Ascorbic Acid Content Research Articles

Evaluation Trial of IVY Gourd (Coccinia grandis L.) Varieties in Prayagraj Agro Climatic Condition

The current trial on commenced in February 2023 at the Horticulture Research Field, Department of Horticulture, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, Uttar Pradesh. This experiment employed a Random Block Design (RBD) with seven varieties replicated three times. The varieties, namely V₁ (Arka Neelachal Khunki), V₂ (Arka Neelachal Sabuja), V₃ (Local Geda), V₄ (Local Denga), V₅ (Surekha), V₆ (CHIV-8), and V₇ (CHIV-9), were assessed based on various growth, yield, and quality parameters. These parameters included vine length, petiole length, appearance of the first female flower anthesis, internode length, fruit length, fruit diameter, average fruit weight, number of fruits per plant, number of seeds per fruit, fruit yield per plant, fruit yield in tonnes per hectare, total soluble solids (TSS), ascorbic acid content, fruit shape, and colour. From the different parameters it was concluded that all the seven varieties showed significant performance in almost all the characters. The variety V₂, Arka Neelachal Sabuja, exhibited superior characteristics in various parameters, including vine length (310.66 cm), internode length (12.71 cm), fruit length (6.11 cm), average fruit weight (21.07g), number of fruits per plant (422), number of seeds per fruit (122), fruit yield per plant (8.53 kg), fruit yield per hectare (17.36t/ha), total soluble solids (TSS - 4.31), and had the minimum days taken for the first female flower anthesis (32.67 days). It featured an ovoid-shaped fruit with dark green fractured strips. On the other hand, variety V₁, Arka Neelachal Khunki, demonstrated maximum petiole length (8.03 cm) and ascorbic acid content (15.30 mg/100g of fruit pulp). The fruit was uniform and cylindrical in shape with light green colour and white stripes.

Characterization of pepper (Capsicum spp.) germplasms based on morphological and phytochemical characters in Bangladesh

Pepper (Capsicum spp.) is a major spice crop around the globe. The major goal of the experiment was to evaluate the genetic diversity amongst 30 pepper germplasms for twelve morphological and phytochemical parameters. The investigation was conducted between November 2019 and April 2020 using a randomized complete block design with three replications in the experimental field of Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh. The results revealed a notable disparity across the genotypes for all studied traits. The genotype C80 displayed the highest fresh fruit weight (20.60 g) and dry fruit weight (1.20 g). Once again, the genotype YF1 had the highest chlorophyll and vitamin-C contents. The most significant correlations were revealed between fresh fruit weight and dry fruit weight (r = 0.83***) followed by between fruit diameter and dry fruit weight (r = 0.80***), and between fruit diameter and fresh fruit weight (r = 0.79***). The Wards-D method was used to cluster thirty genotypes into four clusters based on Euclidean distances. Cluster IV consisted of a maximum of 13 pepper genotypes. Cluster I yielded the greatest fresh fruit weight, measuring 11.75 g, whereas cluster III contained the highest Vitamin-C content, measuring 23.61 mg/ 100 g. The clusters I and III had the highest inter-cluster distances (6.45), while cluster I had the highest intra-cluster distance (2.36). PC1 and PC2 explained 32.8% and 18.3% of the total variances, respectively. In the biplot, the genotypes C54 and C80 favored fresh and dry fruit weights as well as fruit diameters, while the genotypes C29 and YF1 positively favored chlorophyll and vitamin-C contents. Therefore, the diverse pepper genotypes C54, C80 from cluster I and C29 and YF1 from cluster III could be included in future hybridization of pepper breeding.

Impact of Thermosonication Treatment on Parsley Juice: Particle Swarm Algorithm (PSO), Multiple Linear Regression (MLR), and Response Surface Methodology (RSM).

Thermosonication (TS), also known as ultrasonic-assisted heat treatment, is gaining attention in liquid product processing due to its ability to improve quality parameters and can serve as an alternative to thermal treatments. The parsley juice (TS-PJ) was subjected to thermosonication treatment (frequency: 26 kHz; power: 200 W; amplitude 60, 70, 80, 90, and 100%; temperature: 40, 45, 50, 55, and 60 °C; time: 4, 6, 8, 10, and 12 min) and was compared with untreated control parsley juice (C-PJ) and pasteurized treated (P-PJ) (85 °C/2 min) parsley juice samples. The objectives of the research work were to determine the effect of thermosonication on the quality attributes such as total chlorophyll and ascorbic acid of parsley juice using particle swarm algorithm (PSO), multiple linear regression (MLR), and response surface methodology (RSM). Thermosonication enhanced the bioactive compounds of parsley juice. The results showed that 15 phenolic compounds were detected in the samples. There was a significant (p < 0.05) increase in gallic acid contents in ultrasound-treated TS-PJ. There was no significant difference in total chlorophyll and ascorbic acid content between C-PJ and TS-PJ samples. Na and K from macro minerals and Fe and Zn from micro minerals were high in PJ samples. While K contents were increased, P contents were lower in the TS-PJ sample. RSM modeling provided superior prediction compared to MLR. PSO, on the other hand, made good predictions intuitively. Thermosonication enriched parsley juice's bioactive components and had positive health effects.

Dietary vitamin C reduces mortality of pacific white shrimp (Penaeus vannamei) post-larvae by Vibrio parahaemolyticus challenge

This study was conducted to investigate whether optimal vitamin C (VC) levels can enhance non-specific immune response and antioxidant capacity and reduce mortality of Pacific white shrimp (Penaeus vannamei) post-larvae when infected with Vibrio parahaemolyticus. Six experimental diets were formulated to contain six different VC levels of 0, 40, 80, 120, 160 and 320 mg/kg diet (designated as C0, C40, C80, C120, C160 and C320, respectively). Shrimp post-larvae (39.1 ± 0.47 mg) were randomly distributed to 24 tanks with 40 shrimp per tank. Four replicate groups of shrimp were fed one of the diets for 43 days. VC supplemented groups showed significantly higher growth performance than C0 group. Shrimp fed C120 diet had significantly improved feed utilization efficiency than shrimp fed C0 diet. VC concentrations in hepatopancreas and gills were significantly higher with the increase in dietary VC levels. Optimal dietary VC levels significantly upregulated the expressions of growth and digestive enzyme-related genes such as IGF-1, IGF-BP, amylase, trypsin and chymotrypsin, and also upregulated the expressions of innate immunity and antioxidant-related genes such as prophenoloxidase, crustin, penaiedin-3a, superoxide dismutase, glutathione peroxidase and catalase in hepatopancreas. Shrimp fed C80, C120 and C160 diets showed significantly increased resistance to V. parahaemolyticus than shrimp fed C0 diet. The optimum dietary VC level for the shrimp post-larvae was established to be 80.2 mg/kg diet by a broken-line regression analysis based on the growth. The findings from the challenge test indicated that VC levels over 83.0 mg/kg diet could enhance disease resistance of the shrimp against V. parahaemolyticus.

New insights into the relationship between clock genes and ascorbic acid metabolism in spinach during pre- and postharvest periods

In this study, the effects of light and dark conditions on the expression of candidate clock genes (SoLHY, SoPRR5, and SoTOC1), photoreceptor genes (SoPHYA, SoPHYB, and SoZTL), ascorbic acid (AsA) synthesis genes (SoVTC2 and SoGLDH), an AsA degradation gene (SoAPX), an AsA regeneration gene (SoMDHAR), and AsA content of spinach during the pre- and postharvest periods were investigated. The AsA content decreased under constant dark storage, whereas the AsA content was efficiently maintained under a light/dark cycle. Gene expression with rhythmic signals confirmed by the JTK_CYCLE method (P ≤ 0.05) was used for the analysis of partial correlation coefficients. Strong correlations between SoLHY and SoVTC2 were observed under all investigated conditions. AsA synthesis regulation via the clock gene LHY was stable and likely not altered by harvesting stress and/or external light stimuli. After harvesting, SoPRR5 was negatively correlated with SoVTC2. This finding suggested that a reduction in the SoPRR5 expression level might be an alternative way to induce/maintain AsA content during storage. Additionally, the expression of the photoreceptor genes SoPHYA and SoZTL was moderately correlated with that of SoVTC2 during cultivation. Surprisingly, these correlations were not observed during storage even in the presence of light. Instead, SoPHYA expression was correlated with that of another AsA synthesis gene, SoGLDH, under light/dark storage. Moreover, under constant dark storage, SoZTL expression showed a strong correlation with SoVTC2. The considerable variation in the relationship between the expression levels of AsA-related genes and photoreceptor genes during cultivation and storage indicates the contribution of light regulators to maintaining AsA rhythm in spinach. In summary, this study is the first to suggest possible crosslinking of external signals (light/dark), photoreceptor genes, clock genes, and AsA metabolism genes, which are related to changes in the quality of spinach during the pre- and postharvest periods.

Highly efficient electrochemical ascorbic acid determination via a cooperative catalytic effect of dendritic Bi/Bi2O3 junctions and oxygen vacancies

This study developed an electrochemical sensor for ascorbic acid (AA) using dendritic nanostructured (DN) bismuth/bismuth oxide thin films with oxygen-deficient (SOD) surfaces (SOD-DN Bi/Bi2O3-x thin films) that were successfully fabricated through electrodeposition on fluorine-doped tin oxide (FTO) substrates. Using cyclic voltammetry and amperometry, we assessed electrocatalytic activity in neutral media. The prepared SOD-DN Bi/Bi2O3-x thin film was used, for the first time, as electrodes in a highly sensitive and selective electrochemical AA sensor. The SOD-DN Bi/Bi2O3-x thin film with optimal characteristics was shown to be ultrasensitive in AA detection in neutral conditions, whereby high detection sensitivity ∼ 2.30 µA µM-1cm−2 over a wide range of AA concentration ∼ 0.01 µM to 1.0 mM and working potential range ∼ 0.3–1.0 V vs. SCE. The results indicate that SOD-DN Bi/Bi2O3-x can provide large amounts of active reaction sites, thereby enhancing electrocatalytic activity and electrochemical sensitivity. Due to this, it is a unique electrochemical sensor able to detect AA without interference from DA, UA, or other contaminants. A further amperometric test demonstrated that this sensor was capable of detecting AA even under conditions of dopamine and uric acid. Accordingly, the proposed sensor provides a promising avenue for developing electrochemical sensing for AA determination. This strategy introduces a novel type of high-efficiency electrocatalyst for ultrasensitive detection of medical and environmental biomarkers.

BcSRC2 interacts with BcAPX4 to increase ascorbic acid content for responding ABA signaling and drought stress in pak choi

Abstract As a reducing substance, ascorbic acid functioned well in abiotic and biotic stress. However, the regulatory mechanism of drought resistance is rarely known in pak choi. Here we found a gene BcSRC2 containing a C2 domain that responds to ABA signal and drought regulation in pak choi. Silencing of BcSRC2 reduces ascorbic acid content and drought resistance of pak choi. In Arabidopsis, BcSRC2 overexpression promotes ascorbic acid accumulation and increases drought tolerance. Meanwhile, transcriptome analysis between WT and BcSRC2-overexpressing pak choi suggests that ascorbic acid-related genes are regulated. BcSRC2 interacts with BcAPX4 and inhibit APX activity in vitro and in vivo, increasing the ascorbic acid content. We also found that drought stress increases ABA content, which reduces the expression of BcMYB30. BcMYB30 bound to the promoter of BcSRC2 and reduced its expression. Overall, our results suggest that a regulatory module, BcMYB30-BcSRC2-BcAPX4, plays a central role in increasing ascorbic acid content for responding ABA-mediated drought regulation in pak choi.

Modulation of the Human Erythrocyte Antioxidant System by the 5- and 6-Membered Heterocycle-Based Nitroxides.

Nitroxides are stable radicals consisting of a nitroxyl group, >N-O•, which carries an unpaired electron. This group is responsible for the paramagnetic and antioxidant properties of these compounds. A recent study evaluated the effects of pyrrolidine and pyrroline derivatives of nitroxides on the antioxidant system of human red blood cells (RBCs). It showed that nitroxides caused an increase in the activity of superoxide dismutase (SOD) and the level of methemoglobin (MetHb) in cells (in pyrroline derivatives) but had no effect on the activity of catalase and lactate dehydrogenase. Nitroxides also reduced the concentration of ascorbic acid (AA) in cells but did not cause any oxidation of proteins or lipids. Interestingly, nitroxides initiated an increase in thiols in the plasma membranes and hemolysate. However, the study also revealed that nitroxides may have pro-oxidant properties. The drop in the AA concentration and the increase in the MetHb level and in SOD activity may indicate the pro-oxidant properties of nitroxides in red blood cells.

Short‐Term Soil Waterlogging Improves Cotton Tolerance to High Temperature by Triggering Antioxidant Defence System in Cotton Seedlings

ABSTRACTSoil waterlogging and high temperature (HT) are serious abiotic stresses that negatively affect cotton growth and yield. Yet effects of prewaterlogging to HT subsequently in cotton seedlings have not been obtained. To address this, two temperature conditions (30/20°C and 35/25°C) and two soil waterlogging levels (0 and 3 days) were established during the cotton seedling stage. Results showed that indexes of plant performance were decreased markedly under HT. Unexpectedly, plant performance for the treatment of HT combined with 3 days of soil waterlogging (HW) was better than HT treatment (specifically, increase of 7.9%, 9.0%, 10.2%, 5.4% and 4.6% in leaf area, plant height, belowground biomass, aboveground biomass and root‐to‐shoot ratio was detected). Decreases in MDA (malondialdehyde), H2O2 (hydrogen peroxide) contents and (superoxide radicals) generation rate under HW treatment were observed by 14.1%, 7.7% and 14.1%, respectively, compared with HT. Moreover, ASA (ascorbic acid) content and DHAR (dehydroascorbate reductase) activity were improved by 19.7% and 13.8% for HW treatment relative to HT, however, the opposite situation for activities of APX (ascorbate peroxidase) and GR (glutathione reductase). Besides, activities of SOD (superoxide dismutase), CAT (catalase) and POD (peroxidase) in HW treatment were increased by 16.7%, 8.3% and 18.4%, separately. Thus, we concluded that short‐term soil waterlogging improved cotton cross‐tolerance to the continued high‐HT stress by enhanced SOD, CAT, POD and DHAR activities, increased ASA content in cotton seedlings. These results were expected to provide a theoretical basis for understanding cotton's cross‐tolerance to abiotic stress.

Preserving functional properties and inhibiting postharvest peel browning in guava during cold storage via 24-epibrassinolide application

Postharvest peel browning is one of the primary issues accountable for the subdued consumer acceptability and market value of guava fruit. However, postharvest treatment with brassinosteroid can reduce the peel browning to some extent through various modes of action. In current study, the influence of exogenous 24-epibrassinolide (EBL) application on antioxidant system and chilling injury (CI) characteristics of guavas during cold storage at 10 ± 1 ℃ were assessed. The mature green fruit exposed to various concentrations (15, 30, 45, 60 and 75 µg kg−1) of EBL displayed a notably lower fruit weight loss, respiration rate, electrolyte leakage and CI index, while higher consumer acceptability. Further, treatment with EBL has recorded lower amassing of hydrogen peroxide and malondialdehyde by suppressing lipoxygenase activity. Postharvest EBL application also heightened the content of total phenolics, ascorbic acid, total flavonoids and total antioxidant capacity. The enhanced activities of ascorbate peroxidase, catalase, superoxide dismutase and peroxidase due to EBL application impede the burst of reactive oxygen species. Moreover, correlation and regression analysis of tested biochemical parameters including enzymatic and non-enzymatic antioxidants exhibited a strong association and contributed 98.24–99.88 % variability in fruit weight loss, respiration rate, electrolyte leakage, CI index and consumer acceptability. Among different concentrations tested, 60 µg kg−1 EBL-treated guavas exhibited the desirable qualities and least CI index. From the study, it is concluded that the novelty of EBL can be gainfully harnessed in a postharvest handling system to induce cold tolerance and widen the storage life of cold-stored guava fruit.

Transcriptome analysis shows that Glomus versiforme decrease the accumulation and toxicity of cadmium in Ipomoea aquatic Forsk.

So far, the physiological and molecular mechanisms of the impact of arbuscular mycorrhizal fungus (AMF) on Cd absorption, transport and detoxification in Ipomoea aquatica (water spinach) are still unclear. In the present study, a pot experiment was performed to investigate the impact of AMF-Glomus versiforme (Gv) on the photosynthetic characteristics, Cd uptake, antioxidative system and transcriptome in water spinach in the soils supplemented with 5mg Cd kg-1. Gv inoculation improved significantly the photosynthetic characteristics and growth of water spinach. Furthermore, Gv colonization significantly promoted the activities of catalase (CAT), peroxidase (POD) and glutathione reductase (GR), contents of glutathione (GSH) and ascorbic acid (AsA), and the total antioxidant capacity (TCA), but decreased malondialdehyde (MDA) content in water spinach. In addition, Gv inoculation significantly increased pH in rhizosphere soils and decreased the Cd concentrations and uptakes in water spinach. Importantly, 2670 differentially expressed genes (DEGs) were screened in water spinach root colonized with Gv in 5mg Cd kg-1 soil, of which 2008 DEGs were upregulated and 662 DEGs were downregulated. Especially, the expression levels of POD, CAT, GR, dehydroascorbate reductase 2 (DHAR2), glutathione S-transferase U8 (GSTU8) and glutathione synthetase (GSHS) and cytochrome P450 (Cyt P450) genes were significantly up-regulated in water spinach inoculated with Gv. Meanwhile, the plant cadmium resistance protein 2 (PCR2), metal tolerance protein 4 (MTP4), ATP-binding cassette transporter C family member (ABCC), ABC-yeast cadmium factor 1 (ABC-YCF1) and metallothionein (MT) genes were also up-regulated in mycorrhizal water spinach. Our results firstly elucidated the mechanism by which AMF reduced the uptake and phytotoxicity of Cd in water spinach through a transcriptome analysis.

Study of the Effect of Preparation and Formulation Factors on the Stability of Vitamin C Microencapsulated by Solvent-Evaporation Method

This research studied the effect of formulation and processing variables on the stability of vitamin C or Ascorbic Acid (AA) encapsulated in Eudragit RS100 microparticles prepared using a solvent evaporation technique. Microparticles ranged in size from 60 to 102 μm and encapsulation efficiencies between 25% and 44% were obtained. Microencapsulation significantly enhanced the stability of AA compared to the free AA in solution. AA shelf life was extended up to 23 days. Increasing AA concentration and using sucrose or Tween 80 in the outer phase further enhanced AA stability. The results suggest that microencapsulation method under the investigated conditions is a promising approach for protecting AA from degradation in aqueous solutions.

Vitamin C Drives Reentrant Actin Phase Transition: Biphasic Exocytosis Regulation Revealed by Single-Vesicle Electrochemistry.

Unveiling molecular mechanisms that dominate protein phase dynamics has been a pressing need for deciphering the intricate intracellular modulation machinery. While ions and biomacromolecules have been widely recognized for modulating protein phase separations, effects of small molecules that essentially constitute the cytosolic chemical atmosphere on the protein phase behaviors are rarely understood. Herein, we report that vitamin C (VC), a key small molecule for maintaining a reductive intracellular atmosphere, drives reentrant phase transitions of myosin II/F-actin (actomyosin) cytoskeletons. The actomyosin bundle condensates dissemble in the low-VC regime and assemble in the high-VC regime in vitro or inside neuronal cells, through a concurrent myosin II protein aggregation-dissociation process with monotonic VC concentration increase. Based on this finding, we employ in situ single-cell and single-vesicle electrochemistry to demonstrate the quantitative modulation of catecholamine transmitter vesicle exocytosis by intracellular VC atmosphere, i.e., exocytotic release amount increases in the low-VC regime and decreases in the high-VC regime. Furthermore, we show how VC regulates cytomembrane-vesicle fusion pore dynamics through counteractive or synergistic effects of actomyosin phase transitions and the intracellular free calcium level on membrane tensions. Our work uncovers the small molecule-based reversive protein phase regulatory mechanism, paving a new way to chemical neuromodulation and therapeutic repertoire expansion.

Synergistic effect of red-white LED and modified atmosphere packaging on okra quality maintenance and its mechanism in simulated cold chain logistics

Okra is rich in nutritional value, but transportation vibration, cold chain breakage and improper storage can quickly accelerate quality deterioration. In this study, we simulated the cold chain transportation process to find the synergistic effect of red-white LED illumination combined with modified atmosphere packaging (MAP) on okra quality maintenance and its mechanism of action. After 16 d of storage, LED+MAP can better avoid water loss and wilting in okra. The fracturability was 35 %, 33 %, and 40 % of fresh okra for LED, MAP, and LED+MAP, respectively, compared to 17 % for CK. CK produced unpleasant odors, but the odor of LED+MAP was close to the fresh. LED+MAP maintained the stability of the nutrient content of okra. The chlorophyll content of LED+MAP was reduced to 64 % of the original compared to 35 % of that for CK. The total phenol content of LED+MAP was reduced to 55 % of the original compared to 26 % of that for CK. The total flavonoid content of LED+MAP was reduced to 72 % of the original compared to 56 % of that for CK. LED+MAP regulated the activity of antioxidant enzymes, and the antioxidant capacity was significantly higher than that of the other groups. The ascorbic acid content of LED+MAP was reduced to 52 % of the original compared to 38 % of that for CK. The MDA content of LED+MAP was 3.83 times of the original compared to 8.52 times of that for CK. The electrolyte leakage of LED+MAP was 2.12 times of the original compared to 2.86 times of that for CK. With the increase of storage time, O2 concentration in MAP showed a decreasing trend and CO2 showed an increasing trend. O2 in LED+MAP showed a growing trend followed by a decreasing trend and CO2 showed a decreasing trend followed by a rising trend. LED+MAP complemented the shortcomings of the single technology and was more effective in delaying the quality deterioration of okra.

Ascorbic Acid Improves Tomato Salt Tolerance by Regulating Ion Homeostasis and Proline Synthesis.

In this study, processing tomato (Solanum lycopersicum L.) 'Ligeer 87-5' was hydroponically cultivated under 100 mM NaCl to simulate salt stress. To investigate the impacts on ion homeostasis, osmotic regulation, and redox status in tomato seedlings, different endogenous levels of ascorbic acid (AsA) were established through the foliar application of 0.5 mM AsA (NA treatment), 0.25 mM lycorine (LYC, an inhibitor of AsA synthesis; NL treatment), and a combination of LYC and AsA (NLA treatment). The results demonstrated that exogenous AsA significantly increased the activities and gene expressions of key enzymes (L-galactono-1,4-lactone dehydrogenase (GalLDH) and L-galactose dehydrogenase (GalDH)) involved in AsA synthesis in tomato seedling leaves under NaCl stress and NL treatment, thereby increasing cellular AsA content to maintain its redox status in a reduced state. Additionally, exogenous AsA regulated multiple ion transporters via the SOS pathway and increased the selective absorption of K+, Ca2+, and Mg2+ in the aerial parts, reconstructing ion homeostasis in cells, thereby alleviating ion imbalance caused by salt stress. Exogenous AsA also increased proline dehydrogenase (ProDH) activity and gene expression, while inhibiting the activity and transcription levels of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine-δ-aminotransferase (OAT), thereby reducing excessive proline content in the leaves and alleviating osmotic stress. LYC exacerbated ion imbalance and osmotic stress caused by salt stress, which could be significantly reversed by AsA application. Therefore, exogenous AsA application increased endogenous AsA levels, reestablished ion homeostasis, maintained osmotic balance, effectively alleviated the inhibitory effect of salt stress on tomato seedling growth, and enhanced their salt tolerance.

Novel insights into discoloration of crude pine oleoresin during storage: Browning mechanisms via untargeted metabolomics

Quality deterioration due to undesirable discolorations in crude pine oleoresin during storage is a major problem limiting its subsequent processing applications. To reveal the essence of color changes, the browning phenomenon and comprehensive mechanism of crude pine oleoresin during storage were investigated in depth using an approach based on high-resolution mass spectrometry metabolomics. Crude pine oleoresin was stored with sterile, deionized, tap, and pond water for 30, 60, 90, 120, 150, and 180 days, respectively. The changes in browning substrate were detected by tracking analysis protein, reducing sugar, ascorbic acid, and total phenol content, browning was evaluated through colorimeter measurement. The metabolism of crude pine oleoresin in different storage times was uncovered that total color difference (ΔE) increased with storage time, and the browning of crude pine oleoresin soaked in tap water was greatest while soaked in deionized water exhibited the mildest. The content of reducing sugars, proteins, and total phenols increased with storage time, whereas the ascorbic acid content tended to increase and then decrease. Furthermore, the metabolomics analyses showed that 1,194 and 979 differentially metabolized compounds were found between days 120 and days 150, and days 120 and days 180. The metabolite profiles in the water samples changed as crude pine oleoresin storage time increased. Most carbohydrate content decreased, and the phenols and organic acids content increased. Metabolic network mapping linking differentially metabolized compounds by mapping different biosynthetic pathways proved that caffeoylquinic acid and catechin play a key role in the browning of crude pine oleoresin during storage: caffeoylquinic acid forms black iron complexes with iron, and catechin is oxidized to catechol quinone, which eventually produces a yellow dimer. This study will provide a scientific basis for developing or choosing more effective methods for controlling the discoloration of crude pine oleoresin and other similar products during storage.

Metabolic and Functional Interactions of H2S and Sucrose in Maize Thermotolerance through Redox Homeodynamics.

Hydrogen sulfide (H2S) is a novel gasotransmitter. Sucrose (SUC) is a source of cellular energy and a signaling molecule. Maize is the third most common food crop worldwide. However, the interaction of H2S and SUC in maize thermotolerance is not widely known. In this study, using maize seedlings as materials, the metabolic and functional interactions of H2S and SUC in maize thermotolerance were investigated. The data show that under heat stress, the survival rate and tissue viability were increased by exogenous SUC, while the malondialdehyde content and electrolyte leakage were reduced by SUC, indicating SUC could increase maize thermotolerance. Also, SUC-promoted thermotolerance was enhanced by H2S, while separately weakened by an inhibitor (propargylglycine) and a scavenger (hypotaurine) of H2S and a SUC-transport inhibitor (N-ethylmaleimide), suggesting the interaction of H2S and SUC in the development of maize thermotolerance. To establish the underlying mechanism of H2S-SUC interaction-promoted thermotolerance, redox parameters in mesocotyls of maize seedlings were measured before and after heat stress. The data indicate that the activity and gene expression of H2S-metabolizing enzymes were up-regulated by SUC, whereas H2S had no significant effect on the activity and gene expression of SUC-metabolizing enzymes. In addition, the activity and gene expression of catalase, glutathione reductase, ascorbate peroxidase, peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, and superoxide dismutase were reinforced by H2S, SUC, and their combination under non-heat and heat conditions to varying degrees. Similarly, the content of ascorbic acid, flavone, carotenoid, and polyphenol was increased by H2S, SUC, and their combination, whereas the production of superoxide radicals and the hydrogen peroxide level were impaired by these treatments to different extents. These results imply that the metabolic and functional interactions of H2S and sucrose signaling exist in the formation of maize thermotolerance through redox homeodynamics. This finding lays the theoretical basis for developing climate-resistant maize crops and improving food security.

Detection of ascorbic acid by persistent luminescent nanoparticles based on CoOOH nanosheets modification.

Persistent luminescent nanomaterials (PLNPs) Zn0.8Ga2O4: Cr3+, Zr3+ with high brightness and good dispersion were prepared by hydrothermal method. The PLNPs were used as luminescent units, and CoOOH nanosheets were used as quenching agents. Based on the fluorescence internal filtering effect, the luminescence of PLNPs were effectively quenched by CoOOH modification on the surface of PLNPs. However, the introduction of ascorbic acid (AA) restored the luminescence of PLNPs and successfully achieved highly sensitive and selective detection of AA. This was due to a selective redox reaction between CoOOH and AA, in which CoOOH was reduced to Co2+. The degree of luminescence recovery of PLNPs showed a good linear relationship with AA concentration in the range 5-250 µM, with a detection limit of 0.72 µM. Therecovery of actualspikedsamples were 97.9-102.2%. This method isexpected to provide reference for the study of other redox substances in biological systems.

SNaP-C: Validation of a novel, selective silver nanoparticle antioxidant capacity assay for Vitamin C content in beverages

A validated silver nanoparticle assay (SNaP-C) for quantitation of Vitamin C, as ascorbic acid (AA) and total AA (TAA), was applied to 31 beverages. SNaP-C assay results (LOD of 2.2 mg/L AA) were compared to AA and TAA determined by high-performance liquid chromatography with UV/Vis (LOD = 0.4 mg/L AA), and two well-known assays. All approaches were calibrated using meta-phosphoric acid stabilized AA, where the reducing agent tris(2-carboxyethyl) phosphine hydrochloride was added to convert dehydroascorbic acid to AA for determination of TAA. Statistical comparisons of these four resulting datasets were completed. SNaP-C and HPLC were not statistically significantly different (P > 0.05) for comparison of AA and TAA (mg/L) in these samples, whereas the CUPRAC and Folin-Ciocalteu assays statistically significantly overestimated values of AA and TAA content, respectively. The SNaP-C method is a novel assay that has high specificity for AA capable of quantifying TAA with addition of TCEP.

Investigating the Mechanism of Cadmium-Tolerant Bacterium Cellulosimicrobium and Ryegrass Combined Remediation of Cadmium-Contaminated Soil.

Cadmium (Cd) pollution has been rapidly increasing due to the global rise in industries. Cd not only harms the ecological environment but also endangers human health through the food chain and drinking water. Therefore, the remediation of Cd-polluted soil is an imminent issue. In this work, ryegrass and a strain of Cd-tolerant bacterium were used to investigate the impact of inoculated bacteria on the physiology and biochemistry of ryegrass and the Cd enrichment of ryegrass in soil contaminated with different concentrations of Cd (4 and 20 mg/kg). The results showed that chlorophyll content increased by 24.7% and 41.0%, while peroxidase activity decreased by 56.7% and 3.9%. In addition, ascorbic acid content increased by 16.7% and 6.3%, whereas glutathione content decreased by 54.2% and 6.9%. The total Cd concentration in ryegrass increased by 21.5% and 10.3%, and the soil's residual Cd decreased by 86.0% and 44.1%. Thus, the inoculation of Cd-tolerant bacteria can improve the antioxidant stress ability of ryegrass in Cd-contaminated soil and change the soil's Cd form. As a result, the Cd enrichment in under-ground and above-ground parts of ryegrass, as well as the biomass of ryegrass, is increased, and the ability of ryegrass to remediate Cd-contaminated soil is significantly improved.