Optimal Concentration Of Ascorbic Acid Research Articles

Evaluation of the green inhibitor effect on the corrosion of pipeline steel in NS4 medium

Prospects for the use of ascorbic acid as a green corrosion inhibitor of low-alloy steels (17H1S steel) in the model environment NS4 was studied. The influence of ascorbic acid concentration on the potential vs time dependence was investigated. The inhibition effect of ascorbic acid in concentration range 0.1–1.5 g/l was also examined using weight loss and electrochemical methods. The optimal concentration of ascorbic acid for protection of the low-alloy 17H1S steel in the NS4 solution against corrosion was defined.

Study of physicochemical changes and microbiological parameters of semi-finished potato products after electron-beam sterilization

A popular method for electron-beam sterilization of agricultural products consists in their exposure to ionizing radiation, also called beta-radiation. Beta-radiation contributes to the preservation of the quality and safety of freshly harvested crops and can be used to disinfect semi-finished products. In this work, we aimed to study the effect of various doses of ionizing radiation (1, 3, 6 and 9 kGy) on vacuumized peeled and cut potatoes of the Bellarosa variety. Potato samples were treated with ascorbic acid at concentrations of 3, 6 and 9% in order to preserve the native content of vitamin C and the initial structural and mechanical properties. PET packages were used for evacuation, since this material emits no hazardous or harmful impurities in such aggressive environments as 9% ascorbic acid solution and 9 kGy radiation. Studies of organoleptic, physicochemical and microbiological parameters of semi-finished potato products were carried out using conventional methods. According to the obtained results, an irradiation dose of 1 kGy neither affects significantly the quality of a semi-finished potato product, nor contributes to a decrease in the number of pathogens. An irradiation dose of 3 kGy has no significant effect on the controlled parameters, although a decrease in the number of pathogens is observed. An irradiation dose of 6 kGy has a significant effect on the microbiological indicators; however, at low concentrations of ascorbic acid (3 and 6%), the organoleptic indicators of the studied semi-finished products begin to deteriorate. At a dose of 9 kGy, almost all microorganisms die, and the controlled parameters deteriorate regardless of the ascorbic acid concentration. It is concluded that the optimal irradiation doses for semi-finished potato products comprise 3 and 6 kGy. The optimal concentration of ascorbic acid was found to be 9%, at which the quality and safety indicators of semifinished potato products are preserved for 7 days of storage.

Prevention of damage caused by corona discharge-generated reactive oxygen species under electrostatic aerosol-to-hydrosol sampling

Human exposure to airborne pathogens is a major cause of health concerns; therefore, it is imperative to monitor, sample, and detect airborne bio-particles. Among various bio-aerosol sampling methods, electrostatic precipitation (EP) is an efficient technique for capturing bio-aerosols as hydrosols due to a lower pressure drop and less damage to sensitive bio-particles. Corona discharge is the main EP mechanism; however, this inevitably generates reactive oxygen species (ROS), which can be transported and dissolved in the sampling liquid. ROS can modify cellular component structures and damage DNA. Additionally, during the sampling process, the liquid flow rate and sampling liquid type can highly affect sampling efficiency. Here, different liquid types and flow rates are examined and ascorbic acid (AA), known as vitamin C, is added to prevent bio-particle damage. However, a high AA concentration can cause oxidative damage. Therefore, the optimal AA concentration should be chosen to obtain the greatest protective effect.

Real-Time Monitoring of Ascorbic Acid-Mediated Reduction of Cytotoxic Effects of Analgesics and NSAIDs on Tenocytes Proliferation.

Tendinopathy is a common painful musculoskeletal disorder treated by injection of analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs), which are believed to have cytotoxicity toward tenocytes. Ascorbic acid is an antioxidant that promotes collagen biosynthesis and prevents free radical formation. It is believed to protect tenocytes from oxidative stress. The optimal concentration of ascorbic acid, especially when used in conjunction with anesthetics and NSAIDs injection, to treat different stages of tendinopathies is unknown. Human tenocytes were isolated from a torn edge of the supraspinatus tendon of a 51-year-old male patient during arthroscopic repair. We monitored real-time changes in human tenocyte proliferation upon exposure to different concentrations of ascorbic acid, bupivacaine, and ketorolac tromethamine using the xCELLigence system. No significant changes in cell index were observed between the control group and tenocytes treated with the 3 concentrations of ascorbic acid. Tenocytes exposed to 0.5% bupivacaine and 30 or 15 mg/mL ketorolac tromethamine revealed significant reduction in tenocytes proliferation. Bupivacaine 0.5% with 250 μg/mL ascorbic acid and 15 mg/mL ketorolac tromethamine with 250 μg/mL ascorbic acid showed the least cytotoxicity against tenocytes. The optimal ascorbic acid concentration required to reduce the cytotoxic effects of bupivacaine and ketorolac tromethamine was demonstrated using this platform.

33 POST-THAW VIABILITY OF BOVINE EMBRYOS PRODUCED IN VITRO FOLLOWING TREATMENT WITH ASCORBIC ACID, DITHIOTHREITOL, AND CASPASE-3 INHIBITOR DURING CRYOPRESERVATION

The aim of the present experiments was to determine whether treatment with the antioxidants ascorbic acid and dithiothreitol, or an inhibitor of caspase-3, Z-DEVD-FMK, during cryopreservation could improve the cryotolerance of bovine embryos produced in vitro. For all experiments, bovine embryos were produced in vitro using abattoir-derived ovaries. At Day 7 after insemination, blastocyst and expanded blastocyst stage embryos were harvested and subjected to controlled-rate freezing following equilibration for 8 to 10 min in freezing medium [Hepes-TALP (Parrish et al. 1986) plus 1.5 M ethylene glycol and 0.5 M sucrose] with treatments as described below. Embryos were thawed and then cultured for 72 h in SOF-BE1 (Fields et al. 2011) supplemented with 10% (vol/vol) fetal bovine serum at 38.5°C in a humidified atmosphere of 5% CO2, 5% O2, and 90% N2. Re-expansion and hatching rates were recorded at 24, 48, and 72 h. For Experiment 1, embryos (n = 578) were equilibrated in freezing medium containing 0, 0.1, 0.3, or 0.5 mM ascorbic acid. For Experiment 2, embryos (n = 243) were equilibrated in freezing medium containing 0, 50, 100, or 200 μM dithiothreitol. For Experiment 3, embryos (n = 227) were equilibrated in freezing medium containing 0, 50, 100, or 200 μM Z-DEVD-FMK. Embryos frozen in freezing medium containing ascorbic acid had increased (P < 0.05) re-expansion and hatching rates at 24, 48, and 72 h compared with embryos not treated with ascorbic acid (Table 1). The optimal concentration of ascorbic acid for post-thaw cryosurvival was 0.1 mM. In particular, embryos treated with 0.1 mM ascorbic acid during cryopreservation had increased (P < 0.05) re-expansion rates at 24, 48, and 72 h, as well as hatching rates at 48 and 72 h, compared with control-treated embryos (Table 1). There was no effect of treatment with dithiothreitol or Z-DEVD-FMK on re-expansion or hatching rates at 24, 48, or 72 h after thaw. In conclusion, addition of ascorbic acid to freezing medium improves the cryosurvival of bovine embryos produced in vitro. Further research is necessary to determine whether treatment with ascorbic acid can increase pregnancy rates. Table 1.Effect of ascorbic acid during cryopreservation of bovine embryos (%, means ± standard error of the mean)

Effect of Ascorbic Acid and Cysteine Hydrochloride on Growth of <em>Bifidobacterium bifidum</em>

The effects of ascorbic acid and L-Cysteine Hydrochloride (Cys-HCl) on growth of <em>Bifidobacterium bifidum</em> BB01 and BB03 were studied by using MRS broth as the control, the concentrations of ascorbic acid and Cys-HCl were both of 0.4, 0.6, 0.8, 1.0 and 1.2g/L. The result showed as follows: ascorbic acid 0.8g/L or Cys-HCl 0.6g/L on growth of <em>B. bifidum</em> BB01 and ascorbic acid 0.4g/L and Cys-HCl 0.4g/L on growth of <em>B. bifidum</em> BB03 had significant influence (p<0.05), respectively. The OD₆₀₀ of <em>B. bifidum</em> BB01 and <em>B. bifidum</em> BB03 reached 1.32, 1.32, 1.347 and 1.296 at optimal concentration of ascorbic acid and Cys-HCl mentioned above, while the control only reached 1.121 and 1.213 respectively.

Effects of ascorbic acid and uracil on exo-polysaccharide production with Hericium erinaceus in liquid culture

Hericium erinaceus is a well known edible and medicinal mushroom used in East-Asia. Recently, H. erinaceus has attracted a lot of attention owing to its antitumor, immuno-modulatory, and cytotoxic effect. It has been postulated that the fruiting body of H. erinaceus contains a polysaccharide that is similar to β-D-glucan, which is known to have antitumor activity against Sarcoma 180. However, optimized liquid culture conditions for enhanced polysaccharide productivity have yet to be developed, which is a necessary step for industrial applications. Therefore, the aim of this study was to determine the optimal liquid culture conditions for maximum polysaccharide production. In shake flask cultures, the optimal concentration of ascorbic acid was found to be 2.0 g/L, which prevented the broth from changing color from yellow to black. The optimal culture conditions were determined to be 23°C, 200 rpm, and a 10% inoculum size, at an uncontrolled initial pH. In addition, the modified medium contained 20 g/L glucose, 10 g/L yeast extract, and 2.0 g/L ascorbic acid. The maximum mycelial biomass and exo-polysaccharide (EPS) production in the modified medium containing uracil was 13.43 and 1.26 g/L, respectively.

Ascorbate oxidase based amperometric biosensor for organophosphorous pesticide monitoring

An amperometric principle based biosensor containing tissues of cucumber, rich in ascorbic acid oxidase, was used for the detection of organophosphorous (OP) pesticide ethyl paraoxon, which inhibits the activity of ascorbic acid oxidase. The optimal concentration of ascorbic acid used as substrate was found to be 5.67 mM. The biosensor response was found to reach steady state within 2 min. A measurable inhibition (>10%) was obtained with 10 min incubation of the enzyme electrode with different concentrations of the pesticide. There was a linear relationship between the percentage of inhibition of the enzyme substrate reaction and the pesticide (ethyl paraoxon) concentration in the range 1–10 ppm with a regression value 0.9942.

Effect of ascorbic acid on longevity and biochemical alterations in Callosobruchus maculatus F. (Coleoptera: Bruchidae)

Optimal ascorbic acid concentration (1 mM) increased the median (LT 50) and maximum (LT 100) life spans, decreased age-independent susceptibility to death (a 0), reproductive period, number of eggs laid/female but prolonged the post-reproductive period in Callosobruchus maculatus. The activities of respiratory enzymes and the levels of metabolic end-products declined while the activities of antioxygenic enzymes increased. The increased longevity of insects reared on ascorbic acid soaked seeds may be interpreted in terms of conservation of energy by way of decreased reproductive potentiality and the maintenance of a homeostatic balance between pro-oxidant generation and antioxidant defences.

Secretion of peptidylglycine alpha-amidating monooxygenase (PAM) from rat salivary glands.

Peptidylglycine alpha-amidating monooxygenase (PAM) is a regulating enzyme to synthesize the biologically active hormones having carboxy-terminal amide. In the present study we investigated secretion of the enzyme from rat saliva. Property of PAM in the saliva was similar to that in the submandibular gland. Both enzymes showed similar pH optimum at 5.0 and optimal ascorbic acid concentration at 2.5 mM. But molecular size of PAM in the saliva was 75 kDa in the gel permeation chromatography on Superose 12 column, while the size in the submandibular gland was 25 kDa. After the treatment with trypsin, PAM in the saliva was converted to a small size molecule, which is similar to the size in rat submandibular gland. These and other data indicate that a native molecular size of PAM is secreted into saliva and plays some physiological roles.

Cultures of fibroblasts in fibrin lattices: models for the study of metabolic activities of the cells in physiological conditions.

Two techniques for fibroblast culture in three-dimensional fibrin matrices (fibrin lattices) were used to study the behavior and metabolism of cells in this physiological support. When the fibrin lattices were prepared in silicone-coated glass petri dishes, fibroblasts induced retraction of lattices to an extent dependent on both cell density and serum concentration, the cells stopped dividing, and their protein and collagen syntheses proceeded at a lower rate, like that in collagen lattices. When fibrin lattices were prepared in plastic petri dishes, the matrix attached to the walls, there was no retraction, and the protein synthesis was very active even as regards collagen. The optimal concentration of ascorbic acid in nonretracting fibrin lattices was lower (10 micrograms/ml) than in monolayers (50 micrograms/ml). The comparison of collagen and fibrin lattices showed that the collagenic nature of the lattice was not compulsory for supporting the phenomenon of retraction and that fibroblasts, when exposed to a stress in a fibrin matrix prevented from retracting, secreted far more collagen.