Rheological properties and microstructure during rennet induced coagulation of UF concentrated skim milk

Karlsson, Anders Ola; Ipsen, Richard; Ardö, Ylva

doi:10.1016/j.idairyj.2006.08.002

Cited by 55 publications

(71 citation statements)

References 11 publications

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Section: Ultrafiltrationmentioning

confidence: 85%

“…Rennet coagulation time is not affected by concentration if the same amount of rennet is added to unconcentrated or UF concentrate [42,93,98], indicating that the proportion of κ-casein hydrolyzed at the point of flocculation is lower in UF retentate than in unconcentrated milk, as is indeed observed experimentally [25,75,140]. Following 4-fold concentration, hydrolysis of ∼ 50% of κ-casein is required to induce gel formation [25] whereas, at ∼ 7 fold concentration, hydrolysis of only 20% of κ-casein is required [75]. The rate of gel firming can also be enhanced by concentration [97,98], although recent studies by Karlsson et al [75] showed that, following ∼ 7-fold concentration (casein content ∼ 20%, w/w), the rate of gel formation of the UF retentate was lower than that of the unconcentrated milk.…”

Section: Ultrafiltrationmentioning

confidence: 85%

“…(1) The inter-micellar mean free distance is reduced considerably, from ∼ 200 nm in unconcentrated skim Pre-treatment of cheese milk 559 milk [146] to < 10 nm in skim milk concentrated to a casein content of ∼ 20% [75]. The reduced inter-micellar mean free distance forces the micelles to interact more frequently with each other as a result of collisions induced by Brownian motion [27,144].…”

Section: Ultrafiltrationmentioning

confidence: 99%

“…Following 4-fold concentration, hydrolysis of ∼ 50% of κ-casein is required to induce gel formation [25] whereas, at ∼ 7 fold concentration, hydrolysis of only 20% of κ-casein is required [75]. The rate of gel firming can also be enhanced by concentration [97,98], although recent studies by Karlsson et al [75] showed that, following ∼ 7-fold concentration (casein content ∼ 20%, w/w), the rate of gel formation of the UF retentate was lower than that of the unconcentrated milk. The reduced coagulation and flocculation rate was related to a high zero-shear viscosity of milk reducing the rate [75].…”

Section: Ultrafiltrationmentioning

confidence: 99%

“…Microstructural analysis by confocal laser scanning microscopy of rennetinduced gels of ∼ 7-fold concentrated UF retentate revealed that larger rennetinduced casein aggregates are formed in unconcentrated milk than in UF retentate [75]. The degree of macroscopic syneresis, i.e., separation of whey from the gel on a macroscopic level, is considerably less for curd prepared from UF retentate than for curd prepared from unconcentrated milk [75,117].…”

Section: Ultrafiltrationmentioning

confidence: 99%

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Pre-treatment of cheese milk: principles and developments

Kelly

Huppertz

Sheehan

2008

Dairy Sci. Technol.

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-Classically, very few pre-treatments are applied to milk for cheese-making, with some cheese varieties simply made from raw whole milk, but most made from pasteurised milk of which the composition (e.g., fat:protein ratio) may have been standardized. However, there has been consistent interest in more novel and sophisticated strategies for pre-treatment of cheese-milk. Approaches explored include the use of alternative processing technologies (e.g., membrane filtration, high-pressure treatment, homogenisation, heat treatments more severe than pasteurisation) or addition of sources of protein or milk solids (e.g., milk powders, whey protein products) or enzymes. The principal reasons for such pre-treatments of cheese-milk are: (1) to control the microbiology of the raw milk and the resulting cheese better than is possible by pasteurisation (e.g., inactivation or removal of spores, control of non-starter lactic acid bacteria); (2) increasing the yield of cheese, e.g., through heat-or pressure-induced incorporation of whey proteins, or enhancing sensory properties of reduced fat cheese by direct addition of microparticulated whey proteins; (3) manipulation of cheese ripening, e.g., reducing the likelihood of off-flavour development by inactivation of enzymes or accelerating ripening through increasing enzyme-substrate interactions; or (4) improving the texture and other functional properties, e.g., melting. Finally, the considerations for manufacture and ripening of different cheese varieties, or sub-classes of specific varieties (e.g., low-fat cheese) will clearly differ and add to the complexity of the technological options available. This article will review the key principles for pre-treatment of cheese-milk, as summarised briefly above. Résumé -Pré-traitement du lait de fabrication de fromage : principes et avancées.Classiquement, très peu de pré-traitements sont appliqués au lait de fabrication de fromage : quelques variétés de fromage sont faites simplement à partir de lait entier cru, mais la plupart d'entre elles sont fabriquées à partir de lait pasteurisé dont la composition (par exemple rapport matière grasse/protéine) a pu être standardisée. Cependant, un intérêt constant s'est manifesté pour des stratégies nouvelles et plus sophistiquées pour le pré-traitement du lait de fromagerie. Les approches explorées incluent l'utilisation de technologies de traitement alternatives (par exemple filtration membranaire, haute pression, homogénéisation, traitements thermiques plus sévères que la pasteurisation) ou addition de sources de protéines ou de matière sèche de lait (par exemple poudres de lait, protéines de lactosérum) ou d'enzymes. Les principales raisons de tels pré-traitements du lait de fabrication fromagère sont : (1) de contrôler la microbiologie du lait cru et du fromage résul-tant, mieux que ce qui est possible par pasteurisation (par exemple inactivation ou retrait des spores, contrôle des bactéries lactiques non levain) ; (2) d'accroître le rendement en fromage, par exemple en induisant...

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Section: Ultrafiltrationmentioning

confidence: 85%

Section: Ultrafiltrationmentioning

confidence: 85%

Section: Ultrafiltrationmentioning

confidence: 99%

Section: Ultrafiltrationmentioning

confidence: 99%

Section: Ultrafiltrationmentioning

confidence: 99%

See 3 more Smart Citations

Pre-treatment of cheese milk: principles and developments

Kelly

Huppertz

Sheehan

2008

Dairy Sci. Technol.

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Rheological Behavior of Biopolymer Systems

Feng

2013

Handbook of Biopolymer‐Based Materials

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Extent of κ‐casein hydrolysis during renneting of bovine milk: A critical assessment of the analytical and estimation approaches

Kayihura

2023

Food Science & Nutrition

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Renneting is an enzymatic process that turns milk into curd which is then transformed into cheese. Rennet‐induced coagulation of caseins (CNs) is the critical step during this process and the key is the primary hydrolysis of κ‐CN's Phe105‐Met106 bond by chymosin. This article comprehensively reviews the existing data on the extent/degree of κ‐CN hydrolysis during renneting of bovine milk and critically evaluates its determination methods. The data show that under normal cheese‐making conditions, milk gelation occurs at a degree of κ‐CN hydrolysis <80%, which varies due to several factors including analytical and estimation approaches. The common approach involves isolating the macropeptides released, by precipitating whey proteins and residual CN in 1%–12% trichloroacetic acid (TCA), then assuming that the maximum amount obtained is 100% κ‐CN hydrolysis. The drawback is that the estimated degree of κ‐CN hydrolysis may be higher than the actual value as TCA partially precipitates the macropeptide fractions. Moreover, macropeptide isolation seems unnecessary based on current advances in chromatographic and electrophoretic techniques. The present work proposes a simple mass balance‐based approach that will provide accurate estimates in future studies. The accuracy of measuring the degree of κ‐CN hydrolysis has implications on the precision of the data in relation to its partitioning (% distribution between the curd and whey) which is essential for improving whey quality.

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Rheological properties and microstructure during rennet induced coagulation of UF concentrated skim milk

Cited by 55 publications

References 11 publications

Pre-treatment of cheese milk: principles and developments

Pre-treatment of cheese milk: principles and developments

Rheological Behavior of Biopolymer Systems

Extent of κ‐casein hydrolysis during renneting of bovine milk: A critical assessment of the analytical and estimation approaches

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