Modelling of heat stability and heat-induced aggregation of casein micelles in concentrated skim milk using a Weibullian model

2018 ◽  
Vol 71 (3) ◽  
pp. 601-612 ◽  
Author(s):  
Joseph Dumpler ◽  
Felicitas Peraus ◽  
Verena Depping ◽  
Bryndís Stefánsdóttir ◽  
Martin Grunow ◽  
...  
Keyword(s):  
Skim Milk ◽  
Heat Stability ◽  
Casein Micelles ◽  
Induced Aggregation

Stability of buffalo casein micelles

1979 ◽  
Vol 46 (2) ◽  
pp. 401-405 ◽  
Author(s):  
Nripendra C. Ganguli
Keyword(s):  
Sialic Acid ◽  
Gel Filtration ◽  
Skim Milk ◽  
Heat Stability ◽  
Casein Micelles ◽  
Heat Stable ◽  
Micellar Casein ◽  
Acid Release ◽  
The Stability ◽  
Better Than

SUMMARYBuffalo skim-milk is less heat stable than cow skim-milk. Interchanging ultracentrifugal whey (UCW) and milk diffusate with micellar casein caused significant changes in the heat stability of buffalo casein micelles (BCM) and cow casein micelles (CCM). Buffalo UCW dramatically destabilized COM, whereas buffalo diffu-sate with CCM exhibited the highest heat stability.Cow κ-casein stabilizes αs-casein against precipitation by Ca better than buffalo º-casein. About 90% of αs-casein could be stabilized by κ: αs ratios of 0·20 and 0·231 for cow and buffalo, respectively.Sialic acid release from micellar κ-casein by rennet was higher than from acid κ-casein in both buffalo and cow caseins, the release being slower in buffalo. The released macropeptide from buffalo κ-casein was smaller than that from cow κ-casein as revealed by Sephadex gel filtration.Sub-units of BCM have less sialic acid (1·57mg/g) than whole micelles (2·70mg/g). On rennet action, 47% of bound sialic acid was released from sub-units as against 85% from whole micelles. The sub-micelles are less heat stable than whole micelles. Among ions tested, added Ca reduced heat stability more dramatically in whole micelles, whereas added phosphate improved the stability of micelles and, more strikingly, of sub-micelles. Citrate also improved the heat stability of sub-micelles but not of whole micelles.

Heat stability of milk: further studies on the pH-dependent dissociation of micellar κ-casein

1986 ◽  
Vol 53 (2) ◽  
pp. 237-248 ◽  
Author(s):  
Harjinder Singh ◽  
Patrick F. Fox
Keyword(s):  
Whey Protein ◽  
Cetyltrimethylammonium Bromide ◽  
Opposite Effect ◽  
Whey Proteins ◽  
Sodium Dodecyl ◽  
Skim Milk ◽  
Heat Stability ◽  
Casein Micelles ◽  
Acetylneuraminic Acid ◽  
Ph Dependent

SUMMARYWhey protein complexed and became co-sedimentable with casein micelles after heating milk at ≥ 90°C for 10 min at pH ≤ 6·9 while at higher pH values (7·3) whey proteins and κ-casein-rich protein dissociated from the micelles on heating. κ-Casein-deficient micelles were more sensitive to heat, Ca2+ or ethanol than whey protein-coated or native micelles and were readily coagulable by rennet. Isolated κ-casein added to skim milk before preheating (90°C for 10 min) did not associate with the micelles at pH ≥ 6·9. Sodium dodecyl sulphate increased the level of both non-sedimentable N (NSN) and N-acetylneuraminic acid (NANA) and shifted the NSN-pH and NANA-pH curves to more acidic values while cetyltrimethylammonium bromide had the opposite effect. It is suggested that the pH-dependent dissociation in micellar κ-casein, which appears to be reversible, depends on the surface charge on the micelles; at a certain negative charge, disruption of hydrophobic and electrostatic forces could result in the dissociation of κ-casein from the casein micelles.

Effect of pH at heating on the acid-induced aggregation of casein micelles in reconstituted skim milk

LWT ◽  
2004 ◽  
Vol 37 (7) ◽  
pp. 779-787 ◽  
Author(s):  
Skelte G Anema ◽  
Edwin K Lowe ◽  
Siew Kim Lee
Keyword(s):  
Skim Milk ◽  
Casein Micelles ◽  
Effect Of Ph ◽  
Induced Aggregation

Natural variations in the average size of bovine casein micelles: II. Milk samples from creamery bulk silos in south west Scotland

1978 ◽  
Vol 45 (3) ◽  
pp. 347-353 ◽  
Author(s):  
Carl Holt ◽  
D. Donald Muir
Keyword(s):  
Causal Relation ◽  
Skim Milk ◽  
Heat Stability ◽  
Wavelength Dependence ◽  
Unit Weight ◽  
Winter Period ◽  
Casein Micelles ◽  
South West ◽  
Natural Variations ◽  
Average Size

SummarySamples of bulk silo milk from 5 creameries in the south west of Scotland were taken over a 16-month period. The average radii of casein micelles were determined by measuring the wavelength dependence of the turbidity of skim-milk diluted with its own ultrafiltrate. In addition, the concentrations of casein, soluble and colloidal Ca and P1 were measured. The average size of casein micelles followed a pronounced seasonal trend with smaller average sizes in the summer compared to the winter period, confirming earlier observations made on milks from individual cows. The average size of casein micelles correlated positively (r = +0·777, P < 0·001) with the amount of colloidal P1 per unit weight of casein and negatively (r = −0·77, P < 0·001) with casein-bound Ca. Average micelle radius was negatively correlated with heat stability at the natural pH of milk (r = −0·61, P < 0·001), but there did not appear to be any causal relation between these 2 variables.

Studies on the heat stability of milk: I. Behaviour of divalent cations and phosphate in milks heated in a stainless steel system

1987 ◽  
Vol 54 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Douglas G. Dalgleish ◽  
Yves Pouliot ◽  
Paul Paquin
Keyword(s):  
Stainless Steel ◽  
Divalent Cations ◽  
Skim Milk ◽  
Heat Stability ◽  
Total Sample ◽  
Organic Phosphate ◽  
Casein Micelles ◽  
Holding Period ◽  
Stainless Steel Tubing ◽  
Steel Tubing

SummarySkim milk was heated rapidly to 130 °C in stainless steel tubing, and was then held at this temperature for periods of up to 1 h in a stainless steel holding vessel. Samples taken at intervals during the holding period were analysed for cations, inorganic and organic phosphate and protein in the total sample and in the supernatant after centrifugation at 60 500g. The cation and total phosphate (organic+inorganic) contents of the sedimentable material remained constant throughout the heating, although the caseins became extensively dephosphorylated. Dephosphorylated protein dissociated from the casein micelles during the first 20 min of heating, after which its concentration in the serum began to decrease, perhaps indicating the onset of the heat coagulation reaction.

Addition of sodium caseinate to skim milk inhibits rennet-induced aggregation of casein micelles

2012 ◽  
Vol 26 (2) ◽  
pp. 405-411 ◽  
Author(s):  
Zafir Gaygadzhiev ◽  
Valerie Massel ◽  
Marcela Alexander ◽  
Milena Corredig
Keyword(s):  
Skim Milk ◽  
Sodium Caseinate ◽  
Casein Micelles ◽  
Induced Aggregation

Improved heat stability of recombined evaporated milk emulsions by wet heat pretreatment of skim milk powder dispersions

2021 ◽  
pp. 106757
Author(s):  
Jianfeng Wu ◽  
Simin Chen ◽  
Teng Wang ◽  
Hao Li ◽  
Ali Sedaghat Doost ◽  
...  
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Heat Stability ◽  
Skim Milk Powder ◽  
Heat Pretreatment ◽  
Wet Heat

Effect of concentration by ultrafiltration on the heat stability of skim-milk

1980 ◽  
Vol 47 (3) ◽  
pp. 327-335 ◽  
Author(s):  
A. W. Maurice Sweetsur ◽  
D. Donald Muir
Keyword(s):  
Skim Milk ◽  
Heat Stability ◽  
High Protein ◽  
Milk Products ◽  
Total Solids

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.

Ethanol stability of casein micelles – a hypothesis concerning the role of calcium phosphate

1987 ◽  
Vol 54 (3) ◽  
pp. 389-395 ◽  
Author(s):  
David S. Horne
Keyword(s):  
Ionic Strength ◽  
Skim Milk ◽  
Buffer System ◽  
Casein Micelles ◽  
Buffer Solutions ◽  
Relative Response ◽  
Using Data ◽  
The Stability ◽  
Ethanol Stability

SummaryThe ethanol (EtOH) stability of skim milk and the stability towards aggregation of casein micelles diluted into ethanolic buffer solutions were compared using data obtained from previously published experiments. Differences in absolute stability and in relative response were observed when Ca2+ level and pH were adjusted, the buffer system results lying below those from skim milk in both cases. Increasing the ionic strength of skim milk adjusted to pH 7·0 lowered its EtOH stability whereas increasing the ionic strength of the diluting buffer increased the stability of the casein micelles. The hypothesis is put forward that the differences are due to the simultaneous precipitation of Ca phosphate when EtOH is added to skim milk. This draws calcium from the caseinate sites of the micelle, counteracting the destabilizing effects of the EtOH towards the micelle. Such removal and the consequent restructuring are kinetically controlled and micellar precipitation in skim milk finally occurs when the micellar coagulation time falls within the time scale of the restructuring reactions.

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