Some Physical Properties of Milk. III. Effects of Homogenization Pressures on the Viscosity of Whole Milk

Whitnah, C. H.; Rutz, W.; Fryer, H.C.

doi:10.3168/jds.s0022-0302(56)94882-2

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…The slight difference found between homogenized and non-homogenized milk is in disagreement with the results published by Whitnah et al (1956). These authors reported more than a 10% difference, but performed homogenization in one step.…”

Section: Discussioncontrasting

confidence: 83%

Dynamic viscosities of milk and cream from 70 to 135 °C

Bertsch

Cerf²

1983

Journal of Dairy Research

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SummaryThe dynamic viscosities of non-homogenized and homogenized (2-stage) whole and half skim-milk and cream, of unhomogenized skim-milk and of water-diluted milks were measured at temperatures between 70 and 135 °C; this range includes those temperatures used in ultra-high-temperature (UHT) treatments. A tube viscometer was used at the outlet of a continuous flow indirect heater. Above 85 °C the mean residence time of a milk or cream at the test temperature was 3–6 s.An equation relating viscosity μ and temperature θ of the form In μ = aθ2+bθ+c was derived for each product.It proved possible to relate μ, θ and fat content (0·03–15·5%) in a single equation which was appropriate for all the homogenized milks and creams as well as the non-homogenized skim-, half skim- and whole milk; the equation is considered valid for these products under conditions of indirect UHT sterilization. Viscosity values calculated with the equation, even those relating to temperatures as low as 50 °C, were comparable with those reported in the literature.

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Section: Discussioncontrasting

confidence: 83%

Dynamic viscosities of milk and cream from 70 to 135 °C

Bertsch

Cerf²

1983

Journal of Dairy Research

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“…The present experiments on cream: with (#) and without (•) stabilizers. Experiments on homogenized milk without stabilizers: Caffyn (1951) A,Whitnah et al (1956) A-Thomas' (1965) eqn (O) predicts the results for non-interacting spheres.…”

mentioning

confidence: 67%

“…The results are for products homogenized at about the same pressure (14-4-16-1 MPa). The whole milks tested (Caffyn, 1951;Whitnah et al 1956) contained neither carbonate nor citrate.…”

Section: Effect Of Storage Time and Fat Globule Sizementioning

confidence: 99%

A viscometric study of the flocculation of the components in stored homogenized ultra-heat-treated cream

Phipps¹

1982

Journal of Dairy Research

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The apparent relative viscosity (?/ r ) of stored homogenized ultra-heattreated ' coffee' cream increased with time (t) at a rate which was a function of mean fat globule diameter (d) and fat volume fraction (); the rate was also influenced by Na 2 CO 3 and Na citrate when present as stabilizing additives. Viscosity increases were attributed to the progressive flocculation of fat globules and to the strengthening of the structure formed by the gradual accretion of casein micelles on to globule surfaces and their points of contact (bridging). The expressionwhere t is in days and d in jim, was found to hold over a 12-week storage period for a batch of creams ( = 0-143) of different d values prepared from the bulk cream containing carbonate and citrate stabilizers; ij 0 is the relative viscosity at t = 0 and & is a rate parameter. In the absence of stabilizers the parameter k assumed a smaller value and so appeared to be a function of chemical composition of the cream and of forces of particle interaction; seasonal factors were also suspected of influencing k. The effect of the fat volume fraction on storage behaviour was not fully resolved, but there was some evidence that the proportionality log i / r a l /^ was appropriate.The changes that occur in the stability and composition of ultra-heat-treated (UHT) aseptically packed milk and cream during storage has been the subject of several recent studies (Samel et al. 1971; Cheng & Gelda, 1974;Anderson et al. 1977). The proteins in UHT milk were considered by Samel et al. (1971) to undergo several changes on storage which favoured casein aggregation and eventual coagulation of the milk. In the case of UHT 'coffee' cream, morphological alterations in the casein micelles and continuous redistribution of components between the fat and aqueous phases were found to take place during storage of the cream (Anderson et al. 1977). The degree of association between fat globules and casein micelles was also found to depend upon storage time, irrespective of storage temperature.Such structural association of components can produce changes of a progressive kind in the rheological properties of stored products. This paper describes a viscometric study of the aggregation process and structural build-up of the components in stored, homogenized UHT ' coffee' cream and an investigation of the interrelationship of the cream variables, relative viscosity v r , mean milk fat globule (MFG) diameter d, fat phase fraction 0 and the cream storage time t.

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Physikalische Eigenschaften flüssiger Milchprodukte. 2. Mitt. Viskosität von Milch, Rahm und Milchkonzentraten

Konrad¹,

Rambke²

1970

Nahrung

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I 4 :532. I 3Milch, -produkte Viskositat Die gegenwartige Phase der Automatisierung der Molkereiindustrie erfordert eine umfassende Erarbeitung der Werte der charakteristischen Parameter, die fur die Steuerungs-und Regelprozesse von technisch-physikalischer Bedeutung sind. Bei Viskositatsbestimmungen ergeben sich dabei besondere mel3technische Probleme, die in engem Zusammenhang mit reversiblen und irreversiblen Strukturanderungen der zu verarbeitenden Milcherzeugnisse stehen. Von E-Milch, Trinkvollmilch, Rohmilch, 30-und 50prozentigem Rahm wurde die Vikositat im Temperaturbereich 5. -80 "C untersucht. Fur E-Milch-und Vollmilchkonzentrate werden die Beziehungen zwischen Viskositat und Trockenmasse im Temperaturbereich 5-65 "C durch eine Naherungsformel ausgedruckt, die in graphischer Darstellung eine Abschatzung der Viskositat rnit einer fur technisch-technologische Zwecke ausreichenden Genauigkeit ermoglicht.

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Some Physical Properties of Milk. III. Effects of Homogenization Pressures on the Viscosity of Whole Milk

Cited by 9 publications

References 11 publications

Dynamic viscosities of milk and cream from 70 to 135 °C

Dynamic viscosities of milk and cream from 70 to 135 °C

A viscometric study of the flocculation of the components in stored homogenized ultra-heat-treated cream

Physikalische Eigenschaften flüssiger Milchprodukte. 2. Mitt. Viskosität von Milch, Rahm und Milchkonzentraten

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