Oxalic Acid Concentration Research Articles

Aroma precursors of cigars from different tobacco parts and origins, and their correlations with sensory characteristics.

Cigars are developing rapidly around the world, but the content characteristics of aroma precursors and their contribution to sensory perception have not been fully elucidated. In this study, 69 aroma precursors from 61 tobaccos of different parts and origins were systematically determined, and the sensory characteristics of middle leaves from different origins and their correlation with aroma precursors were evaluated. The results showed that tobacco parts mainly affected amino acid content, and contents of nicotine, oxalic acid, malic acid, isovaleric acid, cystine, glutarnine, glycine, isoleucine, glutamicacid, asparticacid, and fructose-proline were significantly changed. Tobacco origins mainly influenced the contents of amino acids, polyacids and high fatty acids, and sugar alcohols, and significantly affected the contents of myosmine, anabasine, nonanoic acid, propanetriol, mannitol, mannose, glucose, alanine, arginine, glutarnine, glutamicacid, histidine, serine, threonine, tryptophan, fructose-alanine, and fructose-asparagine. The flavor characteristics were prominent by wood aroma, and the style and quality characteristics varied greatly among different origins of middle leaves. There were 34, 21, and 22 aroma precursors with high correlations with flavor, style, and quality characteristics. This study provides support for regulating the content and coordination of aroma precursors in different tobacco parts and origins to improve sensory characteristics.

Content of Organic Acid and Essential Fatty Acid in Natural Sweet Chestnuts Growing in Giresun/Turkey

This study investigated organic acid and volatile fatty acid components of sweet chestnut fruits collected from naturally growing chestnut trees within the borders of Giresun province. For this purpose, chestnut samples were collected from 10 trees in different regions of Giresun province. The organic acid composition of chestnuts was determined by high-performance liquid chromatography (HPLC). Essential oil components were determined by gas chromatography-mass spectrometry (GC-MS). Five different organic acids, including oxalic, quinic, maleic, citric and succinic acid, were investigated in chestnut samples, and the highest oxalic and citric acid concentrations were found in chestnut samples. In the GC-MS analysis of chestnut samples, 18 fatty acids were detected and terpilonene (TPO) was the most abundant among them. Another vital component found in chestnut samples is limonene.

Effect of oxalic acid on postharvest life of tomato modified with the TomLoxB gene in anti-sense

Oxalic acid is an organic compound found in green leafy vegetables, which has proven to be effective in delaying ripening by inhibiting ethylene synthesis in fruits such as banana, mango, peach, tomato, plum, and others. In this study, the response of oxalic acid application on postharvest physiology was evaluated in transgenic tomatoes (Solanum lycopersicum) variety TA234 with the TomLoxB gene insertion in antisense, at two concentrations of oxalic acid: 3 and 10 mM, during 30 d of storage at 25 ± 1 ºC and a relative humidity of 65 - 70 %. The fruits were harvested at break stage and immersed for 10 minutes in the oxalic acid solution, which was maintained at 25 ºC. Upon treatment, less weight loss, better retention of lightness, delay in the decrease of firmness and hue angle, decrease in lipoxygenase activity, low electrolyte leakage and increase in total phenolics content were observed. The most effective oxalic acid concentration was 3 mM, that extended postharvest life by up to 30 d and reduced deterioration of the genetically modified (GM) tomatoes. In turn, the untreated GM tomatoes showed an acceptable appearance up to day 24 of storage, while the wild type fruits were kept satisfactorily for 15 d.

Comparative evaluation of biometrical and biochemical characteristics of three Rumex representatives: <i>Rumex acetosa</i> L., <i>Rumex sanguineus</i> L. and <i>Rumex confertus</i> Willd.

Increase in green vegetables popularity in nutrition and medicine promotes investigations of new cultivar and hybrid biochemical parameters. Nutritional value and antioxidant status of three Rumex representatives: Rumex acetosa L. (Krupnolistny cv.), Rumex sanguineus L. (prospect genotype) and Rumex confertus Willd. were studied. Antioxidant defense parameters (total antioxidant activity, polyphenol and ascorbic acid content) decreased in accordance to: Rumex sanguineus L. > Rumes confertus Willd. > Rumex acetosa L. Thus the ascorbic acid content in bloody dock (R. sanguineus) reached 129 mg/100 g which was 1.48 times higher than in Russian dock (R. confertus) and 3.17 times higher than in garden sorrel (R. acetosa). The total chlorophyll content was also the highest in bloody dock (17.74 mg/g d.w.) compared to 15.88 mg/g in R. confertus and 13.07 mg/g in R. acetosa leaves. The new R. sanguineus genotype was characterized by high decorative properties and demonstrated twice higher oxalic acid content compared to R. acetosa, Krupnolistny cv., and 1.5 times higher value than in R. confertus. High decorative and medicinal value of R. sanguineus was connected to a great extent with the intensive anthocyanin accumulation reaching 7.2% and high nitrate content. The results of the present study indicate high prospects of R. sanguineus genotype utilization in landscape design, food industry and medicine.

Ultrathin VO2(B) nanosheets assembled into 3D micro/nano structured flower-like microspheres for high-performance cathode materials of Li-ion batteries

Vanadium oxides, as a potential cathode material for lithium-ion batteries (LIBs), have received extensive attention from researchers owing to their significant advantages in terms of theoretical specific capacity, energy density, and power density. However, vanadium oxides lead to irreversible decay of specific capacity during cycling for reasons such as poor structural stability and electrical conductivity. In this paper, the flower-like VO2(B) microsphere assembled from ultrathin nanosheets was synthesized successfully by hydrothermal method, and their effects on the morphology as well as the phase of VO2(B) are investigated by varying the hydrothermal reaction time and the concentration of oxalic acid. The results show that the flower-like VO2(B) microsphere electrode material not only provides a larger active area, but also offers a faster lithium ion diffusion rate and a shorter charge transport path, resulting in a high reversible capacity, outstanding rate performance, and excellent long cycle life. The flower-like VO2(B) microsphere electrode exhibited a first discharge specific capacity of 282.9 mAh/g (at a current density of 0.1 A/g) and a capacity retention of 80.7 % after 50 cycles. In addition, the electrode material shows a first discharge specific capacity of 209.6 mAh/g at a high current density (1 A/g) and a capacity retention rate of 83.1 % after 200 cycles. Consequently, the VO2(B) provides great development potential as a cathode material for next-generation LIBs.

Influence of Rheum taxa and harvesting date on the content of L-ascorbic acid and oxalic acid in the climatic conditions of South Moravia (Czech Republic)

ABSTRACT Rhubarb (Rheum L.) is a well-known medicinal and culinary plant. Apart from its rich nutritional value, rhubarb contains a higher concentration of oxalates. In this study, the content of L-ascorbic acid (AA) and oxalic acid (OA) within three rhubarb species (Rheum rhabarbarum, R. rhaponticum and R. palmatum × wittrockii) differentiated to 16 accessions in a gene bank rhubarb collection (Lednice, Czech Republic) in the condition of conventional production in the South Moravia region during the harvesting period was evaluated. While L-ascorbic acid is essential in human nutrition, oxalic acid is considered toxic, and high doses may cause serious health issues. AA and OA content, the morphology evaluation and ISSR (inter simple sequence repeats)-based genetic analysis were performed. The results of this study confirm the significant influence of taxonomy and harvesting time on the content of AA in Rheum accessions. The content of AA was determined from 6 mg · 100 g-1 to 10 g · 100 g-1 fresh weight (FW) at the beginning of the harvesting season (May) up to 25 mg · 100 g-1 FW at the end of the harvesting period. The content of OA strongly varied from 300 mg · 100 g-1 to 1800 mg · 100 g-1 FW. Regarding the antinutrient character of oxalate, the optimal harvest period of this region was estimated to be from May to early June, when the OA content was the lowest. The role of AA as a precursor of oxalate formation in rhubarb was not affirmed by the results of this study.

Modification of the Intensity of Compounds Biosynthesis in the Petioles of Rhubarb (Rheum rhaponticum L.) Induced by the Ozonation Process

Abstract Rhubarb (Rheum rhaponticum L.) is a vegetable that, despite many health-promoting properties, contains large amounts of oxalic acid, which has a negative impact on human health. Treatment of rhubarb petioles with gaseous ozone is one way to improve their quality by changing their chemical properties. As part of the research, an analysis of the mechanical and chemical properties of rhubarb petioles was performed. The analyzes showed that the applied doses of ozone of 10 ppm during 1, 3 and 5 minutes lowered the concentration of oxalic acid during 5 days of tests performed after the ozonation treatment. The most favorable effect on the reduction of oxalic acid, amounting to 36%, was caused by gaseous ozone at a concentration of 10 ppm during 5 minutes compared to the control. In addition, it was noted that on the 1st and 3rd day after using ozone gas, the antioxidant activity of the tested raw material increased significantly. Also on the same days of testing, the total amount of polyphenols increased as a result of the use of ozone fumigation. The largest increase in the total amount of polyphenols, amounting to 12%, was observed for a dose of 10 ppm 5 minutes on the 1st day after the ozonation treatment compared to the control variant. In turn, no positive effect of the ozonation process on the content of vitamin C and the value of destructive force during three-point bending of rhubarb leaf petioles was noted.

The translocation and fractionation of rare earth elements (REEs) via the phloem in Phytolacca americana L.

Rare earth elements (REEs) are considered to be emerging contaminants due to their widespread use and lack of recycling. Phytolacca americana L. has great potential for REEs phytoextraction. Our understanding of REEs in P. americana focuses mostly on root absorption and xylem translocation, but the role of phloem translocation has received little attention. In this research, the translocation and fractionation of REEs from phloem to organs in P. americana were investigated. In addition, the effect of organic acids in the REEs translocation via phloem exudates was also examined. The results showed that REEs could transport bidirectionally via the phloem, and 86% of REEs exported from old leaves could move downwards to the root, whereas only 14% of them transported upwards to the young leaves. Heavy rare earth elements (HREEs) enrichment was found in the REEs fractionation processes both from phloem to leaf and from stem to root, indicating that HREEs were preferentially transferred not only down to roots, but also up to the young leaves. The concentration of oxalic acid in phloem exudates was much higher than other organic acids. 94.7% oxalic acid in phloem exudates was preferred to combine with REEs, especially HREEs. Additionally, the concentrations of HREEs had a high positive correlation with oxalic acid in phloem exudates, which demonstrated oxalic acid may play a significant role in the long-distance transport of HREEs in phloem. In conclusion, HREEs have higher translocation ability than light rare earth elements (LREEs) in both xylem and phloem of P. americana. As far as we know, this is the first report focused on the phloem translocation and redistribution of REEs in P. americana, which provides a valuable understanding of the mechanism for phytoremediation of REEs contaminated soils.

Effect of hermetic storage on the development of hard-to-cook characteristics and nutritional properties of mungbean (Vigna radiata (L.) R. Wilczek) and cowpea (Vigna unguiculata (L.) Walp.)

Mungbean and cowpea samples were stored in hermetic PET-bottles and common polybags at room temperature. After 0, 2, 4, and 6 months of storage, the samples were tested for gas composition, grain hardness, cooking time, proximate composition, free fatty acid (FFA) content, phytic acid content, oxalic acid content and antioxidant properties. The oxygen content of the mungbean and cowpea samples dropped to 7.5 ± 1.7% and 10.7 ± 0.8%, respectively, within 30 days of storage in the hermetic condition compared to control. Samples stored in polybags showed a significant increase in grain hardness and cooking-time compared to the initial samples. In contrast, the grain hardness and cooking time of hermetic samples remained within acceptable levels. The FFA values of the mungbean and cowpea samples in polybags increased by approximately 33% and 40%, respectively, after 6 months. The FFA values increased by 7.5% in mungbean and 11% in cowpea stored hermetically, which was 4 times lower than the polybag-stored samples. After 6 months, the phytic acid content of the grain samples stored in PET-bottles and polybags decreased by approximately 15% and 26%, respectively. Similarly, the oxalic acid contents were also reduced in mungbean and cowpea samples stored in polybags by 14–29% compared to the hermetic samples (2–10%). The results showed that the total phenolic content of grain samples stored in polybags was approximately 32% higher compared to grain samples stored in hermetic PET-bottles and 53% higher compared to the initial samples. These results indicated that significantly lower tendency for the development of hard-to-cook defects in grain samples stored in hermetic PET-bottles. DPPH and hydroxyl free radical scavenging activities showed a significant increase with storage time in both mungbean and cowpea samples regardless of storage method. These results revealed that hermetic storage helps to prevent the development of hard-to-cook characteristics of mungbean and cowpea.

Effects of Magnesium Imbalance on Root Growth and Nutrient Absorption in Different Genotypes of Vegetable Crops.

Magnesium (Mg) plays a crucial role in crop growth, but how Mg supply level affects root growth and nutrient absorption in vegetable crops with different genotypes has not been sufficiently investigated. In this study, the responses of tomato (Solanum lycopersicum L.) and cucumber (Cucumis sativus L.) crops to different levels of Mg supply were explored. Four levels of Mg treatment (i.e., 0.2, 1.0, 2.0, 3.0 mmol/L) were applied under hydroponic conditions, denoted as Mg0.2, Mg1, Mg2, and Mg3, respectively. The results showed that with increasing Mg levels, the plant biomass, root growth, and nutrient accumulation in both vegetable crops all increased until reaching their maximum values under the Mg2 treatment and then decreased. The total biomass per tomato plant of Mg2 treatment was 30.9%, 14.0%, and 14.0% higher than that of Mg0.2, Mg1, and Mg3 treatments, respectively, and greater increases were observed in cucumber plant biomass (by 54.3%, 17.4%, and 19.9%, respectively). Compared with the Mg0.2 treatment, the potassium (K) and calcium (Ca) contents in various plant parts of both crops remarkably decreased under the Mg3 treatment. This change was accompanied by prominently increased Mg contents in various plant parts and para-hydroxybenzoic acid and oxalic acid contents in root exudates. Irrespective of Mg level, plant biomass, root growth, nutrient accumulation, and root exudation of organic acids were all higher in tomato plants than in cucumber plants. Our findings indicate that excessive Mg supply promotes the roots to exude phenolic acids and hinders the plants from absorbing K and Ca in different genotypes of vegetable crops despite no effect on Mg absorption. A nutritional deficiency of Mg stimulates root exudation of organic acids and increases the types of exuded organic acids, which could facilitate plant adaption to Mg stress. In terms of root growth and nutrient absorption, tomato plants outperform cucumber plants under low and medium Mg levels, but the latter crop is more tolerant to Mg excess.

Genetic diversity analysis for seed yield and quality characters in sesame (Sesamum indicum L.)

Genetic divergence wasstudied by growing thirty six genotypes ofsesame, Sesamum indicum L. at Agricultural Research Station, Mandor, Jodhpur during rainy season 2010. The mean sum of squares were significant for all the characters, indicating the presence of variability. Characters like seed yield, free fatty acid, oxalic acid content, number of productive capsules/plant and productive branches/plant exhibited high heritability coupled with high genetic advance revealing that these characters were controlled by additive gene action. The hierarchical cluster analysis indicated the presence of considerable genetic divergence among the genotypes. The genotypes were grouped into seven clusters using Ward's minimum variance method. The intercluster Euclidean2 distance was maximum between cluster III and VII (42.71) followed by cluster VI and VII (41.90) and cluster II and VII (39.03) which indicated that the genotypes included in these clusters will give high heterotic response and thus bettersegregants. The maximum cluster means were revealed by cluster III for days to 50% flowering, maturity, number of productive branches/plant, oxalic acid content and free fatty acid followed by cluster VI for seed yield, number of productive capsules/plant and oil content, and clusterI and IV for plant height and 1000 seed weight,respectively. While cluster VII showed minimum cluster mean for days to maturity, plant height and free fatty acid and cluster I and IV for oxalic acid and days to 50% flowering. Among the 10 characters, number of primary branches/plant contributed the most (12.06%) towards the divergence of genotypes.

Correlation between composition and adhesion properties of a zinc oxide-filled, acrylate pressure sensitive adhesive: An experimental design approach

A Box-Behnken response surface methodology (RSM) was adopted to provide a systematic insight on the adhesion properties of an acrylate-based, pressure sensitive adhesive (PSA) filled with nano-zinc oxide (ZnO) particles as a function of its composition. In addition to the nano-filler morphologies (needle- or plate-like) and their content (0–10 per hundred resin, phr), concentrations of triethyl citrate (TEC, 30–50 phr) plasticizer and oxalic acid (OX, 0.5–1.5 phr) crosslinking agent were also changed with respect to the base polymer. Tack and peel strength properties were measured as adhesive performance characteristics. According to the results, ZnO content and its morphology played no significant role (P < 0.05) in adhesion performance of the compositions made. In contrast, the more plasticizer was used, the more peel strength and tack properties were achieved. OX showed an inverse effect on the tack and peel strength properties at a less statistically significant level. A removable PSA was achieved adopting the RSM methodology to develop formulations, which resulted in a removable and repositionable PSA. To understand these effects, molecular structures of the adhesive ingredients and their interactions were thoroughly discussed.

Effect of magnetic field on voltammetric sensor for electrolytic concentration measurement and electrode–electrolyte interface model based on a novel geometry

Voltammetric sensor models are widely used in electrolytic applications in industry and the laboratory. Research in these domains is enriched with data analytics tools and electrode design, which need to be revised to improve the sensitivity near the Nernst limit. Therefore, an intense demand exists for enhancing the sensitivity of conventional voltammetric sensor models with minimum alteration of design parameters. This research article focuses on the possible impact of a magnetic field in a conventional voltammetric sensor for electrolytic concentration measurement. The experimental results show a 45% increase in sensitivity with a 3%–43% increment in signal attenuation due to the magnetic field. Apart from analysing the impact of a magnetic field, this research also investigates sensors with different electrode materials and input excitation. Among different electrode materials, a sensor with Iron-Niobium is found to have maximum electrolytic sensitivity of 15.78 V mol−1 l−1 while measuring the electrolytic concentration of oxalic acid in the range of 0.001–0.01 mol l−1. Similarly, the proposed voltammetric sensor with Iron-Niobium electrodes is implemented to measure the concentration of other electrolytes with 10–130 V mol−1 l−1 sensitivity to enhance applicability. A modified electrical equivalent model with an additional inductive component is also proposed in this research work that explains the waveform dip followed by a peak overshoot due to the influence of the magnetic field. The proposed electrical equivalent model of electrode–electrolyte interface is compatible with a conventional model, which is confirmed based on the experimental observations and mathematical analysis.

Hydrothermal Leaching Kinetics of Vanadium from an Iron Vanadate Mineral Using Oxalic Acid

Hydrothermal leaching vanadium using oxalic acid is a novel method reported recently to overcome the serious environmental problems caused by traditional extracting processes. In view of its promising application potential, the hydrothermal leaching kinetics of vanadium from a concentrate mainly composed of Fe3−xVxO4 mineral via oxalic acid were investigated in this study. Firstly, the effects of the temperature and concentration of oxalic acid on the leaching behavior of vanadium were studied by measuring the leaching efficiency of vanadium at various times. Then, by fitting the measured leaching efficiency data to the proposed kinetic model, the leaching mechanism was analyzed and the rate-controlling step of the leaching process, the apparent activation energy, and the order of the chemical reactions were determined. Finally, a kinetic model was proposed to describe the present investigated leaching process. Detailed results are as follows: (1) an interfacial chemical reaction was the rate-controlling step of the present hydrothermal leaching process within temperatures ranging from 363 to 403 K, and the leaching efficiency was less than 85%; (2) the apparent activation energy of the interfacial chemical reaction was 45.6 kJ/mol; (3) the order of the interfacial chemical reaction to the concentration of oxalic acid was around 1.66.

Antifungal activity of Ligusticum chuanxiong essential oil and its active composition butylidenephthalide against Sclerotium rolfsii.

Peanut stem rot caused by Sclerotium rolfsii is an epidemic disastrous soil-borne disease. Recently, natural products tend to be safe alternative antifungal agents to combat pathogens. This work determined the preliminary antifungal activity of 29 essential oils against S. rolfsii and found that Ligusticum chuanxiong essential oil (LCEO) showed the best antifungal activity, with an EC50 value of 81.79 mg L-1 . Sixteen components (98.78%) were identified in LCEO by gas chromatography-mass spectrometry analysis, the majority by volume comprising five phthalides (93.14%). Among these five phthalides, butylidenephthalide was the most effective compound against S. rolfsii. Butylidenephthalide not only exhibited favorable in vitro antifungal activity against the mycelial growth, sclerotia production and germination of S. rolfsi, but also presented efficient in vivo efficacy in the control of peanut stem rot. Seven days after application in the glasshouse, the protective and curative efficacy of butylidenephthalide at 300 mg L-1 (52.02%, 44.88%) and LCEO at 1000 mg L-1 (49.60%, 44.29%) against S. rolfsii were similar to that of the reference fungicide polyoxin at 300 mg L-1 (54.61%, 48.28%). Butylidenephthalide also significantly decreased the oxalic acid and polygalacturonase content of S. rolfsii, suggesting a decreased infection ability on plants. Results of biochemical actions indicated that butylidenephthalide did not have any effect on the cell membrane integrity and permeability but significantly decreased nutrient contents, disrupted the mitochondrial membrane, inhibited energy metabolism and induced reactive oxygen species (ROS) accumulation of S. rolfsii. Our results could provide an important reference for understanding the application potential and mechanisms of butylidenephthalide in the control of S. rolfsii. © 2023 Society of Chemical Industry.

Ecological toxicity of microplastics, aluminum and their combination to ectomycorrhizal fungi (Lactarius delicious)

&lt;p&gt;To investigate the combined toxic effects of microplastics and aluminum (Al) on ectomycorrhizal fungi, Lactobacillus delicious (Ld) was selected as the experimental subject to conduct research on monodisperse polystyrene microplastics (PS-MPs) (0, 20, 100, 200 mg L-1) and Al3+ (40 mg L-1) single pollution on Ld growth, the antioxidant system and organic acid secretion, followed by their combined effect. The results showed that the growth of Ld was inhibited and the biomass decreased significantly (P &amp;lt; 0.05) under single exposure to PS-MPs or Al3+, and the contents of superoxide anion radical (O2·-) and H2O2 in mycelia increased significantly (P &amp;lt; 0.05). Meanwhile, superoxide dismutase (SOD) and peroxidase (POD) activities were also significantly increased (P &amp;lt; 0.05), while catalase (CAT) activity was significantly decreased (P &amp;lt; 0.05), indicating that PS-MPs or Al3+ stress had different effects on antioxidant enzyme activities in Ld mycelia, which used highly active antioxidant enzymes to eliminate excess reactive oxygen species (ROS) and maintain their dynamic balance. In addition, the electrolyte leakage rate, proline and malondialdehyde (MDA) contents in Ld mycelia were significantly increased (P &amp;lt; 0.05). Under the combined exposure of PS-MPs and Al3+, compared with the control group, the combined exposure of high concentrations of PS-MPs and Al3+ (200+40 mg L-1) had a certain promoting effect on the biomass of Ld. In addition, the O2·-, H2O2, electrolyte leakage rate and malondialdehyde content in Ld mycelia increased significantly (P &amp;lt; 0.05), but these indices were significantly lower than those in the single PS-MPs exposure group at the same concentration. This indicates that the combined effect of PS-MPs and Al3+ could reduce the damage of single pollutants to the Ld biomass membrane and reduce the production of ROS to a certain extent. In addition, correlation analysis showed that H2O2 in Ld mycelia had a highly significant positive correlation with the oxalic acid and total hydrogen ion concentrations in the culture solution (P &amp;lt; 0.01). This indicates that strain Ld could respond to the oxidative damage caused by microplastics and Al by secreting oxalic acid and hydrogen ions into the culture medium.&lt;/p&gt;&#x0D;

High-Performance Methylsilsesquioxane Aerogels: Hydrolysis Mechanisms and Maximizing Compression Properties.

Synthesis of methylsilsesquioxane aerogels by ambient pressure drying instead of supercritical drying has recently emerged as a major trend, but the issues of low mechanical strength and unstable performance still need to be resolved. This work reveals the microscopic formation mechanisms of gel skeleton based on the kinetic characteristics of methyltrimethoxysilane (MTMS) precursor hydrolysis and the associated sol-gel reactions. The effects of oxalic acid concentration (cOA) and hydrolysis time of MTMS solution (th) on the gelation time, morphologies, microstructures, chemical structure, and compression properties of the as-synthesized methylsilsesquioxane aerogels are investigated. The optimal cOA and th are 38.4 mmol/L and 120 min, respectively, endowing the methylsilsesquioxane aerogels with a compression strength of 0.170 MPa and a maximum compression strain of 61.2%. Precise control of the hydrolysis conditions ensures the formation of branched particle-to-particle networks, which is crucial for maximizing the compression properties of methylsilsesquioxane aerogels synthesized under industry-relevant conditions.

Temporal Accumulation of Geosmin, Oxalic Acid, and Total Dissolved Solids in Table Beet

Consumers perceive flavor as a critically important attribute of vegetable crops. Gas chromatography-mass spectrometry (GC-MS), spectrophotometry, and refractometry of tissue samples collected during multiple years from table beet (Beta vulgaris) at various stages of maturity were performed to characterize the endogenous production of geosmin, oxalic acid, and total dissolved solids within the root. The geosmin concentration was primarily influenced by the cultivar and peaked early during the growing season, with root concentrations at 6 weeks after planting that were 312% higher, on average, than those found in harvest stage roots at 15 weeks after planting. The highest average concentration of geosmin in harvest stage roots was detected in tissue from the cultivar Bull’s Blood (16.08 μg⋅kg−1). The oxalic acid concentration showed a strong cultivar influence and statistically significant variability across the growing season. Hybrid beet cultivar Boro had the lowest soluble oxalic acid concentration (95.73 mg⋅100 g−1 fresh tissue) at all locations and during all years. The oxalic acid concentration peaked 12 weeks after planting, and it was lower at the postharvest sampling date 18 weeks after planting. Total dissolved solids (TDS) concentrations were strongly influenced by year and growing environment and displayed crossover interactions for environment × week. TDS measurements had a moderate negative correlation with root mass. ‘Chioggia Guardsmark’ consistently had the highest TDS during all years and at all locations at 12.01 °Brix. The TDS varied significantly according to time, and diurnal sampling revealed fluctuations as large as 4 °Brix over the course of a 12-hour period. The TDS concentrations increased throughout the growing season, although the rate at which they increased changed according to plant age. The results from this study suggest that interactions between cultivar, time, and environment are important determinants of oxalic acid and TDS concentrations, but they have less influence on geosmin. This information may influence the methods that plant breeders use to collect phenotypic data of important flavor compounds in beets.

Response of growth and Pb accumulation characteristics of plants with intercropping Arabis alpina-Zea mays to exogenous oxalic acid

In order to study the effects of oxalic acids on plant growth and Pb accumulation in different parts of the plants of intercropping Arabis alpina and Zea mays, pot experiment was conducted to investigate the changes of oxalic acid contents of the plants and Pb accumulation through exogenous oxalic acid addition (0, 5, 25 and 50 mmol kg−1). The results showed the root biomass of intercropped A. alpina and total biomass of Z. mays increased by 3.22 folds and 2.97 folds with 5 mmol kg−1 oxalic acid treatment. The oxalic acid contents of shoots and root secretions decreased by 86.5% and 44.3%, respectively. The BCF (bio-accumulation factor) and TF (translocation factor) of intercropping A. alpina reduced under 25 − 50 mmol kg−1 oxalic acid treatments. There were relationships between exogenous oxalic acid treatment concentrations and oxalic acid contents of A. alpina shoots, Z. mays root secretions. The Pb contents of shoots of A. alpina and Z. mays were related to exogenous oxalic acid additions and oxalic acid contents of shoots. In general, 5 mmol kg−1 oxalic acid treatment, that can improve plant growth of intercropped A. alpina and Z. mays, which Pb translocation and accumulation of A. alpina were promoted, whereas Pb accumulation of A. alpina was inhibited with 25 − 50 mmol kg−1 concentrations addition. This study will provide a basis for promoting the application of phytoremediation techniques and efficient crop production in heavy metal contaminated areas.

Synergistic extraction of valuable metals from cyanide tailings slurry electrolyte and preparation of ferrous oxalate

A cyanide tailings slurry electrolyte (CTSE) was treated using a synergistic extraction system (P204-T) composed of di(2-ethylhexyl)phosphate (P204, (C8H17O)2PO2H, H2A2), trioctylamine (TOA, ([CH3(CH2)7]3N), R3N), and iso-alkanes, and a collaborative extraction technique involving oxalic acid stripping and photocatalysis was developed to separate and recover valuable metals and prepare ferrous oxalate. The results show that at a pH of 1.5, the P204 concentration of 15 vol%, TOA concentration of 10 vol%, O/A of 1:1, an oscillation time of 10 min, and an oscillation frequency of 190 rpm, the single-stage Fe(III) and Zn(II) extraction efficiencies of P204-T were 99.25% and 99.02%, respectively, and the saturated extraction capacities were 25.01 g•L−1 and 1.20 g•L−1, respectively. TOA destroyed the dimer structure of P204 and promoted the –OH bond and –OP group in P204 to combine with TOA through hydrogen bonding to form N–H+···O–P and N–H+···OP bonds, resulting in the R3NHA·(HA) composite structure. During the collaborative extraction process, ion exchange with FeSO4+ resulted in the formation of FeSO4A·(HA)3 and ion exchange with the intermediate product (R3NH)2SO4 and Zn(SO4)22- formed (R3NH)2Zn(SO4)2, which improves the extraction efficiency of metal ions. In addition, some amount of P204 underwent ion exchange with free Fe3+ and Zn2+ to produce FeA3(HA)3 and ZnA2(HA)2, respectively. At oxalic acid concentration of 1 mol•L−1, an O/A of 1:3, the efficiencies of Fe(III) and Zn(II) stripped from the saturated organic phase reached 99.65% and 99.41%. Zn(II) formed the ZnC2O4·2 H2O precipitate and Fe(III) separation. FeC2O4·2 H2O was successfully synthesized by ultraviolet photocatalysis using iron oxalate complex as the stock solution.