| Authors
Mac Thi Thanh Hoa, Nguyen Quang Hung, Nguyen Pham Thanh Chung, Vuong Quynh Hoa, Le Hong Luyen, Cao Cong Khanh |
Abstract
Difucosyllactose (DFL) is a type of human milk oligosaccharide (HMOs) that is added to infant formula to support gut health, immune development, and the establishment of a beneficial gut microbiota in infants. In this study, LC-MS/MS techniques were used to determine the DFL content in infant formula. The powdered milk samples were reconstituted with water, incubated with 10 U/mL of amyloglucosidase enzyme for 30 minutes, and then the protein was precipitated with 50% acetonitrile. A Waters ACQUITY UPLC BEH Amide chromatographic column (150 mm × 2.1 mm, 1.7 μm) was used and maintained at 55 °C during analysis, with the mobile phase consisting of 10 mM ammonium formate and acetonitrile (ACN) in a gradient program. The samples were detected using a mass spectrometer with negative electrospray ionization mode and multi-reaction monitoring (MRM) using the ion transition m/z 633.5 → 325.58 and m/z 633.5 → 247.2 for quantification and qualification, respectively. The method was validated according to AOAC and SMPR® 2021.006 guidelines. The results showed good specificity, with a linear range of 1-20 μg/mL. The detection and quantification limits of the method were 4.80 - 5.12 μg/g and 11.2 - 17.1 μg/g, respectively. The method was then applied to analyze the DFL content in 24 samples of commercial infant formula purchased in Hanoi. The results showed that the DFL content in the samples ranged from 15.6-214 mg/100g, with significant differences observed between age groups and product types.
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