Showing papers on "Citric acid published in 2018"
TL;DR: Effects of HCl, H2SO4, HNO3, citric acid, and acetic acid on the yield, structure, and emulsifying properties of potato pectins were investigated and SEM showed that all potato pECTins are morphologically different.
206 citations
TL;DR: The results of the investigations into the elucidation of the chemical structure of moieties responsible for the blue and green luminescence of CDs derived from the microwave-assisted pyrolysis of citric acid in the presence of urea are presented.
Abstract: In this report, we present the results of our investigations into the elucidation of the chemical structure of moieties responsible for the blue and green luminescence of CDs derived from the microwave-assisted pyrolysis of citric acid in the presence of urea. The molecular fluorophore that forms during the synthesis of green fluorescing CDs is 4-hydroxy-1H-pyrrolo[3,4-c]pyridine-1,3,6(2H,5H)-trione (HPPT).
169 citations
TL;DR: In this article, transparent and colorless citric acid-incorporated fish gelatin/chitosan composite films were prepared in order to demonstrate the potential use of these films as active food packaging.
140 citations
TL;DR: In this paper, the influence of sodium citrate and citric acid as additives on the mechanical strength, water resistance, setting time, pH change, composition and microstructure of MOS cement were investigated.
97 citations
TL;DR: Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H2SO4 and liquid-to-solid ratio of 20:1.
92 citations
TL;DR: CA coating is suggested as a good strategy to increase the stability of MNPs in solutions with varied pH and electrolyte compositions, as well as with the easy synthesis of CA‐MNPs and their non‐toxicity.
89 citations
TL;DR: Two linked cycles of reactions that each oxidize glyoxylate into CO2 and generate intermediates shared with the modern TCA cycle are reported, shedding light into a plausible TCA protometabolism.
Abstract: The development of metabolic approaches towards understanding the origins of life, which have focused mainly on the citric acid (TCA) cycle, have languished-primarily due to a lack of experimentally demonstrable and sustainable cycle(s) of reactions. We show here the existence of a protometabolic analog of the TCA involving two linked cycles, which convert glyoxylate into CO2 and produce aspartic acid in the presence of ammonia. The reactions proceed from either pyruvate, oxaloacetate or malonate in the presence of glyoxylate as the carbon source and hydrogen peroxide as the oxidant under neutral aqueous conditions and at mild temperatures. The reaction pathway demonstrates turnover under controlled conditions. These results indicate that simpler versions of metabolic cycles could have emerged under potential prebiotic conditions, laying the foundation for the appearance of more sophisticated metabolic pathways once control by (polymeric) catalysts became available.
77 citations
TL;DR: In this article, the production of organic acids and changes during decomposition of rice straw amended with tricalcium phos phate (TCP) and Udaipur rock phosphate (URP) were studied under laboratory conditions.
Abstract: The production of organic acids and changes during decomposition of rice straw amended with tricalcium phos phate (TCP) and Udaipur rock phosphate (URP) were studied under laboratory conditions. The organic C content of rice straw decreased and total N increased with time, resulting in a decrease in C:N ratio as the decomposition progressed. The pH decreased to acidic range in all the treatments on day 15, but became alkaline again later on. Soluble P increased at 15 days after incubation, declined later during decomposition, and was highest in the treatments containing TCP and Aspergillus awamori inoculation. Citric, oxalic, formic and maleic acids were detected during decomposition of rice straw and maximum amounts were present on day 15. Citric and oxalic acids were responsible mainly for P solubilization from TCP and URP; generally, citric acid was the most effective in P solubilization.
75 citations
TL;DR: In this paper, the tomato extract is spiked with lactose and tricarballylic acid as internal standards and loaded onto a NH2 solid phase extraction (SPE) column.
73 citations
TL;DR: In this article, a Pechini method using chelating agent citric acid was used to synthesize CoAl2O4 nanoparticles at different calcination temperatures of 600-900°C.
73 citations
TL;DR: In this article, the authors synthesize and characterize citric acid crosslinked hydrogel films of carboxymethyl cellulose-tamarind gum for topical drug delivery.
Abstract: The objective of this study was to synthesize and characterize citric acid crosslinked hydrogel films of carboxymethyl cellulose-tamarind gum for topical drug delivery. The hydrogel films were characterized by attenuated total reflectance-Fourier-transform infrared spectroscopy, solid state 13C-nuclear magnetic resonance spectroscopy and differential scanning calorimeter. The prepared hydrogel films were evaluated for the carboxyl content and equilibrium swelling ratio. Moxifloxacin hydrochloride was loaded into these hydrogel films and drug release was monitored in the phosphate buffer pH 7.4. Hemolysis assay was used to study biocompatibility of hydrogel films. Results of the attenuated total reflectance-Fourier-transform infrared spectroscopy, solid state 13C-nuclear magnetic resonance and differential scanning calorimeter confirmed the formation of citric acid-crosslinked hydrogel films. Total carboxyl content of hydrogel film was found to be increased when polymer ratio and amount of citric acid was increased. In contrast, swelling of hydrogel film was found to be decreased with increase in polymer ratio and amount of citric acid. Batch B1 showed highest drug loading with non-Fickian release mechanism. All remaining batches showed non-Fickian release behavior with diffusion coefficient greater than 0.5. Results of hemolysis assay indicated that the citric acid crosslinked carboxymethyl cellulose-tamarind gum hydrogels were safe to be used in drug delivery. These results indicated that the citric acid crosslinked carboxymethyl cellulose-tamarind gum composite hydrogel films has the potential to be used in topical novel drug delivery systems.
TL;DR: The results suggested that the accumulation of sugar and organic acid might be related to the dynamic changes of fruit Mg concentrations of 6 citrus cultivars, and found ACO was the key enzyme resulting in the difference of citric acid accumulation, but not quite clear in sucrose metabolism.
TL;DR: In this article, three different deep eutectic solvents (DES) were synthesized using choline chloride as hydrogen bond acceptor and oxalic acid/citric acid/tartaric acid as a hydrogen bond donor.
TL;DR: In vitro antioxidant activity assays indicated that HEP-C extracted with citric acid solution showed stronger scavenging abilities on hydroxyl and DPPH radicals and antioxidant capacities than HEP -W and HEPs, and exhibited the strongest inhibitory effects on α-glycosidase and α-amylase activities.
TL;DR: In this article, the quality and biochemical changes of navel orange (Citrus sinensis L., Osbeck) fruits in response to cinnamaldehyde-chitosan coating were studied during 120 day of storage at 10 ± 1 °C and 80 − 90% RH.
TL;DR: In this paper, the synergistic role of citric acid and castasterone on various physiological and biochemical responses in Brassica juncea seedlings under cadmium stress was evaluated.
Abstract: Brassinosteroids are known to manage various stresses including heavy metals in plants and castasterone is a bioactive form of brassinosteroids. Citric acid, a known metal chelator which is an intermediate of tricarboxylic cycle, is involved in various environmental adaptations. The present study was conducted to evaluate the synergistic role of citric acid and castasterone on various physiological and biochemical responses in Brassica juncea seedlings under cadmium stress. B. juncea seedlings were subjected to two levels of cadmium (0 and 0.6 mM) and citric acid (0 and 0.6 mM), and four levels of castasterone (0, 0.01, 1, and 100 nM). Exposure of cadmium induced phytotoxicity by elevating hydrogen peroxide (H2O2) and superoxide anion (
$${\text{O}}_{2}^{{. - }}$$
) generation, decreasing photosynthetic pigment concentration, altering total carbohydrate content, and inducing stomatal closure. Seed priming with castasterone (at highest level) along with citric acid was most effective in ameliorating cadmium-induced toxicity which was manifested via reduced H2O2 and $${\text{O}}_{2}^{{. - }}$$
levels by 30.71 and 12.12%, respectively. The photosynthetic pigments, namely chlorophyll and carotenoid content, were improved by 47.17 and 34.06%, respectively, whereas total carbohydrates and polyphenolic contents were increased by 32.59 and 42.44%, respectively. Additionally, endogenous low-molecular weight organic acids were altered in response to cadmium toxicity, which were also increased with the castasterone and citric acid treatments. The results suggest that binary treatment of citric acid and castasterone may be more effective than individual treatments in alleviating cadmium-induced physiological damage through antioxidants and organic acids.
TL;DR: Pure and saline water absorption study showed that CHCAUR could be a better adsorbent compared to the super absorbent polymer (SAP) used in commercial diaper material.
TL;DR: Citric acid pretreatment is the most efficient pretreatment method to improve bioethanol fermentation of Saccharomyces cerevisiae TISTR 5606 at 1.94 times higher than untreated biomass.
Abstract: Effective lignocellulosic biomass saccharification is one of the crucial requirements of biofuel production via fermentation process. Organic acid pretreatments have been gained much interests as one of the high potential methods for promoting enzymatic saccharification of lignocellulosic materials due to their lower hazardous properties and lower production of inhibitory by-products of fermentation than typical chemical pretreatment methods. In this study, three organic acids, including acetic acid, oxalic acid, and citric acid, were examined for improvement of enzymatic saccharification and bioethanol production from oil palm trunk biomass. Based on response surface methodology, oxalic acid pretreated biomass released the maximum reducing sugar of 144 mg/g-pretreated biomass at the optimum condition, which was higher than untreated samples for 2.30 times. The released sugar yield of oil palm trunk also corresponded to the results of FT-IR analysis, which revealed the physical modification of cellulose and hemicellulose surface structures of pretreated biomass. Nevertheless, citric acid pretreatment is the most efficient pretreatment method to improve bioethanol fermentation of Saccharomyces cerevisiae TISTR 5606 at 1.94 times higher than untreated biomass. These results highlighted the selection of organic acid pretreatment as a potential method for biofuel production from oil palm trunk feedstocks.
TL;DR: In this article, the effect of citric acid concentration and solution pH on the adsorption equilibrium was investigated in batch experiments, and the results indicated that a maximum adaption capacity towards Zn(II) ions was obtained by using a citric acids concentration 2'M (WS2).
Abstract: In this work, walnut shell (WS) (Carya illinoinensis) treated with citric acid was used as biosorbent to remove zinc ions from aqueous solution. The effect of citric acid concentration and solution pH on the adsorption equilibrium was investigated in batch experiments. Additionally, the overall adsorption rate of Zn ions on walnut shell treated with citric acid was investigated by applying a diffusion model based on superficial diffusion. The results evidenced that a maximum adsorption capacity towards Zn(II) ions is obtained by using a citric acid concentration 2 M (WS2). The modification of walnut shell increases 2.5 times its adsorption capacity to remove Zn(II) from aqueous solutions due to the incorporation of carboxylic groups reaching a maximum adsorption capacity of 27.86 mg/g. The pH effect showed that the adsorption capacity was drastically increased by raising the solution pH from 3 to 6. The adsorption kinetics of Zn(II) on WS2 were interpreted correctly by the surface diffusional model (SDM). The values of Ds varied from 2.25 to 5.25 × 10−9 cm2/s, and increased exponentially as the mass of Zn(II) adsorbed at equilibrium augmented.
TL;DR: In this article, the selective depression of calcite in a monazite-calcite flotation system was systematically studied using micro-flotation and electrokinetic tests as well as X-ray photoelectron spectroscopy (XPS) characterization and solution chemistry calculations.
TL;DR: This study is the first to unravel the global picture of the network of sugar and organic acid metabolism underlying fruit granulation, suggesting that sugar andorganic acid metabolism adjusted to the synthesis pathway of cell wall components upon granulation at the expense of sugars and acids.
TL;DR: C-phycocyanin (C-PC) is a blue pigment often found in cyanobacteria that has commercial and biotechnological value as a nutraceutical for pharmaceutical and biomedical research, as well as a natural colorant for the cosmetic industry.
Abstract: C-phycocyanin (C-PC) is a blue pigment often found in cyanobacteria. It has commercial and biotechnological value as a nutraceutical for pharmaceutical and biomedical research, as well as a natural colorant for the cosmetic industry. Cyanobacteria from the Arthrospira (Spirulina) genus are one of the major sources of C-phycocyanin with up to 20% protein fraction. The biomass-solvent ratio, buffer concentration, temperature, and time regarding C-phycocyanin concentration, extract purity, and yield of C-phycocyanin were evaluated. The optimum extraction conditions for Arthrospira platensis were determined as a biomass-solvent ratio of 0.06 g mL−1 at 25 °C for 24 to 48 h. Temperature is an important factor in C-phycocyanin degradation. Citric acid was added as an edible preservative to increase the thermal stability of C-phycocyanin extracted from A. platensis, followed by incubation at 80 °C for 1 h. The initial concentration of C-phycocyanin with citric acid was reduced from 65 to 19% within 1 h; in contrast, the remaining C-phycocyanin concentration without citric acid reduced from 51 to 11%. The use of citric acid as an edible preservative increased the stability of C-phycocyanin in high thermal processing applications and extraction.
TL;DR: In this paper, the process of biodegradation upon modified thermoplastic starch with various types of carboxylic acids was performed via soil burial testing, and the results showed that both citric acid and ascorbic acid modifications exhibited lower rates of weight loss.
Abstract: The process of biodegradation upon modified thermoplastic starch with various types of carboxylic acids was performed via soil burial testing. As such, modification of thermoplastic starch via esterification with citric acid and ascorbic acid was made varied within the range of 1–4 by weight percentage (% w/w). As a result, after citric acid modification and ascorbic acid modification displayed higher moisture resistivity (15.04 and 20.46%) compared to thermoplastic starch, which resulted in 43.79% respectively. In addition, environmental degradation was determined by performing a biodegradation process by using compost soil. Besides, Fourier transform infrared spectroscopy and high performance liquid chromatography tests were carried out to assess the biodegradability attribute of the starch film. The findings showed that the both citric acid and ascorbic acid modifications exhibited lower rates of weight loss, consequently due to the action demonstrated by of carboxylic acids that inhibited the invasion of microbial after exposure to environmental degradation. Furthermore, the optical analysis revealed that both citric acid and ascorbic acid possessed capability to retard the invasion of microbial upon modifications observed from its rather limited formation of microbial colonies. Nevertheless, the carbonyl index portrayed lower growth rate for citric acid and ascorbic acid, in comparison to unmodified thermoplastic starch. Hence, the study concludes that the addition of carboxylic acid had reduced the rate of degradation for the thermoplastic starch, besides improving moisture resistivity.
TL;DR: In this paper, the effects of weak acids (citric acid, boric acid, and trisodium citrate) with dosages of 0.5, 1.5 and 2.5% of MgO weight on compressive strength, water resistance, and water resistance were investigated.
Abstract: This paper investigates the effects of weak acids (citric acid, boric acid, and trisodium citrate) with dosages of 0.5, 1.5, and 2.5% of MgO weight on compressive strength, water resistance...
TL;DR: Two types of pathway for itaconic acid biosynthesis as well as recent advances by metabolic engineering strategies and process optimization are reviewed to enhance itaconed acid productivity in native producers and heterologous hosts.
Abstract: Itaconic acid, 2-methylidenebutanedioic acid, is a precursor of polymers, chemicals, and fuels. Many fungi can synthesize itaconic acid; Aspergillus terreus and Ustilago maydis produce up to 85 and 53 g l−1, respectively. Other organisms, including Aspergillus niger and yeasts, have been engineered to produce itaconic acid. However, the titer of itaconic acid is low compared with the analogous major fermentation product, citric acid, for which the yield is > 200 g l−1. Here, we review two types of pathway for itaconic acid biosynthesis as well as recent advances by metabolic engineering strategies and process optimization to enhance itaconic acid productivity in native producers and heterologous hosts. We also propose further improvements to overcome existing problems.
TL;DR: As more than one molecule of carvedilol was found to be involved in most co‐amorphous systems with the organic acids, this approach allows for a higher “drug loading” compared to other co‐formers that usually form co‐morphous systems at a 1:1 M ratio.
TL;DR: The enzymatic browning of the apples slices was reduced for all films during storage, however, the films containing citric acid maintained the color characteristics, reducing the loss of quality associated with the maintenance of acidity, soluble solids, water activity, reduction of polyphenol oxidase and peroxidase activity, thus prolonging the shelf life of the iPhones.
TL;DR: In this article, an investigation was carried out to understand the mechanism(s) underlying enhanced Fe or Zn uptake in low Fe-Zn accumulator wheat genotype 4HPYT-414, due to inoculation of siderophore-producing and zinc-solubilizing endophytes.
Abstract: An investigation was carried out to understand the mechanism(s) underlying enhanced Fe or Zn uptake in low Fe–Zn accumulator wheat genotype 4HPYT-414, due to inoculation of siderophore-producing and zinc-solubilizing endophytes—Arthrobacter sulfonivorans DS-68 and Arthrobacter sp DS-179 Root anatomical features, using transmission electron microscopy (TEM), qualitative and quantitative aspects of production of organic acids and sugars in root exudates, and expression of TaZIP genes were analysed to relate to endophyte-mediated higher concentrations of Fe and Zn in the roots and shoots of wheat plants TEM studies revealed that the endodermis, cortical region, root hair extension, xylem and xylem vessels, pericycle and vascular bundles were more pronounced and thicker in inoculated treatments, as compared to control The organic acid profile of root exudates revealed five types of organic acids, with citric acid being predominant Inoculation of A sulfonivorans and Arthrobacter sp brought about 5- and eightfold increases in the amounts of acids, respectively, as compared to control, particularly citric acid, succinic acid and acetic acid Among the four TaZIP genes targeted, expression was achieved only for TaZIP3 and TaZIP7 genes, which showed 1–2 fold increases in the inoculated treatments The results clearly indicated that the endophyte-mediated overexpression of TaZIP3 and TaZIP7 genes in roots and shoots, and the observed anatomical and exudate changes were acting synergistically in facilitating higher Fe and Zn translocation in roots and shoots
TL;DR: Al alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt), and Functionalized yogurts showed an overall maintenance of nutritional properties.
TL;DR: The citric acid yield and the conversion rate of glucose of chsC-3 were both improved by 3.6%, when compared with that of the original strain in the stirred tank bioreactor, and the high-yield strain chsD-3 exhibited excellentcitric acid production potential in the scale-up process.
Abstract: The mycelial morphology of Aspergillus niger, a major filamentous fungus used for citric acid production, is important for citric acid synthesis during submerged fermentation. To investigate the involvement of the chitin synthase gene, chsC, in morphogenesis and citric acid production in A. niger, an RNAi system was constructed to silence chsC and the morphological mutants were screened after transformation. The compactness of the mycelial pellets was obviously reduced in the morphological mutants, with lower proportion of dispersed mycelia. These morphological changes have caused a decrease in viscosity and subsequent improvement in oxygen and mass transfer efficiency, which may be conducive for citric acid accumulation. All the transformants exhibited improvements in citric acid production; in particular, chsC-3 showed 42.6% higher production than the original strain in the shake flask. Moreover, the high-yield strain chsC-3 exhibited excellent citric acid production potential in the scale-up process.The citric acid yield and the conversion rate of glucose of chsC-3 were both improved by 3.6%, when compared with that of the original strain in the stirred tank bioreactor.