Crystal structures and morphologies of fractionated milk fat in nanoemulsions. (15th March 2015)

• Record Type: Journal Article
• Authors: Truong, Tuyen; Morgan, Garry P.; Bansal, Nidhi; Palmer, Martin; Bhandari, Bhesh
• Is Part Of: Food chemistry. Volume 171(2015)
• Page Start: 157
• Page End: 167
• Publication Date: 2015-03-15
• Subjects: cryo-TEM -- DSC -- Milk fat -- Nanoemulsion -- Particle size -- X-ray scattering; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2014.08.113
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Crystalline nano-size milk TAG particles consist of compound crystals. Confinement of nano-size droplets alters crystal structures of emulsified milk TAGs. Single structural elements in crystalline milk TAGs are of 4.1–4.2 nm. Crystalline nano-size milk fat particles have non-spherical morphologies. 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, β 1, and β 2 ) 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.