adjustment for differences in intake, diet SK resulted in the appearance of more hydrogen, chloride and potassium ions but less undigested protein nitrogen in the duodenal digesta than with either diet SKF or HSKF.3. Compared with diets SK and SKF, the whey fluids from diet HSKF took significantly longer to leave the abomasum, less H+ passed through the duodenum during the first 6 h after feeding and less Cl− during the whole postprandial period. More undigested protein N and fat from diet HSKF passed through the duodenum during the first 6 h after feeding, although this difference was significant only for protein N during the 1st hour after feeding.4. Over the 12 h postprandial period, the duodenal digesta contained almost exactly the same quantities of polyethylene glycol (PEG), N and fat as those in the meal. The total volume of digesta was 2.25 l greater than the quantity of milk ingested. When the hourly duodenal flows of PEG and fluid were expressed as the square root of the hourly quantities recovered, the pattern of abomasal emptying was rectilinear. The flows of N and fat were curvilinear, when expressed on the same basis.5. The concentration of ‘sodium-free’chloride in the duodenal digesta, in excess of that ingested in the milk, was used as an indicator of the quantity of acid secreted by the abomasum. The relative quantity of acid secreted was greatest with diet SK and least with diet HSKF.6. The pancreatic secretion of fluid was highest during the period 5–9 h after feeding but the secretion of enzyme activity was highest during the first 2 h after feeding.7. Considerable variability in the secretion of enzyme activity was observed and the rate of secretion did not appear to be related to any component of the duodenal digesta.8. Diet SKF was associated with a greater volume of pancreatic secretion and more pancreatic protease secretion than either diet SK or HSKF, but most amylase activity was secreted when diet HSKF was given. Evidence is presented which suggests that pancreatic enzyme activity adaptation occurred when diet HSKF was offered in succession to diet SK or SKF. The secretion of trypsin activity did not differ between diets.

Changes in Concentration of Aflatoxin M1 during Manufacture and Storage of Skim Milk Powder

2006 ◽  
Vol 69 (3) ◽  
pp. 682-685 ◽  
Author(s):  
ORGUN DEVECİ ◽  
EMEL SEZGİN
Keyword(s):  
Spray Drying ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Aflatoxin M1 ◽  
Weight Changes ◽  
Sample Weight ◽  
Powder Samples ◽  
And Storage ◽  
Different Levels

In this study, skim milk powder was produced from cow's milk contaminated artificially with aflatoxin M1 (AFM1) at two different levels, 1.5 and 3.5 μg/liter (ppb), and the effects of process stages on the AFM1 contents were investigated. Pasteurization, concentration, and spray drying caused losses of about 16, 40, and 68%, respectively, in AFM1 content of the milk contaminated with 1.5 μg/liter AFM1, and losses of 12, 35, and 59%, respectively, in the milk contaminated with 3.5 μg/liter AFM1. These losses were found to be statisticially significant at the level of P &lt; 0.01. After 3- and 6-month storage periods, AFM1 content of the skim milk powder produced from milk with 1.5 μg/liter AFM1 decreased by 2 and 5%, respectively, whereas these rates were 2 and 4%, respectively, for the skim milk powders made from milk with 3.5 μg/liter AFM1 (after adjustment for sample weight). Changes in AFM1 content of milk powder samples were found statistically insignificant (P &gt; 0.05 and P &gt; 0.01) for 3- and 6-month storage periods.

scholarly journals The effect of heat treatment on the nutritive value of milk for the young calf

1969 ◽  
Vol 23 (4) ◽  
pp. 763-782 ◽  
Author(s):  
H. Tagari ◽  
J. H. B. Roy
Keyword(s):  
Heat Treatment ◽  
Nutritive Value ◽  
Milk Powder ◽  
Skim Milk ◽  
Sampling Period ◽  
Skim Milk Powder ◽  
Protein Nitrogen ◽  
High Ph ◽  
N Concentration

1. Four Ayrshire bull calves between 8 and 34 days of age and fitted with duodenal and ileal re-entrant cannulas were used to study the effect of heat treatment of the milk they received on the pH and nitrogen composition of the pyloric outflow and ileal contents.2. Milk A contained a spray-dried skim-milk powder pre-heated during the drying process at 74° for 30 min and milk B a similar powder pre-heated at 77° for 15 sec. In milk A about 50% of the non-casein protein N had been denatured.3. Milk B resulted in a lower pH than milk A in the pyloric outflow throughout the sampling period of 6.5 h after feeding. It resulted also in an increased volume of outflow during the 1st h after feeding, a reduced output of undigested protein, an increased output of non-protein nitrogen (NPN) and a different pattern of flow of NPN during the first 4 h after feeding.4. These differences between milk A and milk B were associated largely with different clotting characteristics, which were demonstrated in vitro at two levels of addition of rennet with or without the addition of calcium. The buffering capacity of the two milks was similar.5. Variation between calves in their response to these two milks was attributed to the age of the calves and to differences in inherent clotting or proteolytic activity.6. In the ileal outflow, bacterial activity, as measured by dehydrogenase activity, was positively related to N concentration, but the N concentration when milk A was given did not appear to differ from that when milk B was given.7. One calf had diarrhoea when given milk A at a young age. This was associated with an increased pyloric outflow, an increased outflow of undigested protein but little difference in the rate of proteolysis, and a high pH. In the ileal outflow the volume and amount of N was much increased although the N concentration was reduced.8. It is concluded that the detrimental effect of milk A, found in earlier experiments, was largely associated with high pH and poor digestibility of protein in the abomasum, conditions which allow multiplication of coliform organisms in the intestine.

REDUCTION OF β-CONGLYCININ ANTIGENICITY AND RATE OF ACID-PEPSIN PROTEOLYSIS OF PROTEINS IN EXTRUDED OR RUMEN FLUID-TREATED SOYBEAN MEAL

1989 ◽  
Vol 69 (3) ◽  
pp. 727-734 ◽  
Author(s):  
P. S. MIR ◽  
J. H. BURTON ◽  
B. N. WILKIE ◽  
F. R. VAN DE VOORT
Keyword(s):  
Soybean Meal ◽  
Rumen Fluid ◽  
Milk Powder ◽  
Skim Milk ◽  
In Vitro Digestion ◽  
Skim Milk Powder ◽  
Negative Control ◽  
Fermented Soybean Meal ◽  
Milk Replacers

The effect of processing commercial soybean meal (HSBM) by either extrusion (ExSBM) or fermentation with microbes in rumen fluid (FSBM) on rate of protein hydrolysis and the activity of the antigen β-conglycinin was evaluated. Ethanol-extracted soybean meal (EtSBM) and skim milk powder (SMP) were included as positive controls while HSBM was the negative control, with regard to antigen content. The rates of proteolysis were determined by acid pepsin hydrolysis and the activity of β-conglycinin in the soluble fraction of the digestion mixtures at 0, 2, 4, 6 and 8 h of in vitro proteolysis was determined by radial immunodiffusion in agar gel containing antibody specific for the antigen. Susceptibility of FSBM and ExSBM to proteolysis by pepsin was greater than that of EtSBM. β-Conglycinin content was greatest in HSBM (1.0 ± 0.2 g dL−1) and only 0.3 ± 0.03 g dL−1 in ExSBM at the beginning of in vitro digestion. The antigen was not detected in either FSBM or EtSBM, therefore these products could be used in milk replacers for calves. Key words: In vitro pepsin proteolysis, extruded soybean meal, fermented soybean meal, antigen, β-conglycinin

QUALITY OF PROTEIN IN MILK REPLACERS FOR YOUNG CALVES. IV. RENNET (CHYMOSIN, RENNIN) COAGULATION OF RECONSTITUTED SKIM MILK POWDER CONTAINING ADDED PROTEINS, FAT, CALCIUM, PHOSPHATE AND CITRATE

1976 ◽  
Vol 56 (2) ◽  
pp. 339-345 ◽  
Author(s):  
D. B. EMMONS ◽  
J. D. JONES ◽  
E. E. LISTER
Keyword(s):  
Soy Protein Isolate ◽  
Milk Powder ◽  
Skim Milk ◽  
High Heat ◽  
Skim Milk Powder ◽  
Protein Isolate ◽  
Active Principle ◽  
Total Solids ◽  
Ph Values ◽  
Milk Replacers

The effects of added nutrient sources on curd firmness of reconstituted skim milk powder (10% total solids) were studied. Defatted rapeseed flour (4%) had little effect whereas whey powder (4%) and fish protein concentrate (2%) decreased gel strength of the reconstituted skim milk by approximately 30%. Soybean meal (4%) and soy protein isolate (2%) markedly reduced curd firmness; addition of CaCl2 restored coagulability and curd firmness. However, addition of CaCl2 did not restore gel firmness in reconstituted, severely heated skim milk powder to that of a low-temperature product. Addition of 0.1% CaCl2 slightly increased firmness of reconstituted low- and high-heat powder at pH 6.1; further addition to 0.4% CaCl2 decreased firmness slightly. It appears that when there is sufficient available Ca, further additions have no effect on curd firmness. The results indicate that milk replacers which coagulate with rennet (containing chymosin or rennin as active principle) can probably be produced even when some of the skim milk protein is replaced by other less expensive proteins. Addition of citrate (14 mM), followed by adjustment of the pH, prevented coagulation at pH 6.1 and markedly reduced firmness at pH 5.6 and 5.2. Addition of citrate at 5.7 mM did not prevent coagulation at those pH values. Addition of phosphate had little effect on curd firmness at these pH values. Addition of fat to skim milk containing 15 or 20% total solids, followed by homogenization, had little effect on curd firmness at pH 6.1. Fat additions, however, decreased curd firmness of skim milk containing 10% total solids and nearly prevented coagulation in skim milk containing 5% total solids.

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