scholarly journals Antioxidant Capacity Determination in Plants and Plant-Derived Products: A Review

2016 ◽  
Vol 2016 ◽  
pp. 1-36 ◽  
Author(s):  
Aurelia Magdalena Pisoschi ◽  
Aneta Pop ◽  
Carmen Cimpeanu ◽  
Gabriel Predoi
Keyword(s):  
Antioxidant Capacity ◽  
Detection Method ◽  
Extraction Procedure ◽  
Capacity Assessment ◽  
Original Source ◽  
Advantages And Disadvantages ◽  
Extraction Step ◽  
The Matrix ◽  
Oxidative Species ◽  
Capacity Determination

The present paper aims at reviewing and commenting on the analytical methods applied to antioxidant and antioxidant capacity assessment in plant-derived products. Aspects related to oxidative stress, reactive oxidative species’ influence on key biomolecules, and antioxidant benefits and modalities of action are discussed. Also, the oxidant-antioxidant balance is critically discussed. The conventional and nonconventional extraction procedures applied prior to analysis are also presented, as the extraction step is of pivotal importance for isolation and concentration of the compound(s) of interest before analysis. Then, the chromatographic, spectrometric, and electrochemical methods for antioxidant and antioxidant capacity determination in plant-derived products are detailed with respect to their principles, characteristics, and specific applications. Peculiarities related to the matrix characteristics and other factors influencing the method’s performances are discussed. Health benefits of plants and derived products are described, as indicated in the original source. Finally, critical and conclusive aspects are given when it comes to the choice of a particular extraction procedure and detection method, which should consider the nature of the sample, prevalent antioxidant/antioxidant class, and the mechanism underlying each technique. Advantages and disadvantages are discussed for each method.

Research Situation Analysis of On-line Detection Technology for Power Transformer Winding Deformation

2020 ◽  
Vol 13 (6) ◽  
pp. 823-832
Author(s):  
Zhenhua Li ◽  
Weihui Jiang ◽  
Li Qiu ◽  
Zhenxing Li ◽  
Yanchun Xu
Keyword(s):  
Detection Method ◽  
Theoretical Research ◽  
Line Detection ◽  
Response Analysis ◽  
Advantages And Disadvantages ◽  
Detection Technology ◽  
The Future ◽  
Transformer Winding ◽  
On Line ◽  
Winding Deformation

Background: Winding deformation is one of the most common faults in power transformers, which seriously threatens the safe operation of transformers. In order to discover the hidden trouble of transformer in time, it is of great significance to actively carry out the research of transformer winding deformation detection technology. Methods: In this paper, several methods of winding deformation detection with on-line detection prospects are summarized. The principles and characteristics of each method are analyzed, and the advantages and disadvantages of each method as well as the future research directions are expounded. Finally, aiming at the existing problems, the development direction of detection method for winding deformation in the future is prospected. Results: The on-line frequency response analysis method is still immature, and the vibration detection method is still in the theoretical research stage. Conclusion: The ΔV − I1 locus method provides a new direction for on-line detection of transformer winding deformation faults, which has certain application prospects and practical engineering value.

scholarly journals Differences in the Phenolic Profile by UPLC Coupled to High Resolution Mass Spectrometry and Antioxidant Capacity of Two Diospyros kaki Varieties

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Adelaida Esteban-Muñoz ◽  
Silvia Sánchez-Hernández ◽  
Cristina Samaniego-Sánchez ◽  
Rafael Giménez-Martínez ◽  
Manuel Olalla-Herrera
Keyword(s):  
Phenolic Compounds ◽  
Antioxidant Capacity ◽  
Fruits And Vegetables ◽  
High Resolution Mass Spectrometry ◽  
Extraction Procedure ◽  
Chemical Species ◽  
Diospyros Kaki ◽  
Phenolic Profile ◽  
Matrix Interferences ◽  
Individual Health

Background: phenolic compounds are bioactive chemical species derived from fruits and vegetables, with a plethora of healthy properties. In recent years, there has been a growing interest in persimmon (Diospyros kaki L.f.) due to the presence of many different classes of phenolic compounds. However, the analysis of individual phenolic compounds is difficult due to matrix interferences. Methods: the aim of this research was the evaluation of individual phenolic compounds and antioxidant capacity of the pulp of two varieties of persimmon (Rojo Brillante and Triumph) by an improved extraction procedure together with a UPLC-Q-TOF-MS platform. Results: the phenolic compounds composition of persimmon was characterized by the presence of hydroxybenzoic and hydroxycinnamic acids, hydroxybenzaldehydes, dihydrochalcones, tyrosols, flavanols, flavanones, and flavonols. A total of 31 compounds were identified and 17 compounds were quantified. Gallic acid was the predominant phenolic compounds found in the Rojo Brillante variety (0.953 mg/100 g) whereas the concentration of p-hydroxybenzoic acid was higher in the Triumph option (0.119 mg/100 g). Conclusions: the results showed that the Rojo Brillante variety had higher quantities of phenolic compounds than the Triumph example. These data could be used as reference in future phenolic compound databases when individual health effects of phenolic compounds become available.

scholarly journals Silica and Silica–Titania Xerogels Doped with Iron(III) for Total Antioxidant Capacity Determination

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2019
Author(s):  
Maria A. Morosanova ◽  
Ksenia V. Chaikun ◽  
Elena I. Morosanova
Keyword(s):  
Antioxidant Capacity ◽  
Surface Area ◽  
Total Antioxidant Capacity ◽  
Solid Phase ◽  
Bet Surface Area ◽  
Sensor Material ◽  
Total Antioxidant ◽  
Sensor Materials ◽  
Ascorbic Acids ◽  
Capacity Determination

In order to design a sensor material for total antioxidant capacity determination we have prepared silica and silica–titania xerogels doped with iron(III) and modified with 1,10-phenanthroline. Titanium(IV) tetraethoxyde content in the precursors (titanium(IV) tetraethoxyde and tetraethyl orthosilicate) mixtures has been varied from 0 to 12.5% vol. Iron(III) concentrations in sol has been varied from 1 to 100 mM. The increase of titanium(IV) content has led to a decrease in BET surface area and average pore diameter and an increase of micropore surface area and volume, which has resulted in better iron(III) retention in the xerogels. Iron(III), immobilized in the xerogel matrix, retains its ability to form complexes with 1,10-phenanthroline and to be reduced to iron(II). Static capacities for 1,10-phenanthroline have been determined for all the iron(III) doped xerogels (0.207 mmol/g–0.239 mmol/g) and they are not dependent on the iron(III) content. Sensor materials—xerogels doped with iron(III) and modified with 1,10-phenanthroline—have been used for antioxidants (catechol, gallic and ascorbic acids, and sulphite) solid phase spectrophotometric determination. Limits of detection for catechol, gallic and ascorbic acids, and sulphite equal 7.8 × 10−6 M, 5.4 × 10−6 M, 1.2 × 10−5 M, and 3.1 × 10−4 M, respectively. The increase of titanium(IV) content in sensor material has led to an increase of the reaction rate and the sensitivity of determination. Proposed sensor materials have been applied for total antioxidant capacity (in gallic acid equivalents) determination in soft beverages, have demonstrated high stability, and can be stored up to 6 months at room temperature.

scholarly journals Analytical Methods Used in Determining Antioxidant Activity: A Review

2021 ◽  
Vol 22 (7) ◽  
pp. 3380
Author(s):  
Irina Georgiana Munteanu ◽  
Constantin Apetrei
Keyword(s):  
Antioxidant Activity ◽  
Hydrogen Atom ◽  
Antioxidant Capacity ◽  
Absorption Capacity ◽  
Detection Mechanism ◽  
Antioxidant Power ◽  
Complementary Method ◽  
Food Engineering ◽  
Advantages And Disadvantages ◽  
Major Interest

The study of antioxidants and their implications in various fields, from food engineering to medicine and pharmacy, is of major interest to the scientific community. The present paper is a critical presentation of the most important tests used to determine the antioxidant activity, detection mechanism, applicability, advantages and disadvantages of these methods. Out of the tests based on the transfer of a hydrogen atom, the following were presented: the Oxygen Radical Absorption Capacity (ORAC) test, the Hydroxyl Radical Antioxidant Capacity (HORAC) test, the Total Peroxyl Radical Trapping Antioxidant Parameter (TRAP) test, and the Total Oxyradical Scavenging Capacity (TOSC) test. The tests based on the transfer of one electron include the Cupric Reducing Antioxidant Power (CUPRAC) test, the Ferric Reducing Antioxidant Power (FRAP) test, the Folin–Ciocalteu test. Mixed tests, including the transfer of both a hydrogen atom and an electron, include the 2,2′-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) test, and the [2,2-di(4-tert-octylphenyl)-1 -picrylhydrazyl] (DPPH) test. All these assays are based on chemical reactions and assessing the kinetics or reaching the equilibrium state relies on spectrophotometry, presupposing the occurrence of characteristic colours or the discolouration of the solutions to be analysed, which are processes monitored by specific wavelength adsorption. These assays were successfully applied in antioxidant analysis or the determination of the antioxidant capacity of complex samples. As a complementary method in such studies, one may use methods based on electrochemical (bio)sensors, requiring stages of calibration and validation. The use of chemical methods together with electrochemical methods may result in clarification of the operating mechanisms and kinetics of the processes involving several antioxidants.

Voltage Phase Difference Detection for Superconductor Quench

2014 ◽  
Vol 933 ◽  
pp. 82-85
Author(s):  
Shi Feng Wang ◽  
Yi Xiang Yue ◽  
Jin Fang
Keyword(s):  
Phase Difference ◽  
Detection Method ◽  
Phase Detection ◽  
Test Results ◽  
Development Platform ◽  
Advantages And Disadvantages ◽  
Difference Detection ◽  
Protection Systems ◽  
Actual Operation ◽  
Voltage Phase

In this paper, the actual operation of the superconducting motor and electrical parameters, a detailed analysis of the advantages and disadvantages of the existing quench detection method. After that I proposed an innovative detection method - voltage phase difference detection. On this basis, the design phase detection method based on the voltage difference quench detection and protection systems, based on stand-alone test and NI development platform test results, we verify its feasibility of the voltage phase difference detection method, and great superiority.

RADIOIMMUNOASSAYS OF 3,5,3′-TRIIODO-L-THYRONINE WITH AND WITHOUT A PRIOR EXTRACTION STEP

1975 ◽  
Vol 80 (1) ◽  
pp. 58-69 ◽  
Author(s):  
A. Burger ◽  
C. Sakoloff ◽  
V. Staeheli ◽  
M. B. Vallotton ◽  
S. H. Ingbar
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Normal Values ◽  
Covalent Binding ◽  
Extraction Procedure ◽  
Mixed Population ◽  
Coupling Agents ◽  
Extraction Step ◽  
The Mean

ABSTRACT Two radioimmunoassays for triiodothyronine (T3) are described, one of which includes an extraction step, while the other does not. To raise antibodies, two carrier proteins and different coupling agents were used, namely haemocyanin and diazotized benzidine or human serum albumin and carbodiimide. In the case of T3 coupled to haemocyanin by diazotized benzidine, evidence of covalent binding of the hapten to the protein was obtained. In the case of T3 coupled to human serum albumin, little evidence of covalent linkage was available. Nevertheless immunization was successful in both cases. The radioimmunoassay in unextracted serum was highly reproducible and precise (intra-assay variability 5.2% inter-assay variability 8.1%). Normal values were determined which clearly indicate a fall in the serum T3 concentration with increasing age. In men the fall occurs in the fifth decade. In women the T3 starts to fall only after 70 years of age. In 31 cases of hyperthyroidism the serum T3 concentration ranged from 2.26 to 10.4 ng T3/ml. In 10 cases of hypothyroidism the values ranged from 0 to 0.8 ng T3/ml. The radioimmunoassay using an extraction procedure was less extensively used since it was found to be less reproducible (intra-assay variability 7.5%, inter-assay 12.25%). The normal values were determined with a mixed population aged 20–50. The mean ± 2 sd was 0.9 ± 0.36 ng T3/ml (n=52). In 17 cases of hypothyroidism the values ranged from 0 to 0.6 ng T3/ml and in 22 cases of hyperthyroidism from 2 to 14.4 ng T3/ml.

scholarly journals Color and Antioxidant Capacity Preservation of Opuntia spp. Juices by Spray-drying Microencapsulation.

2018 ◽  
Vol 7 (3) ◽  
pp. 16 ◽  
Author(s):  
Alberto Castañeda-Yañez ◽  
Sandra T. Martín-del-Campo ◽  
Alejandra San-Martin ◽  
Anaberta Cardador-Martínez
Keyword(s):  
Principal Component Analysis ◽  
Protective Effect ◽  
Antioxidant Capacity ◽  
Spray Drying ◽  
Principal Component ◽  
Natural Colorants ◽  
The Matrix ◽  
Pear Juice ◽  
Antioxidant Characteristics ◽  
Opuntia Spp

In this work, it was evaluated the effect of microencapsulation using spray drying over natural colorants present in two varieties (red and purple) of prickly pear juice (Opuntia spp.), using three kinds of carrier agents (matrixes). The dried samples after microencapsulation retained a high total amount of the betalains and their antioxidant characteristics. However, some individual betalains were lost after microencapsulation. According to ANOVA results, matrix 3204 showed a more protective effect than matrix 4801 in both microencapsulated juices over color, individual betalains, and antioxidant capacity. Globally, the protective effect was better for purple juices than red juices no matter the matrix used. Principal Component Analysis (PCA) confirmed these results. Matrix 3204 resulted in the best carrier agent since it gave a less disperse PCA group for both color juices. The parameters that separated both PCA matrixes groups were L*, a*, b* and DPPH. 

scholarly journals Формирование среды реализации цифровых инициатив сотрудников банка

2019 ◽  
pp. 48-54
Author(s):  
Тарас Гриценко ◽  
Жанна Передера ◽  
Анна Теряева
Keyword(s):  
Banking Sector ◽  
Economic Security ◽  
New Professionals ◽  
Advantages And Disadvantages ◽  
Study Results ◽  
The Matrix ◽  
Banking Business ◽  
The Stability ◽  
Definition Of ◽  
The Impact

В работе рассматривается возможность формирования в банковском секторе среды, в которой сотрудники смогут самостоятельно реализовывать цифровые инициативы для развития компании и самообучения. Обоснована необходимость её наличия. Проведен анализ соответствия поставленной проблемы российским и мировым трендам на основе изучения федеральных программ и оценок рейтинговых агентств. В результате исследования разработан бизнес-процесс реализации цифровых инициатив, про-веден конкурентный анализ его преимуществ и недостатков перед традиционным подходом к обучению. The article discusses the possibility of forming in the banking business an environment in which employees will be able to in-dependently implement digital initiatives for the development of the company and self-learning. The necessity of its presence is grounded. The analysis of compliance of the problem with the trends in Russia and the world based on the study of Federal programs and ratings agencies. To attract new staff with the necessary knowledge, banks have a number of tools - business classes, sponsorship programs, mentoring, hackathons, man-agement fights, case-championships, etc. It has been revealed that new professionals with technical skills can solve complex problems and generate products. But it’s difficult for them to dive into the banking sector, study its features and offer their own solutions to problems. It was also revealed that the company is interested in product results that are practice oriented. Com-bining product results and training is only possible by creating an environment in which they can discuss their ideas, find sup-port and implement them. As a result, a business process for the implementation of digital initiatives has been formed, a competi-tive analysis of its advantages and disadvantages over the tradi-tional approach to training has been conducted. strategies. The leading method of research is the definitions according grouping to the principles of the matrix method. It was revealed that the economic security concept is disclosed using factors freely com-bined into three groups (includes: sustainability, protection of interests, ensuring sovereignty), and the most common definitions are built using words-markers: state, security, advantage, process. One of the main study results is an algorithm for constructing the definition of the economic security concept, which allows to model and refine the definition of the concept based on the initial categories, consider-ing the economic context. The author's definition is also formulated, which reflects the interrelation of such components as the protection of interests, the impact of threats, the stability preservation, inde-pendence, ensuring development, self-adaptation and self-reproduction.

The development of a matrix metalloproteinase-1 biosensor based on the surface plasmon resonance imaging technique

2016 ◽  
Vol 8 (34) ◽  
pp. 6428-6435 ◽  
Author(s):  
Anna Tokarzewicz ◽  
Lech Romanowicz ◽  
Iosif Sveklo ◽  
Ewa Gorodkiewicz
Keyword(s):  
Surface Plasmon Resonance ◽  
Matrix Metalloproteinase ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Detection Method ◽  
Imaging Technique ◽  
Surface Plasmon Resonance Imaging ◽  
Matrix Metalloproteinase 1 ◽  
The Matrix

The purpose of this study was to create a new, highly selective biosensor, which uses surface plasmon resonance as a detection method for the quantitative determination of the matrix metalloproteinase-1.

Improved FIA-ABTS Method for Antioxidant Capacity Determination in Different Biological Samples

2004 ◽  
Vol 38 (8) ◽  
pp. 831-838 ◽  
Author(s):  
Stefano Bompadre ◽  
Luciana Leone ◽  
Alessia Politi ◽  
Maurizio Battino
Keyword(s):  
Antioxidant Capacity ◽  
Biological Samples ◽  
Capacity Determination
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