title: Crystal structures and morphologies of fractionated milk fat in nanoemulsions.
abstract: The triacylglycerol (TAG) crystal structures and morphologies of fractionated milk lipids in nanoemulsions were investigated at 4°C. Droplet size (0.17 versus 1.20 μm), lipid composition (stearin versus olein) and cooling rate (1 versus 10°C min(-1)) had an influence on the structural properties. Five crystal polymorphs (α, β'1, β'2, β1, and β2) were formed with either triple and/or double chain length structures in the solid phases of the emulsified systems. X-ray scattering peak intensities were reduced with the nanoemulsion particles. The internal structure of TAG exhibited stacking of individual lamellar layers (3.8-4.2 nm). Various anisometric shapes of fat nanoparticles were formed due to a highly sharp curvature of the nano-size droplets. The shape of olein nanoparticles was more polyhedral compared to the stearin. TAG crystals arranged in a planar-layered organisation at the slower cooling rate. These differences imply that the nanometric confinement of oil droplets modifies the fat crystal habit.
authors.affiliation: School of Agriculture & Food Sciences, The University of Queensland, St Lucia, QLD 4072, Australia. Electronic address: t.truong1@uq.edu.au.
authors.forename: Tuyen
authors.initials: T
authors.lastname: Truong
authors.affiliation: Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia, QLD 4072, Australia. Electronic address: g.morgan1@uq.edu.au.
authors.forename: Garry P
authors.initials: GP
authors.lastname: Morgan
authors.affiliation: School of Agriculture & Food Sciences, The University of Queensland, St Lucia, QLD 4072, Australia. Electronic address: n.bansal@uq.edu.au.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Bansal
authors.affiliation: Dairy Innovation Australia Limited, Werribee, VIC 3030, Australia. Electronic address: mpalmer@dairyinnovation.com.au.
authors.forename: Martin
authors.initials: M
authors.lastname: Palmer
authors.affiliation: School of Agriculture & Food Sciences, The University of Queensland, St Lucia, QLD 4072, Australia. Electronic address: b.bhandari@uq.edu.au.
authors.forename: Bhesh
authors.initials: B
authors.lastname: Bhandari
mesh_terms: D000818:Animals; D016880:Anisotropy; D002152:Calorimetry, Differential Scanning; D020285:Cryoelectron Microscopy; D003460:Crystallization; D018360:Crystallography, X-Ray; D004655:Emulsions / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology; D010316:Particle Size; D012542:Scattering, Radiation; D013696:Temperature; D014280:Triglycerides / Q000737:chemistry; D014965:X-Rays
chemical_list: D004655:Emulsions; D008055:Lipids; D008894:Milk Proteins; D014280:Triglycerides; C022618:tristearin
keywords: DSC; Milk fat; Nanoemulsion; Particle size; X-ray scattering; cryo-TEM