Folic acid analysis

In terms of amino acids bacterial protein is similar to fish protein. The yeast s protein is almost identical to soya protein fungal protein is lower than yeast protein. In addition, SCP is deficient in amino acids with a sulphur bridge, such as cystine, cysteine and methionine. SCP as a food may require supplements of cysteine and methionine whereas they have high levels of lysine vitamins and other amino acids. The vitamins of microorganisms are primarily of the B type. Vitamin B12 occurs mostly hi bacteria, whereas algae are usually rich in vitamin A. The most common vitamins in SCP are thiamine, riboflavin, niacin, pyridoxine, pantothenic acid, choline, folic acid, inositol, biotin, B12 and P-aminobenzoic acid. Table 14.4 shows the essential amino acid analysis of SCP compared with several sources of protein. 

Akhtar et al. [20] have studied the identification of photoproducts of fohc acid and their degradation pathways in aqueous solution using preparative TLC. An aqueous solution of folic acid irradiated with UV at pH 2.4 to 10.0 for 6 h was subjected to TLC analysis, which gave separation of fohc add (Rj 0.67), p-woi-nobenzolyl-L-glutamic acid (Figure 10.12). The photolyzed solutions were... 

A concentration of 0.15 pg/ml gave a fluorescence of 10% full-scale deflection at maximum instrumental sensitivity. These authors explored analyzing folinic acid in the presence of folic acid and found that excitation at 290 nm effectively shifted the emission band of the compound of interest to 370 nm, thus enabling analysis of a mixture. 

Cobalamin, 25 803 folic acid and, 25 802 Cobalt (Co), 7 207-228. See also Co-base superalloys 60Co isotope 60Co nucleus Fe-Ni-Co alloys Dicobalt octacarbonyl Tetracobalt dodecacarbonyl analysis, 7 215-216 in ceramic-matrix composites, 5 554t coke formation on, 5 266 colloidal suspensions, 7 275 economic aspects, 7 214-215 effect on copper resistivity, 7 676t environmental concerns, 7 216 health and safety factors, 7 216-218 in M-type ferrites, 11 66, 69 occurrence, 7 208... 

Immunosensors have been developed commercially mostly for medical purposes but would appear to have considerable potential for food analysis. The Pharmacia company has developed an optical biosensor, which is a fully automated continuous-flow system which exploits the phenomenon of surface plasmon resonance (SPR) to detect and measure biomolecular interactions. The technique has been validated for determination of folic acid and biotin in fortified foods (Indyk, 2000 Bostrom and Lindeberg, 2000), and more recently for vitamin Bi2. This type of technique has great potential for application to a wide range of food additives but its advance will be linked to the availability of specific antibodies or other receptors for the various additives. It should be possible to analyse a whole range of additives by multi-channel continuous flow systems with further miniaturisation. 

Linear dependence of log k on the number of molecule units in homologs is observed to hold for a variety of substances, such as for oli-goalanines (20J) and oligo-y-glutamates of folic acid 204) depicted in Figs. 40 and 41, respectively. The analysis of such plots is complex because ol the pulai functions present in the molecules. Moreover, the effect of ionization must be considered. 

More recently [635], a unique extraction step in supplemented foods, by using hot water and a precipitation solution, following by HPLC-ELD/UV analysis has been performed for the simultaneous determination of pyridoxine, thiamine, riboflavin, niacin, pantothenic acid, folic acid, cyanoco-balamin, and ascorbic acid. The mobile phase consisting of phosphate buffer and methanol has been modified in order to perform ion-liquid chromatography by adding l-octanesulfonic acid sodium salt. Furthermore, triethylamine has been also added to improve peak symmetry. 

Tanner, J.T., Barnett, S.A., and Mountford, M.K. 1993. Analysis of milk based infant formula. Phase V. Vitamins A and E, folic acid, and pantothenic acid Food and Dairy Administration-Infant Formula Council Collaborative study. J. AOAC Int. 76 399-401. 

RJ Mullin, DS Duch. Folic acid. In AP De Leenheer, WE Lambert, HJ Nelis, eds. Modern Chromatographic Analysis of Vitamins. 2nd ed. New York Marcel Dekker, 1992, pp 261-283. 

LT Vahteristo, V Ollilainen, PE Koivistoinen, P Varo. Improvements in the analysis of reduced folate monoglutamates and folic acid in food by high-performance liquid chromatography. J Agric Food Chem 44 477-482, 1996. 

Far from the metal trace analysis, our initial studies with BCFMEs were focused on the determination of folic acid [122], In this case, the main goal was the optimisation of the electrode pretreatment for this analyte. An acidic medium (0.1M perchloric acid) was considered optimum for folic acid determination by differential pulse voltammetry. A linear range between 2.0 x HT8 and 1.0 x 10 6M with a detection limit of 1.0 x 10 8M was obtained. Nevertheless, in this work, the adsorptive properties of the folic acid on mercury were noted and the employment of mercury-coated carbon fibre UMEs for folic acid determination has been targeted as a future goal. 

Some of the structural properties which have been ascribed to DA receptors appear to deserve attention for their heuristic value, but painfully few should engender much confidence in their reality. A sobering lesson is available from analysis of complexes of dihydrofolate reductase (], 8). Methotrexate is a very close analog of folic acid and is a potent inhibitor of the enzyme, but it is now almost certain that these ligands bind in the enzyme active site in aspects differing by a rota-... 

Dietary supplementation with B vitamins is also highly effective in lowering homocysteine in most individuals with mild or moderate hyperhomocysteinemia. A meta-analysis of 12 randomized trials performed prior to folic acid fortification concluded that treatment with folic acid (0.5 to 5 mg daily) decreased homocysteine levels by 25%, and that the addition of... 

Brattstrom L, Landgren F, Israelsson B, et al. Lowering blood homocysteine with folic acid based supplements—meta-analysis of randomised trials. BMJ 316 894-898,1998. 

Homocysteine and cardiovascular disease evidence on causality from a meta-analysis. British Medical Journal 325 1202-1206 Wald DS, Law M, Morris JK (2004). The dose-response relationship between serum homocysteine and cardiovascular disease implications for treatment and screening. European Journal of Cardiovascular Prevention and Rehabilitation 11 250-253 Wang X, Qin X, Demirtas H et al. (2007). Efficacy of folic acid supplementation in stroke prevention a meta-analysis. Lancet 369 1876-1882... 

Homocysteine Lowering Trialists Collaboration (1998) Lowering blood homocysteine with folic acid based supplements meta-analysis of randomized trials. British Medical Journal 316, 894-8. 

The rapid technological progress in X-ray crystallography has enabled the structural analysis of numerous enzymes involved in coenzyme biosynthesis. Complete sets of structures that cover all enzymes of a given pathway are available in certain cases such as riboflavin, tetrahydrobiopterin, and folic acid biosynthesis. Stmctures of orthologs from different taxonomic groups have been reported in certain cases. X-ray structures of enzymes in complex with substrates, products, and analogs of substrates, products, or intermediates have been essential for the elucidation of the reaction mechanisms. Structures of some coenzyme biosynthesis enzymes have been obtained by NMR-structure analysis. 

In a meta-analysis of 307 patients with rheumatoid arthritis from seven randomized clinical trials, of whom 147 took folate supplementation, hematological adverse effects were not significantly reduced in the folate group (8). However, there was a 79% reduction in mucosal and gastrointestinal adverse effects in patients taking folic acid and a non-significant trend toward a reduction (42%) in patients taking folinic acid. Disease activity was not modified by low doses of folate. Finally, the authors noted that folinic acid is more expensive. 

Folates are generally present in low concentration in foods thus, any method of analysis requires isolation and sensitive detection (Vahteristo et. al., 1996). The method described here uses extraction of the folic acid (Fig. 9.13) with rapid microwave heating and enzymatic deconjugation with hog-kidney con-jugase and chicken pancreatic enzymes. The extracts are purified with strong anion-exchange SPE. The final analysis is with HPLC. 

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