Collaborative study: Quantification of total folate in food using an efficient single-enzyme extraction combined with LC-MS/MS. (15th December 2020)

• Record Type: Journal Article
• Authors: Ložnjak Švarc, Petra; Oveland, Eystein; Strandler, Hanna Sara; Kariluoto, Susanna; Campos-Giménez, Esther; Ivarsen, Elise; Malaviole, Isabelle; Motta, Carla; Rychlik, Michael; Striegel, Lisa; Jakobsen, Jette
• Is Part Of: Food chemistry. Volume 333(2020)
• Publication Date: 2020-12-15
• Subjects: Tetrahydrofolate (PubChem CID: 135444742) -- 5, 10-Methenyltetrahydrofolate (PubChem CID: 135398657) -- 10-Formylfolic acid (PubChem CID: 135405023) -- 5-Formyltetrahydrofolate (PubChem CID: 135402009) -- 5-Methyltetrahydrofolate (PubChem CID: 135415868) -- Folic acid (PubChem CID: 135398658); Tetrahydrofolates -- Inter-laboratory study -- Deconjugase -- Plant enzyme -- Homogenization; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2020.127447
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Specific LC-MS/MS method for folate analysis in food is inter-laboratory validated. Total folate results acceptable in six tested food samples; for salmon unacceptable. HorRat values for total folate and 5-CH3 -H4 folate were within the acceptable range. Acceptability of HorRat values for other studied vitamers depends on food matrix. For total folate: repeatability at 2.3%–15% and reproducibility at 8.7%–58% Abstract: Quantification of the specific folate vitamers to estimate total folate in foods is not standardized. A collaborative study, including eight European laboratories, was conducted in order to determine the repeatability and reproducibility of the method for folate quantification in foods using the plant-origin γ-glutamyl hydrolase as part of the extraction procedure. The seven food samples analyzed represent the food groups; fruits, vegetables, dairy products, legumes, offal, fish, and fortified infant formula. The homogenization step was included, and six folate vitamers were analyzed using LC-MS/MS. Total folate content, expressed as folic acid equivalent, was 17–490 μg/100 g in all samples. Horwitz ratio values were within the acceptable range (0.60–1.94), except for fish. The results for fortified infant formula, a certified reference material (NIST 1869), confirmed the trueness of the method. The collaborative study is part of a standardization project within the Nordic Committee on Food Analysis (NMKL).