Riboflavin Content Research Articles

Differential riboflavin deposition in white and variegated white mutants of Drosophila hydei.

Riboflavin deposition in organs of Drosophila hydei was studied by means of a growth test using a riboflavin-deficient strain of the fungus Aspergillus nidulans. In wild-type animals, riboflavin is deposited in Malpighian tubules (MT) and testes but not in adult eyes. Certain white (w) mutants do not contain riboflavin, whereas intermediately colored w mutants contain minor amounts of the substance. Riboflavin-containing MT cells contain special globules that can be fixed and stained with the redox dye phenazine-methosulphate. The number and size of these granules is related to growth effect and point to a role of the w locus in the intracellular deposition of riboflavin in special organs. In white-mottled (wm) position-effect variegation mutants, a significant correlation was found between the extent of variegation (percentage of yellow cells) and riboflavin content (growth effect) of the MT. However, the individual variation of cell phenotype was extremely large and exaggerated types were observed indicating "overdominance" of the rearranged w+ gene. This contradicts an unsubstantiated dogma of position-effect variegation that assumes that the affected gene simply switches between the on and off state, as is discussed.

ASCORBIC ACID AND RIBOFLAVIN CONTENT OF ASPARAGUS DURING MARKETING

ABSTRACTCalifornia‐grown asparagus purchased from wholesale markets and retail stores in the greater New York area 6 to 9 days after harvest, and California asparagus purchased at retail stores in the greater New York area then stored 3 days at 5.5 °C and 90–95% relative humidity to simulate consumer holding were analyzed for total ascorbic acid (AA), L‐ascorbic acid, dehydroascorbic acid (DHAA) and riboflavin content. Asparagus from wholesale markets, retail stores and storage averaged 15, 10, and 9mg AA/100g freshweight, respectively. The average was 77% less than reported in freshly harvested California asparagus. Samples of asparagus from wholesale markets contained significantly more AA than were found in retail or stored samples. Riboflavin content in asparagus from wholesale, retail and storage levels were .030, .029, and .033 mg/100g freshweight, respectively. These values were not statistically different, and were on the average 79% less than those reported for fresh California asparagus. DHAA ranged from 1.5 mg/100g freshweight in asparagus purchased from wholesale markets to 3.0 mg/100g freshweight in stored asparagus. Sixteen percent of the total AA in samples of wholesale, retail and stored asparagus was oxidized to DHAA. Thus it is questionable whether or not L‐ascorbic acid is a good indication of the total vitamin C in asparagus purchased at terminal markets.

High Performance Liquid Chromatographic Analysis of Riboflavin (Vitamin B2) with Visible Absorbance Detection in Italian Cheeses

ABSTRACTA high‐performance liquid chromatographic method for riboflavin determination in cheese samples was developed. Reverse phase conditions were used, i.e., a C‐18 column isocratically eluted with an acetonitrile water mixture (20:80). A shift of the detection wavelength from 267 to 446 nm was proposed as a simple and very effective means for circumventing the problem of incomplete resolution of riboflavin from interfacing peaks. The detection limit of riboflavin was 2.5 ng, a value well above the level required for determining the riboflavin content in cheese samples. From both high‐ and low‐fat cheese, the riboflavin recovery was the same (90.2%). The riboflavin content of several different Italian cheeses was determined.

Nonhaem complexes of FeIII stimulate cell attachment and growth by a mechanism different from that of serum, 2‐oxocarboxylates, and haemproteins

Most cell lines, even those producing their own growth factors, need a serum supplement when growing in several commonly used media. The requirement for serum to sustain attachment and growth in RPMI 1640 and MEM has been found to be met by a range of 2-oxocarboxylates, by diverse coordination complexes of FeIII, and by a variety of haem-containing proteins including catalase. The latter directly implicates H2O2 in the serum shift-down effects. H2O2 was found to accumulate in low serum media under normal laboratory lighting conditions to levels that were shown to be sufficient, when added to freshly prepared media, to explain the depressed cell performance. With the exception of some of the nonhaem FeIII coordination complexes, substances found to stimulate cell attachment and growth were capable of scavenging H2O2. This suggests that an important function of serum and the 2-oxocarboxylates (alpha-keto acids) frequently used as "nonessential" medium additives is to remove H2O2 produced photodynamically during the storage and manipulation of media containing a high content of riboflavin. However, the nonhaem FeIII complexes with saturated coordination shells, although capable of reducing photodynamic generation of H2O2 to a greater or lesser extent, have their prime effect by an unknown, intriguing mechanism, probably based on a common redox function.

ヒラメの白化とリボフラビン含量との相関について

To elucidate the relationship between riboflavin content and body color (melanin content), albinic juvenile flounder Paralicthys olivaceus were examined for riboflavin in the skin and muscle. In the normal juvenile fluounder, the riboflavin content reached 1, 200μg/100g in the black skin of the ocular side. The values obtained from the albinic individuals were less than one tenth of that of the normal ones; the more the degree of albinism, the smaller the amount of riboflavin. There was little difference between the albinic and the normal individuals as for riboflavin content in the blind side. The riboflavin content in the muscle of the normal individuals was roughly proportional to that in the skin and was higher in the ocular side than in the blind side. In piebald individuals the riboflavin content of the skin was remarkably higher in the black part than in the white part. It was confirmed by paper chromatography that all of the riboflavin in the skin of both the norrnal and the albinic individuals existed as free type. From the above results, it seems that there is a close relationship between riboflavin con-tent and body color (melanin content). As riboflavin is a photosensitive substance, melanin formation should be accelerated by its photosensitive action under the sun light.

Effect of fermentation on the thiamin, riboflavin and niacin contents of melon seed ( Citrullus vulgaris) and African oil bean seed ( Pentaclethra macrophylla)

An automated thiochrome method and high performance liquid chromatography (HPLC) with fluorescence detection were used to determine thiamin and riboflavin, respectively, in unfermented, and fermented melon seeds ( Citrullus vulgaris) and African oil bean seeds ( Pentaclethra macrophylla). Niacin was determined microbiologically. In all the methods used, fermentation significantly increased the content of thiamin, riboflavin and niacin in African oil bean seeds and thiamin and riboflavin in melon seeds. There was no change in the niacin content of melon seeds.

Display practices and changes in riboflavin content of non-fermenting palm juice

Changes in riboflavin content of industrially bottled palm juice stored at different light intensities similar to display patterns practised by traders was studied. The loss of riboflavin in the first 24 hours was significantly higher than in the second 24 hours in both transparent (P<0.001) and green bottles (P<0.02) exposed to bright sunlight. Riboflavin loss from samples stored in transparent bottles occurred at a faster rate (24–71% of initial) than from samples in green bottles (0–29%) over a 36-hour period. Further loss of riboflavin did not occur over the next 36 hours due to cool weather conditions. In contrast, only 6% of initial riboflavin was lost after 72 hours of continuous exposure to fluorescent light: this increased by 53% by the ninth week. The data showed that riboflavin loss from bottled palm juice varied with the container, the environmental conditions and period of storage. It is recommended that palm juice should be displayed in dark bottles and protected from bright light.

Photodegradation of Sulfa Drugs by Fluorescent Light

Thin layer chromatographic and liquid chromatographic procedures were used to show that sulfonamides containing a heterocyclic amine moiety and free N1 acidic hydrogen will photodegrade under fluorescent light in model systems containing riboflavin. The photodegradation product was characteristic of the drug. In-depth studies on sulfamethazine showed that the drug also photodegraded in the presence of lumichrome and flavin mononucleotide; the rate of photodegradation depended on the photosensitizer and its concentration. Crude polar liver extracts sensitized the photodegradation of sulfamethazine, but to a degree less than expected on the basis of reported riboflavin content of livers. It is recommended that procedures for quantitating sulfa drugs and their metabolites be performed in subdued lighting and/or that amber or low actinic vessels be used to prevent losses due to photochemical reactions.

Aging changes of riboflavin concentration and glutathione reductase activity in erythrocytes

Aged erythrocytes obtained by fractionation using gradient centrifugation with Dextran 40, showed lower glutathione reductase activity and riboflavin content than young cells. However, both young and old cells displayed almost the same increase in enzyme activity upon addition of flavin adenine dinucleotide to the test hemolysate in vitro. The lipid peroxide content in the cell membranes showed no consistent changes with aging.

Nutritive value ofzostera marinaand cardon (pachycereus pringlei)as consumed by the Seri Indians in Sonora Mexico

The grain of eelgrass (Zostera marina) consumed by Sen Indians of Sonora Mexico is the only known case of a sea grain used as human food. Z. marina was combined with the seed of Cardon (Pachycereus pringlei), a columnar cactus of the Sonoran Desert. Protein quality was determined by the NPR and RNU methods. The NPR results showed significant differences (p<0.05) between raw and toasted Z. marina that could be related to the lysine lost in the toasting process. P. Pringlei, as well as the blend, showed lower values (p<0.05) than the grain of Z. marina, possibly due to high fiber content or the presence of antinutritional factors. Additionally, the iron and riboflavin content seem to be considerable.

The influence of milling on the nutritive value of flour from cereal grains. 7. Vitamins and tryptophan

Rye, wheat, barley, rice, maize and sorghum were milled into more or less refined fractions, and the content of thiamin, riboflavin, vitamin B6, folate, biotin, niacin and tryptophan were determined. Differences in vitamin content between the different cereal grains were rather small. Refining resulted in marked losses of all vitamins studied. On average, 70%–80% of the vitamins were lost during the milling process. The lowest vitamin content was found in highly refined rice, containing only about 5% of the folate and 10% of the niacin present in brown rice. Maize had a low content of tryptophan, and the concentration was greatly reduced by degerming. For the other cereal grains, milling had only a slight effect on tryptophan concentrations.

Comparison of Top Round Steaks Cooked by Microwave-Convection, Forced-Air Convection and Conventional Ovens

AbstractThis study compared microwave-convection, forced-air convection and conventional electric ovens as to time and energy requirements, uniformity of cooking, and effect on cooking losses, sensory characteristics, moisture, fat, thiamin and riboflavin content of top round beef steaks. Sensory evaluation indicated no significant difference in juiciness; tenderness, including number of chews; intensity of beef flavor; and external color of the steaks cooked by the three ovens. Also, moisture, fat, thiamin and riboflavin content of the meat did not differ among treatments. Total cooking losses and percentage evaporation were greater (P<0.05) for steaks cooked in the microwave-convection oven than for those cooked by the other two methods. Drip losses were greater (P<0.05) with the microwave-convection than with the forced-air convection method of cooking top round beef steaks. The least total cooking time was required for the microwave-convection oven and the most for the forced-air convection oven. On a...

Effect of irradiation and germination on selected nutrients of corn

The effect of germination on potential nutrients (mineral matter, protein, lipids, fibre, carbohydrates and total energy) and an antinutrient (phytate) of corn, was studied. The influence of irradiation (5–20 krad) and germination on the vitamin contents (ascorbic acid, riboflavin) was also investigated. Comparison of the coefficients of variability revealed striking differences in the contents of these nutrients as a result of germination. Total mineral matter increased from 1·15% to 1·40%, protein from 9·6% to 14·0%, lipids from 4·36% to 4·60% and fibre from 0·71% to 0·82% whereas phytate decreased from 200 to 105 mg 100 g and carbohydrates from 85·5% to 70·0%. Radiation and germination significantly affected the ascorbic acid and riboflavin contents of corn (p < 0.05). A maximum value of ascorbic acid ( 19·4 mg 100 g ) was observed in the 10 krad treated seeds as compared with 14·3 mg 100 g in the control after 120 h of germination. Similarly, riboflavin increased from an initial value of 1·5 μg/g to 13·1 μg/g in the 20krad sample as compared with 6·0 μg/g in the unirradiated control.

4-Dimethylaminoazobenzenes: Carcinogenicities and reductive cleavage by microsomal azo reductase

Twenty-four 4-dimethylaminoazobenzenes (DABs) in which systematic structural modifications have been made in the prime ring have been studied for substrate specificity for microsomal azo reductase. The DABs were also evaluated for carcinogenicity and it was found that there was no correlation between carcinogenicity and extent of azo bond cleavage by azo reductase. While any substituent in the prime ring reduces the rate of cleavage of the azo bond relative to the unsubstituted dye, there is a correlation between substituent size and susceptibility to the enzyme. Substituent size was also found to be a significant factor in the induction of hepatomas by the dyes. Preliminary studies have shown that there appears to be a positive correlation between microsomal riboflavin content and the activity of the azo reductase.

Influence of Initial Riboflavin Content on Retention in Pasta During Photodegradation and Cooking

ABSTRACTSamples of enriched pasta were stored under controlled lighting conditions and the loss of riboflavin was determined. After an initial rapid degradation, the riboflavin level continued to decrease slowly. After 12 wk, more than 80% the riboflavin had degraded. When pasta samples‐ with varied levels of riboflavin enrichment were exposed to light for 2 days, riboflavin losses ranged from 57.8–64.3%. Riboflavin leaching from pasta during cooking was also shown to be concentration independent with 34.5–37.6% of the riboflavin solubilized in the cooking water. Riboflavin in pasta which had been exposed to light for 2 days prior to cooking had a similar percentage of the undegraded riboflavin leached into the cooking water.

Symptoms of severe riboflavin deficiency without ocular opacity in rainbow trout ( Salmo gairdneri)

In the present communication the gross symptoms of severe riboflavin deficiency are reported as observed in six experiments conducted with four independent stocks of rainbow trout fry and fingerlings. Unlike other reports on salmonids, ocular opacities were infrequently observed, and neither their rate of incidence nor their severity was related to dietary riboflavin content. Compared with both satiety-fed and pair-fed controls, riboflavin-deficient trout exhibited lethargy, apparent muscular weakness, reduced appetite and growth rate, severe fin erosion (all fins), rapid opercular movements, light greenish-yellow skin coloration and high mortality rate. These symptoms, although due to riboflavin deficiency per se, are nonspecific. As the cataracts produced by others in riboflavin-deficient trout appear to be a specific, diagnostic symptom, it is important to identify those conditions which can preclude their development in riboflavin deficiency.

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Thioacetamide (TAA) was administered to inbred male ACI rats for 1 year to determine its hepatocarcinogenicity. The carcinogen was fed at a level of 0.035% in a semipurified diet so that other components could be manipulated. The following groups were used: group I, TAA alone; group II, TAA with riboflavin content at 0.002% (one-third of the daily requirement); group III, TAA plus a supplement of 0.05% crude bovine thyroid; and group IV, TAA, 0.002% riboflavin, and thyroid supplement. All groups demonstrated cirrhosis, neoplastic nodules, and cholangiofibromas to varying degrees. Group IV was invariably the most advanced in all lesions, while group II demonstrated the next most advanced picture of cholangiofibromas. These lesions persisted for 1 year after cessation of the diet. Primary hepatocarcinomas (PHC) were produced by groups I, III, and IV, with the highest number being in group IV. Group II evoked only primary cholangiocarcinomas (PCC). A number of both types of carcinomas transplanted successfully. Thus TAA appears to be a hepatocarcinogen capable of inducing either PHC or PCC, with the tumor type evoked somewhat dependent on the associated diet.

Storage of milk powders under adverse conditions. 2. Influence on the content of water-soluble vitamins.

Storage of milk powder under unfavourable conditions accelerates the normally slow deterioration in nutritional quality. The effects of such storage on the water-soluble vitamin composition were examined. (a) Spray-dried whole milk containing 25 g water/kg was stored at 60 degrees and 70 degrees and sampled weekly to 9 weeks. (b) Spray-dried whole milk and skimmed milk were adjusted to contain 40 and 100 g water/kg and stored at 37 degrees in nitrogen and in oxygen. Samples were taken for analysis at intervals during storage. The samples were analysed for eight B-complex vitamins and ascorbic acid, and also for total lysine, 'reactive lysine' and 'lysine as lactulosyl-lysine'. Storage at 60 degrees caused rapid destruction of folic acid (53% loss at 4 weeks) and slower loss of thiamin, vitamin B6 and pantothenic acid (18% at 8 weeks). There was no change in the content of riboflavin, biotin, nicotinic acid and vitamin B12. At 70 degrees the rate of destruction of the four labile vitamins was much increased; 18% or less survived at 4 weeks. At 37 degrees and 40 g water/kg there was little change in total and 'reactive' lysine during storage for 57 d. Lactulosyl-lysine was demonstrably present but at low concentration. There was considerable loss of folate (72%) and ascorbate (91%) during storage for 30 d in O2, but no significant loss in N2. Thiamin fell by approximately 12% in 57 d, equally in O2 and N2. The content of the remaining vitamins was unchanged. At 100 g water/kg there were progressive Maillard changes. During 27 d in N2 the colour changed from cream to pale brown, but in O2 there was no perceptible colour change. Total lysine fell by 20% in 27 d, and 'reactive lysine' by 30%. Folate was stable during 16 d in N2, but largely (94%) destroyed in O2. Ascorbic acid was also destroyed in N2 as in O2. Thiamin fell by 41% in 27 d, equally in O2 and N2. Vitamin B6 was more labile, especially in N2, falling by 71% in 16 d. With skimmed-milk powder containing 100 g water/kg, storage at 37 degrees in O2 and N2 gave much the same results as for the corresponding whole-milk powder. The presence of milk fat had no marked effect on the stability of the water-soluble vitamins. Destruction of vitamins was clearly linked to the progress of Maillard-type reactions and was strongly influenced by time and temperature of storage, moisture content and, in some instances, by the presence of O2.

Phosphates of riboflavin and riboflavin analogs: A reinvestigation by high-performance liquid chromatography

Phosphoric acid esters of riboflavin can be easily separated by reverse-phase high-performance liquid chromatography using eluants of 0.1 m ammonium formate in aqueous methanol. Commercial FMN preparations contained seven different flavin phosphates; the content of riboflavin 5′-phosphate was 70–75% and is in agreement with previous studies. Millimole amounts of crude FMN can be processed by preparative HPLC. The method permits the preparation of >99%-pure 5′-FMN. The following compounds were isolated in pure form and their structures determined: riboflavin 4′-phosphate, riboflavin 3′-phosphate, riboflavin 4′,5′-diphosphate; riboflavin 3′,4′-diphosphate, and riboflavin 3′,5′-diphosphate. The latter compound binds tightly to apoflavodoxin from Megasphaera elsdenii ( K D = 9.7 × 10 −9 m). The bound flavin has high catalytic activity, thus representing a novel type of FMN analog. A wide variety of structural analogs of FMN can be obtained in pure form by preparative HPLC.

Changes in Nutrient Content during Chill‐holding of Ice‐packed and Deep‐chilled Broilers

ABSTRACTThe changes in nutrient composition of broiler breast meat subjected to the following handling methods were determined: 1) ice‐packed whole birds (IW), 2) ice‐packed breasts (IB) and 3) deep‐chilled, tray‐packed breasts (DCB). All were chill‐held for 14 days in ice or dry in 2°C storage. Significant losses of Mg, K, Na and P (20, 37, 12 and 36%, respectively) were found in 14 days IB samples. The loss in IW was 11, 26 and 27% for Mg, K and P, respectively. DCB meat retained more minerals than those packed in ice. The highest loss after 7–14 days of chill‐holding of DCB was 18% for P and 15% for K. Significant increase of Ca content was found (68–144% gain) for all samples stored after 7 days suggesting migration of Ca from bone to tissue. Proximate data, thiamin and riboflavin content did not change.