18C-23 |
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L. CHEN1, L. Ye1, J. Lee2, and R. R. Eitenmiller1. (1) Dept. of Food Science & Technology, Univ. of Georgia, Food Science Bldg, Athens, GA 30602-7610, (2) Department of Food Science and Technology, Chungbuk National University, 48 Gaeshin-dong, Heungduk-gu, Cheong-ju, 361-763, South Korea Microbiological assay using microplate techniques in combination with trienzyme digestion with PronaseR, α-amylase and conjugase (γ-glutamyl hydrolase) is commonly applied to the measurement of total folate in foods. This research provides method performance evaluations for the assay. To determine method performance parameters for a microplate assay for total folate in food using a trienzyme extraction.Total folate was assayed by extraction by the trienzyme method and quantification with Lactobacillus casei (ssp rhamnosus) (AOAC Method 2004.05). All assays were completed with microplate techniques. Method performance studies included determination of accuracy (trueness, repeatability and intermediate precision), limit of detection (LOD) and limit of quantification (LOQ). Accuracy studies were completed on Standard Reference Material (SRM) 1546 (meat homogenate), SRM 2383 (baby food composite), SRM 1846 (infant formula), Certified Reference Material (CRM) 121 (wholemeal flour) and CRM 485 (mixed vegetables), covering a broad selection of food matrices. Trueness expressed as bias (% error) ranged from 96% for CRM 121 to 113% for SRM 1546. Mean values for each SRM and CRM were within accepted or reported ranges. Repeatability and intermediate precision values for the standard reference materials expressed as % relative standard deviation (RSD) ranged 3.6 to 10.2 and 4.7 to 13.8, respectively. LOD and LOQ values were 0.2 and 0.5 μg/100g, respectively. Method performance evaluation shows that the combination of microplate techniques with the accepted trienzyme extraction for the microbiological assay of total folate provides a highly accurate, reproducible and sensitive method for assay of folate from food matrices.
Session 18C, Food Chemistry: Food composition, analysis and volatiles
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |