Enhanced characterisation of milk fat globules by their size, shape and refractive index with scanning flow cytometry

We present a high-precision method for characterisation of a milk sample by the distributions over milk fat globules (MFG) size, shape, and refractive index (RI). We measured light-scattering profiles of individual MFGs and used global optimisation to retrieve their characteristics. We tested two optical models, a sphere and an oblate spheroid, and found that the latter is a more adequate model for part of the MFGs. We applied the developed method to samples of raw bovine milk and milk from two commercial manufacturers. Diameter and RI of individual MFGs were determined with median errors of 74 nm and 0.0094, respectively, which proves the method to be sensitive to small changes in the MFG properties. Moreover, the distributions over size, surface area, and RI showed a good sensitivity to the details of the milk treatment. In particular, the MFG specific surface area is significantly different for all three milk samples studied.

[1]  R. Jiménez-Flores,et al.  Using confocal laser scanning microscopy to probe the milk fat globule membrane and associated proteins. , 2010, Journal of agricultural and food chemistry.

[2]  T. W. Keenan,et al.  Preparation and characterization of the inner coat material associated with fat globule membranes from bovine and human milk. , 1979, Experimental cell research.

[3]  C. Lopez,et al.  The size and interfacial composition of milk fat globules are key factors controlling triglycerides bioavailability in simulated human gastro-duodenal digestion , 2014 .

[4]  Thomas Wriedt,et al.  Mie theory 1908, on the mobile phone 2008 , 2008 .

[5]  C. Lopez,et al.  Milk fat globules enveloped by their biological membrane: Unique colloidal assemblies with a specific composition and structure , 2011 .

[6]  E. Dumay,et al.  High-pressure homogenisation of raw bovine milk. Effects on fat globule size distribution and microbial inactivation , 2003 .

[7]  W. Steen.  Absorption and Scattering of Light by Small Particles , 1999 .

[8]  P. Paquin,et al.  Evaluation of the particle size of fat globules in a milk model emulsion by photon correlation spectroscopy , 1991 .

[9]  P. Walstra.  Physical Chemistry of Milk Fat Globules , 1983 .

[10]  Danielle G. Lemay,et al.  Milk Fat Globule structure & function; nanosciece comes to milk production. , 2008, Trends in food science & technology.

[11]  T. Beresford,et al.  Recent advances in cheese microbiology , 2001 .

[12]  C. Lopez,et al.  Effect of the size and interface composition of milk fat globules on their in vitro digestion by the human pancreatic lipase: Native versus homogenized milk fat globules , 2012 .

[13]  V L Spitsberg,et al.  Invited review: Bovine milk fat globule membrane as a potential nutraceutical. , 2005, Journal of dairy science.

[14]  L. Berner.  Defining the role of milkfat in balanced diets. , 1993, Advances in food and nutrition research.

[15]  D. Everett,et al.  Adsorption of κ-casein onto native milk fat globule, latex particle, and emulsion surfaces , 2003 .

[16]  B. Guamis,et al.  Changes in the surface protein of the fat globules during ultra-high pressure homogenisation and conventional treatments of milk , 2012 .

[17]  V. Maltsev,et al.  Calibration-free method to determine the size and hemoglobin concentration of individual red blood cells from light scattering. , 2000, Applied optics.

[18]  Maxim A Yurkin,et al.  Light-scattering flow cytometry for identification and characterization of blood microparticles. , 2012, Journal of biomedical optics.

[19]  Harjinder Singh.  The milk fat globule membrane—A biophysical system for food applications , 2006 .

[20]  Dmitry I. Strokotov,et al.  Is there a difference between T- and B-lymphocyte morphology? , 2009, Journal of biomedical optics.

[21]  G. Impoco,et al.  Microstructural properties of milk fat globules , 2013 .

[22]  Dmitry I Strokotov,et al.  Polarized light‐scattering profile—advanced characterization of nonspherical particles with scanning flow cytometry , 2011, Cytometry. Part A : the journal of the International Society for Analytical Cytology.

[23]  A. V. Chernyshev,et al.  Single-particle sizing from light scattering by spectral decomposition. , 2004, Applied optics.

[24]  A new design of the flow cuvette and optical set-up for the scanning flow cytometer. , 1998, Cytometry.

[25]  C. A. Miles,et al.  Attenuation of ultrasound in milks and creams , 1990 .

[26]  Maxim A Yurkin,et al.  Accurate measurement of volume and shape of resting and activated blood platelets from light scattering , 2013, Journal of biomedical optics.

[27]  T. W. Keenan,et al.  Intracellular origin and secretion of milk fat globules. , 2005, European journal of cell biology.

[28]  M. Michalski,et al.  Differently sized native milk fat globules separated by microfiltration: fatty acid composition of the milk fat globule membrane and triglyceride core , 2005 .

[29]  Alfons G. Hoekstra,et al.  Experimental and theoretical study of light scattering by individual mature red blood cells by use of scanning flow cytometry and a discrete dipole approximation. , 2005, Applied optics.

[30]  V. Maltsev.  Scanning flow cytometry for individual particle analysis , 2000 .

[31]  Maxim A Yurkin,et al.  High‐precision characterization of individual E. coli cell morphology by scanning flow cytometry , 2013, Cytometry. Part A : the journal of the International Society for Analytical Cytology.

[32]  C. Belka,et al.  Milk fat globule-EGF factor 8 mediates the enhancement of apoptotic cell clearance by glucocorticoids , 2013, Cell Death and Differentiation.

[33]  C. D. Perttunen,et al.  Lipschitzian optimization without the Lipschitz constant , 1993 .

[34]  Larry D. Travis,et al.  Capabilities and limitations of a current FORTRAN implementation of the T-matrix method for randomly oriented, rotationally symmetric scatterers , 1998 .

[35]  D. Grier,et al.  Technical note: characterizing individual milk fat globules with holographic video microscopy. , 2009, Journal of dairy science.

[36]  J. Camp,et al.  Nutritional and technological aspects of milk fat globule membrane material , 2008 .

[37]  R. Dagastine,et al.  The effect of milk processing on the microstructure of the milk fat globule and rennet induced gel observed using confocal laser scanning microscopy. , 2010, Journal of food science.

[38]  H. El-Zeini.  Microstructure, rheological and geometrical properties of fat globules of milk from different animal species , 2006 .

[39]  M. Michalski,et al.  Optical parameters of milk fat globules for laser light scattering measurements , 2001 .

[40]  Absolute real-time determination of size and refractive index of individual microspheres , 1997 .