Showing papers on "Citric acid published in 1984"
TL;DR: Elevated aluminium concentrations in the cerebral cortex and bone were also observed in the animals fed citric acid suggesting possible absorption of the citrate chelate presumably formed with the traces of aluminium present in the diet.
164 citations
TL;DR: A functionally truncated Krebs cycle in cholesterol-rich tumor mitochondria is found, and a mechanism for providing higher cytoplasmic levels of precursor metabolite intermediates which help sustain deregulated cholesterogenesis in hepatomas and other malignant neoplasms is highlighted.
140 citations
TL;DR: The activity of aconitase showed a direct relationship to the citric acid production rate, and the activity was highest when sucrose was the sugar source, and lowest when galactose was the source.
Abstract: Under otherwise identical fermentation conditions, the sugar source has been shown to have a marked effect on citric acid production by Aspergillus niger. Sucrose was the most favourable source, followed by glucose and fructose and then lactose. No citric acid was produced from galactose. Strong relationships were observed between citric acid production and the activities of certain enzymes in myccelial cell-free extracts prepared from fermentation samples. When sucrose, glucose, or fructose was the sugar source pyruvate carboxylase activity was high, but 2-oxoglutarate dehydrogenase activity was not detected. When galactose was the sugar source pyruvate carboxylase activity was low, but 2-oxoglutarate dehydrogenase activity was high. It is suggested that whereas glucose and fructose repress 2-oxoglutarate dehydrogenase, thereby causing accumulation of citric acid, galactose does not. The activity of aconitase showed a direct relationship to the citric acid production rate. Thus, the activity was highest when sucrose was the sugar source, and lowest when galactose was the source. It is suggested that when large amounts of citric acid are lost from the cell the activity of aconitase increases as a response to the diminished intracellular supply of its substrate.
138 citations
TL;DR: It is concluded that several methods are available for increasing iron absorption from a Latin American meal and that the choice of method depends on several factors, particularly cost.
135 citations
123 citations
TL;DR: Potassium citrate supplementation may be superior to potassium chloride supplementation in patients receiving thiazide in whom stones form, because of the propensity for the spontaneous precipitation of calcium oxalate in urine.
105 citations
TL;DR: Acidification observed in cultures of Penicillium cyclopium was mostly due to the extrusion of protons into the medium, in the absence of NH+ 4 protons were extruded together with citrate.
Abstract: Summary: Acidification observed in cultures of Penicillium cyclopium was mostly due to the extrusion of protons into the medium. In the absence of NH+
4 protons were extruded together with citrate. The citric acid thus produced underwent a dynamic equilibrium of continuous efflux and uptake, which was shifted towards the latter at decreasing glucose concentrations. In cultures supplied with NH+
4 and glucose a stoichiometric coupling of H+ excretion with NH+
4 uptake was observed. If the protons excreted were not absorbed by external buffers (e.g. tartrate ions), the pH of the medium dropped to below 2, thereby exceeding the capacity of the cells to maintain their internal pH. The decrease of intracellular pH was accompanied by the cessation of NH+
4 uptake, H+ extrusion and growth. In the presence of tartrate ions the NH+
4/H+ exchange proceeded until the glucose concentration of the medium dropped below 25 mm. Here, the external pH was kept above 3, without seriously affecting the intracellular pH. After termination of H+ extrusion an appreciable amount of NH+
4 was taken up together with hydrogentartrate anions, thereby causing a further acidification of the medium, which was finally reversed due to the uptake of tartaric acid in the late phase of growth.
99 citations
TL;DR: Apple pomace was used as a fsubstrate for citric acid production by five strains of Aspergillus niger, and A. niger NRRL 567 produced the greatest amount of citric acids in the presence of 4% methanol.
Abstract: Apple pomace was used as a fsubstrate for citric acid production by five strains of Aspergillus niger. A. niger NRRL 567 produced the greatest amount of citric acid from apple pomace in the presence of 4% methanol. The yield was 88% based on the amount of sugar consumed.
91 citations
Patent•
13 Mar 1984
TL;DR: In this paper, effervescent, water-soluble compositions containing water soluble and oil soluble vitamins and amino acid chelated minerals in bioavailable form are contained in a composition consisting of 20-30% of a vitamin blend.
Abstract: Flavored, effervescent, water soluble compositions containing water-soluble and oil-soluble vitamins and amino acid chelated minerals in bioavailable form are contained in a composition consisting of 20-30% of a vitamin blend consisting of water-soluble and oil-soluble vitamins adsorbed on a lactose carrier containing a minor amount of propylene glycol, 5-25% of one or more amino acid chelated minerals selected from the group consisting of calcium, magnesium, iron, zinc, copper and manganese, 20-45% citric acid, 5-25% of one or more alkali or alkaline earth metal bicarbonates or carbonates, 1-5% flavoring agent, 0.5-2% of a sweetening agent and sufficient additional lactose carrier to provide the desired vitamin and mineral content per unit dosage which will normally vary between about 2 and 6 grams. When dissolved in water a flavored, lightly carbonated drink is provided which will contain in soluble bioavailable form between about 50 to 100% of the U.S. RDA of one or more vitamins contained in a dosage unit of the composition and between about 20 to 50% of the U.S. RDA of one or more of the trace minerals iron, zinc, copper and magnesium as contained in a unit dosage of the composition as amino acid chelates. Separate effervescent vitamin compositions without minerals and mineral compositions without vitamins are also disclosed.
89 citations
TL;DR: Aspergillusniger NRRL 567 was found to produce the greatest amount of citric acid from grape pomace in the presence of methanol at a concentration of 3% (vol/wt), based on the amount of fermentable sugar consumed.
Abstract: Apple pomace, the residue left from juice extraction, can be employed as a substrate for citric acid production using Aspergillus niger as the fermentation agent.
87 citations
TL;DR: The slow rate of tricarballylate metabolism by mixed rumen bacteria and its potential as a magnesium chelator suggest that tricballylate formation could be an important factor in the hypomagnesemia that leads to grass tetany.
Abstract: Mixed rumen bacteria from cows fed either timothy hay or a 60% concentrate were incubated with 7.5 mM citrate, trans-aconitate, malate, malonate, quinate, and shikimate. Citrate, trans-aconitate, and malate were fermented at faster rates than malonate, quinate, and shikimate. Acetate was the primary fermentation product for all six acids. Quinate and shikimate fermentations gave rist to butyrate, whereas malate and malonate produced significant amounts of propionic acid. High-pressure liquid chromatography of fermentation products from trans-aconitate incubations revealed a compound that was subsequently identified as tricarballylate. As much as 40% of the trans-aconitate acid was converted to tricarballylate, and tricarballylate was fermented slowly. The slow rate of tricarballylate metabolism by mixed rumen bacteria and its potential as a magnesium chelator suggest that tricarballylate formation could be an important factor in the hypomagnesemia that leads to grass tetany.
TL;DR: The spores of Aspergillus niger were entrapped in calcium-alginate beads and precultivated in growth media with various amounts of nitrogen and an optimum of acid formation and yield was observed after the precultivation with 100–200 mg/l NH4NO3.
Abstract: The spores of Aspergillus niger were entrapped in calcium-alginate beads and precultivated in growth media with various amounts of nitrogen. During the following citric acid production in shaking cultures an optimum of acid formation and yield was observed after the precultivation with 100–200 mg/l NH4NO3. The productivity of the immobilized Aspergillus was found to be 1.5 times higher than in the case of free pellets. The outgrowth of free mycelia into the medium could be provided by increasing the ratio particle-volume: medium volume, using a 1-l air-lift fermenter, by which means the productivity was increased twice as much as obtained in shaking culture.
TL;DR: In this paper, it was shown that citric acid greatly perturbs the interaction of hydroxy-Al ions with orthosilicic acid, and thus hinders the subsequent formation of imogolite, leading to the formation of disordered aluminosilicates and pseudoboehmite.
Abstract: Imogolite, a hydrous aluminosilicate with paracrystalline cylindrical structures1, has been extensively isolated from the B horizon of ando soils2–4 and podzols5–9. Imogolite imparts significant effects on ion exchange properties, acidity, stability and biodegradability of organic matter, and physical and engineering properties of soils3,10. Its formation and stability are therefore of great interest in soil and environmental sciences. Imogolite was synthesized from a solution containing hydroxy-Al ions and orthosilicic acid at pH<5 (refs 11–13). The interaction of hydroxy-Al ions with orthosilicic acid may be influenced by low molecular weight organic acids which are constantly introduced to soils through natural vegetation and farming. However, relatively few data are available on the impeding effect of low molecular weight organic acids on the formation of imogolite14 and on the properties of the reaction products. We report here that citric acid (molar ratio of citric acid to Al at ≤0.1) greatly perturbs the interaction of hydroxy-Al ions with orthosilicic acid, and thus hinders the subsequent formation of imogolite, leading to the formation of disordered aluminosilicates and pseudoboehmite in the precipitation products. The soluble products formed in the presence of citric acid were characterized by the predominance of proto-imogolite sol and Al-citrate chelates.
TL;DR: Acid‐induced growth Cell wall acidification Cytosolic acidification Indoleacetic acid Membrane potential Zea mays
Patent•
14 Feb 1984
TL;DR: A liquid bactericide for foods and food processing machines or utensils, said bactericide comprising as active ingredients 98.0 to 96.7% (W/V) of an organic acid selected from the group consisting of lactic acid, acetic acid, citric acid, tartaric acid, gluconic acid and ascorbic acid.
Abstract: A liquid bactericide for foods and food processing machines or utensils, said bactericide comprising as active ingredients 98.0 to 2.3% (W/V) of ethyl alcohol, 1.0 to 96.7% (W/V) of an organic acid selected from the group consisting of lactic acid, acetic acid, citric acid, tartaric acid, gluconic acid, malic acid, ascorbic acid and phytic acid and 1.0 to 96.7% (W/V) of phosphoric acid; said bactericide being capable of sterilizing within 30 seconds when used in an aqueous solution, such that the concentration of active ingredients in solution consists of 14 to 1% (W/V) of ethyl alcohol, 13.0 to 0.3% (W/V) of said organic acid and 0.7 to 0.03% (W/V) of phosphoric acid.
TL;DR: In this paper, a 0.125 mg/ml solution of phosvitin in distilled water for 20 and 40 min at 110°C was shown to free iron.
Abstract: Most of the iron in egg yolk is bound by phosvitin. Heating whole egg or yolk in a double boiler does not release this iron. Also, heating a 0.125 mg/ml solution of phosvitin in distilled water for 20 and 40 min at 110°C did not free iron. A second phosvitin solution mixed equally with 0.04M citric acid, 2 M NaCl and 0.03M Na2 EDTA. Only EDTA released (ca) iron from phosvitin without heating.
TL;DR: A combined treatment of molasses with tricalcium phosphate, hydrochloric acid, and Sephadex fractionation minimizes the level of inorganic and organic inhibitors in molasses and increases the production of citric acid.
Abstract: Surface culture citric acid fermentation was carried out by Aspergillus niger T55, a strain isolated from its natural source, using cane molasses, either untreated or treated by various methods. Citric acid biosynthesis is seriously impaired by both organic and inorganic inhibitors. A combined treatment of molasses with tricalcium phosphate, hydrochloric acid, and Sephadex fractionation minimizes the level of inorganic and organic inhibitors in molasses and increases the production of citric acid (65% weight yield based on total reducing sugar). The optimum level of individual metal ions for citric acid production depends on the concentration of other metals in the medium.
Journal Article•
TL;DR: In this article it has been found that citric acid is produced fermentatively by many moulds and yeasts of which Aspergillus niger has been widely used, and many trials have been done to increase the potentialities of strains of A. niger by exposure of the spores to ultra-violet irradiation and x-rays.
TL;DR: In most hypocitraturic patients with renal stones, potassium citrate 60 meq/day restored normal urinary citrate, and the slow‐release preparation when given in a twice‐daily or thrice‐daily schedule virtually eliminated the normally wide circadian fluctuation in urinary citrates.
Abstract: The time course, dose frequency schedule, and dose-response relationship of the citraturic response to orally administered potassium citrate was examined in 22 normal volunteers and 21 patients with uric acid or calcium nephrolithiasis. The slow-release (wax matrix) preparation of potassium citrate produced a rapid and sustained rise in urinary citrate lasting for up to 12 hours following a single oral administration. Probably owing to this prolonged action, the slow-release preparation when given in a twice-daily or thrice-daily schedule at a dosage of 60 meq or 3.78 Gm citrate/day virtually eliminated the normally wide circadian fluctuation in urinary citrate and maintained urinary citrate at a higher, more constant level throughout the day. The liquid preparation of potassium citrate was less effective in this regard. However, the two preparations of potassium citrate caused an equivalent rise in total 24-hour urinary citrate. When 24-hour excretions of citrate were examined, urinary citrate was shown to reach its peak level by the second day of potassium citrate treatment and to return to the pretreatment level by the second day after the treatment was stopped. The rise in urinary citrate produced by treatment was directly proportional to the dose of potassium citrate. In most hypocitraturic patients with renal stones, potassium citrate 60 meq/day restored normal urinary citrate (greater than 320 mg/day).
TL;DR: The “in vitro” uptake of glucose and 2-desoxyglucose by whole mycelia of Aspergillus niger, pregrown under citric acid producing conditions, is inhibited by citrate, which affects a high affinity glucose transport system.
Abstract: The “in vitro” uptake of glucose and 2-desoxyglucose by whole mycelia of Aspergillus niger, pregrown under citric acid producing conditions, is inhibited by citrate (I 0.5 15 mM), which affects a high affinity glucose transport system (Km 0.14 – 0.17 mM).
Patent•
24 Sep 1984
TL;DR: A reagent for blood analysis comprises, as a lysing reagent, tetradecyltrimethylammonium bromide and/or hexadecyltrimylthio-1oxide (2-pyridylthios-1-oxide) sodium, and citric acid as mentioned in this paper.
Abstract: A reagent for blood analysis comprises, as a lysing reagent for leukocyte count, tetradecyltrimethylammonium bromide and/or hexadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, and citric acid. This reagent is characterized by showing three-peaks fractionation of leukocytes in measuring by means of an automatic blood-analysis instrument. The lysing reagent is used together with a diluent comprising boric acid buffer solution, ethylenediaminetetraacetic acid and (2-pyridylthio-1-oxide) sodium.
TL;DR: Using gravimetrically prepared citrate standards, it is determined that assay results varied linearly with concentration up to sixfold the upper reference limit for serum citrate.
Abstract: A kit method for rapid analysis of citrate in foodstuffs, based on use of citrate lyase (EC 4.1.3.6), has been adapted and evaluated for use with clinical samples. Membrane filters removed serum proteins, which interfere with the analysis, and reagent and sample volumes were decreased from those in the manufacturer's protocol, thereby decreasing the cost of the assay. Using gravimetrically prepared citrate standards, we determined that assay results varied linearly with concentration up to sixfold the upper reference limit for serum citrate. Intra- and interassay variation were within acceptable limits (CVs less than 3% and less than 8.5%, respectively). Kit reagents were stable for four weeks at -20 degrees C. Assay results were unaffected by hemolysis or other biochemical interferences. The method evidently provides a rapid, convenient microassay for citrate in clinical samples.
TL;DR: In this article, the effect of citric acid on the formation of hydroxy-Al-montmorillonite complexes depended greatly on the initial citrate/Al molar ratio.
Abstract: Montmorillonite from Upton, Wyoming (< 2 μn) was aged 30 days in the presence of Al-citrate solutions both in the absence of NaOH and at an initial NaOH/Al molar ratio of 2.5. The effect of citric acid on the formation of hydroxy-Al-montmorillonite complexes depended greatly on the initial citrate/Al molar ratio. A low citrate/Al ratio of 0.1 did not significantly affect the CEC and X-ray diffraction patterns of hydroxy-Al-montmorillonite complexes. An intermediate citrate/Al ratio of 0.5 reduced the amount of Al depleted from solution and increased the proportion of 1 M KCl-exchangeable Al and 0.2 M HCl-extractable Al and the CEC of the samples; the structural perturbation in the interlamellar hydroxide sheet as revealed by XRD is attributed to the fixation of hydroxy-Al-citrate in the interlamellar spaces. At a high citrate/Al ratio of 1.0, most of the Al remained in solution and was prevented from being adsorbed by montmorillonite. The complexation between Al and citrate is a competitive reaction for t...
TL;DR: It was concluded that chelation by citrate could be the most important factor in determining the low activity of Ca++ in semen.
Abstract: The concentrations of calcium and citrate in 52 samples of human semen obtained from 10 donors were 11.07 +/- 0.41 (mean +/- SEM) and 27.2 +/- 1.62 mM, respectively, and were strongly correlated (r = + 0.79). The pH of the semen was 7.65 +/- 0.069. All 3 parameters varied significantly between the donors (P less than 0.001 in each case), but the activity of calcium ions measured with a calcium electrode was 0.24 +/- 0.022 mM (n = 45) and did not vary significantly between donors. The expected activity of calcium ions was calculated on the hypothesis that the chelation of calcium by citrate could explain the discrepancy between the concentration and the activity of the ion. The result was 0.57 +/- 0.043 mM (n = 52). It was concluded that chelation by citrate could be the most important factor in determining the low activity of Ca++ in semen.
Patent•
03 Oct 1984TL;DR: Citrate-ester plasticized polyvinyl chloride containers for the storage of blood and blood components have high 0 2 transmissibility, withstand breakage at low temperatures and extractables which degrade into biologically acceptable products.
Abstract: @ Citrate-ester plasticized polyvinyl chloride containers for the storage of blood and blood components Preferred plasticizers include tri-esters of citric acid (or acylated citric acid) and 4-10 carbon alcohols such as acetyl tri-butyl citrate, n-butryl tri-n-hexyl citrate and acetyl tri-n-octyl or decyl citrate Blood bags and multiple blood bags made from such citrate plasticized PVC film materials have high 0 2 transmissibility, withstand breakage at low temperatures and extractables which degrade into biologically acceptable products
Patent•
05 Nov 1984TL;DR: In this paper, steel strips are electroplated with a Zn-Fe base alloy containing 10 to 30% by weight of iron in a chloride bath which contains zinc and ferrous chlorides to give a total concentration of zinc and iron ions of from 1.0 mol/1 to the solubility limit with a weight ratio of Fe2+ /Zn2+ between 0.10 and 0.35.
Abstract: OF THE DISCLOSURE Steel strips are electroplated with a Zn-Fe base alloy containing 10 to 30% by weight of iron in a chloride bath which contains zinc and ferrous chlorides to give a total concentration of zinc and ferrous ions of from 1.0 mol/1 to the solubility limit with a weight ratio of Fe2+ /Zn2+between 0.10 and 0.35, and chloride ions in a total concentration of at least 6.0 mol/l under electrolytic conditions: pH 1.0 - 6.0, current density 80 - 200 A/dm2, and relative flow velocity 30 - 200 m/min. The bath may further contain a polycarboxylic acid such as citric acid and a Zn-Fe-P alloy plating may be deposited when the bath further contains hypophosphorous acid.
TL;DR: Two β-(1→4)-endoglucanases have been purified from industrial waste broth of Aspergillus niger grown under conditions which produce citric acid and exhibited very similar properties: a rather broad pH optimum between pH 2 and 7 for CM-cellulose hydrolysis and an inability to degrade crystalline cellulose.
Abstract: Two β-(1→4)-endoglucanases have been purified from industrial waste broth of Aspergillus niger grown under conditions which produce citric acid. Molecular weights for endoglucanase A were 43,000 and 25,000 for endoglucanase B. Both enzymes exhibited very similar properties: a rather broad pH optimum between pH 2 and 7 for CM-cellulose hydrolysis and an inability to degrade crystalline cellulose. The endoglucanases have a higher thermal stability at acid pH (up to 60°C) than at alkaline pH. They are inhibited by iodine, HgCl2 and N-bromosuccinimide.
TL;DR: In this paper, an acid vacuum hydration process followed by canning in EDTA/brine was evaluated for improving color and reducing thermophilic spoilage of canned mushrooms.
Abstract: An acid vacuum hydration process followed by canning in EDTA/brine was evaluated for improving color and reducing thermophilic spoilage of canned mushrooms. Blanching in citric, fumaric or phosphoric acids and vacuum hydration in 0.05 M citric acid (pH 3.5) improved the color of the canned product significantly over untreated controls. EDTA (500 ppm) in the canning brine further improved color. Application of the citric acid vacuum hydration process to 227 kg quantities of fresh mushroom tissue in a commercial cannery resulted in no loss in canned product yield, significantly improved product color, greatly minimized thermophilic spoilage and did not significantly influence flavor and texture.