Food analysis riboflavin

MSFIA chromatographic analysis was also applied to food analysis (Fernandez et ak, 2012), including orange juice, strawberry milkshake, and malt, for simultaneous determination of six water-soluble vitamins (thiamine, riboflavin, ascorbic acid, nicotinic... 

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. 

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. 

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. 

From an analytical perspective, the single most important physicochemical characteristic of riboflavin is its photosensitivity (80-82). Exposure of this vitamin to ultraviolet and visible light results in irreversible photoreduction to lumiflavin and lumichrome and loss of vitamin activity. In addition, the coenzymes are subject to hydrolysis by endogenous phosphatases that are present in a number of foods. Since these enzymes are generally inactivated by thermal processing, they are a concern only in the analysis of fresh products. 

The potential of PBI LC-MS in the analysis of various vitamins was explored by Careri et al. [99-100]. The fat-soluble vitamins A, D, and E were analysed in food and multivitamin preparations [99]. Absolute detection limits in SIM mode were 0.6-25 ng after fast leversed-phase separation using a 97% aqueous methanol as mobile phase. Mass spectra in El, positive-ion and negative-ion Cl were obtained and discussed. The mass-spectral and quantitative performance of PBI LC-MS in the analysis of eleven water-soluble vitamins was also explored [100]. Detection limits were determined in SIM mode under positive-ion Cl, and were below 15 ng for ascorbic acid, nicotinamide, nicotinic acid, and pyridoxal, around 100 ng for dehydroascorbic acid, panthothenic acid, and thiamine, and above 200 ng for biotin, pyridoxamime, and pyridoxine. Riboflavine was not detected. 

Vitamin B2 Food contains three B2 vitamers, riboflavin and its two coenzyme forms, flavin mononucleotide and flavin adenine dinucleotide, which are the predominant vitamers in foods and are usually bound to proteins. Their analysis usually takes place after extraction with dilute mineral acids with or without enzymatic hydrolysis of the coenzymes (which is necessary to convert all forms to riboflavin and to quantify them as total riboflavin). The extracts may be purified using SPE with Cig cartridges. All the operations performed prior to analysis need to be done under subdued lighting to avoid decomposition of riboflavin upon exposure to light. RP chromatography with Cig columns is used along with fluorescence detection (excitation, 440 nm emission, 520 nm). 

Blind samples of homogenized beef baby food were provided to three laboratories for analysis. Results from the three labs agreed well for protein, fat, zinc, riboflavin, and palmitic acid. Results for iron were questionable Lab A ... 

To ascertain whether dietary food records were inaccurate because of associated mild cognitive deficits, blood levels of these nutrients were measured. Scores on the Halstead-Reitan Category Test were worse in subjects with lower blood levels of ascorbate, riboflavin, Bj2, and folate, while those on the Wexler Memory Test were correlated with ascorbate and Bj2 levels. These findings do not appear to be explained by age variation within the group, since there was no overall correlation between any nutritional variable and age per se. To correct for any effects of educational status and income level, analysis of covariance was performed it did not alter the degree or the statistical significance of the associations between performance on the cognitive tests and blood levels of the vitamins. 

Fluorimetry is the standard technique for riboflavin analysis in food. 

Vinas, P., Balsalobre, N., Lopez-Erroz, C., and Elernandez-Cordoba, M., 2004a. Liquid chromatographic analysis of riboflavin vitamers in foods using fluorescence detection. Journal of Agricultural and Food Chemistry. 52 1789-1794. 

Tang, X., Cronin, D.A., and Brunton, N.P., 2006. A simplified approach to the determination of thiamine and riboflavin in meats using reverse phase HPLC. Journal of Food Composition and Analysis. 19 831-837. 

Ollilainen, V., Mattila, P., Varo, P., Koivistoinen, P., and Huttunen, J., 1990. The HPLC determination of total riboflavin in foods. Journal of Micronutrient Analysis. 8 199-207. 

Table 3.28 shows that the composition of hydroperoxide isomers derived from an unsaturated acid by autoxidation ( 02) differs from that obtained in the reaction with 02- The isomers can be separated by analysis of hydroperoxides using high performance liquid chromatography and, thus, one can distinguish Type I from Type II photooxidation. Such studies have revealed that sensitizers, such as chlorophylls a and b, pheophytins a and b and riboflavin, present in food, promote the Type II oxidation of oleic and linoleic acids. 

P Wimalasiri, RBH Wills. Simultaneous analysis of thiamin and riboflavin in foods by high-performance liquid chromatography. J Chromatogr 318 412-416, 1985. 

C Hassehnann, D Franck, P Grimm, PA Diop, C Soules. High-performance hquid chromatography analysis of thiamin and riboflavin in dietetic foods. J Micronutr Anal 5 269-279, 1989. 

Riboflavin (vitamin B2) also acts as a cofactor and is a precursor for the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These coenzymes are used in metabolism and catalyze numerous oxidation—reduction reactions. Among the good dietary sources for riboflavin, most animal-derived products, milk and dairy products, are pointed out. Foods are usually pretreated before analysis of riboflavin following similar procedures to those described for vitamin Bi. Similarly, fluorescence detection is mostly employed (370 nm ex., 520 ran em.) after RP separation. 

Vidal-Valverde C, Reche A. Reliable system for the analysis of riboflavin in foods by high performance liquid chromatography and UV detection. J Liq Chromatogr 1990 13(10) 2089-101. 

Stancher B, Zonta F. High performance liquid chromatographic analysis of riboflavin (vitamin B2) with visible absorbance detection in Italian cheeses. J Food Sci 1986 51(3) 857-8. 

Einglas, P. and Paulks, R., The HPLC analysis of thiamin and riboflavin in potatoes. Food... 

Kamman, J., Labuza, T., and Warthesen, J., Thiamin and riboflavin analysis by high-performance liquid chromatography, J. Food Sci., 45, 1499-1504, 1980. 

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