Ascorbic Acid Solution Research Articles

Behavioral Study of Parkinson's Disease Rats Model with DigiGait<sup>TM</sup> Imaging System

<bold>Objective</bold> To detect the feasibility of DigiGait^TM Imaging System in evaluating gait changes in rats model with Parkinson's disease (PD). <bold>Methods</bold> A total of 24 clean male SD rats were randomly divided into normal group, sham operation group and model group, with eight rats in each group. In the model group, 6-Hydroxydopamine (6-OHDA) was injected into the brain with unilateral 2-point method to establish PD rats model. The sham operation group was injected with 0.2% ascorbic acid solution with the same method, and the normal group did not receive any surgical treatment. After successful preparation of the model, DigiGait^TM Imaging System was used to analyze temporal subcomponent (swing duration, braking duration, stance duration, stance factor), spatial subcomponent (stride frequency, stride length, stance width, gait symmetry, paw overlap distance, paw placement positioning) and postural subcomponent (paw angle, step angle, paw area). <bold>Results</bold> 1) Temporal subcomponent: compared with the normal group, the swing duration, braking duration and stance duration of left front paw, left hind paw and right front paw in the model group were significantly prolonged (<italic>P</italic>&lt;0.05), and the braking duration and swing duration of right hind paw in the model group were significantly prolonged (<italic>P</italic>&lt;0.05). Compared with the sham operation group, the swing duration, braking duration and stance duration of left front paw, left hind paw and right front paw in the model group were significantly prolonged (<italic>P</italic>&lt;0.05), and the braking duration of right hind paw in the model group was significantly prolonged (<italic>P</italic>&lt;0.05). 2) Spatial subcomponent: compared with the normal group and the sham operation group, the front and hind limb stance width of the model group significantly increased (<italic>P</italic>&lt;0.05), step frequency of four paws, stride length of left paws and paw placement positioning and gait symmetry in the model group significantly decreased (<italic>P</italic>&lt;0.05). But stride length of right paws and overlap distance of left and right paws in the model group had no significant changes (<italic>P</italic>&gt;0.05). 3) Postural subcomponent: compared with the normal group and the sham operation group, the contact area of left front paw, left hind paw and right hind paw with running belt in the model group significantly decreased (<italic>P</italic>&lt;0.05), there was no significant difference in paw area, paw angle and gait angle between the right front paw and the running belt (<italic>P</italic>&gt;0.05). <bold>Conclusion</bold> DigiGait^TM Imaging System can objectively evaluate walking, balance and coordination functions of PD rats, which has the potential to be widely applied in PD related basic research.

Development of Copper Nanoparticle Conjugated Chitosan Microparticle as a Stable Source of 2nm Copper Nanoparticle Effective against Methicillin- resistant Staphylococcus aureus.

Copper nanoparticle (CuNP) has well-established antimicrobial activity. Instability in an aqueous medium due to aggregation into larger particles, conversion into metal ions, and oxidation into metal oxides are the major limitations of its practical use against bacterial infections. Development of CuNP Conjugated Chitosan Microparticles as a reservoir that will release CuNP effective against notorious bacteria like Methicillin-resistant Staphylococcus aureus. CuNP conjugated chitosan microparticles (CNCCM) were synthesized using a simple twostep process. In the first step, a solution of chitosan in 2% (w/v) ascorbic acid was added dropwise in copper sulphate solution to prepare Cu ion conjugated chitosan beads. In the second step, these beads were soaked in sodium hydroxide solution to get the CNCCM. The dried CNCCM were characterized thoroughly for surface conjugation of CuNP, and the release of CuNP in a suitable medium. The physicochemical properties of release CuNP were further verified with the in silico modelled CuNP. The Antimicrobial and antibiofilm activities of released CuNp were evaluated against methicillin-resistant Staphylococcus aureus (MRSA). 2% (w/v) ascorbic acid solution (pH 3.5) was the optimum medium for the release of ~2 nm CuNP from CNCCM. The CuNP had an optical band gap of ~ 2 eV. It inhibited the cell wall synthesis of MRSA. The minimum inhibitory concentration was 200 nM. At 100 nM dose, the CuNP caused ~73% reduction in biofilm development after 24 h of growth. The cytotoxic effect of CuNP on the human cell line (HEK 293) was significantly less than that on MRSA. The 48 h IC50 value against HEK 293 was 3.45-fold higher than the MIC value against MRSA after 24 h treatment. CuNP Conjugated Chitosan Microparticle has been developed. It works as a stable reservoir of ~2 nm CuNP. The CuNP is released in an aqueous medium containing 2% (w/v) ascorbic acid (pH 3.5). The released CuNP has a bacteriostatic effect against MRSA at a concentration safe for human cells.

Influence of Sweeteners (Sucrose, Sucralose, and Stevia) on Bioactive Compounds in a Model System Study for Citrus-Maqui Beverages.

Recently, new formulations of beverages with low sugar and high bioactive compound contents are being demanded because of their association with metabolic health. However, the sweeteners’ influences on the bioactive compounds remain underexplored. In this sense, this work aims to evaluate the interactions between different bioactive compounds such as flavonoids, vitamin C, and sweeteners (sucrose, stevia, and sucralose) in a functional citrus–maqui beverage. For this purpose, the phytochemical behavior was studied, in model system solutions, during one-month storage at 4 °C. The results obtained corroborated previous descriptions of the interactions between these compounds. However, when studying the bioactives in the model solutions, the loss of flavanones in the citrus solution increased up to 29%, while anthocyanin losses decreased to 27%. The vitamin C losses ranged from 100% (beverage) to 46% (ascorbic acid solution). Regardless, an influence of the sweeteners was observed. Sucrose reduced the anthocyanin and flavanone losses in both model solutions and the beverage, while sucralose increased flavanone loss. Finally, all sweeteners increased vitamin C degradation (up to 75%) when compared to the model solution. In conclusion, sweeteners added to beverages should be taken into account, depending on the bioactive compounds that should be preserved during storage.

Influence of in-ovo vitamin E and ascorbic acid injections on chick development, hatching performance and antioxidant content in different tissues of newly-hatched quail chicks

ABSTRACT 1. This study determined the influence of in ovo (IO) vitamin E and ascorbic acid injections on hatching performance, chick development and antioxidant content of different tissues in day-old quail chicks. The experiment compared a control group (C: non-injection group) and injection groups, which had the yolk sac injected with 3.75 mg α- tocopherol (T1), or had the amniotic sac injected with 0.9% saline solution (T2), 2.5 mg ascorbic acid containing 0.9% saline solution (T3) and 2.5 mg ascorbic acid solution (T4), respectively. 2. Mean relative asymmetry (RA) of bilateral lengths increased in the T2, T3 and T4 groups, whereas it decreased in the T1 group compared to C. The highest total carotene content in the residual yolk sac (RYS) was seen for the T1 group, which was significantly higher compared to T2, T3 and T4 groups. The highest total carotene concentration in the liver was in the T1 group. 3. The concentrations of delta-tocopherol, gamma-tocopherol and total vitamin E in RYS tissue were significantly higher in the T1 group than T2, T3 and T4 groups. Alpha-tocopherol and total vitamin E levels in the liver were significantly higher in the T2 and T4 groups than C. 4. In ovo injections of vitamin E and ascorbic acid to different embryonic sacs caused antioxidant-specific effects on developmental stability of bilateral traits, RYS absorption, concentrations of total carotene and derivatives of vitamin E in newly hatched quail chicks.

One-pot multi-step synthesis of high-aspect-ratio Cu nanowires based on an environment-friendly manner for low-cost and high-performance transparent conductive films

High-aspect-ratio Cu nanowires (NWs) were synthesized based on an environment-friendly synthesis method in which aqueous Cu–Cl complexes were reduced to Cu atoms in a weak ascorbic acid solution. Constant reaction temperatures led to many reduced Cu atoms relative to NWs and then the synthesized Cu atoms were deposited on the end and side faces of Cu NWs, resulting in low aspect ratios. Two-step temperature synthesis was suggested to suppress Cu atoms during the Cu NW growth. High temperatures during the early reaction stage maximized NW seeds and low temperatures in the late stage decreased the number of Cu atoms under precisely controlled temperature and temperature drop time, leading to Cu deposition on the end faces rather than side faces. Additionally, optimum Cu-source additions continuously facilitated the preferential growth in length of Cu NWs. The one-pot multi-step synthesis controlled the reduction rate of Cu complexes and substantially increased the aspect ratio of Cu NW from 313 to 760, showing that the precise control was suitable for changing the NW sizes. Finally, transparent conductive films comprising the NWs showed high performances (transmittance = 90.8 %, sheet resistance = 94 Ω/sq).

Commercial Screen-Printed Electrode Decorated with Carbonaceous Binary Sulfides for Direct Glucose Detection in Human Fluid Samples

We hereby demonstrate a highly controllable, green, and rapid synthesis strategy for the production of binary metal sulfides on carbon nano-horns (CNHs) for the fabrication of non-enzymatic glucose sensor using commercial graphite screen-printed electrodes (GSPEs). CNHs were synthesized using the submerged arc discharge method as described elsewhere. In the next step, one droplet (50 µL) of the well-dispersed CNHs was carefully cast on the surface of the GCE (and GSPE). In the final step of preparing the modified electrodes, CNH/GCEs were covered by a thin layer of nickel cobalt sulfide by a simple electrochemical deposition procedure.Following the structural examination of the prepared electrocatalyst were examined. In this regard, several microscopic methods like FE-SEM or TEM were used to know more regard the morphology of the material. The FE-SEM images confirmed the successful formation of sponge like nanosheets of NiCo-S on carbonaceous material. Since CNHs are prepared from graphene sheets with open ends in horn-like shapes, they can be considered as being formed from the origami-like or crushing contortion of a single graphene sheet. According to the FE-SEM images, the agglomeration of CNHs establishes discrete nano-sphere structures with diameters in the range of 50 to 150 nm. The TEM images also confirm this nano-sphere strictures.Following detailed structural characterization, the electrocatalytic activity of the fabricated NiCo-S/CNH electrodes toward electro-oxidation of glucose is examined in detail. The cyclic voltammetry was also used for glucose electro-oxidation mechanism investigation. In addition, parameter optimization was also done by utilizing cyclic voltammetry technique. These include medium pH, deposition cycles, and metals mole ration. Moreover, the effect of the presence and absence of CNH on the electrochemical performance of glucose oxidation were also examined. It shows that in the presence of CNH the peak current density for glucose oxidation is higher that is perfect for analytical purposes and increase the analytical sensitivity. The structural properties and electrochemical response of the fabricated electrodes were also compared to their corresponding mono-metallic counterparts.The amperometric method was utilized as one of the most prevalent and momentous techniques for the quantitative determination of glucose. The applied potential in amperometric tests was optimized to be +0.5 V (vs. Ag/AgCl). The proposed electrodes were operated within two distinct linear dynamic ranges of 0.001- 0.330 mM and 0.330 - 4.53 mM of standard glucose with sensitivities of 1842 µA.mM-1.cm-2, and 854 µA.mM-1.cm-2, respectively. On the other hand, an analytical sensitivity of 467 µA.mM-1.cm-2, within the linear dynamic range of 0.5 - 6 mM was obtained for the static chronoamperometric measurements for modified commercial screen-printed electrode (GSPE). The proposed sensor showed outstanding selectivity against iso-structures and co-existing interferences, long-term durability, rapid response (1.7 s), excellent poisoning resistance against chloride ions, good repeatability, and reproducibility. The tested interferences were 0.1 mM solutions of fructose, galactose, sucrose, lactose, ascorbic acid, uric acid, dopamine hydrochloride, and NaCl. In order to demonstrate the capability of the fabricated electrodes and to evaluate their potential for glucose measurements in real physiological specimens, the glucose level was successfully measured in human blood serum, urine, and saliva samples, without any sample pre-treatment. All in all, the encouraging results make NiCo-S/CNH electrodes immensely promising for clinical and physiological glucose-level measurements.Figure 1. (a) FE-SEM image of CNH. (b) FE-SEM image of NiCo-S/CNH. (c) TEM image of CNHs. (d) Cyclic voltammogarm of NiCo-S/CNH in the absence and presence of various concentration of glucose. (e) The amperometric responses of the NiCo-S/CNH/GCEs after addition of 1 mM glucose followed by successive injection of 0.1 mM fructose, galactose, sucrose, lactose, AA, UA, DA, and NaCl. (f) Chrono amperograms of the NiCo-S/CNH/GSPEs in the presence of the different glucose concentration ranging from 0.5 ~ 10.0 mM under applying +0.5 V. Amperogram of the NiCo-S/GCEs current response obtained from the addition of (g) 50 µL human blood serum, (h) 200 µL urine, and (i) 100 µL saliva followed by injection of 400 µM standard glucose solutions under the optimum potential of +0.5 V, the amperograms of five successive glucose addition. Figure 1

Kağıt Tabanlı Kolorimetrik Yöntemle Askorbik Asit (Vitamin C) Tayini

Ascorbic acid (AA) is the most important water-soluble organic biomolecule with antioxidant properties, known as vitamin C in many foods and beverages. The number of different methods developed for the determination of antioxidant properties of foods is increasing. Paper-based microfluidic analytical devices (µPADs) have been applied in the development of fast, simple, and cost-effective field analyzes in recent years. These developed analyzes are used as an alternative to laboratory-equipped qualitative and quantitative analyzes. In this study, a paper-based colorimetric method was applied for the determination of ascorbic acid. Geometric shapes with hydrophobic barrier were created on Whatman filter papers with the help of a wax pen. Using the principle of reduction of the AgNO3 solution in the presence of antioxidants in these shapes, the images of the color transformations were recorded with the help of a smartphone camera. ImageJ software was used in the image processing to determine the concentrations of standard AA solutions. Linear calibration curves for AA concentrations in the 0,2 to 1,0 mM range were obtained in grayscale and RGB (Red-Green-Blue) values. The coefficient of determination of the calibration curves (R2), respectively; 0,9389 for grayscale, 0,9728, 0,9628, and 0,8859 for Red, Green, and Blue channels. High-Performance Liquid Chromatography (HPLC) was used as a standard method to compare with the paper-based method. Freshly squeezed orange juice was used for the determination of ascorbic acid in the real food sample. The ascorbic acid value determined in orange juices by HPLC and colorimetric methods were statistically compared.

Quality of culinary products based on flour mixture with Atherina pontica powder

Introduction. The development of technology for flour culinary products for health purposes requires finding ways to create multicomponent flour mixtures. Problem. The introduction of non-traditional raw materials into the dough recipe leads to structural and mechanical changes, which requires finding ways to improve them technologically. The aim is to improve the structural-mechanical and organoleptic properties of fresh dough based on flour mixture with Atherina pontica powder for the production of high-quality culinary products. Methods. The object of research – model dough semi-finished products of fresh dough based on a flour mixture of high-grade wheat flour, Atherina pontica powder and germinated wheat grain flour ("Health" flour) in a ratio of 6 : 1 : 3 (Experiment 1) and the same , but with the addition of ascorbic acid solution from 2.0 to 12.0 % (Experiment 2), flour culinary products from fresh dough: dumplings "Chornomorski", dumplings "Aterinka", noodles "Ryb’yacha", control samples – fresh dough traditional recipes, dumplings with potatoes, fish dumplings, noodles "Domashnj". The structural and mechanical parameters of fresh dough (deformation, plastic viscosity, ultimate shear stress) and organoleptic evaluation of the quality of flour culinary products were studied. Results. The influence of the components of the flour mixture on the structural and mechanical properties of fresh dough for flour culinary products was determined and the rational concentration of ascorbic acid solution, which is 10 % in the recipe of fresh dough, was determined. The research confirmed the prospects of introducing components for the development of the recipe of the dough semi-finished product, which is the basis for the production of dumplings "Сhornomorski", dumplings "Aterinka" and noodles " Ryb’yacha " with high organoleptic properties. Conclusions. The use of the composition of the composition in the technology of fresh dough (Еxperiment 1) leads to the deterioration of its structural and mechanical properties relative to the control, which requires finding ways to improve them. It is proved that in the model compositions of fresh dough using a 10 % solution of ascorbic acid, certain structural and mechanical parameters are improved. This allows you to provide sufficient elasticity and form high-quality culinary products. According to the developed recipe, the obtained semi-finished dough for dumplings Chornomorski", dumplings "Aterinka", noodles "Ryb’yacha", was confirmed by a high organoleptic evaluation.

Molecular interaction studies on the binding ability of hydrated zinc sulphate with aqueous solution of ascorbic acid at different temperatures

Abstract The ternary systems containing Water, Ascorbic acid (AA) and ZnSO4·7H2O were investigated using three approaches namely volumetric studies, viscosity studies and conductance studies. The solvent systems used were 2, 4 and 6% (by weight) of AA in water. The studies were conducted at four temperatures (303.15–318.15 K with an interval of 5 K) and pressure 0.1 MPa with concentration of ZnSO4·7H2O in the solution ranging from 0.01 to 0.12 m. Various parameters like partial molar volume (ϕ v), apparent molar volume ( ϕ v o ) $({\phi }_{\text{v}}^{\text{o}})$ , Hepler’s constant ( ( d 2 ϕ v o / d T 2 ) p ) $({({d}^{2}{\phi }_{\text{v}}^{\text{o}}/d{T}^{2})}_{p})$ , partial molar expansibility ( ϕ E o ) $({\phi }_{\text{E}}^{\text{o}})$ and transfer volume ( Δ t r ϕ v o ) $({{\Delta}}_{tr}{\phi }_{\text{v}}^{\text{o}})$ have been evaluated from volumetric studies. The viscosity studies have yielded Jones-Dole parameters (A and B) and free energy of activation per mole for solvent ( Δ μ 1 0 ‡ ) $({\Delta}{\mu }_{1}^{0{\ddagger}})$ and solute ( Δ μ 2 0 ‡ ) $({\Delta}{\mu }_{2}^{0{\ddagger}})$ . The conductance data has been used to calculate molar conductance (Λm), limiting molar conductance ( Λ m o ) $({{\Lambda}}_{\text{m}}^{\text{o}})$ and Walden product ( Λ m o η o ) $({{\Lambda}}_{\text{m}}^{\text{o}}{\eta }_{\text{o}})$ . The results of these studies agree with each other and have concluded the structure breaker behavior of ZnSO4·7H2O in the solvent system containing AA and water.

Green synthesis of highly aligned reduced graphene oxide films with competitive performance assisted by sandwiching restriction

Green synthesis of reduced graphene oxide films (RGOFs) with high performance is one of prerequisites for graphene materials toward industrialization application. However, maintaining stabilized precursor graphene oxide films (GOFs) in green reducing solutions without disintegration or deformation is still a significant challenge. In this work, the mechanism of GOF deformation during a typical green reduction process in ascorbic acid solution was analyzed. Based on the findings, a method for restraining the disintegration and deformation during the reduction process by sandwiching GOF between two perforated Teflon release films was proposed. Such a sandwiching restriction technique enabled one to overcome the bubbles effect effectively, thus obtaining the highly aligned layered structure of RGOFs after the reduction. The investigation of the mechanical and electrical properties indicated that the obtained RGOF possessed a competitive performance (the tensile strength of 30.2 MPa and the electrical conductivity of 3125 S·m−1). This demonstrates a straightforward way of fabricating highly aligned RGOFs for graphene industrialization.

Exploring effects of slice thickness, pretreatment and drying air temperature on nutritional, functional and pasting properties of Gardenia erubescens Stapf. &amp; Hutch. fruit powder

Gardenia erubescens fruits are outstanding sources of essential nutrients as well as health-promoting phytochemicals and minerals. However, fresh fruits are highly perishable and difficult to store. To reduce losses and extend their uses, fresh G. erubescens fruits could be converted into powder. The present study investigated the effect of slice thickness, pretreatment, and drying air temperature on the nutritional, functional, and pasting properties of G. erubescens fruits. Fresh G. erubescens fruits were sliced into 3 mm and 5 mm thickness, subjected to different pretreatments (steam blanching at 100 °C for 3 min, dipping in 2% (w/v) ascorbic acid solution for 3 min and no treatment) and then dried at 40 °C, 50 °C, 60 °C and 70 °C. The treatments significantly (p < 0.05) affected almost all the quality properties with trends only observed in terms of main effects. The 5 mm thick samples had relatively higher fibre, carbohydrate, zinc, iron, magnesium, manganese, swelling capacity (SC), swelling index (SI), water absorption capacity (WAC), and final viscosity (FV) but lower protein, fat, dietary energy, calcium, potassium, and sodium contents as compared to the 3 mm samples. Futher, the pretreated samples had lower protein, fat and dietary energy contents as compared to the control. Generally, potassium, calcium, zinc, iron, SI, and FV of the fruits improved by blanching but reduced by dipping in ascorbic acid solution. The SC, SI, and FV generally corresponded linearly with drying temperature with the peaks at 60 °C while WAC decreased as drying temperature increased. Blanching and dipping in ascorbic acid solution reduced SC and WAC. Though there was no three-factor combination that was ultimately the best, drying 5 mm thick G. erubescens fruit slices at 60 °C without pretreatment preserves most of the proximate and mineral contents, functional and pasting properties. • The effect of slice thickness, pretreatment and drying temperature on nutritional, functional and pasting properties of Gardenia erubescens fruit powders was studied. • The treatments affected the quality attributes of the fruit powders with no linear trends for the interactions. • The 5 mm thickness resulted in better quality attributes of the fruit powders compared to the 3 mm. • Steam blanching and dipping in ascorbic acid reduced most of the quality attributes when compared with the control. • Drying of 5 mm fruit slices at 60 °C preserves most of the proximate and mineral contents, functional and pasting properties.

Fabrication of Silver Electrical Circuits on Textile Substrates by Reactive Inkjet Printing

Delivery of electronic functionality such as sense and response to the human body using smart textiles is important for developing wearable electronics. As the key component of connecting various devices in smart textiles, electrical circuit with excellent electrical performance is an essential effort for ongoing research in textronics. In this work, a new liquid phase chemical reduction method combined with inkjet printing technology for fabricating electrical circuits on textile substrates is adopted. The aqueous silver nitrate is ejected spot by spot onto textiles that are wetted with ascorbic acid solution and placed on the copper foil. After redox and replacement reactions, silver particles are deposited to form conductive layer for electrical circuits. Deposited layers of silver with high conductivity up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${0.86201}\times {10}^{{6}}$ </tex-math></inline-formula> S/m and the sheet resistance in the range 0.0116- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.06913~\Omega $ </tex-math></inline-formula> /sq. Based on these findings, we realized the textile capacitive sensor with good response time, and stability for 1500 cycles of repeated loading. The fabricated textile electrocardiogram (ECG) electrode attached to braces could be effective for human heart rate and ECG signal monitoring.

Growth, Physicochemical, Nutritional, and Postharvest Qualities of Leaf Lettuce (Lactuca sativa L.) as Affected by Cultivar and Amount of Applied Nutrient Solution

The effects of different nutrient solution quantities on growth, physicochemical, nutritional, and postharvest qualities of lettuce were investigated. Two differently pigmented Korean leaf lettuce cultivars “Geockchima” and “Cheongchima” were grown in soilless perlite culture supplied with 250, 500, 1000, and 2000 mL·d−1·plant−1 nutrient solutions. Several growth parameters (plant height, leaf number, fresh weight, dry matter) were evaluated. The highest lettuce growth was observed when plants were supplied with 1000 mL·d−1·plant−1. Cultivating lettuces in the lowest nutrient solution quantity showed higher dry matter, crude fiber, osmolality, chlorophyll, and anthocyanin contents. Upon increasing the nutrient solution, the crispiness, greenness, and levels of ascorbic acid, nitrogen, and potassium, increased, while phosphorus and magnesium were unaffected, and calcium content declined. Postharvest qualities were better maintained in lettuces irrigated with the least amount of nutrient solution, extending their shelf life. We conclude that lettuce can be grown with 1000 mL·d−1·plant−1 for higher yield, and short-term storage and/or transportation. However, when lettuces need to be stored for a certain period, such as long-distance shipment, they should be cultivated with a limited nutrient solution, which requires further detailed investigation. The results of this study can be applied for distributing, storing, transporting, and marketing lettuce.

Synthesis of a sulfonated methylene blue-backboned polymer for biodetections

Poly (methylene blue) prepared by the widely used electrochemical polymerization method suffers from the undefined chemical structure and difficulty in modification with functional groups. The chemical polymerization of methylene blue is a challenging but attractive subject. We designed and prepared a methylene blue-backboned polymer (MBP-SO3) with the side chain modified with sulfonic acid groups. The polymer retains the redox activity of methylene blue and has a good mass transfer effect in electro-catalyzing the oxidation of dopamine, epinephrine, and uric acid. The negative charges carried by MBP-SO3 under physiological conditions are beneficial to attract cationic biomolecules, and its nanosheet-like morphology is conducive to charge transfer, which amplifies electrochemical signals in detection of target biomolecules. Using the Nafion film coating the electrode surface to block ascorbic acid and nicotinamide adenine dinucleotide (NADH), the MBP-SO3 modified electrode can selectively detect dopamine (0.02–25 mM), epinephrine (0.1–30 mM) and uric acid (0.03–3 mM) without interference from high-concentration of ascorbic acid and NADH solutions. The detections are also effective in serum samples. This work paves a way for methylene blue-backbone polymers in electrochemical sensing.

Assessing the Oxidative State of the Skin by Combining Classical Tape Stripping with ORAC Assay.

The antioxidant barrier system of the skin acts as the main defence against environmental pro-oxidants. Impaired skin oxidative state is linked to unhealthy conditions such as skin autoimmune diseases and cancer. Thus, the evaluation of the overall oxidative state of the skin plays a key role in further understanding and prevention of these disorders. This study aims to present a novel ex vivo model to evaluate the skin oxidative state by the measurement of its antioxidant capacity (AOC). For this the ORAC assay was combined with classical tape stripping and infrared densitometry to evaluate the oxidative state of the stratum corneum (SC). Outcomes implied the suitability of the used model to determine the intrinsic antioxidant capacity (iAOC) of the skin. The average iAOC of untreated skin was determined as 140 ± 7.4 µM TE. Skin exposure to UV light for 1 h reduced the iAOC by about 17%, and exposure for 2 h decreased the iAOC by about 30%. Treatment with ascorbic acid (AA) increased the iAOC in a dose-dependent manner and reached an almost two-fold iAOC when 20% AA solution was applied on the skin. The application of coenzyme Q10 resulted in an increase in the iAOC at low doses but decreased the iAOC when doses > 1% were applied on the skin. The results show that the combination of classical tape stripping and ORAC assay is a cost-effective and versatile method to evaluate the skin oxidative state and the pro-oxidate and antioxidative effects of topical skin treatments on the iAOC of the skin. Therefore, the model can be considered to be a valuable tool in skin research.

Ascorbic acid as an alternative coreactant for luminol reaction and sensitive chemiluminescence determination of ascorbic acid in soft drinks

Ascorbic acid can serve as an efficient coreactant for luminol chemiluminescence (CL) reaction. An observable CL emission is produced when mixing ascorbic acid with luminol in an alkaline condition. The CL signal is further dramatically enhanced by cobalt(II) ions. This CL system was exploited as a new method for direct determination of ascorbic acid with a flow injection mode. A good linear response is acquired between the CL signal and ascorbic acid concentration in 5.0–1000.0 ng/mL range with a detection limit of 1.3 ng/mL. The relative standard deviations are 2.3% for intra–day (n = 11) and 3.7% for inter–day (n = 3) by parallel determination of 0.5 μg/mL ascorbic acid solution. The method has good selectivity for ascorbic acid since no obvious responses are observed for a variety of inorganic ions and biological substances. The practicability of the method has been demonstrated by the analysis of ascorbic acid in some soft drinks.

Ultrasensitive photoelectrochemical immunosensor for carcinoembryonic antigen detection based on pillar[5]arene-functionalized Au nanoparticles and hollow PANI hybrid BiOBr heterojunction

In this study, an ultrasensitive and specific photoelectrochemical (PEC) immunosensor was designed for carcinoembryonic antigen (CEA) detection. Benefitting from the ascorbic acid (AA) used as an electron donor that led to a notable change in the photocurrent density, pillar[5]arene functionalized Au and Polyaniline-Bismuth oxybromide heterojunction (Au@WP5/PANI-BiOBr) displayed superior PEC performance for CEA sensing. In detail, the localized surface plasmon resonance (LSPR) of the Au NPs and host-guest complexation between WP5 and AA increased the photocurrent signal, the photogenerated holes on BiOBr accelerated the oxidation of AA, and the fast electron transfer of the hollow PANI tubes benefited an increase in the photocurrent. The antibody effectively bound with CEA when bovine serum albumin blocked the residual sites on the Au@WP5/PANI-BiOBr electrode, generating a clear decrease in photocurrent density in AA solution. Under the optimum condition, the developed PEC immunosensor exhibited a sensitive response to CEA which was linear in the range of 0.01 ng mL-1 to 50 ng mL-1 with a detection limit of 3 pg mL-1. The proposed PEC immunosensor displayed high specificity, good stability, and excellent reproducibility, paving a new way to construct sensitive and specific photoactive heterojunction materials for biomarker immunosensing.

The Influence of Soaking and Sprouting on the Physicochemical Characteristics of Tigernut Tubers (Cyperus esculentus L.)

The influence of soaking and germination on the physicochemical characteristics of tigernut tubers (Cyperus esculentus L.) are investigated. Tubers (Ø &gt; 1 cm) were soaked in an ascorbic acid solution (0.1%) for 48 h at 40 °C before undergoing germination for 6 days. The textural profile, the capacity and germination energy and the biochemical composition of these tubers were determined. The germination energy varied from 76.18 to 79.48% for the quantities of solution of 24 and 48 mL, respectively. The textural profile of the tubers varied depending on the type of treatment. Germination resulted in a considerable reduction in amylose content from 14.15% for the native tigernut tuber to 9.98% for the sprouted one. This treatment also increased the protein, ascorbic acid and ash contents, which ranged from 7.54 to 8.82 g/100 g DM, 250 to 275.39 mg/100 g DM and 2.60 to 3.84 g/100 g DM, respectively. The starch content of the tubers following germination remained high, which could come up against the pasteurization of the milk from these tubers.

Study of interaction between cationic surfactant (CTAB) and ascorbic acid/ascorbic acids derivatives by tensiometric and spectroscopic methods

The interactions between the cationic surfactant-cetyltrimethylammonium bromide (CTAB) and ascorbic acid and its derivatives in an aqueous media were investigated by using tensiometric and spectroscopic methods. On the basis of the surface tension isotherms, the values of the critical micelle concentration were determined also the adsorption parameters (the Gibbs free energy of adsorption, the surface excess at the saturated interface, the minimum molecular area in the adsorption layer at the saturated interface) were calculated using the Szyszkowski equation. The charged pseudophase model was adopted for define the Gibbs free energy of micellization. The infrared analysis (FTIR) contributed to the estimation of the possibility of the existence of interactions prevailing in the analyzed systems. The effect of CTAB-ascorbic acid/ascorbic acid derivatives interactions on their antioxidant activity was analyzed. Sets of ascorbic acid, 3-O-ethyl ascorbic acid and ascorbyl glucoside solutions differing in CTAB concentration were prepared. For the total antioxidant capacity determination, the Ferric Reducing Antioxidant Power (FRAP) assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) assay were used. The results obtained for CTAB - ascorbic acid/ascorbic acid derivatives systems were compared with the ones obtained for pure antioxidants.

Optimization of Superchilling Liquid Formula and Solutions for Storage of Duck Meat

In order to optimize the proportion of materials in the superchiling solution, a freezing temperature superchiling solution was designed to meet the requirements of storage of duck meat. Response surface analysis (RSM) method was used to investigate the effect of salt and alcohol on the change of freezing point. The CCD response surface model was used to determine the optimum conditions and the optimal ratio was obtained. The results showed that the optimum design conditions were 6 % Cacl2 and 3% 1,2-Propanediol The freezing point temperature is -5.21°C. And optimizing the sorbitol solution, the ascorbic acid solution, and the chitosan solution with different mass ratios based on obtaining the optimal proportion of the micro-freezing liquid. The results showed that 2% sorbitol, 0.3% ascorbic acid and 0.6% chitosan were good in duck meat quality.