Showing papers on "Citric acid published in 1979"

Production of citric acid in continuous culture

Abstract: Work has been carried out on the production of citric acid by Aspergillus foetidus in single‐stage continuous culture, operated under nitrogen‐limiting conditions at dilution rates between 0.04 to 0.21 hr−1. Citric acid concentration increased rapidly as the dilution rate decreased and appears to be critically dependent on the pH in the culture vessel and the nitrogen concentration in the feed. A mathematical model based on a distinction between basic cells, which require nitrogen but do not produce citric acid, and stroage cells, which accumulate carbon and simultaneously produce citric acid, is proposed.

Dithranol compositions stabilized with alpha hydroxyacids

Abstract: Chemically stable dithranol compositions useful as topical treatment for inflammatory disorders such as psoriasis, eczema and seborrheic dermatitis are disclosed. Incorporation of a certain alpha hydroxyacid as its free acid, lactone, amide or salt form in dithranol containing compositions has been found to chemically stabilize said compositions. The alpha hydroxyacids include glyceric acid, gluconic acid, galacturonic acid, glucuronic acid, glucoheptonic acid, galactonic acid, malic acid, mucic acid, citric acid, saccharic acid, tartaric acid, tartronic acid, isocitric acid and glucuronamide. A single member of the above alpha hydroxyacids may be present in a total amount of from 0.01 to 1 percent by weight of the total composition, or a plurality thereof may be present in a preferred concentration range of from 0.02 to 0.5 percent by weight of the total composition.

Betanine stability in buffered solutions containing organic acids, metal cations, antioxidants, or sequestrants

Abstract: The rate of betanine degradation as affected by monocarboxylic acids (lactic acid, acetic acid), metal cations (Fe+++, Cu++), antioxidants (ascorbic acid, α-tocopherol) and sequestrants (citric acid, Na2 EDTA) was studied. Betanine was extracted from beets using water, and purified by molecular exclusion and adsorption chromatography. Column packings used were Sephadex G-25, polyacrylamide, and polyvinylpolypyrrolidone. The effect of food additives on the rate of oxidation of betanine in buffered systems was determined using a modification of the active oxygen method. A betanine solution was placed in a reaction chamber, held at 75° C, and oxygen was passed through the solution at a rate of 3 ml/min. The half-life value of betanine at 75° C, pH 5.0 in a phosphate buffer was 48.0 ± 1.0 min (control). Addition of 100 ppm lactic acid had no effect on stability (41 ± 1.7 mm), while 5.9% acetic acid caused a decrease in stability (33.4 ± 1.9 min) possibly as a result of pH changes at elevated temperatures. Metal ions at a level of 100 ppm caused an increase in the degradation rate compared to that of the control with addition of iron resulting in a half-life value of 33 ± 1.4 min. Copper had the greatest effect, reducing the half-life value to 6.0 ± 0.2 mm. Neither 100 ppm ascorbic acid nor 100 ppm a-tocopherol affected the half-life value of betanine (45.3 ± 2.3 and 50.2 ± 3.4 min, respectively). Ascorbic acid at 1000 ppm decreased the halt-life value (32.3 ± 3.3 min), whereas 10,000 ppm citric acid and 10,000 ppm EDTA caused an increase in the half-life value of 1.5 times compared to that of the control (69.4 ± 3.1 and 70.7 ± 7.1 min). Both 100 and 1000 ppm citric acid had no effect on betanine stability.

Manganese deficiency leads to elevated amino acid pools in citric acid accumulating Aspergillus niger

Abstract: Free amino acid pools have been investigated in a citric acid accumulating strain of Aspergillus niger during batch growth under manganese sufficient and deficient conditions by means of an improved chromatographic method. Studies on the mycelial content of several nitrogenous compounds under manganese sufficient and deficient conditions showed that manganese deficiency resulted in lower amino acid pool sizes during trophophase and considerable accumulation during idiophase, and in a reduction of the protein and nucleic acid contents. Addition of cycloheximide to mycelia grown with sufficient manganese also caused an elevation of free amino acid pool sizes, thus indicating that impairment of protein synthesis by manganese deficiency is responsible for the observed rise in amino acid concentration. Furthermore it was observed that the manganese deficient mycelia excreted high amounts of all amino acids suggesting that manganese deficiency may also affect membrane permeability.

Long-Chain F-18 Fatty Acids for the Study of Regional Metabolism in Heart and Liver; Odd-Even Effects of Metabolism in Mice

Abstract: In view of the potential usefulness of fluorine-tagged fatty acids in the study of regional metabolism in the heart and liver, the time courses of uptake and release of 9,10-(/sup 18/F)fluorostearic acid, 2-(/sup 18/F)fluorostearic acid, 16-(/sup 18/F)fluorohexadecanoic acid, 17-(/sup 18/F)fluoroheptadecanoic acid have been investigated in several organs of NMRI mice. Whereas 2-(/sup 18/F)fluorostearic acid shows very little uptake in the heart muscle but an increasing accumulation in the liver, the fatty acids with the F-18 label in the middle or at the end of the carbon chain exhibit uptake and elimination behavior similar to that of the analogous C-11-labeled compounds. After rapid concentration in the heart within 1 min, clearance takes place with fast and slow components. 16-(/sup 18/F)fluorohexadecanoic acid and 17-(/sup 18/F)fluoroheptadecanoic acid have different half-times of elimination. These differences are also reflected by the fact that nearly all the activity present in the heart can be recovered as fluoride(F-18) in the case of 17-(/sup 18/F)fluoroheptadecanoic acid, whereas practically no fluoride was found among the metabolites of 16-(/sup 18/F)fluorohexadecanoic acid. Similar differences were observed for the F-18 activity in bone. The results can be interpreted in terms of the odd-even rule: ..beta.. oxidation of even-numbered fatty acids ends upmore » with (/sup 18/F)fluoroacetic acid, whereas the odd-numbered fatty acids give rise to ..beta..-(/sup 18/F)fluoropropionic acid. Only in the latter case does dehalogenation take place leading to free fluoride, whereas fluoroacetic acid undergoes further reactions in the citric acid cycle.« less

The Relative Influence Of Low-molecular-weight, Complexing Organic Acids On The Hydrolysis And Precipitation Of Aluminum

Abstract: The stability constants of the complexes of aluminum and the low-molecular-weight organic acids decreased in the order: citric acid > malic acid > tannic acid > aspartic acid > p-hydroxybenzoic acid. This order of affinity of organic ligands to aluminum was in agreement with the sequence of the effectiveness of the organic acids to hinder and perturb the normal course of hydrolytic and precipitation reaction of aluminum. In systems where organic acids were present in varying concentrations, the hindrance to the hydrolytic reactions of aluminum increased with the increasing concentration of organic acids present during aluminum transformation.

Citric acid production from glucose. I. Growth and excretion kinetics in a stirred fermentor

Abstract: The growth and citric acid production kinetics of Saccharomycopsis lipolytica on glucose are investigated in an aerated stirred fermentor. Cellular growth first proceeds exponentially until exhaustion of ammonia in the fermentation medium. Cells then continue to grow at a reduced rate with a concomitant decrease in intracellular nitrogen content. Citric and isocitric acid production starts at the end of the growth phase. During about 80 hr excretion proceeds at a constant rate of 0.7 g/liter/hr for citric acid and 0.1 g/liter/hr for isocitric acid. The final citric and isocitric acid concentrations are 95 and 10 g/liter, respectively. During acid excretion cellular respiration accounts for 60 and 35% of consumed oxygen and glucose. Both acid and CO/sub 2/ production rates follow a Michaelis-Menten-type dependence on oxygen concentration with Michaelis-Menten constants of 0.9 and 0.15 mg/liter for acid and CO/sub 2/ productions, respectively.

Surface Reactivity of Aluminum Hydroxides Precipitated in the Presence of Low Molecular Weight Organic Acids1

Abstract: The surface reactivities of aluminum hydroxides precipitated in systems at the initial Al concentration of 1.1 × 10⁻³M and the OH/Al molar ratio of 3.0 in the individual presence of 0, 10⁻⁶, and 10⁻⁴M, respectively, of citric, L-malic, DL-aspartic, and p-hydroxybenzoic acids were investigated. The organic acids enhanced the specific surface of the precipitation products of hydrolytic reactions of Al through structural distortion. The development of surface charge and active sites for the retention of phosphate and Ca were thus promoted. The enhancement of the surface reactivities of the precipitation products of Al by the organic acids followed the sequence of the stability constants of the complexes of Al with the organic acids, namely, citric acid > malic acid > aspartic acid > p-hydroxybenzoic acid. At the concentration of 10⁻⁴M organic acids, deviation from the latter sequence occurred in the development of positive surface charge and in the retention of phosphate. Specific adsorption of anions, while favoring the retention of Ca, counteracted the promoting influence of high specific surface on the development of the net surface positive charge and on the retention of phosphate of the precipitation products of Al. Among the organic acids used, with the exception of p-hydroxybenzoic acid, a concentration of 10⁻⁴M, in contrast to 10⁻⁶M, was sufficiently high to stabilize the high specific surface and phosphate retention capacity of the precipitation products of Al during aging. This information is of significance in understanding the role of low molecular weight organic acids in the formation of short-range ordered aluminum hydroxides and their subsequent surface reactivities with respect to P and Ca.

Calcined Christmas Island C-grade rock phosphate fertilizers: Mineralogical properties, reversion and assessment by chemical extraction

Abstract: Calcination of Christmas Island C-grade ore at temperatures up to 1050°C produces phosphorus fertilizers that differ greatly in effectiveness as determined by citrate extraction and plant growth. Maximum effectiveness is obtained by calcination at temperatures between 500° and 650°C, and is best predicted by extractions of between 1 and 3 h duration in neutral ammonium citrate. Alkaline ammonium citrate and citric acid are poorer indicators of phosphorus availability. The mineralogical and chemical properties of the calcines may be used to explain variations in amounts of citrate soluble phosphorus for different temperatures of calcination. Incubation of moist 500°C calcined C-grade ore induces recrystallization (i.e. reversion) of some crandallite, resulting in a decrease in the solubility of phosphorus in neutral ammonium citrate and its availability to plants.

Citric acid production from glucose. II. Growth and excretion kinetics in a trickleflow fermentor

Abstract: The growth and citric acid production kinetics of Saccharomycopsis lipolytica on glucose is investigated in a trickle-flow fermentor. Liquid hold-up and oxygen-transfer coefficient in the reactor column filled with cylindrical wood chips have been determined and found in agreement with chemical engineering correlations. Citric acid production starts at the end of the growth phase and proceeds at a constant specific rate of 0.025 hr−1for about 80 hr. The fermentor can then be regenerated by addition of ammonia, which induces new growth and excretion phases. Comparing the metabolic behavior of free and immobilized cells, two main kinetic differences are observed. First, the growth phase is linear with the bound cells instead of exponential in the stirred fermentor. Second, in the trickle-bed fermentor acid productivity and oxygen acid yield are reduced by 30%. Oxygen diffusional limitations, mainly in the biomass film, and alterations in bound cell metabolism are shown to be responsible of the kinetic modifications. Simple modelizations of oxygen diffusion effects are also presented to support the interpretation of the experimental data.

An indirect method for studying the fine control of citric acid formation byAspergillus niger

Abstract: During the main period of citric acid fermentation byAspernillus niger product formation is easily determinable from oxygen uptake and carbon dioxide output rates. This was applied in a study on the response of citrate formation to shifts of some environmental parameters of known importance during fermentation.

RELATIVE SWEETNESS OF FR.UCTOSE AND SUCROSE IN MODEL solutions, LEMON BEVERAGES AND WHITE CAKE

Abstract: The relative sweetness of fructose and sucrose was evaluated at various concentrations in distilled water, in citric acid solutions (pH = 2.35, and 3.0), in lemon flavored beverages (pH = 2.35 and 2.7), and in vanilla cake. In distilled water and in the less acidic beverage and citric acid solutions, magnitude estimates of sweetness revealed fructose to be sweeter than sucrose by a factor of 1.6 – 1.9 at lower sugar concentrations. However, the greater relative sweetness of fructose declined- with increasing sugar concentration. In the more acidic beverage and citric acid solutions, no difference in perceived sweetness between fructose and sucrose was found at any sugar concentration. Similarly, no difference in the perceived sweetness of the two sugars was found when each was used as a sweetener in vanilla cake. These data suggest that the greatest sweetening advantage of fructose over sucrose occurs at the lower concentrations of the two sugars: However, when used in certain beverages or foods, concomitant tastes may mask or mitigate this differential sweetness.

Metabolism of [U-14C; 2,3-3H]-L-valine by the isolated perfused goat udder.

Abstract: Two lactating mammary glands excised from 2 goats were perfused for several hours in the presence of [U-14C; 2,3-3H]-L-valine and received adequate quantities of glucose, acetate and amino acids. In the synthesized milk 96 and 89% respectively of the casein valine was derived from free plasma valine. Valine was extensively catabolized by mammary tissue, resulting in a considerable 14CO2 production and in the incorporation of 14C into milk citric acid and to a lesser extent into casein aspartic acid and glutamic acid. About 30% of the valine molecules which were taken up by the mammary gland were oxidized to CO2 and 70% were incorporated in casein as valine residues. About 10% of the plasma valine molecules were reversibly transaminated during one passage through the udder. An important amount of radioactivity of plasma was present in unknown metabolites. Only 7% of this activity was localized in isobutyrate. The radioactivity of total milk fat was very low. Mainly iso-14:0, iso-16:0 and 15:0 were labelled.

Extraction of citric acid

Abstract: Citric acid can be extracted from aqueous citric acid solutions by contacting such solutions with an N-substituted alkyl amide containing a total of at least twelve carbon atoms.

Urinary Inhibitors of the Formation of Calcium Oxalate

Abstract: Normal urine was examined for substances which inhibited the formation of calcium oxalate, using a separation scheme which involved ultrafiltration, alcohol precipitation, electrophoresis and paper chromatography. The major anionic inhibitors were found to be citric acid, isocitric acid and pyrophosphate. The inhibitory activity of urine and that of an artificial urine having the same concentration of urea, creatinine, sodium, potassiu, magnesium, calcium, ammonia, sulphate, chloride, inorganic phosphate, oxalate, citrate, isocitrate and pyrophosphate, and the same pH were identical. This confirmed that urine does not contain an unidentified potent substance which inhibits the formation of calcium oxalate.

Preparation of carbonated beverage

Abstract: PURPOSE: To prepare a carbonated beverage having both a flavor like beer and that of fruit juice, and foaming properties, not containing alcohol substantially, by adding fruit juice to a sugar solution, adjusting it to pH in acidic side with an organic acid, followed by adding water and carbon dioxide to the prepared solution. CONSTITUTION: Any sugar solution, e.g., a saccharification solution obtained from starch, cellulose, etc. as a raw material, or a solution containing honey, preferably a sugar solution having a balling degree 10W25°, is prepared. Any fruit juice is added to the solution. An organic acid, e.g., lactic acid, citric acid, etc. is added to the solution to adjust to pH2W6, and the solution is filtered. Water and carbon dioxide are added to the filtrate. COPYRIGHT: (C)1981,JPO&Japio

Rapid determination of malic and citric acid in apple juice by high performance liquid chromatography

Abstract: Malic and citric acid can easily be determined in apple juice by means of reversed-phase high-performance liquid chromatography. Sample preparation is not necessary. For some juices a comparison is made with the enzymatic and Rebelein methods. Adulterations can rapidly be recognised by this method.

Method for preparing a proteinic isolate from sunflowerseed meal using aluminum salts

Abstract: A method for preparing nontoxic, edible proteinic concentrates adapted also for human nutrition, is disclosed according to which undesirable compounds such as polyphenols (e.g. chlorogenic and caffeic acids) are complexed by aluminum salts to prevent oxidizing these polyphenols to quinones. It is important that aluminum be constantly kept in soluble form to prevent it from being precipitated together with the proteins when protein-precipitating acidification is carried out. Citric acid has been found to be the best complexing agent.

Method of removing iron oxide deposits from heat transfer surfaces

Abstract: Iron oxide deposits which are found on heat transfer surfaces can be removed by first contacting these deposits with an aqueous solution of a hydrolyzable tanning extract such as sumach, valonea, or chestnut tannin which conditions the deposits and forms a complex thereof The thus-formed complex is subsequently removed by treatment with dilute solutions of citric acid

The use of deionised date syrup as a substrate for citric acid fermentation

Abstract: Production of citric acid from date syrup by fermentation has been undertaken usingAspergillus niger as the producer organism. Poor yields were obtained when untreated and ferrocyanide treated date syrup were used. However, acceptable yields, in excess of 60% were obtained when the date syrup was deionised using an ion exchange column at 80°C.

Continuous cultures of tomato and citron roots in vitro

Abstract: Initial trials with tomato-root cultures disclosed the desirability of employing a gently agitated liquid medium containing iron in the chelated form. For the normal cultivars “Ace” and “Tropic”, subcultures were best achieved by utilizing sectors that possessed one or more newly emerged laterals. Continuous cultures of a nonlateral-forming tomato mutant, “Diageotropica”, and of citron were accomplished by subculturing tips of the elongating primary roots. The tomato roots were cultured in White's medium with the Fe2(SO4)3 replaced by 0.03 mM NaFeEDTA. Sustained growth of citron-root tips necessitated the use of a medium containing Murashige and Skoog salts, 7.5% sucrose, 100 mg per I each of citric acid and thiamine HCl, and 5000 mg per li-inositol. The success with citron-root cultures was extendable to all cultivars ofC. medica L., but not to otherCitrus species relatives. Both citron and “Diageotropica” root cultures manifested undiminished elongation through repeated subcultures; but neither produced laterals in response to any cultural treatments.