title: Effect of Phytosterols on the Crystallization Behavior of Oil-in-Water Milk Fat Emulsions.
abstract: Milk has been used commercially as a carrier for phytosterols, but there is limited knowledge on the effect of added plant sterols on the properties of the system. In this study, phytosterols dispersed in milk fat at a level of 0.3 or 0.6% were homogenized with an aqueous dispersion of whey protein isolate (WPI). The particle size, morphology, ζ-potential, and stability of the emulsions were investigated. Emulsion crystallization properties were examined through the use of differential scanning calorimetry (DSC) and Synchrotron X-ray scattering at both small and wide angles. Phytosterol enrichment influenced the particle size and physical appearance of the emulsion droplets, but did not affect the stability or charge of the dispersed particles. DSC data demonstrated that, at the higher level of phytosterol addition, crystallization of milk fat was delayed, whereas, at the lower level, phytosterol enrichment induced nucleation and emulsion crystallization. These differences were attributed to the formation of separate phytosterol crystals within the emulsions at the high phytosterol concentration, as characterized by Synchrotron X-ray measurements. X-ray scattering patterns demonstrated the ability of the phytosterol to integrate within the milk fat triacylglycerol matrix, with a concomitant increase in longitudinal packing and system disorder. Understanding the consequences of adding phytosterols, on the physical and crystalline behavior of emulsions may enable the functional food industry to design more physically and chemically stable products.
authors.affiliation: Food Chemistry and Technology Department, Teagasc Food Research Centre , Moorepark, Fermoy, County Cork, Ireland.|School of Food and Nutritional Sciences, University College Cork , Cork, Ireland.|CSIRO Food and Nutrition, Werribee, Victoria 3030, Australia.|School of Applied Science, RMIT University , Melbourne, Victoria 3000, Australia.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Zychowski
authors.affiliation: CSIRO Food and Nutrition, Werribee, Victoria 3030, Australia.
authors.forename: Amy
authors.initials: A
authors.lastname: Logan
authors.affiliation: CSIRO Food and Nutrition, Werribee, Victoria 3030, Australia.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Augustin
authors.affiliation: School of Food and Nutritional Sciences, University College Cork , Cork, Ireland.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Kelly
authors.affiliation: School of Applied Science, RMIT University , Melbourne, Victoria 3000, Australia.
authors.forename: Alexandru
authors.initials: A
authors.lastname: Zabara
authors.affiliation: School of Food and Nutritional Sciences, University College Cork , Cork, Ireland.
authors.forename: James A
authors.initials: JA
authors.lastname: O'Mahony
authors.affiliation: School of Applied Science, RMIT University , Melbourne, Victoria 3000, Australia.
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Conn
authors.affiliation: Food Chemistry and Technology Department, Teagasc Food Research Centre , Moorepark, Fermoy, County Cork, Ireland.
authors.forename: Mark A E
authors.initials: MA
authors.lastname: Auty
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D003460:Crystallization; D004655:Emulsions / Q000737:chemistry; D005223:Fats / Q000737:chemistry*; D008892:Milk / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D010316:Particle Size; D010840:Phytosterols / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D004655:Emulsions; D005223:Fats; D009821:Oils; D010840:Phytosterols; D014867:Water
keywords: bioactive; crystallization; delivery systems; emulsion; functional foods; milk fat; phytosterols; plant sterols; synchrotron