scholarly journals Determination of the Antioxidant Activity of Samples of Tea and Commercial Sources of Vitamin C, Using an Enzymatic Biosensor

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 324
Author(s):  
Danilo Braga Ribeiro ◽  
Gabriela Santos Silva ◽  
Djanira Rubim dos Santos ◽  
Andressa Rose Castro Costa ◽  
Eliane Braga Ribeiro ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Prussian Blue ◽  
Chemical Species ◽  
Cobalt Phthalocyanine ◽  
Operational Parameters ◽  
Enzymatic Biosensor ◽  
Commercial Sources ◽  
Meldola Blue

Antioxidants are synthetic or natural compounds capable of preventing or delaying oxidative damage caused by chemical species that can oxidize cell biomolecules, such as proteins, membranes, and DNA, leading to the development of various pathologies, such as cancer, atherosclerosis, Parkinson, Alzheimer, and other diseases serious. In this study, an amperometric biosensor was used to determine the antioxidant activity of teas and effervescent products based on vitamin C, available on the market. A sensor composed of three electrodes was used. The performance of the following electrochemical mediators was evaluated: meldola blue combined with Reineck salt (MBRS), Prussian blue (PB), and cobalt phthalocyanine (CoPC), as well as the time of polymerization in the enzymatic immobilization process and the agitation process during chronoamperometric measurements. Prussian blue proved to be more efficient as a mediator for the desired purposes. After optimizing the construction stages of the biosensor, as well as the operational parameters, it presented stability for a period of 7 months. The results clearly indicate that the biosensor can be successfully used to detect fraud in products called “antioxidants” or even in drugs containing less ascorbic acid than indicated on the labels. The detection limit was set at 4.93 µmol·L−1.

scholarly journals Spectrophotometric determination of ascorbic acid in grapes with the Prussian Blue reaction

2012 ◽  
Vol 23 (2) ◽  
pp. 174-179 ◽  
Author(s):  
Nicoleta Matei ◽  
Simona Dobrinas ◽  
Gabriel Lucian Radu
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Vitis Vinifera ◽  
Prussian Blue ◽  
Spectrophotometric Determination ◽  
Pinot Noir ◽  
Cabernet Sauvignon ◽  
Red Grapes ◽  
Blue Reaction

AbstractThe objective of the present work was to adapt the Prussian Blue reaction for the determination of ascorbic acid. The procedure was successfully applied for the determination of ascorbic acid in red and white grapes (Vitis vinifera L.) just previous ingathering. In the present work was used the red and white grapes from Murfatlar vineyard: Mamaia, Cabernet Sauvignon, Merlot, Pinot Noir, Chardonnay, Sauvignon, Muscat Ottonel and Riesling Italian. The results were situated in the range of 0.67 - 1.79 mg vitamin C/100g product for red grapes and respectively 0.50 - 1.49 mg vitamin C/100g for white grapes.

scholarly journals Nutrients and bioactive compounds of pulp, peel and seed from umbu fruit

2019 ◽  
Vol 49 (4) ◽  
Author(s):  
Leilson de Oliveira Ribeiro ◽  
Eliseth de Souza Viana ◽  
Ronoel Luiz de Oliveira Godoy ◽  
Sidinea Cordeiro de Freitas ◽  
Suely Pereira Freitas ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Bioactive Compounds ◽  
Nutritional Composition ◽  
Total Phenolic ◽  
Total Carotenoids ◽  
Fresh Pulp ◽  
Main Barrier ◽  
By Products

ABSTRACT: The objective of this research was to evaluate the nutritional composition and bioactive compounds of whole umbu fruit, including pulp, seed and peel, and also of a commercial umbu pulp. Samples of the fractions and of commercial pulp were analyzed for determination of minerals and proximate composition, total phenolic and antioxidant activity. Pulps and peel were also analyzed for vitamin C and carotenoids contents. Commercial pulp presented better nutritional composition than fresh pulp (P<0.05) and the peel presented higher phenolic content and antioxidant activity than seed. Peel also stood out by its vitamin C (79 mg.100 g-1) and total carotenoids (2,751 µg.100 g-1) contents, showing that, as the main barrier of the fruit for its protection, it is a fraction rich in bioactive compounds. The highest dietary fiber and iron contents were observed in umbu seed (P<0.05). Therefore, umbu by-products may be ingredients proper for development of food richer in nutrients and bioactive compounds.

scholarly journals Determination of Antioxidant Activity of Vitamin C by Voltammetric Methods

Proceedings ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 23 ◽  
Author(s):  
Klaudia Suliborska ◽  
Monika Baranowska ◽  
Agnieszka Bartoszek ◽  
Wojciech Chrzanowski ◽  
Jacek Namieśnik
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Chemical Properties ◽  
Differential Pulse ◽  
Antioxidant Compounds ◽  
Redox Active ◽  
Physical And Chemical ◽  
Kinetics Of ◽  
Voltammetric Methods

Voltammetric methods—cyclic (CV) and differential pulse voltammetry (DPV) are considered the most appropriate way to evaluate antioxidant activity of redox active compounds. They provide information about both mechanism and kinetics of electrochemical oxidation of antioxidants as well as their physical and chemical properties such as the redox potential or the number of electrons transferred. These methods are helpful for understanding the mechanisms of oxidation or reduction processes of antioxidant compounds. This work presents the electrochemical properties of vitamin C obtained by both CV and DPV methods.

scholarly journals Determination of Total Flavonoid Contents and Antioxidant Activity of Leucaena Leucocephala Leaves's Extract

2020 ◽  
Vol 9 (2) ◽  
pp. 70-77
Author(s):  
Taupik Hidayat ◽  
Baharuddin Hamzah ◽  
Minarni R. Jura
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Leucaena Leucocephala ◽  
Positive Control ◽  
Total Flavonoid ◽  
Antioxidant Vitamin ◽  
Antioxidant Power ◽  
Sample Extract ◽  
Ic50 Values

The study of the determination of total flavonoid contents and antioxidant activity of extract of Leucaena leucocephala leaves had been carried out using UV-Vis spectrophotometry method. This study aimed to determine the total flavonoid contents and the antioxidant power of Leucaena leucocephala extract. Extraction of chemical content from Leucaena leucocephala was carried out by the maceration method using absolute ethanol. The total flavonoid contents from the sample extract were taken up for absorption at wavelength 510 nm and 700 nm. The variation of the concentration of Leucaena leucocephala leaves' extract was respectively 20, 40, 60, and 80 ppm. The results of the study showed that the total flavonoid contents of extracts of Leucaena leucocephala leaves was 2.242 g/100 grams. The antioxidant activity of Leucaena leucocephala leaves extract was carried out using DPPH (1,1-diphenyl-2-picrylhydrazine) and the measurement of absorption was at a wavelength of 517 nm, and by varying the sample concentration. Positive control used was vitamin C solution with the same variation of extract's concentration. The results showed that the IC50 values of Leucaena leucocephala leaves extract and vitamin C were 175.388 and 28.907 ppm. Based on the IC50 data it can be stated that the antioxidant vitamin C was stronger than the Leucaena leucocephala leaves extract which was classified as a weak type of natural antioxidant.

scholarly journals WITHANIA SOMNIFERA: DETERMINATION OF ANTIOXIDANT SCAVENGING POTENTIAL ACTIVITY

2014 ◽  
Vol 1 (2) ◽  
pp. 89-93
Author(s):  
Rajamani Gokila ◽  
Naganathan Srinath
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Petroleum Ether ◽  
Withania Somnifera ◽  
Sexual Problems ◽  
Distilled Water ◽  
Scavenging Activity ◽  
Ic50 Value ◽  
Potential Activity

Due to an increase in modernization, people suffer from various stresses related and sexual problems. In India, with various herbal reservoirs, Withania somnifera (Ashwagandha) plays an important role in treating the vital and vigour problem as well as in treating sexual problems. We made an attempt toelevate the importance of this herbal source by understanding its antioxidant scavenging activity. We have utilized the powder of this plant fruit and processed using different solvents in 1:10 dilution by dissolving with 3g of powder with 30ml of each solvent such as petroleum ether, chloroform ethanol, hexane, methanol and distilled water. It was found that methanol and chloroform extracts of W. somnifera, has higher antioxidant activity when compared with the standard Vitamin C was observed using the graph plotted as the percentage of inhibition of scavenging activity vs concentration and IC50 value was observed to be nearly 50 μg/mL for all the tests.

scholarly journals Anthocyanins, pigment stability and antioxidant activity in jabuticaba [Myrciaria cauliflora (Mart.) O. Berg]

2011 ◽  
Vol 33 (3) ◽  
pp. 877-887 ◽  
Author(s):  
Annete de Jesus Boari Lima ◽  
Angelita Duarte Corrêa ◽  
Adelir Aparecida Saczk ◽  
Mariana Pereira Martins ◽  
Rachel Oliveira Castilho
Keyword(s):  
Antioxidant Activity ◽  
Free Radical ◽  
Vitamin C ◽  
Lipid Oxidation ◽  
Dry Matter ◽  
Oxidation Process ◽  
Pigment Extraction ◽  
Pigment Stability ◽  
The Stability

Different solvents were evaluated for the extraction of jabuticaba anthocyanin pigments, identifying, quantifying and verifying the stability of the anthocyanins, as well as the conduction of three antioxidant activity assays and determination of the vitamin C levels. The maceration with ethanol acidified with HCl 1.5 mol L-1 (85:15) provides better pigment extraction and stability. The skin is anthocyanin rich, presenting 1.59 and 2.06 g 100 g-1 of dry matter in the Paulista and Sabará varieties, respectively. Cyanidin 3-glucoside is the majority pigment of the skins, followed by delphinidin 3-glucoside. The highest level of vitamin C was found in the skins and seeds of both varieties. It was verified that the skins, presented more antioxidant activity, in free radical capture, as well as in retarding the lipid oxidation process.

Overpressured-layer chromatographic determination of ascorbigen (bound vitamin C) inBrassicavegetables

2004 ◽  
Vol 17 (5) ◽  
pp. 360-364 ◽  
Author(s):  
György Kátay ◽  
Zsolt Németh ◽  
Szilárd Szani ◽  
Oszkár Köck ◽  
Levente Albert ◽  
...  
Keyword(s):  
Vitamin C ◽  
Chromatographic Determination
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