title: Investigation of caking by fat bridging in aged infant formula.
abstract: Three commercial infant formulas (denoted as P1, P2 and P3) were stored at 25, 45 and 60°C for up to 6weeks to study the caking phenomenon caused by fat bridging. At 60°C, both the surface free-fat content and the caking strength increased significantly. Analysis of the fatty acid composition of P1 showed that high-melting-point fatty acids were present on powder surface whereas low-melting-point fatty acids remained within powder particles. There was no preferential migration or retention of specific fatty acids in P2. The stearic acid content in the surface free-fat of P3 increased, largely due to a concentration gradient which contributed to the increased caking strength. The melting characteristics of surface free-fat analyzed by DSC were consistent with their fatty acid compositions analyzed by GC-MS/FID. Confocal laser scanning microscopy (CLSM) showed higher occurrence of large fat globules after 6weeks' storage.
authors.affiliation: Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Tammie Wei Yi
authors.initials: TWY
authors.lastname: Tham
authors.affiliation: Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Xu
authors.initials: X
authors.lastname: Xu
authors.affiliation: Wyeth Nutritionals (S) Pte Ltd, 1 Tuas South Avenue 4, Singapore 637609, Singapore.
authors.forename: Andrew Ti Heong
authors.initials: ATH
authors.lastname: Yeoh
authors.affiliation: Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore. Electronic address: chmzwb@nus.edu.sg.
authors.forename: Weibiao
authors.initials: W
authors.lastname: Zhou
mesh_terms: D004041:Dietary Fats / Q000032:analysis*; D005227:Fatty Acids / Q000737:chemistry*; D005511:Food Handling; D061353:Food Storage; D006358:Hot Temperature; D041943:Infant Formula / Q000737:chemistry*; D011208:Powders / Q000737:chemistry
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D011208:Powders
keywords: CLSM; Caking strength; DSC; Fatty acid composition; GC–MS/FID; Infant formula; Surface free-fat