Vitamin concentrations

The infrared technique has been described in numerous publications and recent reviews were published by Davies and Giangiacomo (2000), Ismail et al. (1997) and Wetzel (1998). Very few applications have been described for analysis of additives in food products. One interesting application is for controlling vitamin concentrations in vitamin premixes used for fortification of food products by attenuated total reflectance (ATR) accessory with Fourier transform infrared (FTIR) (Wojciechowski et al., 1998). Four vitamins were analysed - Bi (thiamin), B2 (riboflavin), B6 (vitamin B6 compounds) and Niacin (nicotinic acid) - in about 10 minutes. The partial least squares technique was used for calibration of the equipment. The precision of measurements was in the range 4-8%, similar to those obtained for the four vitamins by the reference HPLC method. 

At all study days, subjects had venous blood samples taken after fasting for at least 12 h. Afterwards, the vitamins were administered. On day 0, the subjects were instructed to suck the jelly baby slowly and keep it in the mouth as long as possible in order to achieve a more or less constant salivary vitamin concentration. On days 10 and 20, the jelly baby or supplement, respectively, was swallowed with some water. Further venous blood samples were taken 1, 5, 15, 30, 60, 180, 240, 300, and 320 min after ingesting the vitamins. 

In summary, our bioavailability study provided for fhe firsf time data for fhe shorf-ferm bioavailability of ot-tocopherol solubilizate in comparison to regular fat-soluble preparations. Our results pointed to a higher short-term bioavailability of vitamin E in micelles versus fat-soluble forms of fhis vifamin in healthy adult volunteers both with regard to AUCs and with regard to maximum increases in plasma vitamin concentrations. 

Three types of inline HPLC detector have been used to measure fat-soluble vitamin concentrations in food sample extracts absorbance, fluorescence, and electrochemical detectors. Each of these detectors provides a continuous electrical output that is a function of the concentration of solute in the column effluent passing through the flow cell. 

EJ de Vries, J Zeeman, RJE Esser, B Borsje, FJ Mulder. Analysis of fat-soluble vitamins. XXI. High pressure liquid chromatographic assay methods for vitamin D in vitamin concentrates. J Assoc Off Anal Chem 62 129-135, 1979. 

The desugaring of cane juice concentrates the heat- and alkali-stable vitamins in the final molasses. Even after this accumulation, only myo-inositol may have reached the level of minimum dietary requirements.109 Niacin, pantothenic acid and riboflavin are also present in significant quantities109 the thiamine, pyridoxin, pantothenic acid, biotin and folic acid contents of molasses have been estimated by bioassay.110 111 The biotin content of Hawaiian and Cuban molasses was 2.1 and 1.7 gammas per gram, respectively.119 The antistiffness factor (closely related to stigmasterol) has been found in cane molasses.88 89 The distillery slop from the yeast fermentation of molasses is marketed as a vitamin concentrate this product also contains vitamins originating in the yeast. 

Alterations in plasma vitamin concentrations have been observed in oral contraceptive users, and attributed to reduced absorption and changes in plasma protein-binding capacity (177). 

While most vitamin concentrations in the blood fall (173), vitamin A concentrations increase, although carotene concentrations fall. Curiously, an isolated report of hyper-carotenemia has been published (178). 

Hiller GW, Clark DS, Blanch HW (1994), Transient response of hybridoma cells in continuous culture to step changes in amino acid and vitamin concentrations, Biotechnol. Bioeng. 44 303-321. 

Naurath, H. J., Joosten, E., Riezler, R.,Stabler, S. P., Allen, K. ii.,and Lindenbaum, J. (1995). Effects of vitamin Bu, folate, and vitamin Bt, supplements in elderly people with normal serum vitamin concentrations. Lantet 346, 85-89. 

Oleovitamins Preparations using fish liver oil, fish liver oil diluted with an edible vegetable oil, or a solution of vitamin concentrate in fish liver oil or in an edible vegetable oil. Oleovitamins were created during World War II to fill a therapeutic gap created by the interruption in cod liver oil supplies. The class became official in the second supplement to the United States Pharmacopeia XI (1942) as a source of vitamins A and... 

Increased tHcy combined with low vitamin concentrations should be handled as a potential vitamin deficiency. Other causes of increased tHcy should be considered. 

Baeckert PA, Greene HL, Fritz I, Oelberg DG, Adcock EW. Vitamin concentrations in very low birth weight... 

Louw JA, Werbeck A, Louw ME, Kotze TJ, Cooper R, Labadarios D. Blood vitamin concentrations during the acute-phase response. Crit Care Med 1992 20 934-41. 

Figure 2 Anaerobic acidogenic fermentation of sediment mud suspension without vitamin addition (a) and with vitamin addition (b). The vitamin concentration added to the suspension was 1 mg/L of thiamine, I mg/L of nicotinic acid and 10 gg/L-of biotin. . 200 g sediment mud/L artificial sea water , 400 g sediment mud/L artificial sea water.

Vitamin G (Riboflavin) Booher84 employed adsorbents to prepare a vitamin G concentrate from whey. In one procedure, the vitamin in the whey is adsorbed on fullers earth at low temperature and then eluted with hot water. The vitamin in the eluate from the fullers earth is further concentrated by adsorption on activated carbon from which it is subsequently desorbed with an ethanol-benzene mixture, the latter being separated from the vitamin concentrate by evaporation. 

A. Specific levels. Serum vitamin A (retinol) or carotenoid assays may assist in the diagnosis of hypervitaminosis A. Levels of 25-hydroxy vitamin D are useful in assessing excessive intake. Other serum vitamin concentration measurements are not useful. 

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