AOAC SPIFAN Nutrients ERP-Final Review (Oct. 2018)

B handari et al . : J ournal of AOAC I nternational V ol . 101, N o . x , 2018  1

INFANT FORMULA AND ADULT NUTRITIONALS

Total Folate in Infant Formula and Adult Nutritionals by Trienzyme Extraction and LC-MS/MS Quantitation: AMultilaboratory Testing Study, Final Action 2011.06 S neh D. B handari , M ing G ao , and J ohn S zpylka Merieux NutriSciences, Silliker Food Science Center, 3600 Eagle Nest Dr, Crete, IL Collaborators: N. Collopy; H. Chen; M. Gao; R. Grahn; R. Juskelis; O. Lopez; I. Malaviole; R. McKenna; E. Oveland; K.M. Prabeesh; J. Stevens; J. Wang

Received April 10, 2018. Accepted by SG May 25, 2018. The method was approved by the AOAC Official Methods Board as Final Action. See “Standards News,” (2018) Inside Laboratory Management , May/June issue. The AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) invites method users to provide feedback on the Final Action methods. Feedback from method users will help verify that the methods are fit for purpose and is critical to gaining global recognition and acceptance of the methods. Comments can be sent directly to the corresponding author. Corresponding author’s e-mail: sneh.bhandari@mxns.com 11 MLT samples in blind duplicates. Results: The results were compared with the Standard Method Performance Requirements (SMPR 2011.006) established for folate. The precision results met the requirements stated in the SMPR for all of the samples. Repeatability and reproducibility relative standard deviations ranged from 3.5 to 6.6 and from 9.0 to 15.7%, respectively. Horwitz ratio values for all of the samples were well below 2 (0.61–1.06). Conclusions: The ERP determined that the method performance met the SMPR requirements in September 2017 after Background : The need for an updated reference method for folate was identified as a priority by the AOAC’s Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) in 2011. An Expert Review Panel (ERP) found AOAC Official Method  SM 2011.06 suitable for the purpose and approved it as a First Action Official Method . Objective : To determine the repeatability and reproducibility of Method 2011.06: Total Folate in Infant Formula and Adult Nutritionals by Trienzyme Extraction and LC-MS/MS Quantitation. Methods: A multilaboratory collaborative study was conducted. Eleven laboratories located in five countries participated and completed analysis of all multilaboratory testing (MLT) samples. The study was divided into two parts. In the first part, the laboratories analyzed two practice samples (blindly coded) using the updated folate Method 2011.06. The laboratories providing results within the expected range qualified for part two, in which they analyzed

reviewing the presented MLT data. Highlights: The ERP recommended the method for Final Action status. “F olate” is a generic term for the class of compounds having chemical and nutritional properties similar to pteroyl-L-glutamic acid (folic acid; 1). Folic acid is produced synthetically and is more stable than reduced natural folates, and it is often used in supplements and fortified foods (2). The most common naturally occurring folates found in foods are pteroylpolyglutamate forms of 5-methyltetrahydrofolic acid (5-CH3-THF), tetrahydrofolic acid (THF), and 5-formyltetrahydrofolic acid (5-CHO-THF). Of these, 5-CH3-THF is the predominant folate vitamer found naturally in foods (3). Folate is essential for all organisms and provides one-carbon groups for nucleotide biosynthesis, amino acid metabolism, and deoxyribonucleic acid (DNA) methylation (4). Folate plays a significant role in DNA synthesis during cell growth and development. Folate deficiency has been implicated in numerous negative health outcomes, including neural tube defects (NTDs) and other congenital defects, vascular diseases, neuropsychiatric disorders, and cancer (5). The observation that periconceptional folic acid supplementation reduces the risk of NTDs led to mandatory folic acid fortification of the North American food supply in 1998 (6, 7). Codex has established a lower limit of 10 μg/100 kcal and a guidance upper level of 50 μg/100 kcal in infant formulas (8). Current Codex type II methods for folate analysis in infant formula are microbiological assay-based methods, including AOAC Official Method SM 992.05 and EN 14131:2003. The microbiological methods have been found to be lengthy, laborious, and have poor precision (9–11). These methods are susceptible to interference from growth-affecting artifacts in sample extracts (12, 13) and are also compromised by variable vitamer response (9, 13). The bioavailability of natural food folate has been found to be less than that of synthetic folic acid (5, 14, 15). Research has indicated that relative bioavailability of natural food folate is approximately 60% compared with folic acid in food (5, 15). The difference in bioavailability of natural folates relative to synthetic folic acid consumed in diet can be described using the fol­ lowing equation: 1 μg Dietary Folate Equivalent (DFE) = 0.6 μg

DOI: https://doi.org/10.5740/jaoacint.18-0114