Characterisation of fractionated skim milk with small-angle X-ray scattering

Sørensen, Helle; Pedersen, Jan Skov; Mortensen, K.; Ipsen, Richard

doi:10.1016/j.idairyj.2013.05.006

Cited by 19 publications

(11 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a result, the use of MCI for small-angle scattering studies on casein micelles may induce undesirable artefacts. The use of skimmed milk powder, as done by Hansen et al (1996), Moitzi et al (2011), Jackson & McGillivray (2011), Pignon et al (2004) and Shukla et al (2009), or microfiltration retentates (Sørensen et al, 2013) will generally prevent the aforementioned solubility issue, but the presence of fat in skimmed milk powder is still an issue of concern here.…”

Section: Fat Removalmentioning

confidence: 99%

The structure of casein micelles: a review of small-angle scattering data

Kruif

2014

J Appl Crystallogr

View full text Add to dashboard Cite

Casein micelles are association colloids found in mammalian milk. Small‐angle scattering data on casein micelles have been collected and are reviewed, including contrast variation. The scattering spectra are quite consistent at medium and high scattering wavevectors [Q = 4πnsin(θ/2)/λ, where n is the refractive index, λ is the wavelength and θ is the scattering angle]. Differences are noted, especially at low Q, which may be attributed to sample preparation, particularly the presence of residual fat globules. Scattering spectra are calculated using a generalized scattering function and a composite particle model, and it is possible to give a self‐consistent calculation of the spectra using one set of parameters for all contrasts in both small‐angle X‐ray scattering and small‐angle neutron scattering. The data and calculations show that a casein micelle is a homogeneous particle. The polydispersity in size is about 35% and therefore experimental data on particle size depend very much on the method used. A `reference set' of numbers is proposed for casein micelles from pooled cows' milk, which may be given as follows: β = 0.35, R10 = 60 nm, Rg = 110 nm, Rhydr = 96 nm (at 90° scattering). Often, use is made of dynamic light scattering (DLS), which gives an Rhydr = 〈R6〉/〈R5〉 of 80–100 nm at 90° scattering. Values will be considerably higher at low(er) angles, and lower at backscattering angles, which are currently used in many DLS setups. Larger values are probably due to clusters of casein micelles or residual fat. The structure of a casein micelle can best be described as a protein matrix in which calcium phosphate clusters (2 nm radius) are dispersed. The protein matrix has density variations on a similar length scale. The casein micelle–submicelle model and models with large voids and channels are highly improbable.

show abstract

Section: Fat Removalmentioning

confidence: 99%

The structure of casein micelles: a review of small-angle scattering data

Kruif

2014

J Appl Crystallogr

View full text Add to dashboard Cite

show abstract

“…Indeed, Roach and Harte [57] observed a significant reduction in particle size when pressures \250 MPa were applied to casein micelles and casein micelle isolates. However, UHPH at 300 MPa of fractionated milk concentrate affected casein micelles at pH 5.8, but not at pH 6.6 suggesting the need of some colloidal calcium phosphate dissociation to cause micellar disruption [73].…”

Section: Particle Disruption and Food Stabilitymentioning

confidence: 90%

Opportunities for Ultra-High-Pressure Homogenisation (UHPH) for the Food Industry

2014

View full text Add to dashboard Cite

Ultra-high-pressure homogenisation (UHPH) is a novel technology with applications in the processing of fluids. While the technology is based on conventional balland-seat homogenisers, developments in valve design and materials have enabled pressures of 400 MPa to be achieved. The benefits of UHPH include shelf-life extension through inactivation of microorganisms and improvements in functionality due to increased emulsion capacity and stability, with minimal effects on nutritional value and sensory characteristics. It is also envisaged that the thermal effects of UHPH are minimal as the treated fluid reaches its maximum temperature for less than a second. European research projects have recently supported the studies of UHPH for food applications, including dairy products, vegetable milk, and fruit juices. These projects have been focused on the evaluation of the effects of UHPH on a large number of food components, with a particular emphasis on control of enzymes and physical functionality. UHPH is a sustainable process that has potential application in a large number of liquid foods, including milk (cow, goat, soy, rice, and almond), fruit juices (orange, apple, and grape), and manufactured food products (yoghurt, soghurt, and cheese) as a novel process for the production of a wide variety of safe and nutritious foods.

show abstract

“…Sodium ions will replace micellar calcium and increase the concentration of calcium ions in the serum phase, while acidification also transfer calcium from the colloidal to the soluble form (Gaucheron, 2010). Previous trials based on UHPH treated whey protein-depleted milk concentrate, showed an unchanged serum calcium level at 4% casein compared with non-UHPH treated samples, while at 8% casein a higher serum calcium level was observed when applying UHPH treatment (Sørensen et al, 2013). Increased destabilisation of the casein micelle with increased casein concentration followed by UHPH treatment could explain the higher soluble calcium level in the samples with 8% casein.…”

Section: Mineralsmentioning

confidence: 99%

“…Only few studies, all using piston-gap type homogenisers, have investigated the effect of UHPH treatment on the functional properties of whey protein-depleted or partial depleted milk concentrate solutions (Chevalier-Lucia, Blayo, Gr acia-Juli a, Picart-Palmade, & Dumay, 2011;Roach & Harte, 2008;Sørensen, Pedersen, Mortensen, & Ipsen, 2013). Roach and Harte (2008) described the changes in casein micelle size induced by different UHPH pressures (100,200,250,300 and 350 MPa) and levels of CaCl 2 (0, 5, 10 and 15 mM).…”

Section: Introductionmentioning

confidence: 99%

“…Sørensen et al (2013) studied fractionated microfiltrated milk with varying protein content and pH, and observed an increased viscosity and serum calcium level at higher protein content (8%, w/w) and low pH (pH 5.8). UHPH treatment has also been applied to milk containing whey protein (Datta, Hayes, Deeth, & Kelly, 2005;Hayes, Fox, & Kelly, 2005;Hayes & Kelly, 2003;Pereda, Ferragut, Quevedo, Guamis, & Trujillo, 2009;Sandra & Dalgleish, 2005Zamora, Ferragut, Guamis, & Trujillo, 2012a) as well as milk gels, cheese systems and yoghurt (Escobar et al, 2011;Lodaite, Chevalier, Armaforte, & Kelly, 2009;Serra, Trujillo, Guamis, & Ferragut, 2009;Venir, Marchesini, Biasutti, & Innocente, 2010;Zamora, Ferragut, Jaramillo, Guamis, & Trujillo, 2007;Zamora, Ferragut, Juan, Guamis, & Trujillo, 2011;Zamora, Ferragut, Quevedo, Guamis, & Trujillo, 2012b) and modifications of yield of cheese, chemical composition and texture have been observed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation