scholarly journals Application of a New Dehydroascorbic Acid Reducing Agent in the Analysis of Vitamin C Content in Food

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6263
Author(s):  
Artur Mazurek ◽  
Marzena Włodarczyk-Stasiak
Keyword(s):  
Vitamin C ◽  
High Performance ◽  
Dehydroascorbic Acid ◽  
Total Content ◽  
High Reactivity ◽  
Reducing Agent ◽  
Spectrophotometric Detection ◽  
Acidic Solutions ◽  
Low Efficiency ◽  
Acid Reduction

The analysis of total vitamin C content in food is most frequently performed by reducing dehydroascorbic acid to ascorbic acid, which is then assayed with the technique of high-performance liquid chromatography combined with spectrophotometric detection. Tris(2-carboxyethyl)phosphine is currently the only agent in use that efficiently reduces dehydroascorbic acid at pH < 2. Therefore, there is a continued need to search for new reducing agents that will display a high reactivity and stability in acidic solutions. The objective of the study was to verify the applicability of unithiol and tris(hydroxypropyl)phosphine for a reducing dehydroascorbic acid in an extraction medium with pH < 2. The conducted validation of the newly developed method of determining the total content of vitamin C using tris(hydroxypropyl)phosphine indicates its applicability for food analysis. The method allows obtaining equivalent results compared to the method based on the use of tris(2-carboxyethyl)phosphine. The low efficiency of dehydroascorbic acid reduction with the use of unithiol does not allow its application as a new reducing agent in vitamin C analysis.

Note: Quantification of Ascorbic Acid and Dehydroascorbic Acid in Fresh Olives and in Commercial Presentations of Table Olives

2005 ◽  
Vol 11 (3) ◽  
pp. 199-204 ◽  
Author(s):  
A. López ◽  
A. Montaño ◽  
P. Garcia ◽  
A. Garrido
Keyword(s):  
Ascorbic Acid ◽  
High Performance Liquid Chromatography ◽  
Vitamin C ◽  
High Performance ◽  
Dehydroascorbic Acid ◽  
Maximum Level ◽  
Table Olives ◽  
Total Vitamin ◽  
Low Levels ◽  
To Come

Ascorbic acid (AA) and dehydroascorbic acid (DHAA) were determined by high performance liquid chromatography (HPLC) in fresh green olives as well as a diversity of commercial presentations of table olives (based on both Spanish-style green olives and directly brined olives). Fresh green olives (Manzanilla cv.) immediately after harvest contained about 9mg total ascorbic acid/100g f.w., with DHAA representing more than 90% of this amount. During the post-harvest period (till 2 weeks) the total vitamin C remained stable when olives were stored at 6°C, but significant degradation occurred at ambient temperature (~35% loss after 7 days). In commercial presentations of table olives, in general, the main contribution to the total vitamin C level appeared to come from AA added as an antioxidant, the maximum level being found in Manzanilla olives stuffed with anchovy streams (36.1mg/100g f.w.). However, in some samples (e.g. plain olives) that did declare any added AA, very low levels (0.1-0.6mg total AA/100g f.w.) were found. Our hypothesis is that, in those samples, AA would be degraded by lactic acid bacteria and/or yeast from olive fermentation, whereas pasteurisation in other presentations (e.g. stuffed olives) would stabilise added AA.

scholarly journals Carbonized Dehydroascorbic Acid: Aim for Targeted Repair of Graphene Defects and Bridge Connection of Graphene Sheets with Small Size

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 531 ◽  
Author(s):  
Jing Li ◽  
Jinfeng Lai ◽  
Jialiang Liu ◽  
Rubai Lei ◽  
Yuxun Chen
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Vitamin C ◽  
High Performance ◽  
Transfer Problem ◽  
Dehydroascorbic Acid ◽  
Reduction Reaction ◽  
Thermal Dissipation ◽  
Innovative Strategy ◽  
Graphene Layers

The thermal dissipation issue of electronics devices becomes increasingly prominent as they evolve to smaller sizes and more complicated structures. Therefore, the development of materials with excellent heat conduction properties and light weight turns out to be an urgent demand to solve the heat transfer problem of electronics devices with high performance. For this purpose, we put forward an innovative strategy that carbonized dehydroascorbic acid (CDA) be applied to graphene layers for the targeted repair of defects among them and bridge connection of the layers to produce graphene heat conduction materials with excellent properties. Firstly, hydrogen bonds formed from dehydroascorbic acid (DHAA, products of the oxidation of vitamin C) and each of ketone, carboxyl, and oxhydryl groups on graphene layers were absorbed at targeted locations where oxidation graphene produces defects, then targeted repair was conducted for those defects to be filled and for the graphene layers of a small size to grow into large sheet materials with improved continuity by CDA generated in thermally pressing reduction reaction at 800 °C. In our investigation, the planar thermal conductivity of rGO/VC membrane reached 1031.9 ± 10.2 Wm−1K−1, while the added mass content of vitamin C (VC) was 15%. Being a reference, the planar thermal conductivity of primitive graphene membrane was only 610.7 ± 11.7 Wm−1K−1.

scholarly journals The content of ascorbic and dehydroascorbic acids and vitamin C in non-preserved juices, depending on their type and storage time

2021 ◽  
pp. 373-379
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
High Performance ◽  
Storage Time ◽  
Apple Juice ◽  
Dehydroascorbic Acid ◽  
Hplc Method ◽  
The Body ◽  
Water Soluble ◽  
And Storage

Background. Vitamin C is one of the most important water-soluble vitamins. It is responsible for many important functions in the body, including: it has a positive effect on maintaining immunity, protects the body against free radicals, and also participates in the synthesis of hormones. Juices can be a good source of this vitamin. Most of the juices available on the market are processed products. Untreated juices, which do not contain added preservatives, sugar and are not pasteurized, constitute a smaller group on the market. Therefore, this group of juices can be a valuable product in human nutrition. Objective. The aim of the study was t o analyze the content of ascorbic acid (AA), dehydroascorbic acid (DHAA) and vitamin C (TAA) in non-preserved juices, depending on their type and storage time. Material and methods. The analysis of T AA, AA and DHAA content in juices was carried out in ten types of nonpreserved juices from two companies (A and B), purchased in a chain of retail outlets. The analyzed juices in company A were: sauerkraut and carrot, grapefruit, orange, apple and mandarin, while in company B: orange, apple, apple and quince, grapefruit and mandarin. In test 1, the first ten juices were analyzed, in test 2 - another ten juices after one month, in test 3 - juices from test 2 were used, and three days after opening the package and storing the juices in standard refrigeration conditions, the stability test of AA was analyzed. The AA and TAA contents were determined using the high performance liquid chromatography (HPLC) method. The DHAA content was calculated by subtracting the AA content from the TAA content. Results. The highest TAA content was found in citrus juices, i.e. grapefruit, orange and mandarin, and the lowest in sauerkraut and carrot juices and apple juice. Moreover, ascorbic acid in apple juice was characterized by the lowest durability. Conclusions. In the production of non-preserved apple juice, consideration should be given to the natural protection of ascorbic acid by the addition of citrus or other fruit juice, vegetable juice or by using a mild technology in the production process.

scholarly journals The relation between gastric vitamin C concentrations, mucosal histology, and CagA seropositivity in the human stomach

Gut ◽  
1998 ◽  
Vol 43 (3) ◽  
pp. 322-326 ◽  
Author(s):  
Z W Zhang ◽  
S E Patchett ◽  
D Perrett ◽  
P H Katelaris ◽  
P Domizio ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Gastric Juice ◽  
Acid Concentration ◽  
High Performance ◽  
Dehydroascorbic Acid ◽  
Human Stomach ◽  
Ascorbic Acid Concentration ◽  
H Pylori ◽  
The Individual

Background—Vitamin C may be protective against gastric cancer though infection withHelicobacter pylori is associated with a reduction in intragastric concentrations of vitamin C.Aims—To examine the effects ofH pylori infection, gastric juice pH, the severity and extent of gastric inflammation, and CagA antibody status of the individual on gastric juice and mucosal vitamin C concentrations.Patients—One hundred and fifteen patients undergoing routine gastroscopy for investigation of dyspepsia.Methods—High performance liquid chromatography was used to determine vitamin C concentrations. CagA antibody was detected by western blot analysis.Results—Gastric juice ascorbic acid concentration was significantly lower in patients infected withH pylori compared with those uninfected (19.3 μmol/l (interquartile range (IQR) 10.7–44.5) versus 66.9 μmol/l (IQR 24.4–94.2), p=0.003). The reduction in gastric juice ascorbic acid concentration was inversely related to the severity of gastritis (p=0.01). CagA positive patients had significantly lower gastric juice ascorbic acid concentrations than CagA negative ones (14.8 μmol/l (IQR 7.9–52.2) versus 39 μmol/l (IQR 19.9–142.2), p=0.05). Decreased gastric juice dehydroascorbic acid concentrations were observed in patients with gastric atrophy and intestinal metaplasia. Mucosal ascorbic acid concentrations were also significantly lower in infected patients than uninfected patients (p=0.04).Conclusions—The reduction in gastric vitamin C concentrations is related to gastric juice pH, the severity and extent of gastritis, the presence of H pylori, and the CagA antibody status of the individual. These findings may have implications in H pyloriassociated carcinogenesis.

Tetraphenylbenzene-based AIEgens: the Horizontally Oriented Emitters for highly Efficient Non-doped Deep Blue OLEDs and Host for High-Performance Hybrid WOLEDs

2020 ◽  
Author(s):  
Pengbo Han ◽  
Zeng Xu ◽  
Chengwei Lin ◽  
Dongge Ma ◽  
Anjun Qin ◽  
...  
Keyword(s):  
High Performance ◽  
General Strategy ◽  
Flat Panel Displays ◽  
Light Emitting ◽  
Horizontal Orientation ◽  
Deep Blue ◽  
Full Color ◽  
High Emission ◽  
White Oleds ◽  
Low Efficiency

Deep blue organic-emitting fluorophores are crucial for application in white lighting and full color flat-panel displays but emitters with high color quality and efficiency are rare. Herein, novel deep blue AIE luminogens (AIEgens) with various donor units and an acceptor of cyano substituted tetraphenylbenzene (TPB) cores were developed and used to fabricate non-doped deep blue and hybrid white organic light-emitting diodes (OLEDs). Benefiting from its high emission efficiency and high proportion of horizontally oriented dipoles in the film state, the non-doped deep blue device based on CN-TPB-TPA realized a maximum external quantum efficiency 7.27%, with a low efficiency roll-off and CIE coordinates of (0.15, 0.08). Moreover, efficient two-color hybrid warm white OLEDs (CIE<sub>x,y</sub> = 0.43, 0.45) were achieved using CN-TPB-TPA as the blue-emitting layer and phosphor doped host, which realized maximum current, power, external quantum efficiencies 58.0 cd A<sup>-1</sup>, 60.7 lm W<sup>-1</sup> and 19.1%, respectively. This work provides a general strategy to achieve high performance, stable deep blue and hybrid white OLEDs by construction of AIEgens with excellent horizontal orientation

Revealing changes in curcumin bioavailability using vitamin C as an enhancer by HPLC-MS/MS

2019 ◽  
Vol 16 ◽  
Author(s):  
Xufen Dai ◽  
Jiaxue Hao ◽  
Ying Feng ◽  
Jing Wang ◽  
Qiannan Li ◽  
...  
Keyword(s):  
Vitamin C ◽  
High Performance ◽  
Internal Standard ◽  
Fold Increase ◽  
Rat Plasma ◽  
Pharmacokinetic Parameters ◽  
Solution Ph ◽  
Esi Ms ◽  
Simple Strategy ◽  
Isolated Compound

Background: Curcumin (CUR), a natural isolated compound from turmeric, has been the promising star in fighting many diseases but the broad application of curcumin has been limited ascribed to low bioavailability. Objective: The aim of this study is to pursue the enhancement of curcumin bioavailability through co-administration of vitamin C. Methods: Such purpose was achieved through the analysis of curcumin pharmacokinetics by high performance liquid chromatography coupled with electrospray ionization - tandem mass spectrometry (HPLC - ESI - MS/MS). The plasma was separated on a C18 reverse phase column using acetonitrile and ammonium formate solution (pH 6.5; 2.0 mM) at 0.8 mL/min. MS/MS detection was carried out in negative mode using mass patterns of m/z 367.0 > 216.7 for curcumin and m/z 265.2 > 223.9 for internal standard (honokiol). Results: Successful application of the proposed method in the pharmacokinetic study presented clear changes in key pharmacokinetic parameters including the growth of AUC (0-t) up to 2.4 times, 2.2-fold increase of Cmax, 2.2-fold loss of CL, and 1.5-fold diminishment of t1/2. Conclusion: We developed an HPLC-ESI-MS/MS method for determination of curcumin in rat plasma and validated the improvement of bioavailability of curcumin through co-administration of vitamin C. We reasoned these changes to the inhibition of lipid peroxidation induced by the use of vitamin C. Such a simple strategy is possible to become an alternative for enhancing curcumin efficiency in practice.

scholarly journals The Effect of Ripening Stages on the Accumulation of Carotenoids, Polyphenols and Vitamin C in Rosehip Species/Cultivars

2021 ◽  
Vol 11 (15) ◽  
pp. 6761
Author(s):  
Brigita Medveckienė ◽  
Jurgita Kulaitienė ◽  
Dovilė Levickienė ◽  
Ewelina Hallmann
Keyword(s):  
High Performance Liquid Chromatography ◽  
Vitamin C ◽  
High Performance ◽  
Hplc Method ◽  
Total Carotenoid ◽  
Ripening Stage ◽  
Rosa Rugosa ◽  
Total Polyphenols ◽  
Rosa Canina ◽  
Ripening Stages

Our research was aimed at assessing the effect of accumulation of carotenoids, polyphenols, vitamin C and ripening stage in the rosehip fruits of two species—Rosa canina, Rosa rugosa and two cultivar—Rosa rugosa ‘Rubra’ and Rosa rugosa ‘Alba’. The amounts of carotenoids, polyphenols and vitamin C were determined using the high-performance liquid chromatography (HPLC) method. The obtained results showed that the significantly highest amount (107.15 mg 100 g−1) of total carotenoid was determined in the fruits of Rosa canina at ripening Stage V. While results indicated that significant amount of total polyphenols were established at Stages I and II in the Rosa Rugosa ‘Alba’ and Rosa rugosa ‘Rubra’ cultivars (110.34 mg 100 g−1, 107.88 mg 100 g−1 and 103.20 mg 100 g−1 103.39 mg 100 g−1). At ripening Stage I, in the fruits of Rosa rugosa the greatest increases were established in the contents of vitamin C (3036.08 mg 100 g−1).

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