67C-26 |
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E. M. GUJSKA, Department of Food Science, University of Warmia and Mazury, Olsztyn, 10-957, Poland and A. Kuncewicz. The important role of folates in the possible prevention of neural-tube defect pregnancies and arteriosclerosis has been well recognized in the last decade. However, estimating dietary intake of folate is difficult due to the lack of dependable data on food folate contents. The objective of this study was to develop procedures applicable to determination of folate forms present in some cereals and cereals-grain products. Folates were extracted by homogenizing samples in buffer and heat treatment, followed by deconjugation of polyglutamates derivatives to their respective monoglutamate forms with rat serum conjugase and destruction of matrix by amylase and protease. Determination of naturally occurring reduced folates was achieved after clean-up by affinity chromatography using folate binding protein (FBP) bovine milk. The folates were separated by HPLC with a C18 column and with a combination of fluorescence (excitation at 290 and 360 nm, emission at 356 and 460 nm, respectively) and ultraviolet detection (absorption at 290 nm). Gradient elution was performed with acetonitrile and 33 mM phosphoric acid, pH=2.3, and a flow rate of 1.0 ml/min. 5-Formyltetrahydrofolate was the main derivative in all cereals studied, but 5-methyltetrahydrofolate and 10-formylfolic acid were also detected. The sum of the monitored folate derivatives (as µg folic acid) in cereals and commercial cereals-grain products ranged from 19.1 to 196 µg per 100 g dry wt. and from 5.8 to 339 µg per 100 g dry wt., respectively.
Session 67C, Food Chemistry: Food analysis, irradiation and toxicology
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