Naturally occurring folates in selected traditionally prepared foods in Southern India

Abstract

A wide range of Indian foods (cereals, pulses, vegetables and milk based preparations) were analysed for five folate vitamers naturally present in the foods (n = 44). A liquid chromatography-mass spectrometry (LC-MS/MS) method using reversed phase chromatography and tandem mass spectrometry, coupled via positive mode electrospray ionization was used for the detection and quantification of the vitamers. The optimized LC-MS/MS method was capable of analysing the five most commonly-occurring folates (folic acid, 5-methyl tetrahydrofolic acid, tetrahydrofolic acid, 10-formyl folic acid and 5-formyl tetrahydrofolic acid) in 20 min. Quantification of folates was performed using C labelled internal standards. 5-methyl tetrahydrofolate was predominant in cereals, pulses and vegetable preparations. Fermented cereal preparations, beverages (coffee and tea) and green leafy vegetables were the main sources contributing to 5-formyl THF. Folic acid was identified in home-made yoghurt. All the values obtained in the present study using LC-MS/MS were compared to the total folate analysed using the microbiological assay in 2010 to generate data on the same foods. Findings suggest that the data obtained using both techniques showed agreement in the values (total folate calculated by adding the individual vitamers in the case of the LC-MS/MS values) particularly when foods were predominant in 5 methyl tetrahydrofolate.

Identification of the prepared foods promising for dietary folate intake in Beijing, China

“…5‐M‐THF was the dominant folate derivative in almost all the vegetables, accounting for up to 40.9%–95.3% of the total folates, followed by 5‐F‐THF and 10‐F‐FA. This result was consistent with the previous report, in which 5‐M‐THF was also found as the main folate derivative in vegetables (Vishnumohan et al., 2017). Notably, peanut had similar amount of 5‐F‐THF and 5‐M‐THF (15.64 ± 1.99 µg/100 g vs. 13.0 ± 1.53 µg/100 g).…”

The use of a plant enzyme for rapid and sensitive analysis of naturally-occurring folates in food by liquid chromatography-tandem mass spectrometry

“…Furthermore, it is not possible to distinguish between the folate forms present in food samples which is necessary due to the presumed different bioavailability of various folate forms [24,25]. Chemical assays have been introduced using chromatographic techniques combined with different detectors such as; ultra-violet (UV), diode array (PDA) and fluorescence [26][27][28], electrochemical [29,30], mass spectrometry or tandem mass spectrometry [31][32][33][34]. These methods are able to quantify each of the folate forms separately.…”

“…Rychlik et al [51] investigated deconjugase activity which was 42% when using rat serum, and 96% when using rat serum combined with chicken pancreas. Various use of deconjugases such as: rat plasma [33] or human plasma [21,34], possibility of tri-enzyme treatment or analysis without any enzyme [52], resulted in discrepancies between total folate content results. Czarnowska-Kujawska et al [53] compared rat plasma and porcine kidney deconjugases on the same samples (strawberries, blackcurrant and green peas), where the use of rat plasma resulted in significantly higher folate content.…”

Kinetic modeling of four folates in a model solution at different temperatures and pH to mimic their behavior in foods during processing

“…These different structures are associated with different biological properties which is important for nutritional considerations. As a consequence, individualization of their content in food is important (Vishnumohan et al, 2017). The most common, by order of occurrence in foods, are 5‐methyl tetrahydrofolic acid (5MTHF) (R 1 = CH 3 ; R 2 = H; R 3 = H), 5‐formyl tetrahydrofolic acid (5FTHF) (R 1 = CHO, R 2 = H, R 3 = H), tetrahydrofolic acid (THF) (R 1 = H; R 2 = H; R 3 = H), 10‐formyl folic acid (10FFA) (R 1 = N 5 ; R 2 = CHO; R 3 = N 8 ), and 5‐formyl tetrahydrofolic acid (5FTHF) (R 1 = CHO; R 2 = H; R 3 = H) (Figure 1), (Czarnowska‐Kujawska et al, 2020; Vishnumohan et al, 2017).…”