Effect of exogenous organic acids on chemical compositions and sensory attributes of fortified sweet wines from dehydrated grapes

In this study, acidity was regulated with the addition of exogenous tartaric acid and citric acid before bottling. The effect of exogenous organic acids on chemical compositions and sensory attributes of fortified sweet wines from dehydrated grapes were investigated. The results indicated that exogenous organic acids promoted the conversion of monomeric anthocyanins to copigmented anthocyanins in wines. Specifically, the combination of malvidin-3-O-glucoside and flavanols (catechin and epicatechin) was facilitated to form copigmented anthocyanins. Sensory analysis suggested that exogenous organic acids improved the balance of sugar and acidity and benefited the harmony in wines on the taste. Wines with a residual sugar and titratable acidity ratio of about 11:1 exhibited the more harmonious taste. In addition, it was also observed changes in the aroma profile related to volatile compounds, namely, more intense fruity aroma in wines with the addition of organic acids.

Tartaric acid ameliorates experimental non-alcoholic fatty liver disease by activating the AMP-activated protein kinase signaling pathway

Tartaric acid (TA) has been shown beneficial effects on blood pressure and lipid levels. However, its effect on non-alcoholic fatty liver disease (NAFLD) remains unknown. This study aimed to investigate the role of TA in experimental NAFLD. Mice were fed a Western diet for 8 weeks, followed by administration of TA or a vehicle for an additional 12 weeks while continuing on the Western diet. Blood biochemistry including transaminases and glucose tolerance test and liver tissue RNA sequencing (RNA-seq), lipid content, and histology were investigated. The HepG2 cell line was used to explore the mechanism by which TA regulates lipid metabolism. We found that TA significantly improved weight gain, insulin resistance, hepatic steatosis, inflammation and fibrosis in Western diet-fed mice. By comparing gene expression differences, we found that TA affects pathways related to lipid metabolism, inflammatory response, and fibrosis. Furthermore, TA effectively reduced oleic acid-induced lipid accumulation in HepG2 cells and downregulated the genes associated with fatty acid synthesis, which were enriched in the AMP-activated protein kinase (AMPK) signaling pathway. TA also enhanced the phosphorylation of AMPK which could be reverted by the AMPK inhibitor Compound C in HepG2 cells. Our study suggests that TA improves experimental NAFLD by activating the AMPK signaling pathway. These findings indicate that TA may serve as a potential therapy for the human NAFLD.

Enrichment of grape berries and tomato fruit with health-promoting tartaric acid by expression of the Vitis vinifera transketolase VvTK2 gene

Tartaric acid (TA) is a major non-fermentable plant soluble acid that abundantly occur in grapes and wines, imparting low pH and tart flavour to berries thereby regulating numerous quality attributes of wine, such as flavour, microbial stability, and aging potential. Evaluation of acidity in mature fruits of 21 wine grape (Vitis vinifera) varieties revealed significant variation between 'Beichun' and 'Gewürztraminer', which was correlated with TA content. RNA-seq analysis of fruits from the two cultivars at different developmental stages revealed that a transketolase gene, VvTK2, was significantly dominantly expressed in the high TA phenotype 'Beichun' variety. Subcellular localization assay showed that VvTK2 protein was located in the chloroplast. Virus-induced VvTK2 gene silencing significantly decreased the expression of 2-keto-L-gulonic acid reductase (Vv2-KGR) as well as L-idonate dehydrogenase (VvL-IdnDH3) and inhibited TA accumulation, while its transient over-expression in grape showed the opposite results. Heterologous VvTK2 over-expression in tomato demonstrated its obvious capacity to induce TA synthesis. Overall, these results highlights a novel role of VvTK2 in modulating TA biosynthesis, which could be an excellent strategy for future genetic improvement of grape flavour.

Selenite reduced cadmium uptake, interfered signal transduction of endogenous phytohormones, and stimulated secretion of tartaric acid based on a combined analysis of non-invasive micro-test technique, transcriptome and metabolome

Selenium (Se) can reduce uptake and translocation of cadmium (Cd) in plants via plenty of ways, including regulation of root morphology. However, the underlying mechanisms on how Se will regulate root morphology under metal(loid) stresses are not fully illustrated. To fill up this knowledge gap, we investigated the effects of 0.5 mg L-1 selenite (Se(IV)) on root exudates, root morphology, root endogenous hormones, and Cd uptake efficiency of rice under the 1 mg L-1 Cd stress condition. The results showed that Se(IV) significantly reduced shoot and root Cd concentrations, and decreased Cd uptake efficiency via root hairs determined by a non-invasive micro-test (NMT) technology. When compared to the 1 mg L-1 Cd (Cd1) treatment, addition of 0.5 mg L-1 Se(IV) (1) significantly reduced root surface area and tip numbers, and non-significantly reduced root length, but significantly enhanced root diameter and root volume; (2) significantly enhanced concentrations of tartaric acid in the root exudate solution, root auxin (IAA) and root jasmonic acid (JA) via a UHPLC or a HPLC analysis; (3) significantly up-regulated metabolites correlated with synthesis of IAA, JA, gibberellin (GA), and salicylic acid, such as GA53, M-SA, (+/-)7-epi-JA, and derivatives of tryptophan and indole in the metabolome analysis. However, results of transcriptome analysis showed that (1) no upregulated differentially expressed genes (DEGs) were enriched in IAA synthesis; (2) some upregulated DEGs were found to be enriched in JA and GA53 synthesis pathways. In summary, although Se(IV) stimulated the synthesis of IAA, JA, and GA53, it significantly inhibited root growth mainly by 1) affecting signal transduction of IAA and GA; 2) altering IAA polar transport and homeostasis; and 3) regulating DEGs including SAUR32, SAUR36, SAUR76, OsSub33, OsEXPA8, OsEXPA18, and Os6bglu24.

Influencing mechanisms of tartaric acid on adsorption and degradation of tetracycline on goethite: insight from solid and liquid aspects

The interactions between organic pollutants and iron minerals play an important role in their environmental fate. In this study, the effects of low-molecular-weight organic acids (LMWOAs) on the adsorption and degradation of tetracycline (TC) on goethite were investigated. Tartaric acid (TA) was taken as the representative of LMWOAs to study the influencing mechanism through batch experiments and microscale characterization. In addition, the properties of TC-TA clusters under different pHs were determined by density functional theory (DFT) calculations. The results showed that all five LMWOAs inhibited TC adsorption and degradation. The preferential adsorption of TA on goethite changed TC adsorption from inner spherical to outer spherical complexation and mainly inhibited TC adsorption and degradation of the singly coordinated hydroxyl group. TC degradation rate decreased from 0.0287 to 0 h-1 in the first stage. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results showed that TA could influence the interactions of amide groups, C = O on the A-ring, and dimethylamino group of TC with goethite, and the formation of ≡Fe(II) was inhibited. In addition to competing for the effective sites, the effects of complexation between TA and TC in solution should be considered. According to DFT calculations, hydrogen bonds could be formed between the carboxyl group of TA and the H atom of TC at different pH. These findings can provide evidence for estimating the contribution of adsorption and degradation to TC removal by iron oxides with the coexistence of LMWOAs in a soil-water environment.

Enhancing enzymatic saccharification of sunflower straw through optimal tartaric acid hydrothermal pretreatment

Sunflower straw, a usually neglected and abundant agricultural waste, has great potential for contributing to environmental protection realizing its high-value of valorization if utilizing properly. Because hemicellulose contains amorphous polysaccharide chains, relatively mild organic acid pretreatment can effectively reduce its resistance. Through hydrothermal pretreatment, sunflower straw was pretreated in tartaric acid (1 wt%) at 180 ^oC for 60 min to enhance its reducing sugar recovery. After tartaric acid-assisted hydrothermal pretreatment, 39.9% of lignin and 90.2% of hemicellulose were eliminated. The reducing sugar recovery increased threefold, while the solution could be effectively reused for four cycles. The properties of more porous surface, improved accessibility, and decreased surface lignin area of sunflower straw were observed through various characterizations, which explained the improved saccharide recovery and provided a basis for the mechanism of tartaric acid-assisted hydrothermal pretreatment. Overall, this tartaric acid hydrothermal pretreatment strategy greatly provided new impetus for the biomass refinery.

Assessment of natural low molecular weight organic acids in facilitating cadmium phytoextraction by Lepidium didymus (Brassicaceae)

The present study examined the ability of three naturally occurring low molecular weight organic acids (tartaric, TA; citric, CA; and oxalic, OA) to improve the efficiency of cadmium (Cd) phytoextraction in Lepidium didymus L. (Brassicaceae). The plants were grown in soil containing three different concentrations, i.e., 35, 105, and 175 mg kg^-1, of total Cd and 10 mM of TA, CA, and OA. After 6 weeks, plant height, dry biomass, photosynthetic traits, and metal accumulation were determined. All three organic chelants significantly increased the Cd accumulation in L. didymus plants; however, the greatest accumulation was seen with TA (TA > OA > CA). In general, Cd accumulation was the highest in the roots, followed by the stems, and the leaves. Highest BCF_Stem was observed upon the addition of TA (7.02) and CA (5.90) at Cd₃₅, compared to Cd-alone (3.52) treatment. The BCF was the highest in the stem (7.02) and leaves (3.97) under Cd₃₅ treatment supplemented with TA. The BCF_Root in the plants under different chelant treatments were in the following order: Cd₃₅ + TA (~ 100) > Cd₃₅ + OA (~ 84) > Cd₃₅ + TA (~ 83). The stress tolerance index and translocation factor (root-stem) were maximal at Cd₁₇₅ with TA and OA supplementation, respectively. The study concludes that L. didymus could be a viable option for Cd-remediation projects, and the addition of TA improved its phytoextraction efficiency.

To compare the efficacy of various organic solvents on retrievability of Biodentine and their effect on microhardness of Biodentine and radicular dentin: An in vitro study

Background

Rotary and ultrasonic instruments are not appreciable in the complete removal of Biodentine from root canals. Therefore, organic solvents can be used as an adjunct for its retrieval.

Aim

The aim of this study was to compare the efficacy of 10% citric acid, 2% acetic acid, and 20% tartaric acid on the microhardness of Biodentine and radicular dentin.

Materials and Methods

Forty single-rooted extracted teeth were decoronated at the cementoenamel junction and root canals were prepared with peeso reamers. Two-millimeter sections were obtained and restored with Biodentine. All samples were subjected to Vicker's microhardness test to record the microhardness of Biodentine and radicular dentin. Samples were randomly divided into four experimental groups and treated with (n = 20) - distilled water, 10% citric acid, 2% acetic acid, and 20% tartaric acid groups for 10 min, after which specimens were again subjected to the same microhardness test.

Statistical Analysis

The data were subjected to Kruskal-Wallis ANOVA test, followed by Wilcoxon signed-rank test with a level of significance set at P ≤ 0.05.

Results

10% citric acid followed by 2% acetic acid exhibited the lowest mean microhardness values after immersing in respective solutions, whereas 20% tartaric acid exhibited the highest mean microhardness values on Biodentine and radicular dentin.

Conclusion

10% citric acid can be used for retrieving Biodentine from root canals for a limited time without adversely affecting the physical and chemical composition of radicular dentin.

Organocatalytic acetylation of pea starch: Effect of alkanoyl and tartaryl groups on starch acetate performance

Organocatalytic acetylation of pea starch was systematically optimized using tartaric acid as catalyst. The effect of the degree of substitution with alkanoyl (DSacyl) and tartaryl groups (DStar) on thermal and moisture resistivity, and film-forming properties was investigated. Pea starch with DSacyl from 0.03 to 2.8 was successfully developed at more efficient reaction rates than acetylated maize starch. Nevertheless, longer reaction time resulted in granule surface roughness, loss of birefringence, hydrolytic degradation, and a DStar up to 0.5. Solid-state 13C NMR and SEC-MALS-RI suggested that tartaryl groups formed crosslinked di-starch tartrate. Acetylation increased the hydrophobicity, degradation temperature (by ~17 %), and glass transition temperature (by up to ~38 %) of pea starch. The use of organocatalytically-acetylated pea starch with DSacyl ≤ 0.39 generated starch-based biofilms with higher tensile and water barrier properties. Nevertheless, at higher DS, the incompatibility between highly acetylated and native pea starches resulted in a heterogenous/microporous structure that worsened film properties.

Tartaric acid soil-amendment increases phytoextraction potential through root to shoot transfer of lead in turnip

The phytoextraction potential of turnip and comparative effectiveness of three different organic ligands towards removal of lead (Pb) was investigated under field conditions. The 20 d old turnip seedlings were exposed to different Pb levels (0.0218, 2.42 and 4.83 mM Pb) spiked in the soil. After 10 d of Pb application, the soil was spiked with 2.4 mM concentration of different chelates viz. ethylenediaminetetraacetic acid (EDTA), citric acid (CA) and tartaric acid (TA). The 60 d old plants were harvested for growth analyses and determination of photosynthetic pigments, while Pb-concentration in different plant parts was determined from 60 and 90 d old plants. Yield attributes were recorded at the harvesting stage (HS, 90 d old plants). No suppression (rather a stimulation) in the root and shoot growth was evident upon Pb exposure whereas, a reduction in the chlorophyll content occurred at 4.83 mM Pb level. Soil amendment with TA improved chlorophyll contents irrespective of Pb levels while the effect of CA and EDTA was differential. A reduction in the root length while an increase in its diameter was recorded particularly at 4.83 mM Pb stress in 90 d old plants. The turnip retained maximum Pb-fraction in the roots at early growth stages, while EDTA application further increased its retention in root at 4.83 mM Pb regime. Nonetheless, only TA amendment promoted the transfer of Pb to shoot (∼30%) irrespective of Pb regimes. At the HS, application of both TA and EDTA caused substantial uptake of Pb in the root while the maximum shoot Pb-fraction was recorded again due to TA application, particularly at 4.83 mM Pb level. Above all, TA was identified as the most effective chelate that mobilized Pb from root to shoot leading to better growth possibly due to dilution effect, and thus enhanced phytoextraction efficiency in turnip.

Bio-Degradable Polyesters with Rigid Cyclic Diester from Camphor and Tartaric Acid

Despite their excellent, useful, and stable properties, thermoplastics are constantly subject to environmental risks because of their low degradability under thermal, chemical, and mechanical stresses. To overcome the aforementioned issues, we hereby introduce an eco-friendly camphor (Ct) cyclic diester. The Ct diester is designed as a monomer, including a ketal group from the Ct, and shows high thermal stability via a rigid spiro-ring and a bridged bicyclic structure. A series of polyester was synthesized using the Ct diester, including various types of diols and dimethyl terephthalate. PETxCty copolyesters showed appropriate thermal stability up to 414 °C and a high glass transition temperature. This thermal behavior led to amorphous regions as the Ct diester content increased. Regarding the proportion of the Ct diester in the polyester, it was sensitive to hydrolysis and contributed to the degradation of the polyester in acid buffer conditions.

Biochemical changes and quality characterization of cold-stored 'Sahebi' grape in response to postharvest application of GABA

In this study, the effect of γ-aminobutyric acid (GABA) at 0 (control), 20 and 40 mM on maintaining postharvest quality, chilling tolerance and fungal decay of 'Sahebi' grapevine (Vitis vinifera L.) was investigated during 60 days storage at 1 °C. GABA-treated fruits especially at 40 mM showed less weight loss (35%), rachis browning (30%) and decay incident (63%) compared to the control. GABA-induced abscisic acid was linked to lower membrane electrolyte leakage (13%) in treated grapes. Moreover, at the end of 60 days, GABA treatment at 40 mM resulted in higher activities of antioxidant enzymes including superoxide dismutase (50%), catalase (35%), guaiacol peroxidase (65%), and ascorbate peroxidase (47%) and lower malondialdehyde (21%) compared to control samples. The highest soluble sugars and organic acids were related to 40 mM GABA-treated grape clusters. Phenolic compounds (phenolic acids, stilbenes, flavonoids and anthocyanidins) and antioxidant capacity increased in 40 mM GABA-treated grape due to lower polyphenol oxidase activity. Therefore, GABA is recommended for maintaining internal quality and reduction in fungal decay and chilling injury of grapes during postharvest storage.

Robust Cr(VI) reduction over hydroxyl modified UiO-66 photocatalyst constructed from mixed ligands: Performances and mechanism insight with or without tartaric acid

Hydroxyl modified UiO-66 ((OH)₂-UiO-66-X%, X represents the mass content ratio of introduced 2,5-dihydroxyterephthalic acid) was prepared via a solvothermal reaction between zirconium tetrachloride, benzene-1,4-dicarboxylic acid (H₂BDC), as well as 2,5-dihydroxyterephthalic acid (H₂BDC-(OH)₂). It was found that hydroxyl groups can act as the intramolecular hole scavenger to boost the photo-induced charge carrier separation to enhance Cr(VI) reduction. The photocatalytic Cr(VI) reduction activities of (OH)₂-UiO-66-X% were investigated upon the irradiation of low-power ultraviolet LED light. The findings demonstrated that (OH)₂-UiO-66-20% with good cyclicity and stability exhibited superior photocatalytic performances to both UiO-66 and (OH)₂-UiO-66. The introduction of hydroxyl groups can also extend the light absorption region to longer wavelength in visible range, which provides possibility for displaying photocatalytic activities under sunlight. The effect of small molecule organic acid (SOAs), pH value, and co-existing inorganic ions on photocatalytic performances of (OH)₂-UiO-66-20% were investigated. Tartaric acid (TA) as typical SOAs was introduced to the reaction system to further boost the photocatalytic Cr(VI) reduction via acting as hole scavenger, constructing charge-transfer-complex for quick electron transportation, and producing COO·^- radicals. This work opened a new opportunity for modified MOFs for boosted elimination activities for environmental pollutants.

Photocatalytic reduction of Cr(VI) over cinder-based nanoneedle in presence of tartaric acid: Synergistic performance and mechanism

Cr(VI) is a common heavy metal ion, which will seriously harm human body and environment. Therefore, the removal of Cr(VI) has become an attractive topic. In this work, cinder was used as a raw material to synthesize a nanoneedle material: γ-(AlOOH@FeOOH) (γ-Al@Fe). The physicochemical properties of γ-Al@Fe were thoroughly characterized, and its effectiveness as a catalyst for photocatalytic reduction of Cr(VI) was evaluated. The results showed that Cr(VI) could be efficiently reduced by γ-Al@Fe in the presence of tartaric acid (TA) under visible light. The variable factors on the reaction were investigated in detail, and the results showed that under optimal conditions (γ-Al@Fe 0.4 g/L, TA 0.6 g/L, pH 2), Cr(VI) was completely reduced within 7 min. Besides, scavenger experiments and EPR proved that O₂^{• -} and CO₂^{• -} played a significant role in the photocatalytic reduction of Cr(VI). TA acts as a sacrificial agent to trap the holes and generate strong reducing free radicals: CO₂^{• -}. Dissolving O₂ could react with electrons to generate O₂^{• -}. This work discussed the performance and mechanism of photocatalytic reduction of Cr(VI) in detail, which provided a new idea for the resource utilization of solid waste and the treatment of heavy metal sewage.

Photoreductive dissolution of schwertmannite loaded with Cr(VI) induced by tartaric acid

Schwertmannite (SCH) as an adsorbent for Cr(VI) removal has been widely investigated. However, there are limited reports on photoreduction driven dissolution of SCH loaded with Cr(VI) (SCH-Cr(VI)) and the fate of Cr(VI) in the presence of dissolved organic matter (DOM). In this study, the effect of tartaric acid (TA) on the stability of SCH-Cr(VI) exposed to simulated solar radiation was examined. The results demonstrated that TA could greatly enhance the release of the dissolved total Fe (TFe) from SCH-Cr(VI). Conversely, the dissolved total Cr (TCr) obviously declined. Low pH promoted the liberation of TFe and TCr. The presence of ions including Al³⁺, Ca²⁺, K⁺ and CO₃^2- exerted different impact on the photoreductive dissolution of SCH-Cr(VI) induced by TA. On the basis of the species distribution of iron and chromium and the characterization of the solid samples, the underlying mechanism is proposed for the transformation and the fate of Cr(VI). Cr(VI) was reduced to Cr(III) by Fe(II) generated from Fe(III)-TA_n via ligand to metal charge transfer. The produced Cr(III) was adsorbed by SCH or co-precipitates with Fe(III). Thus, this study helps us to gain an insight into the mobility and fate of Cr(VI) in acid mining drainage containing DOM, and will help design remediation strategies for Cr contamination.

Metagenomics reveals functional profiling of microbial communities in OCP contaminated sites with rapeseed oil and tartaric acid biostimulation

Organochlorine pesticides (OCPs) contaminated sites pose great threats to both human health and environmental safety. Targeted bioremediation in these regions largely depends on microbial diversity and activity. This study applied metagenomics to characterize the microbial communities and functional groups composition features during independent or simultaneous rapeseed oil and tartaric acid applications, as well as the degradation kinetics of OCPs. Results showed that: the degradation rates of α-chlordane, β-chlordane and mirex were better when (0.50% w/w) rapeseed oil and (0.05 mol L^-1) tartaric acid were applied simultaneously than singular use, yielding removal rates of 56.4%, 53.9%, and 49.4%, respectively. Meanwhile, bio-stimulation facilitated microbial enzyme (catalase/superoxide dismutase/peroxidase) activity in soils significantly, promoting the growth of dominant bacterial communities. Classification at phylum level showed that the relative abundance of Proteobacteria was significantly increased (p < 0.05). Network analysis showed that bio-stimulation substantially increased the dominant bacterial community's proportion, especially Proteobacteria. The functional gene results illustrated that bio-stimulation facilitated total relative abundance of degradation genes, phosphorus, carbon, nitrogen, sulfur metabolic genes, and iron transporting genes (p < 0.05). In metabolic pathways, functional genes related to methanogenesis and ammonia generation were markedly upregulated, indicating that bio-stimulation promoted the transformation of metabolic genes, such as carbon and nitrogen. This research is conducive to exploring the microbiological response mechanisms of bio-stimulation in indigenous flora, which may provide technical support for assessing the microbial ecological remediation outcomes of bio-stimulation in OCP contaminated sites.

Novel Fe(III)-Polybasic acid coordination polymer nanoparticles with targeted retention for photothermal and chemodynamic therapy of tumor

The development of Fe-coordination polymer-based nanoparticles, with safe and high anti-tumor effects, for the treatment of tumor is facing challenges such as limited resources and poor targeting. In this study, we prepared Fe-polyhydroxy coordination polymer nanoparticles (TA-Fe@MNPs), based on tartaric acid (TA)-Fe(III) coordination polymer as the new photothermal agent, mannose (M) as the target, and bovine serum albumin (BSA) and polyethyleneimine (PEI) as the carrier materials, and investigated them for targeting the multifunctional therapy of tumors. The TA-Fe@MNPs synthesized via a simple coordination of Fe³⁺ with TA, bovine serum albumin, and polyethyleneimine under ambient conditions exhibited an appropriate size (~125 nm), electrically neutral surfaces, good biocompatibility, and low normal cell toxicity. The TA-Fe@MNPs are the first to exhibit a remarkable photothermal performance. They also showed a pH-sensitive Fenton-like response that was further enhanced via glutathione response. Interestingly, after a single injection, the TA-Fe@MNPs could be retained at the tumor site for 36 h with an effective photothermal dose, which was attributed to the reduced protein adsorption and slow elimination in tumor cells with the aid of M modification and carrier materials, while that for the TA-Fe@NPs did so for only 2 h. Tumor ablation was demonstrated by in vivo photothermal and chemokinetic therapy using TA-Fe@MNPs, and their safety was evident from the weight changes and blood parameters. These results indicated that the TA-Fe@MNPs, as new photothermal and CDT agents, have the potential to be used in clinical tumor therapy nanoplatforms.

Cough-Inducing Method Using a Tartaric Acid Nebulizer for Patients with Silent Aspiration

The tartaric acid nebulizer is a well-known cough test to evaluate cough function. This study aimed to evaluate the effectiveness of a cough-inducing method using tartaric acid (CiTA). Patients with dysphagia examined by videofluoroscopic examination of swallowing (VF) at a single institution from May 2017 to August 2017 were included in this retrospective observational study. Although undergoing VF, patients who had aspirated without reflexively coughing or who had coughed insufficiently, were instructed to cough voluntarily. Patients who could not cough voluntarily or had expectorated insufficiently underwent the CiTA method. The rate of cough induction and the effectiveness of expectoration using the CiTA method were evaluated. One hundred fifty-four patients (mean age 69.2 ± 16.8 years) were evaluated. Eighty-seven patients aspirated during VF. Of those patients, 15 were able to expectorate via the cough reflex, 18 were able to expectorate with a voluntary cough, and 12 required suctioning for removal of aspirated material. The remaining 42 patients underwent the CiTA method. Thirty-eight patients (90.4%) could reflexively cough, and 30 (71.4%) could expectorate the aspirated material. This novel method, CiTA, was effective for cough induction in patients with dysphagia, especially for those with silent aspiration.

New insights into the mechanisms of tartaric acid enhancing homogeneous and heterogeneous copper-catalyzed Fenton-like systems

The specific roles of tartaric acid (TA), as an eco-friendly ligand, in homogeneous and heterogeneous copper-catalyzed systems were systematically revealed and new mechanisms of TA enhancing the three Fenton-like processes were proposed to provide a theoretical significance in overcoming the deficiency of conventional Fenton processes. The results identified hydroxyl radical (•OH) as the main species responsible for the simultaneous decomposition of TA and metronidazole (MNZ) according to TOC removal. The ESR technique was used to detect superoxide radicals (•O₂^-), carbon-centered radical (•R) and hydrogen radical (•H) in the Cu²⁺/TA/H₂O₂ system, which contributed to the acceleration of the Cu²⁺/Cu⁺ redox cycle. The enhancing effect of TA on the homogeneous process was ascribed to the formation of a soluble complex with Cu²⁺, which favored the pH range extension, Cu⁺ oxidation, and radical generation. Moreover, the adsorption of TA on the catalysts surface promoted the consumption of H₂O₂, inducing •OH generation. The formed surface complex (≡Cu²⁺-TA) also accelerated the regeneration of ≡Cu⁺, which was confirmed by density functional theory (DFT) calculation and surface characterization analysis (SEM, XRD, and XPS). The possible degradation pathways of MNZ in TA-modified Fenton-like system were also clarified.

Simultaneous measurement of Cr(III) and Cu(II) based on indicator-displacement assay using a colorimetric nanoprobe

High-performance analysis of heavy metal ions is great importance in both environment and food safety. In this work, a facile and reliable colorimetric sensor was presented for simultaneous detection of Cu²⁺ and Cr³⁺ based on indicator-displacement assay (IDA). As a typical silicate nanomaterials, ZnSiO₃ hollow nanosphere (ZSHS) exhibited an outstanding ion exchange capacity. Zincon was incorporated with the ZSHS to form a zincon/ZSHS hybrid ionophore with a blue color. Upon the addition of Cr³⁺, IDA reaction and selective ion exchange occurred with the color change of zincon/ZSHS ionophore from blue to yellow. With such a design, colorimetric measurement of Cr³⁺ was realized. The linear concentration for Cr³⁺ detection ranged from 0.5 μM to 75 μM with the LOD of 83.2 nM. Furthermore, we also screened different kinds of complexing agents that may respond with zincon/ZSHS ionophore and various metal ions. It was found that tartaric acid (TA) showed the chelation capability of Zn²⁺-TA is stronger than that of Zn²⁺-zincon. Thus zincon/ZSHS/TA presented a yellow color due to the chelation reaction of Zn²⁺-TA, releasing the zincon as a free state. After addition of Cu²⁺, a stronger chelation reaction of Cu²⁺-zincon occurred. This process involved in the color change from yellow to blue and realized colorimetric measurement of Cu²⁺. The detection limit of Cu²⁺ was calculated to be 43.7 nM with linear range from 0.1 to 20 μM. In addition, the zincon/ZSHS nanoprobe was successfully applied for simultaneous measurement of Cu²⁺ and Cr³⁺ in sorghum and river water, indicating that the zincon/ZSHS nanoprobe provided a promising sensing platform in environment and food safety.

Synthesis, Structure Study, First-Principles Investigations and Luminescence Properties of Europium and Terbium Complexes

The synthesis of 1-benzyl-2-((2-Aminoethyl) amino)-5-oxopyrrolidine-3,4-diyl diacetate (boad), an oxopyrrolidine type ligand; designed to coordinate lanthanides (Eu³⁺ and Tb³⁺) to get luminescent material. The target complexes showed good photoluminescence properties, which indicate that this type of compound can be used as sensitizers having luminescence for the green (Tb³⁺) and red (Eu³⁺) emission. The obtained results revealed that sensitizer efficiency can be improved by adding ligands like acac (Eu(acac)₃, which has also enhanced the luminescence quantum output and period for Eu³⁺ ions. The ground state geometries were developed by using density functional theory at B3LYP/6-31G** level. The charge transfer analysis and electronic properties were performed. The Europium and Terbium complexes formation with boad ligand was explored based on molecular electrostatic potential, MDC-q charges, and frontier molecular orbitals (FMOs) analysis.

Effect of ethanol, glycerol, glucose/fructose and tartaric acid on the refractive index of model aqueous solutions and wine samples

The refractive index is a basic optical property of materials. This study explores the effect of ethanol, glycerol, tartaric acid and glucose/fructose on the refractive index in model aqueous solutions and in dry white wines. Various model aqueous solutions consisting of these components were prepared and the refractive index was measured at 20 °C and each component was studied both alone and in mixtures with the others. The refractive index of white dry wines samples was also measured. A linear regression analysis was performed and linear multi-dependence equations were derived. The resulting regression models had a coefficient of determination over 97.3%. Glucose/fructose was found to have the greatest effect on the refractive index, followed by tartaric acid and glycerol while ethanol had the smallest effect. The knowledge of the correlation of the concentration of each wine component to the refractive index can be of value for the estimation of fermentation kinetics.

High strength brushite bioceramics obtained by selective regulation of crystal growth with chiral biomolecules

Chirality seems to play a key role in mineralization. Indeed, in biominerals, the biomolecules that guide the formation and organization of inorganic crystals and help construct materials with exceptional mechanical properties, are homochiral. Here, we show that addition of homochiral l-(+)-tartaric acid improved the mechanical properties of brushite bioceramics by decreasing their crystal size, following the classic Hall-Petch strengthening effect; d-(-)-tartaric acid had the opposite effect. Adding l-(+)-Tar increased both the compressive strength (26 MPa) and the fracture toughness (0.3 MPa m^1/2) of brushite bioceramics, by 33% and 62%, respectively, compared to brushite bioceramics without additives. In addition, l-(+)-tartaric acid enabled the fabrication of cements with high powder-to-liquid ratios, reaching a compressive strength and fracture toughness as high as 32.2 MPa and 0.6 MPa m^1/2, respectively, approximately 62% and 268% higher than that of brushite bioceramics prepared without additives, respectively. Characterization of brushite crystals from the macro- to the atomic-level revealed that this regulation is attributable to a stereochemical matching between l-(+)-tartaric acid and the chiral steps of brushite crystals, which results in inhibition of brushite crystallization. These findings provide insight into understanding the role of chirality in mineralization, and how to control the crystallographic structure of bioceramics to achieve high-performance mechanical properties. STATEMENT OF SIGNIFICANCE: Calcium-phosphate cements are promising bone repair materials. However, their suboptimal mechanical properties limit their clinical use. Natural biominerals have remarkable mechanical properties that are the result of controlled size, shape and organization of their inorganic crystals. This is achieved by biomineralization proteins that are homochiral, composed of l- amino acids. Despite the importance of chiral l-biomolecules in biominerals, using homochiral molecules to fabricate bone cements has not been studied yet. In this study, we showed that homochiral l-(+)-tartaric acid can regulate the crystal structure and improve the mechanical properties of a calcium-phosphate cement. Hence, these findings open the door for a new way of designing strong bone cement and highlight the importance of chirality in bioceramics.

Unique root exudate tartaric acid enhanced cadmium mobilization and uptake in Cd-hyperaccumulator Sedum alfredii

Low molecular weight organic acids (LMWOA) involved in heavy metal tolerance, translocation, and accumulation in plants. However, underlying mechanism of LMWOA secretion in metal mobilization and uptake in hyperaccumulator still need to be identified. In this study, a ¹³C labeling rhizobox was designed to investigate the composition and distribution of LMWOA in the rhizosphere of S. alfredii. The result showed that about 2.30%, 2.25% and 2.35% of the assimilated ¹³C was incorporated into oxalic acid, malic acid, and tartaric acid in rhizosphere of S. alfredii after ¹³CO₂ assimilation, respectively. Oxalic acid, malic acid, and tartaric acid were the predominant LMWOA in rhizosphere soil solution of hyperaccumulating ecotype (HE) S. alfredii, however, almost no tartaric acid was detected for non-hyperaccumulating ecotype (NHE). Tartaric acid was identified as the unique root exudate from HE S. alfredii which was mainly distributed within the range of rhizosphere 0-6 mm. Tartaric acid significantly increased the solubility of four Cd minerals. HE S. alfredii treated with tartrate + CdCO₃ had higher Cd contents and larger biomass than CdCO₃ treatment. Cadmium accumulation in HE S. alfredii was promoted by the exudation of tartaric acid, which was highly efficient in Cd solubilization due to the formation of soluble Cd-tartrate complexes.

Synthesis, characterization and application of crosslinked alginate as green packaging material

Plastic films for food wrapping, packing are widely used due to their special properties. These fossil fuel derived films are associated with long degradation time, toxicity and environmental pollution. Pineapple waste, sea weed can be very good renewable, alternative carbon sources to produce edible films. These edible films can be consumed by lower animals thereby overcoming the disposal problems of accumulating waste plastic and hence reducing pollution. In the present study, crosslinked polymers are prepared from pectin (P)/sodium alginate (SA) through crosslinking with bio-based acids such as citric acid (CA) and tartaric acid (TA). Pectin was extracted from waste pineapple shell and sodium alginate extracted from seaweed. The crosslinked films were characterized by using various analytical techniques such as FT-IR, thermogravimetry, and scanning electron microscopy (SEM). Mice feed study (testing of edibility), plant growth substrate and vermicomposting of these films was studied. Finally a suitable application of these newly prepared polymeric films has been evaluated as wrapping material on food products such as chocolate and Indian vegetable puff to enhance the shelf life of food.

Effect of ethanol, glycerol, glucose and tartaric acid on the viscosity of model aqueous solutions and wine samples

Viscosity is a property that exerts great influence on the body of wines, since it affects the sensation of thickness in the mouth. The present study refers to the quantitative correlation of the major components of wine, alcohol, reduced sugar, glycerol and total acidity, in its viscosity. Various model aqueous solutions consisting of these components were prepared and viscosity was measured at 20 °C. Each component was studied either alone or in mixtures with the others. Viscosity of white dry wines samples was also measured. From the experimental results, linear multi-dependence equations were derived, which correlate the viscosity with the concentration of the components of the solutions, each of them alone and in combination. Glucose was found to affect viscosity of model aqueous solutions the most, whereas ethanol had the least effect. The knowledge of these factors may have a practical value in optimizing wine's body.

Goethite catalyzed Cr(VI) reduction by tartaric acid via surface adsorption

The surface catalysis of goethite on the Cr(VI) reduction by tartaric acid was examined together with its adsorption characteristics towards the two reactants. The results showed the adsorption of tartaric acid by goethite was favorable at low pH and adsorption isotherm could be properly described by Langmuir model. The adsorption kinetic curves for both reactants obeyed the pseudo second-order rate model (R² >0.99). The FTIR spectrum suggested the formation of bidentate binuclear surface complexes between tartaric acid and goethite. At pH 4.50, the reduction percentage of 0.1 mM Cr(VI) by 1.0 mM tartaric acid alone was about 12% after 72 h, while which was increased to 100% in the presence of goethite within 24 h. Kinetic results revealed the Cr(VI) reduction only occurred between the adsorbed tartaric acid and the aqueous Cr(VI) since the Cr(VI) adsorption was completely inhibited under the examined conditions. Meanwhile, the catalysis of aqueous Fe(III) released from the goethite surfaces was excluded due to its low concentration (<5 μM). With the initial concentration of tartaric acid decreased to 0.1 mM, Cr(VI) reduction could be completed within 4 h, confirmed by the XPS result that only Cr(III) species existed on the goethite surfaces. In this case, electron transfer was suggested to occur directly between the two adsorbed reactants or goethite was believed to serve as an ideal channel to allow electron excited from the adsorbed tartaric acid to transfer to the adsorbed Cr(VI). The findings above were helpful for us to understand the Cr(VI) reduction by organic compounds in soils with rich contents of Fe-oxides.

First ethnobotanical inventory and phytochemical analysis of plant species used by indigenous people living in the Maromizaha forest, Madagascar

ETHNOPHARMACOLOGICAL RELEVANCE

Characterized by one of the highest rates of endemism and biodiversity in the world, Madagascar provides a wide variety of medicinal plants, that could represent a potential source of new drugs. The main aim of this study was to investigate the potential medicinal properties of the plant species used by indigenous people in Maromizaha forest and to provide the first ethnobotanical inventory of the area.

MATERIALS AND METHODS

Data were collected through open semi-structured interviews with local informants, the reported plants were collected and identified to create a specimen herbarium. Informant Consensus Factor (ICF) was calculated for each ailment category mentioned in the use-reports. A selection of seven medicinal plants was submitted to phytochemical and antimicrobial analysis. The results were discussed and compared with those described in ethnobotanical and pharmacological literature.

RESULTS

One hundred and three villagers were interviewed and a total of 509 use-reports were recorded. Information on 117 plant species belonging to 57 botanical families were provided. 12 categories of indigenous uses were recognized, among them the higher ICF values were recorded for cardiovascular complaints (0.75), general and unspecific diseases (0.74), digestive disorders (0.69), and diseases of the skin (0.55). The traditional medicinal uses of 18 species (15 endemic) were described for the first time. In total, 22 different bioactive compounds were identified; polyphenols, monoterpenes, organic acids, and vitamin C were observed in the chemical composition of all the analyzed samples. Macaranga perrieri showed the highest values of both total polyphenolic compounds and antioxidant activity. Antimicrobial activity was observed in leaf and bark extracts of Dilobeia thouarsii.

CONCLUSION

These results confirmed the importance of investigating the traditional use of plant species, suggesting the crucial role of ethnobotanical studies for rural development, biodiversity conservation, and the sustainable use of plant resources in the studied area.

Tartaric acid-induced photoreductive dissolution of schwertmannite loaded with As(III) and the release of adsorbed As(III)

Schwertmannite (SCH) has strong adsorption ability to As(III). However, there are few reports on the stability of SCH load with As(III) (SCH-As(III)). In this study, the effects of tartaric acid (TA), pH and coexisting ions including K⁺, Ca²⁺, Al³⁺ and CO₃^2- on the photoreductive dissolution of SCH- As(III) and the release of the adsorbed As (III) were investigated. The results showed that under UV irradiation TA could greatly enhance the release of total Fe and total As from SCH-As(III). Nevertheless, the total Fe and total As in the solution decreased when TA was consumed up. Compared to SCH, the reductive dissolution of SCH-As(III) was obviously suppressed. In the dark, TA could slowly enhance the dissolution of SCH-As(III), but its effect on the release of adsorbed As(III) was weak. Low pH was conducive to the release of iron and arsenic. Ca²⁺, K⁺, and CO₃^2- promoted the decrease of the dissolved total Fe in the later reaction. However, Al³⁺ inhibited the decrease of the dissolved total Fe and total As. The analyses of FTIR and XRD demonstrated that the mineralogical phase of SCH-As(III) after reaction changed. With light, the dissolved total Fe and total As existed mainly as Fe(II) and As(V), respectively. This is because Fe(II) was generated via ligand to metal charge transfer and As(III) was oxidized to As(V) by ·OH produced during the reaction. Thus, this study provides us with a comprehensive understanding of the stability of SCH-As(III) and the release of adsorbed As(III) in natural environments.

A stimuli-responsive fluorescence platform for simultaneous determination of d-isoascorbic acid and Tartaric acid based on Maillard reaction product

An activatable fluorescence monitoring platform based on a novel Maillard reaction product from d-glucose and L-arginine was prepared through a facile one-pot approach and applied for simultaneous detection of d-isoascorbic acid and tartaric acid. In this work, the new Maillard reaction product GLA was first obtained, and its fluorescence intensity can be effectively quenched by KMnO₄, resulting from a new complex (GLA-KMnO₄) formation between GLA and KMnO₄. Upon addition of d-isoascorbic acid or tartaric acid, an enhanced fluorescence was observed under the optimumed experimental conditions, indicating a stimuli-responsive fluorescence turn on platform for d-isoascorbic acid or tartaric acid can be developed. The corresponding experimental results showed that this turn on fluorescence sensing platform has a high sensitivity for d-isoascorbic acid or tartaric acid, because the detection limits were 5.9μM and 21.5μM, respectively. Additionally, this proposed sensing platform was applied to simultaneously detection of d-isoascorbic acid and tartaric acid in real tap water samples with satisfactory results.

Synthesis and Kinetics of Highly Substituted Piperidines in the Presence of Tartaric Acid as a Catalyst

Aim & Scope

The synthesis of highly substituted piperidine from the one-pot reaction between aromatic aldehydes, anilines and β-ketoesters in the presence of tartaric acid as a catalyst has been investigated in both methanol and ethanol media at ambient temperature. Different conditions of temperature and solvent were employed for calculating the thermodynamic parameters and obtaining an experimental approach to the kinetics and mechanism. Experiments were carried out under different temperature and solvent conditions.

MATERIAL AND METHODS

Products were characterized by comparison of physical data with authentic samples and spectroscopic data (IR and NMR). Rate constants are presented as an average of several kinetic runs (at least 6-10) and are reproducible within ± 3%. The overall rate of reaction is followed by monitoring the absorbance changes of the products versus time on a Varian (Model Cary Bio- 300) UV-vis spectrophotometer with a 10 mm light-path cell.

RESULTS

The best result was achieved in the presence of 0.075 g (0.1 M) of catalyst and 5 mL methanol at ambient temperature. When the reaction was carried out under solvent-free conditions, the product was obtained in a moderate yield (25%). Methanol was optimized as a desirable solvent in the synthesis of piperidine, nevertheless, ethanol in a kinetic investigation had none effect on the enhancement of the reaction rate than methanol. Based on the spectral data, the overall order of the reaction followed the second order kinetics. The results showed that the first step of the reaction mechanism is a rate determining step.

CONCLUSION

The use of tartaric acid has many advantages such as mild reaction conditions, simple and readily available precursors and inexpensive catalyst. The proposed mechanism was confirmed by experimental results and a steady state approximation.

Adsorption of aliphatic polyhydroxy carboxylic acids on gibbsite: pH dependency and importance of adsorbate structure

BACKGROUND

Aliphatic (poly)hydroxy carboxylic acids [(P)HCA] occur in natural, e.g. soils, and in technical (waste disposal sites, nuclear waste repositories) compartments . Their distribution, mobility and chemical reactivity, e.g. complex formation with metal ions and radionuclides, depend, among others, on their adsorption onto mineral surfaces. Aluminium hydroxides, e.g. gibbsite [α-Al(OH)₃], are common constituents of related solid materials and mimic the molecular surface properties of clay minerals. Thus, the study was pursued to characterize the adsorption of glycolic, threonic, tartaric, gluconic, and glucaric acids onto gibbsite over a wide pH and (P)HCA concentration range. To consider specific conditions occurring in radioactive wastes, adsorption applying an artificial cement pore water (pH 13.3) as solution phase was investigated additionally.

RESULTS

The sorption of gluconic acid at pH 4, 7, 9, and 12 was best described by the "two-site" Langmuir isotherm, combining "high affinity" sorption sites (adsorption affinity constants [Formula: see text] > 1 L mmol^-1, adsorption capacities < 6.5 mmol kg^-1) with "low affinity" sites ([Formula: see text] < 0.1 L mmol^-1, adsorption capacities ≥ 19 mmol kg^-1). The total adsorption capacities at pH 9 and 12 were roughly tenfold of that at pH 4 and 7. The S-shaped pH sorption edge of gluconic acid was modelled applying a constant capacitance model, considering electrostatic interactions, hydrogen bonding, surface complex formation, and formation of solved polynuclear complexes between Al³⁺ ions and gluconic acid. A Pearson and Spearman rank correlation between (P)HCA molecular properties and adsorption parameters revealed the high importance of the size and the charge of the adsorbates.

CONCLUSIONS

The adsorption behaviour of (P)HCAs is best described by a combination of adsorption properties of carboxylic acids at acidic pH and of polyols at alkaline pH. Depending on the molecular properties of the adsorbates and on pH, electrostatic interactions, hydrogen bonding, and ternary surface complexation contribute in varying degrees to the adsorption process. Linear distribution coefficients K_d between 8.7 and 60.5 L kg^-1 (1 mmol L^-1 initial PHCA concentration) indicate a considerable mineral surface affinity at very high pH, thus lowering the PHCA fraction available for the complexation of metal ions including radionuclides in solution and their subsequent mobilization.

Synthesis and α-glucosidase inhibition activity of dihydroxy pyrrolidines

A new series of Deacetylsarmentamide A and B derivatives, amides and sulfonamides of 3,4-dihydroxypyrrolidines as α-glucosidase inhibitors were designed and synthesized. The biological screening test against α-glucosidase showed that some of these compounds have the positive inhibitory activity against α-glucosidase. Saturated aliphatic amides were more potent than the olefinic amides. Among all the compounds, 5o/6o having polar -NH₂ group, 10f/11f having polar -OH group on phenyl ring displayed 3-4-fold more potent than the standard drugs. Acarbose, Voglibose and Miglitol were used as standard references. The promising compounds 6i, 5o, 6o, 10a, 11a, 10f and 11f have been identified. Molecular docking simulations were done for compounds to identify important binding modes responsible for inhibition activity of α-glucosidase.

De novo transcriptome analysis of rose-scented geranium provides insights into the metabolic specificity of terpene and tartaric acid biosynthesis

Background

Rose-scented geranium (Pelargonium sp.) is a perennial herb that produces a high value essential oil of fragrant significance due to the characteristic compositional blend of rose-oxide and acyclic monoterpenoids in foliage. Recently, the plant has also been shown to produce tartaric acid in leaf tissues. Rose-scented geranium represents top-tier cash crop in terms of economic returns and significance of the plant and plant products. However, there has hardly been any study on its metabolism and functional genomics, nor any genomic expression dataset resource is available in public domain. Therefore, to begin the gains in molecular understanding of specialized metabolic pathways of the plant, de novo sequencing of rose-scented geranium leaf transcriptome, transcript assembly, annotation, expression profiling as well as their validation were carried out.

Results

De novo transcriptome analysis resulted a total of 78,943 unique contigs (average length: 623 bp, and N50 length: 752 bp) from 15.44 million high quality raw reads. In silico functional annotation led to the identification of several putative genes representing terpene, ascorbic acid and tartaric acid biosynthetic pathways, hormone metabolism, and transcription factors. Additionally, a total of 6,040 simple sequence repeat (SSR) motifs were identified in 6.8% of the expressed transcripts. The highest frequency of SSR was of tri-nucleotides (50%). Further, transcriptome assembly was validated for randomly selected putative genes by standard PCR-based approach. In silico expression profile of assembled contigs were validated by real-time PCR analysis of selected transcripts.

Conclusion

Being the first report on transcriptome analysis of rose-scented geranium the data sets and the leads and directions reflected in this investigation will serve as a foundation for pursuing and understanding molecular aspects of its biology, and specialized metabolic pathways, metabolic engineering, genetic diversity as well as molecular breeding.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3437-0) contains supplementary material, which is available to authorized users.

Tartaric acid induced conversion of protopanaxadiol to ginsenosides Rg3 and Rg5 and their in situ recoveries by integrated expanded bed adsorption chromatography

Panax ginseng has been applied in traditional Chinese medicine for over 2000 years. It is still one of the most popular herbs in recent decades. The prescribed ginseng-containing medicines consist of protopanaxadiol and protopanaxatriol ginsenosides, which are the major constituents of the herb. Minor ginsenosides at low levels in the herb, such as Rg3 and Rg5 , have attracted more rising attention than the major ones. The existing approaches to prepare Rg3 and Rg5 usually rely on either steamed red ginseng as the source or chemical/enzymatic conversion of protopanaxadiol to the targets. It is still highly desirable to effectively achieve such minor components. In this paper, a method integrated extraction of protopanaxadiol and conversion of it to Rg3 and Rg5 has been proposed. Protopanaxadiol was extracted and simultaneously converted to Rg3 and Rg5 by d,l-tartaric acid. The targets were absorbed by resins on expanded bed adsorption chromatography and were then separated from other ginsenosides in different stages. Compared with conventional methods, the developed process has advantages in shortening time consumption and improving the conversion ratio of protopanaxadiol, which is promising in directly achieving Rg3 and Rg5 from P. ginseng.

Physiological responses in roots of the grapevine rootstock 140 Ruggeri subjected to Fe deficiency and Fe-heme nutrition

Iron (Fe)-heme containing fertilizers can effectively prevent Fe deficiency. This paper aims to investigate root physiological responses after a short period of Fe-heme nutrition and Fe deficiency under two pH conditions (with or without HEPES) in the Fe chlorosis-tolerant grapevine rootstock 140 Ruggeri. Organic acids in root exudates, Fe reduction capacity, both roots and root exudates contributions, together with other physiological parameters associated to plant Fe status were evaluated in plants grown in hydroponics. Analyses of root tips by SEM, and Raman and IR spectra of the precipitates of Fe-heme fertilizers were performed. The physiological responses adopted by the tolerant 140 Ruggeri to the application of Fe-heme indicated an increased Fe reduction capacity of the roots. This is the first report showing oxalic, tartaric, malic and ascorbic as major organic acids in Vitis spp. root exudates. Plants reacted to Fe deficiency condition exuding a higher amount of ascorbic acid in the rhizosphere. The presence of HEPES in the medium favoured the malic acid exudation. The lowest concentration of oxalic acid was found in exudates of plants subjected to Fe-heme and could be associated to a higher accumulation in their root tips visualized by SEM analysis.

Chemical modeling for pH prediction of acidified musts with gypsum and tartaric acid in warm regions

Winemaking of musts acidified with up to 3g/L of gypsum (CaSO4 2H2O) and tartaric acid, both individually and in combination, as well as a chemical modeling have been carried out to study the behaviour of these compounds as acidifiers. Prior to fermentation gypsum and tartaric acid reduce the pH by 0.12 and 0.17 pH units/g/L, respectively, but while gypsum does not increase the total acidity and reduces buffering power, tartaric acid shows the opposite behaviour. When these compounds were used in combination, the doses of tartaric acid necessary to reach a suitable pH were reduced. Calcium concentrations increase considerably in gypsum-acidified must, although they fell markedly after fermentation over time. Sulfate concentrations also increased, although with doses of 2g/L they were lower than the maximum permitted level (2.5g/L). Chemical modeling gave good results and the errors in pH predictions were less than 5% in almost all cases.

Enhancement of carvedilol solubility by solid dispersion technique using cyclodextrins, water soluble polymers and hydroxyl acid

Aim of the present work is to enhance aqueous solubility of carvedilol (CV) by solid dispersion technique using wide variety of carriers such as: β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD), tartaric acid (TA), polyvinyl pyrrolidone K-30 (PVP K-30) and poloxamer-407 (PLX-407). Various products of 'CV-solid dispersion' had been studied extensively in various pH conditions to check enhancement of solubility and dissolution characteristics of carvedilol. Any physical change upon interaction between CV and carriers was confirmed by instrumental analysis: XRD, DSC, FTIR and SEM. Negative change of Gibb's free energy and complexation constants (Kc, 75-240M(-1), for cyclodextrins and 1111-20,365M(-1), for PVP K-30 and PLX-407) were the evidence of stable nature of the binding between CV and carriers. 'Solubility enhancement factor' of ionized-CV was found high enough (340 times) with HPβCD in presence of TA. TA increases the binding efficiency of cyclodextrin and changing the pH of microenvironment in dissolution medium. In addition, ionization process was used to increase the apparent intrinsic solubility of drug. In vitro, dissolution time of CV was remarkably reduced in the solid dispersion system compared to that of pure drug. This may be attributed to increased wettability, dispersing ability and transformation of crystalline state of drug to amorphous one.

Effect of different coagulants at varying strengths on the quality of paneer made from reconstituted milk

A study was conducted to determine the effect of different types of acids viz., citric acid, tartaric acid and malic acid each at 2, 3 and 5% concentrations on the quality of paneer made using reconstituted milk. The moisture, total solid recovery and yield and sensory scores for flavour, body and texture and overall acceptability of paneer decreased with the increasing strength of acid. However, these parameters for paneer made using coagulants at 2 and 3% levels were statistically comparable (P > 0.05). Fat and protein per cent increased with the increase in the concentration of the acid. No difference was observed in the levels of ash and fat on dry matter basis and pH and appearance scores at all the three concentrations of the coagulants. The type of coagulant also elicited variations in most of the constituents of paneer. The paneer samples made with citric acid and tartaric acid had significantly higher (P ≤ 0.05) values for fat, protein, ash, total solids recovery, fat on dry matter basis, body and texture and overall acceptability scores than paneer made with malic acid at all concentrations. No significant difference was seen in appearance and flavour scores among all the samples. In order to produce paneer with the most desirable characteristics from reconstituted milk, it is suggested citric acid and tartaric acid at 2% concentration can be utilized as coagulants.

High-shear granulation as a manufacturing method for cocrystal granules

Cocrystal formation allows the tailoring of physicochemical as well as of mechanical properties of an API. However, there is a lack of large-scale manufacturing methods of cocrystals. Therefore, the objective of this work was to examine the suitability of high-shear wet granulation as a manufacturing method for cocrystal granules on a batch scale. Furthermore, the cocrystal granules were characterized regarding their mechanical properties as well as their dissolution behavior. High-shear wet granulation was found to be a feasible manufacturing method for cocrystal granules. Cocrystal formation depended on the exposure time of the solids to the granulation liquid (water), the amount of liquid, the impeller speed of the granulator, and on the excipients (hydroxyl propylcellulose, microcrystalline cellulose, calcium hydrogenphosphate) used in the formulation. Storage stability was strongly influenced by the excipients, since in presence of calcium hydrogenphosphate, the poorly water-soluble salt calcium tartrate monohydrate was formed at high relative humidity. Interestingly, compactability was increased by cocrystal formation compared to that of the reference granules (piracetam and the respective excipients). The drug release was slightly decreased by cocrystal formation, most likely due to the lower solubility of the cocrystal. In the presence of calcium hydrogenphosphate however, no influence of cocrystal formation on either compactability or on drug release were observed, compared with the reference tablets. It was concluded that high-shear wet granulation is a valuable, however complex, manufacturing method for cocrystals. Cocrystal formation may influence compactability and drug release and thus affect drug performance and should be investigated during pre-formulation.

A remarkable cyclization of TADDOL-bisthioacetate under oxidative conditions

Abstract

Attempted oxidation of a TADDOL-derived bisthioacetate resulted in a rather unexpected and remarkable cyclization and deprotection reaction, giving a thiolane-1,1-dioxide as the main product. Systematic in situ ESI-HRMS studies revealed a bicyclic, highly acid labile key intermediate of this reaction. Supported by force field calculations, the high sensitivity of this intermediate was judged to be due to the formation of a highly strained trans-configured bicyclo[3.3.0]skeleton.

Graphical abstract