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.

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.

QUALITY OF PROTEIN IN MILK REPLACERS FOR YOUNG CALVES. I. FACTORS AFFECTING IN VITRO CURD FORMATION BY RENNET (CHYMOSIN, RENNIN) FROM RECONSTITUTED SKIM MILK POWDER

1976 ◽  
Vol 56 (2) ◽  
pp. 317-325 ◽  
Author(s):  
D. B. EMMONS ◽  
E. E. LISTER
Keyword(s):  
Heat Treatment ◽  
Milk Powder ◽  
Skim Milk ◽  
High Heat ◽  
Skim Milk Powder ◽  
Factors Affecting ◽  
Fresh Milk ◽  
Milk Solids ◽  
Milk Replacers

Fresh milk coagulates with chymosin (rennin) in the calf stomach to form relatively strong curds. With respect to calf milk replacers it is of interest to study factors affecting curd formation of reconstituted skim milk powder by this enzyme. Curd firmness was increased by lower pH of the skim milk over a range of 5.6–6.6, higher concentration of skim milk solids over a range of 5–20%, higher concentrations of chymosin, lower temperatures of heat treatment of skim milk prior to spray drying, and higher temperature of coagulation, 37 vs. 30 C. Reconstitution of powder in water above 56 C for 2 min remarkedly reduced the firmness of the curd. The following coagulation conditions were selected for comparison of powders and milk replacers: addition of 1 ml of a 1:50 dilution of standard strength commercial rennet to 100 ml of milk previously adjusted to pH 6.1, 10% of nonfat solids in the aqueous nonfat phase, temperature of 37 C, and measurements of firmness 30 min after adding rennet. Commercially produced skim milk powders designated high-heat, medium-heat and roller products yielded soft curds. Commercial low-heat powders yielded strong curds. All coagulated in less than 4 min at pH 6.1, the time being relatively independent of heat treatment.

Thermal Resistance of Listeria monocytogenes Scott A in Ultrafiltered Milk as Related to the Effect of Different Milk Components

2010 ◽  
Vol 73 (11) ◽  
pp. 2110-2115 ◽  
Author(s):  
KINGA SZLACHTA ◽  
SUSANNE E. KELLER ◽  
ARLETTE SHAZER ◽  
STUART CHIRTEL
Keyword(s):  
Listeria Monocytogenes ◽  
Thermal Resistance ◽  
Milk Fat ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Single Measure ◽  
Total Solids ◽  
Whole Milk ◽  
Milk Components

Pasteurization parameters for grade A milk are well established and set by regulation. However, as solids levels increase, an increased amount of heat is required to destroy any pathogens present. This effect is not well characterized. In this work, the effect of increased dairy solids levels on the thermal resistance of Listeria monocytogenes was examined through the use of ultrafiltered (UF) milk, reconstituted milk powder, and the milk components lactose and caseinate. From the results obtained, lactose and caseinate did not appear to affect thermal resistance. In addition, the level of milk fat, up to 10% of the total solids in UF whole milk, did not result in statistically significant changes to thermal resistance when compared with UF skim milk. Reconstituted skim milk powder at 27% total solids (D62-value = 1.16 ± 0.2 [SD] min, z = 5.7) did result in increased thermal resistance, as compared with reconstituted skim milk powder at 17.5% (D62-value = 0.86 ± 0.02 min, z = 5.57) and UF whole milk at 27% total solids (D62-value = 0.66 ± 0.07 min, z = 5.16). However, that increase appeared to be due to the increase in salt levels, not to increases in caseinate, fat, or lactose. Consequently, total solids, as a single measure, could not be used to predict increased thermal resistance of L. monocytogenes in concentrated milk.

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.

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

Use of an infant food formula based on groundnut protein isolate and skim milk powder in feeding infants

1963 ◽  
Vol 30 (11) ◽  
pp. 365-368 ◽  
Author(s):  
T. R. Doraiswamy ◽  
M. R. Chandrasekhara ◽  
B. H. Subbaraya ◽  
A. N. Sankaran ◽  
M. Swaminathan ◽  
...  
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Protein Isolate ◽  
Infant Food

USE OF THE WILLEMS POLYTRON® TO HOMOGENIZE FAT AND DISPERSE INSOLUBLE INGREDIENTS IN HIGH-FAT LIQUID MILK REPLACERS

1972 ◽  
Vol 52 (3) ◽  
pp. 477-484 ◽  
Author(s):  
A. D. L. GORRILL ◽  
J. W. G. NICHOLSON
Keyword(s):  
Dry Matter ◽  
Soybean Lecithin ◽  
Milk Powder ◽  
Skim Milk ◽  
Nitrogen Retention ◽  
Liquid Mixtures ◽  
Skim Milk Powder ◽  
High Fat ◽  
Liquid Milk ◽  
Milk Replacers

The operation of the Willems Polytron® to prepare batches of high-fat (27–35%, air dry basis) milk replacers is described. Most milk replacers were mixed at 40% solids to minimize foaming, and were diluted prior to feeding. The Polytron homogenized fat in liquid mixtures at 55 or 65 C, and partially dispersed insoluble ingredients in soybean, rape-seed, and fish flours. The inclusion of 25% or more of partially delactosed acid whey powder increased the viscosity of the mixtures, and held insoluble ingredients in suspension for several hours. Homogenization of a milk replacer containing 73% skim milk powder and 27% bleachable fancy tallow (3% soybean lecithin added) markedly improved growth (425 vs. 190 g/day), dry matter, nitrogen, and energy digestion (92 vs. 73% for energy) and nitrogen retention (44 vs. 24%) by calves. Calf responses were similar when the liquid diet was homogenized at either 55 or 65 C. Homogenization with 3% soybean lecithin in the tallow increased digestion of dry matter, nitrogen, and energy by chives by 5–6% units (P < 0.2), and Ca by 16% units (P < 0.05) compared with no lecithin. Bleachable fancy or crude tallow and 3% soybean lecithin or 0.2% glyceryl monostearate in the fat gave similar calf responses.

Kinematic viscosities of New Zealand skim-milk

1978 ◽  
Vol 45 (1) ◽  
pp. 25-35 ◽  
Author(s):  
J. H. Buckingham
Keyword(s):  
New Zealand ◽  
Seasonal Variations ◽  
Kinematic Viscosity ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Total Solids ◽  
Solids Concentration ◽  
Powder Manufacture ◽  
Single Batch

SummaryThe variation in kinematic viscosity (ν) with solids concentration and temperature has been determined for native skim-milk concentrates and reconstituted New Zealand skim-milk. Below 40% (w/v) total solids, samples reconstituted from a single batch of skim-milk powder model the behaviour of native concentrates obtained from an evaporation plant at all times of the year. Above 40% (w/v) agethickening and seasonal variations in the viscosity of native concentrates become significant. Age-thickening can be reduced by cooling the concentrate. These results are discussed in relation to milk powder manufacture.

scholarly journals The influence of GDL concentration on milk pH change during acid coagulation

2002 ◽  
Vol 47 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Safet Fetahagic ◽  
Ognjen Macej ◽  
Jelena Denin-Djurdjevic ◽  
Snezana Jovanovic
Keyword(s):  
Buffer Capacity ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
90 C 10 ◽  
Ph Change ◽  
Protein Ratio ◽  
Milk Samples ◽  
Ph Values ◽  
Heat Treated

Skim milk powder was reconstituted to obtain milk A (with 8.01% TS). Milk A was standardized with 3% of skim milk powder and 3% of demineralized whey powder (DWP), respectively, to obtain milk B (with 11.15% TS) and milk C (with 11.10% TS). Milk samples were heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min, respectively. Untreated milk was used as control. Acidification was carried out at 25?C, 35?C and 45?C during 240 min with GDL (glucono-d-lactone), namely with the amount of 0.5%, 0.75%, 1.0%, 1.25% 1.5%, 1.75%, 2.0% and 3.0% of GDL, respectively. The results showed that all investigated factors, explicitly GDL concentration, acidification temperature and applied heat treatment of milk as well as added DWP influence the change of pH during acidification. Milk samples standardized with DWP had smaller buffer capacity and faster change of pH than samples standardized with skim milk powder. Only at acidification temperature of 25?C, added DWP did not influence the change of milk buffer capacity regardless of the change of casein:whey protein ratio. Under this acidification condition, both milk samples standardized with skim milk powder and DWP had similar final pH values.

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