Yeast riboflavin

Biosynthetic Mechanism. Riboflavin is produced by many microorganisms, m( dtm. A.shhyagossjpii A.sperigiUus sp remothecium ashbyii Candida yeasts, Debaryomjces yeasts, Hansenu/a yeasts, Picbia yeasts, A. tobactor sp, Clostridium sp, and Bacillus sp. 

Riboflavin is also made by aerobic culturing of Pichiaguilliermondii on a medium containing n-Q g-Q paraffins in a yield of 280.5 mg/L (53). A process employing Pichia yeasts, such as P. miso, P. miso Mogi, or P. mogii, in a medium containing a hydrocarbon as the carbon source, has been patented... 

Flavin mononucleotide was first isolated from the yellow en2yme in yeast by Warburg and Christian in 1932 (4). The yellow en2yme was spHt into the protein and the yellow prosthetic group (coen2yme) by dialysis under acidic conditions. Flavin mononucleotide was isolated as its crystalline calcium salt and shown to be riboflavin-5Lphosphate its stmeture was confirmed by chemical synthesis by Kuhn and Rudy (94). It is commercially available as the monosodium salt dihydrate [6184-17 /, with a water solubiUty of more than 200 times that of riboflavin. It has wide appHcation in multivitamin and B-complex solutions, where it does not require the solubili2ers needed for riboflavin. 

Uses. Inactive dried yeasts are used as iagredients ia many formulated foods baby foods, soups, gravies, and meat extenders as carriers of spice and smoke flavors and ia baked goods. Yeasts used ia the health food iadustry are geaeraHy fortified with minerals and contain higher concentrations of the B vitamins, especially thiamin, riboflavin, and niacia (see Vitamins). 

Riboflavin was first isolated from whey in 1879 by Blyth, and the structure was determined by Kuhn and coworkers in 1933. For the structure determination, this group isolated 30 mg of pure riboflavin from the whites of about 10,000 eggs. The discovery of the actions of riboflavin in biological systems arose from the work of Otto Warburg in Germany and Hugo Theorell in Sweden, both of whom identified yellow substances bound to a yeast enzyme involved in the oxidation of pyridine nucleotides. Theorell showed that riboflavin 5 -phosphate was the source of the yellow color in this old yellow enzyme. By 1938, Warburg had identified FAD, the second common form of riboflavin, as the coenzyme in D-amino acid oxidase, another yellow protein. Riboflavin deficiencies are not at all common. Humans require only about 2 mg per day, and the vitamin is prevalent in many foods. This vitamin... 

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. 

Riboflavin E101 Orange yellow Yeast or nature identical... 

Riboflavin (E101). This is vitamin B2. Riboflavin can be extracted from yeast but is normally encountered as a nature identical substance. Unfortunately, riboflavin has an intensely bitter taste. The colour produced is an orange yellow. It is stable to acid but is unstable in water. Riboflavin is sometimes used for panned goods. 

Pantothenic acid and biotin were thus found to be growth factors for yeast. Like riboflavin these molecules are incorporated into larger molecules in order to exert their essential metabolic function. Unlike the other vitamins there has been no evidence of pathological signs in man which can be attributed to dietary deficiencies in biotin or pantothenic acid. 

In foods vitamin B2 occurs free or combined both as FAD and FMN and complexed with proteins. Riboflavin is widely distributed in foodstnffs, but there are very few rich sources. Only yeast and liver contain more than 2mg/100g. Other good sources are milk, the white of eggs, fish roe, kidney, and leafy vegetables. Since riboflavin is continuously excreted in the urine, deficiency is qnite common when dietary intake is insufficient. The symptoms of deficiency are cracked and red lips, inflammation of the lining of the month and tongue, mouth ulcers, cracks at the comer of the mouth, and sore throat. Overdose of oral intake present low toxicity, probably explained by the limited capacity of the intestinal absorption mechanism [417]. 

Riboflavin Nutritional factor found in milk, eggs, malted barley, Hver, kidney, heart, and leafy vegetables. The richest natural source is yeast. It occurs in the free form only in the retina of the eye, in whey, and in urine its principal forms in tissues and cells are as FMN and FAD. [nih]... 

Vitamin Bj (8.44, riboflavin) is a benzopteridine derivative carrying a ribityl (reduced ribose) side chain. It occurs in almost all foods, the largest amounts being found in eggs, meat, spinach, liver, yeast, and milk. Riboflavin is one of the major electron carriers as a component of flavine-adenine dinucleotide (FAD), which is involved in carbohydrate and fatty acid metabolism. A hydride ion and a proton are added to the pyrazine ring of... 

Vitamins are required for satisfactory development or function of most yeasts. Wickerham (177) devised a complete yeast medium which included eight vitamins biotin, pantothenic acid, inositol, niacin, p-aminobenzoic acid, pyridoxine, thiamine, and riboflavin. The concentrations of these growth factors varied widely with inositol in the greatest concentration and biotin in trace amounts. Many of these vitamins are considered major growth factors for yeast multiplication and development, as noted in several studies and reviews (178, 179, 180, 181, 182). Generally, the benefit of adding vitamins to musts and wines has not been established as a normal winery practice. This lack of response is because vitamins occur naturally in sufficient quantities in grapes and are produced by yeasts themselves (3). 

Yeast extract, liver extract, or cornmeal can be added to whey, thus achieving normal fermentation and avoiding addition of iron. The presence of these added solids (1%) in whey ensures normal fermentation and high yields of riboflavin. 

Riboflavin was found to be most responsible for the stimulation of rat growth, while vitamin B6 was needed to prevent a facial dermatitis or "rat pellagra." Pantothenic acid was especially effective in curing a chick dermatitis, while nicotinamide was required to cure human pellagra. Biotin was required for growth of yeast. 

Some metalloflavoproteins contain heme groups. The previously mentioned flavocytochrome b2 of yeast is a 230-kDa tetramer, one domain of which carries riboflavin phosphate and another heme. A flavocytochrome from the photosynthetic sulfur bacterium Chromatium (cytochrome c-552)279 is a complex of a 21-kDa cytochrome c and a 46-kDa flavoprotein containing 8a-(S-cysteinyl)-FAD. The 670-kDa sulfite reductase of E. coli has an a8P4 subunit structure. The eight a chains bind four molecules of FAD and four of riboflavin phosphate, while the P chains bind three or four molecules of siroheme (Fig. 16-6) and also contain Fe4S4 clusters.280 281 Many nitrate and some nitrite reductases are flavoproteins which also contain Mo or... 

L ses for lactose include Infant foods bacteriology hacking and confectionery margarine and butter manufacture manufacture of penicillin, yeast, edible protein, and riboflavin culture media adsorbent in chromatography and pharmacy... 

High riboflavin content (1000-10,000 micrograms/100 grams). Beef (kidneys, liver), calf (kidneys, liver), chicken (liver), pork (heart, kidneys, liver), sheep (kidneys, liver), yeast (killed)... 

Food yeast, molasses-grown, is dried to about 5% moisture and has the same chemical composition as bakers yeast. In terms of micrograms per gram of yeast, the vitamin content is 165 thiamine 100 riboflavin 590 niacin 20 pyridoxine 13 folacin 100 pantothenic acid 0.6 biotin 160 para-ainiiiobeuzoie acid 2710 choline and 3000 inositol. YeasL crude protein contains 80% amino acids 12% nucleic acids and 8% ammonia. The latter components lower the true protein content to 40% of the dry cell weight. 

Yeast protein is easily digested (87%) and provides amino acids essential to human nutrition. Most commercial yeasts show the following pattern of amino acids, among others, as percent of protein 8.2% lysine 5.5% valine 7.9% leucine 2.5% methionine 4.5% phenylalanine 1.2% tryptophan 1.6% cystine 4% histidine 5% tyrosine and 5% arginine. The usual therapeutic dose of dried yeast is 40 grams/day, which supplies significant daily needs of thiamine, riboflavin, niacin, pyridoxine, and general protein. 

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. 

The first organism employed primarily for riboflavin production was Clostridium aceto-butylicum, the anaerobic bacterium used for the microbial production of acetone and butanol. Riboflavin was purely a byproduct and was found in the dried stillage residues in amounts ranging from 40 to 70 xg/g of dried fermentation solids. Later investigations disclosed that riboflavin could be produced by yeast such as Candida flareri or C. guillier-mondi, and the yield was as high as 200 mg/L. 

Very good sources of riboflavin are milk and milk products other sources are beef muscle, liver, kidney, poultry, tomatoes, eggs, green vegetables, and yeast (Table 9-19). 

Yellow Riboflavin E101 Riboflavin Milk, yeast, normally... 

FAD is cleaved by an FAD-adenosine monophosphate (AMP) lyase in liver to yield AMP and riboflavin 4, 5 -cyclic phosphate it is not known whether this has any coenzyme or cell signaling function, but it is a substrate for phosphodiesterase and has also been identified in small amounts in yeast (Fraiz et al., 1998 Cabezas et al., 2001). 

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