title: Tracking Structural Changes in Lipid-based Multicomponent Food Materials due to Oil Migration by Microfocus Small-Angle X-ray Scattering.
abstract: One of the major problems in the confectionery industry is chocolate fat blooming, that is, the formation of white defects on the chocolate surface due to fat crystals. Nevertheless, the mechanism responsible for the formation of chocolate fat blooming is not fully understood yet. Chocolate blooming is often related to the migration of lipids to the surface followed by subsequent recrystallization. Here, the migration pathway of oil into a cocoa butter matrix with different dispersed particles was investigated by employing microfocus small-angle X-ray scattering and contact angle measurements. Our results showed that the chocolate powders get wet by the oil during the migration process and that the oil is migrating into the pores within seconds. Subsequently, cocoa butter is dissolved by the oil, and thus, its characteristic crystalline structure is lost. The chemical process provoked by the dissolution is also reflected by microscopical changes of the surface morphology of chocolate model samples after several hours from the addition of oil to the sample. Finally, the surface morphology was investigated before and after oil droplet exposure and compared to that of water exposure, whereby water seems to physically migrate through the particles, namely cocoa powder, sucrose, and milk powder, which dissolve in the presence of water.
authors.affiliation: †Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21075 Hamburg, Germany.
authors.forename: Svenja K
authors.initials: SK
authors.lastname: Reinke
authors.affiliation: ‡Photon Science, DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: Stephan V
authors.initials: SV
authors.lastname: Roth
authors.affiliation: ‡Photon Science, DESY, Notkestr. 85, 22607 Hamburg, Germany.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Santoro
authors.affiliation: §Nestlé Product Technology Centre York, P.O. Box 204, Haxby Road, York YO91 1XY, England, United Kingdom.
authors.forename: Josélio
authors.initials: J
authors.lastname: Vieira
authors.affiliation: †Institute of Solids Process Engineering and Particle Technology, Denickestr. 15, 21075 Hamburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Heinrich
authors.affiliation: ∥Nestlé SA, Avenue Nestlé 55, 1800 Vevey, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Palzer
mesh_terms: D002099:Cacao / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D003124:Colorimetry; D004041:Dietary Fats; D005502:Food; D008055:Lipids / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009821:Oils / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry; D011208:Powders; D053838:Scattering, Small Angle; D000074242:Sunflower Oil; D013696:Temperature; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D004041:Dietary Fats; D008055:Lipids; D009821:Oils; D010938:Plant Oils; D011208:Powders; D000074242:Sunflower Oil; C052387:cocoa butter
keywords: chocolate; microstructure; migration; synchrotron; μSAXS