Showing papers on "Citric acid published in 1978"

Effects of citric acid on diseased root surfaces.

Abstract: The effect of topically applied citric acid on periodontally diseased root surfaces was evaluated using the scanning (SEM) and transmission (TEM) electron microscopes. Results with the SEM indicate that acid application had no effect on specimens that had not been root planed. After application to root planed surfaces, however, the acid priduced a fiber-like surface with frequent depressions. TEM observations showed that the acid application produced a four micron wide demineralized zone, which was characterized by exposed collagen fibrils. These fibrils seemed to be continuous between the mineralized and demineralized zones of the root. It appears that the relative success of the citric acid application in periodontal reattachment procedures is realted to the fact that the acid causes exposure of collagen fibrils in the dentin matrix, thus providing a suitable nidus for splicing with new fibrils during the healing process.

Treatment of skin keratoses with α-hydroxy acids and related compounds

Abstract: Preventive as well as therapeutic treatment to alleviate the symptoms of skin keratoses consisting of topical application of a solution, gel, lotion, cream or ointment containing one or more of the α- or β-hydroxy acids or α-keto acids, esters thereof, and their amine salts is disclosed. The compounds include free acid or amine salt forms of α-hydroxy-butyric acid, α-hydroxyisobutyric acid, α-hydroxyisocaproic acid, α-hydroxyisovaleric, atrolactic acid, β-hydroxybutyric acid, β-phenyl lactic acid, β-phenylpyruvic acid, citric acid, ethyl pyruvate, galacturonic acid, glucoheptonic acid, glucoheptono 1,4-lactone, gluconic acid, gluconolactone, glucuronic acid, glucuronolactone, glycolic acid, isopropyl pyruvate, lactic acid, malic acid, mandelic acid, methyl pyruvate, mucic acid, pyruvic acid, saccharic acid, saccharic acid 1,4-lactone, tartaric acid, and tartronic acid. The therapeutic composition may include one or more of the compounds present in the total amount of from three to thirty percent. Topical application to affected areas has been found to achieve from substantial to complete remissions of the keratoses in humans.

The effect of topical citric acid application on the healing of experimental furcation defects in dogs.

Abstract: Chronic periodontal disease was induced and through-and-through furcation pockets created in mandibular premolars in two groups of beagles consisting of five and six animals respectively. The furcation defects were treated by surgical debridement supplemented with citric acid conditioning of the instrumented root surface. The relative importance of three adjunctive therapeutic measures was assessed. Thus, the effect of systemic antibiotics was evaluated by inter-group comparison. Gelfoam as a matrix support for the blood coagulum during healing was evaluated by intraindividual, contralateral comparisons in one group of animals. Coronal repositioning of the muco-periosteal flaps was evaluated by contralateral comparisons in the second group of animals. Block specimens for histological evaluation were removed six weeks after surgery. A high rate of regeneration and new attachment of the furcations was obtained irrespective of the use of systemic antibiotics, Gelfoam and high or low flap positioning. Thus, topical acid application seems to be the crucial therapeutic factor in achieving new attachment in the present model of through-and-through furcation pockets.

Treatment of dry skin

Abstract: Preventive as well as therapeutic treatment to alleviate the symptoms of disorders characterized by cracking, flaking or scaling of the skin consisting of the topical application of a lotion, cream or ointment containing one or more of the α- or β-hydroxy acids or α-keto acids and esters thereof, their amides and their ammonium salts is disclosed. The compounds include free acid, amide and/or ammonium salt forms of citric acid, glycolic acid, glucuronic acid, galacturonic acid, glucuronolactone, gluconolactone, α-hydroxybutyric acid, α-hydroxyisobutyric acid, lactic acid, malic acid, mandelic acid, mucic acid, pyruvic acid, methyl pyruvate, ethyl pyruvate, β-phenyllactic acid, β-phenylpyruvic acid, saccharic acid, tartaric acid, tartronic acid, and β-hydroxybutyric acid. The therapeutic composition may include one or more of the compounds present in the total amount of from one to twenty percent. Topical application to affected areas has been found to achieve amelioration of the dry skin.

Oral composition for caries prophylaxis

Abstract: An oral composition is disclosed which comprises a stannous salt such as stannous fluoride, a water-soluble fluoride salt such as sodium fluoride and an orally acceptable acid such as L-ascorbic acid, lactic acid, malonic acid, tartaric acid, citric acid, hydrochloric acid and pyrophosphoric acid, the molar ratio of fluoride ion to stannous ion being in the range of 3.2 to 7:1, preferably 3.5-6:1, in an aqueous condition and the pH of the composition being in the range of from 2 to 4. The composition exhibits excellent effects on the inhibition of dental caries.

STABILITY OF CONCORD GRAPE (V. labrusca) ANTHOCYANINS IN MODEL SYSTEMS

Abstract: An anthocyanin extract was prepared by treating Concord grape filter trim with methanol acidified with 0.01% citric acid. The extract was concentrated to provide an aqueous extract for testing as a colorant for beverages. The concentrate was freeze-dried on a dextran carrier for use with a dry beverage mix. The stability of the anthocyanins in beverages with added glucose or sucrose was not pH dependent over the range from pH 2.8—3.6. Presence of ascorbic acid increased the pigment degradation rate. 5-hydroxymethyl-Zfurfural (HMF) did not accumulate on storage in sufficient amounts to affect appreciably the degradation rate. D2 1 2 and z values were determined under aerobic conditions for several systems. The calorimetric “a/” L' function correlated well with anthocyanin content at higher storage temperatures. The pigment was very stable in carbonated beverages, jelly and dry beverage base mix.

The role of the tricarboxylic acid cycle in citric acid accumulation by Aspergillus niger

Abstract: Determinations of the momentary levels of various intermediates related to the activity of the tricarboxylic acid cycle have been made during citric acid production in high-accumulating (manganese deficient) and lowaccumulating (manganese supplemented) mycelia of Aspergillus niger. During the growth period the levels of almost all TCA cycle acids, with the exception of 2-oxo-acids, were unusually high; during the induction phase of citrate accumulation malate, fumarate, and isocitrate decreased, whereas pyruvate, oxalacetate, and citrate increased. The presence of succinate could not be demonstrated. The interrelations of the momentary concentrations of the intermediates mainly demonstrate a lack in activity of 2-oxoglutarate dehydrogenase, representing a block in the TCA cycle concomitant with a strongly operating glycolysis as a prerequisite for citrate accumulation. Inhibition studies with crude enzyme preparations suggest that an inhibition of malate dehydrogenase by citrate and also inhibition of isocitrate dehydrogenase by citrate and 2-oxoglutarate occur during the production phase as additional factors.

Production of citric acid in batch culture

Abstract: Work has been carried out on the production of citric acid in batch culture using Aspergillus foetidus. It is shown that the dry weight increases throughout the fermentation. The supply of nitrogen is exhausted early and the subsequent increase in dry weight is due to accumulation of carbon by the cells. It appears that the exhaustion of nitrogen is a necessary prerequisite for the production of citric acid, which is produced by carbon‐storing cells. The pH history in the early part of the fermentation did not affect the final yields.

Cholestyramine compositions and method for treating biliary gastritis

Abstract: A solid pharmaceutical composition comprising anhydrous cholestyramine, 0.6 to 1.7 parts by weight of low viscosity grade alginic acid/sodium alginate per weight of cholestyramine, the low viscosity grade alginic acid/sodium alginate having 0 to 75% of the acid groups neutralized, 0.1 to 0.3 parts by weight of citric acid per weight of sodium alginate, and sufficient sodium carbonate or bicarbonate mixtures thereof to neutralize the acid groups of the alginic and citric acids. The compositions may be used in the treatment of conditions associated with duodeno-gastric reflux of bile into the stomach.

Composition and method for cleaning drinking water tanks

Abstract: A composition and method for cleaning tanks for drinking water, particularly for removing deposits consisting mainly of an agglomerate of algae, microorganisms and ochre sediments. The composition is an aqueous solution comprising about 3 to 6% of ascobic acid, 2 to 3% of formic acid, 7 to 10% of phosphoric acid, 1 to 3% of citric acid, 13 to 15% of hydrochloric acid and 10 to 15% of an aqueous isopropyl alcohol (all % by weight). The method involves spraying said aqueous solution under pressure onto the deposits.

Influence of orange juice composition on the thermal resistance of spoilage yeasts

Abstract: The increased heat resistance of yeasts in orange concentrates as compared with single-strength juices cannot be accounted for on the basis of sugar contents only. Citric acid is demonstrated to play a role in the heat resistance of spoilage yeasts in concentrated orange juices. Other major chemical constituents of citrus juices, namely, ascorbic acid and pectin, did not exhibit any significant effect. A model system, based on sucrose, glucose, fructose, citric acid and tripotassium citrate, is pro-posed for the evaluation of the thermal resistance of yeasts in citrus concentrates.

Sorption of phosphate by hydrolytic reaction products of aluminium

Abstract: THE practical importance of hydrated aluminium oxides in the terrestrial and aquatic environments, is well known primarily through the significant role they have in the retention of nutrients in agriculture1 and in the control of pollutants such as phosphate in eutrophication processes2. Anion adsorption on hydrous aluminium oxides has also attracted the interest of engineers mainly because in tertiary waste-water treatment, the removal of phosphate with alum salts seems to be through adsorption on the hydrated oxide floc particles3,4. Consequently the adsorption of anions on hydrated aluminium oxides has been extensively investigated. These studies have shown that organic anions such as citrate compete with phosphate for adsorption sites on the surfaces of the hydrated aluminium oxides thereby decreasing their capacity to retain phosphate5–8. Our studies9 show that citric acid even at very low concentrations hampers the formation of crystalline aluminium hydroxides. We report here that due to the hindrance of the crystallisation processes, the .retention of phosphate by the hydrolytic reaction products of aluminium is enhanced and not reduced when they are precipitated in the presence of low concentration of citric acid which represents an organic acid commonly occurring in nature.

Citrus tissue culture: stimulation of fruit explant cultures with orange juice.

Abstract: In vitro growth of explant (juice vesicle or albedo tissues) cultures from citron (Citrus medica), lemon (C. limon), grapefruit (C. paradisi), sweet orange (C. sinensis), and mandarin (C. reticulata) fruits was stimulated by addition of orange juice (10% v/v optimum) to a basal medium containing Murashige and Skoog salts, 50 grams per liter sucrose, 100 milligrams per liter myo-inositol, 5 milligrams per liter thiamine·HCl, 2 milligrams per liter 2,4-dichlorophenoxyacetic acid and 0.5 milligrams per liter kinetin. In analyzing this effect of orange juice on citron explant cultures, we failed to obtain increased yields by addition of appropriate concentrations of citric acid to the basal medium but obtained growth stimulation when the medium was supplemented with juice from an “acidless” orange variety (cv. Lima). These facts suggest that some component(s) other than citric acid is involved. Addition of the inorganic ash corresponding to 10% (v/v) orange juice to the basal medium had no effect on yields. Similarly, the stimulatory effect of orange juice could not be explained based on its content of sucrose or of organic growth factors already present in the basal medium.

STABILITY OF ALPHA‐ AND GAMMA‐TOCOPHEROL: Fe3+ AND Cu2+ INTERACTIONS

Abstract: Both alpha- and gamma-tocopherol are degraded by Fe2+ and Cu2+. Ascorbic acid and EDTA completely inhibit the Cu2+ oxidation but only ascorbic acid completely prevented the Fe3+ oxidation although EDTA and citric acid gave some protection. On the other hand pure tocopherols, undiluted, were stable to air and light over a period of years.

Excretion of citric and isocitric acids by the yeast Saccharomycopsis lipolytica

Abstract: We investigated the excretion of citric and isocitric acids in a strain of Saccharomycopsis lipolytica grown on either n-paraffins, glucose, or glycerol. These acids were excreted in the ratio of 67:33 on n-paraffins and roughly 92:8 on either glucose or glycerol. However, with all the carbon sources used, the relative amount of isocitric acid in the intracellular pool remained below 10%. The assimilation of citric and isocitric acids was prevented when glucose or glycerol were the carbon sources, but not when n-paraffins were used. Citric acid stopped isocitric acid assimilation. These phenomena of selective assimilation and/or uptake might explain the variations observed in the ratio of citric to isocitric acids excreted on different carbon sources.

Zur Kinetik der Citronensäurebildung bei Candida lipolytica

Abstract: The kinetics of citrate and isocitrate accumulation by Candida lipolytica has been studied, with special emphasis of the carbon sources glucose and n-alkanes and the shifts from one carbon source to the other. The accumulation of the citric acids starts with the beginning of ideophase. Trophophase and ideophase behaviour is in parts different. Ideophase behaviour may be influenced by exogenic factors during growth. From the course of the curves for the citric acids two phases can be distinguished: The specific production rate of the first phase is higher than in the second phase (π1 ˜ 0.19 h−1; π2 ˜ 0.14 h−1). The influence of the carbon source on the course of the curves and the numeric value for the specific production rate is negligible. Alcane grown cells accumulate citric acids from added glucose and left-over n-alcanes simultaneously. When both substrates are added from the beginning only glucose is taken up for growth, for citric acid production both substances are utilized simultaneously. Glucose grown cells do not utilize alcanes for production of citric acids. Citric acids are accumulated only as long as glucose is available. Alcane uptake starts after addition of a nitrogen source.

The effect of pH and ligands on the sorption of heavy metal ions by cellulose

Abstract: The adsorption of copper, lead, cadmium and zinc ions by cellulose suspensions has been examined at pH values ranging from 3.5 to 11. The chemical form of the metal ions has been changed by adding ligands such as oxalic acid, citric acid, tartaric acid, ethylenediaminetetraacetic acid, ethylene- diamine, glycine, cysteine and α,α'-bipyridyl. Stable anionic complexes were not sorbed by the cellulose, and at a given pH cationic complexes were sorbed less than hydrated ions. The presence of excess ligand generally served to mask the precipitation of the metal- hydroxy species which can occur in the pH 6-7 region. The amount of metal cation sorbed increased with pH. This has been attributed to increased ionization of acid functional groups having a pKa value of around 4.4. The implication of the results, in respect to aqueous metal ion levels in natural systems, has been considered.

Method for detersifying and oxide coating removal

Abstract: A method and composition is disclosed for removing oxide film from metals and alloys and for detersification of objects. The composition is at least a 1% aqueous solution of gluconic acid or its alkali metal including ammonium salts, citric acid or its alkali metal including ammonium salts, and tartaric acid or its alkali metal including ammonium salts, at least one of these materials being acid in sufficient strength to provide a pH of 4 or less. Also, preferably a non-ionic surfactant is included.

Kinetics of citric acid production in Candida lipolytica

Abstract: The kinetics of citrate and isocitrate accumulation by Candida lipolytica has been studied, with special emphasis of the carbon sources glucose and n-alkanes and the shifts from one carbon source to the other. The accumulation of the citric acids starts with the beginning of ideophase. Trophophase and ideophase behaviour is in parts different. Ideophase behaviour may be influenced by exogenic factors during growth. From the course of the curves for the citric acids two phases can be distinguished: The specific production rate of the first phase is higher than in the second phase (pi1 approximately 0.19 h-1; pi2 approximately 0.14 h-1). The influence of the carbon source on the course of the curves and the numeric value for the specific production rate is negligible. Alcane grown cells accumulate citric acids from added glucose and left-over n-alcanes simultaneously. When both substrates are added from the beginning only glucose is taken up for growth, for citric acid production both substances are utilized simultaneously. Glucose grown cells do not utilize alcanes for production of citric acids. Citric acids are accumulated only as long as glucose is available. Alcane uptake starts after addition of a nitrogen source.

Process for stably sequestering iron while acidizing a reservoir

Abstract: In a well treating process in which an acidic solution having a pH of less than about 2 tends to dissolve ferric ion-containing materials from the well conduits and to precipitate ferric ion-containing solids when the pH of the solution increases beyond about 3, such a precipitation can be prevented by dissolving limited proportions of both 5-sulfosalicylic acid and citric acid within the acidic solution to be injected.

Method for stabilizing tin or tin alloy electroplating baths

Abstract: A method for stabilizing tin or tin alloy electroplating baths containing citric acid or its salt and an ammonium salt, by adding at least one saturated hydroxycarboxylic acid or its salt other than citric acid or citrate and/or at least one saturated dibasic carboxylic acid.

Improved production of citric acid by a diploid strain of Aspergillus niger.

Abstract: Aspergillus niger strain CGU 87 was treated with UV radiation and some auxotrophic mutants were obtained. These mutants were less productive than CGU 87, which produced an average of 7.4% citric acid. All possible crosses in pair wise combinations were carried out between these auxotrophs, and three heterokaryons were synthesised. Finally, one heterozygous diploid was isolated from each of them. These heterokaryons and diploids showed improved productivity when compared with their component parents, but except in one diploid D5, all others produced less citric acid than CGU 87. The yield of D5 exceeded that of CGU 87 by 1.2 times and it produced 9% citric acid. This is a significant improvement and the increased productivity seems to be the result of successful adaptation of D5 to its fermentation environment.

Etch bleaching liquid with iron(III)ions

Abstract: An aqueous acidic etch-bleach solution comprising hydrogen peroxide, iron(III)ions and inorganic anions that form a silver salt having a solubility product not greater than 1×10-8 determined in water at 20° C., characterized in that such solution contains in the dissolved state the combination of citric acid and a polymer containing alkylene oxide units for improved stabilization of the hydrogen peroxide.