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Article
Publication date: 4 March 2014

Robert Benjamin Adams, Karen Nkechiyere Egbo and Barbara Demmig-Adams

The purpose of this review is to summarize new research indicating that high-dose supplements of the antioxidant vitamin C can interfere with the benefits of physical…

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Abstract

Purpose

The purpose of this review is to summarize new research indicating that high-dose supplements of the antioxidant vitamin C can interfere with the benefits of physical exercise for athletic performance and the risk for chronic disease.

Design/methodology/approach

This article reviews current original literature on the regulation of human metabolism by oxidants and antioxidants and evaluates the role of exercise and high-dose vitamin C in this context. The presentation in this article aims to be informative and accessible to both experts and non-experts.

Findings

The evidence reviewed here indicates that single, high-dose supplements of the antioxidant vitamin C abolish the beneficial effects of athletic training on muscle recovery and strength as well as abolishing the benefits of exercise in lowering the risk for chronic disease. In contrast, an antioxidant-rich diet based on regular foods apparently enhances the benefits of exercise. These findings are consistent with an updated understanding of the critical importance of both oxidants and antioxidants in the regulation of human metabolism. While more research is needed to address the role of timing and level of antioxidant consumption, it is clear that a balance between oxidants and antioxidants is essential.

Practical implications

The information presented in this review is important for both athletes and the public at large in their efforts to choose nutrition and exercise regimes appropriate to maximize the outcome of their training efforts and lower their risk for chronic disease.

Originality/value

This article provides accessible and comprehensive information to researchers, nutritionists, and consumers interested in optimal nutrition during athletic training and for obtaining the full benefit of physical exercise in lowering the risk for chronic disease.

Details

Nutrition & Food Science, vol. 44 no. 2
Type: Research Article
ISSN: 0034-6659

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Article
Publication date: 27 March 2009

Amin Ismail, Ngee‐Wen Tiong, Seok‐Tyug Tan and Azrina Azlan

The purpose of this paper is to determine the antioxidant properties (capacity and component) of four non‐leafy vegetables. The correlation between the antioxidant

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767

Abstract

Purpose

The purpose of this paper is to determine the antioxidant properties (capacity and component) of four non‐leafy vegetables. The correlation between the antioxidant capacity and its components of the studied vegetables was also assessed.

Design/methodology/approach

Winged beans, also known as four‐angled bean (Psophocarpus tetragonolobus), French bean (Phaseolus vulgaris), string bean (Vigna sinensis) and snow pea (Pisum sativum) were selected as samples from among the common non‐leafy vegetables consumed by Malaysians. These fresh vegetables were lyophilised and ground and their ethanolic extracts were prepared for antioxidant capacity assays and total phenolic, β‐carotene and ascorbic acid contents.

Findings

Among the vegetables, string beans showed the highest antioxidant capacity compared to the other vegetables studied (p < 0.05). The total phenolic, ascorbic acid and β‐carotene contents of snow peas were significantly higher (p < 0.05) than the other vegetables. There was a significant positive correlation between scavenging activity and antioxidant components studied. On the other hand, a negative correlation was found between antioxidant activity and its components of the studied vegetables.

Originality/value

Previous reports have indicated that vegetables contain high levels of antioxidants. However, data on antioxidant capacity of these non‐leafy vegetables are still lacking. This research paper shows the non‐leafy vegetables studied is a promising source of antioxidants with good antioxidant capacity. Beside that, along with the studied antioxidant components, other compounds in these vegetables could also contribute to their antioxidant capacity.

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Nutrition & Food Science, vol. 39 no. 2
Type: Research Article
ISSN: 0034-6659

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Article
Publication date: 1 March 1997

Nicholas J. Miller and Catherine A. Rice‐Evans

Examines the antioxidant activities of a range of hydroxy‐substituted phenolic acids by estimating their relative abilities to scavenge the ABTS_+ radical cation generated…

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1215

Abstract

Examines the antioxidant activities of a range of hydroxy‐substituted phenolic acids by estimating their relative abilities to scavenge the ABTS_+ radical cation generated in the aqueous phase, expressed as the Trolox equivalent antioxidant capacity (TEAC value). These common food components have varying reducing abilities, dependent on the positions and extent of hydroxylation of their phenol ring. Reports the research results which suggest that some simple phenolic acids are most effective antioxidants, up to two to three times as active as vitamin C. Their relative abundance in fruits, oils, etc. indicates that they may be highly significant contributors to the overall dietary antioxidant intake. Para‐coumaric acid (4‐hydroxycinnamic acid) was found to have a TEAC value of 2.2mM (more than twice the antioxidant activity of vitamin C). Ferulic acid (3‐methoxy, 4‐hydroxycinnamic acid), the active component of oryzanol (rice bran oil) was found to have a TEAC value of 1.9 mM and gallic acid (3, 4, 5‐trihydroxybenzoic acid) a TEAC of 3.0mM (i.e. three times the antioxidant activity of vitamin C). Discusses the significance of these and other related compounds as food antioxidants and as non‐nutrient antioxidants in the diet.

Details

British Food Journal, vol. 99 no. 2
Type: Research Article
ISSN: 0007-070X

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Article
Publication date: 26 July 2021

Penghao Qi, Shijian Wang, Jing Li, Yue Li and Guangneng Dong

The purpose of this study is to reduce the use of Zinc dialkyl dithiophosphates (ZDDP) and improve the frictional properties and thermal oxidation stability of…

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68

Abstract

Purpose

The purpose of this study is to reduce the use of Zinc dialkyl dithiophosphates (ZDDP) and improve the frictional properties and thermal oxidation stability of Perfluoropolyether (PFPE) grease by adding antioxidant additives. The addition of antioxidants can reduce the consumption of ZDDP as an antioxidant, thus improving the anti-wear efficiency of ZDDP and reducing the excess phosphorus element in the grease.

Design/methodology/approach

In this study, an antioxidant with good comprehensive performance was selected from several antioxidants by tribological tests and high-temperature tests. Then, the effect of its combination additive with ZDDP on PFPE grease was investigated. The anti-wear property, anti-friction property, thermal oxidation stability and extreme pressure property of greases containing different proportions of ZDDP and antioxidant were tested by four-ball tester and synchronous thermal analyzer (STA). The effects of additives on properties of grease were analyzed by SEM, EDS, LSCM, XPS and FT-IR.

Findings

The research shows that 2,6-Di-tert-butyl-4-methylphenol (BHT) can be used as an antioxidant in combined additives to reduce the antioxidant reactions of ZDDP, thus improving the anti-wear efficiency of ZDDP and further enhancing the anti-wear performance of the grease. Moreover, BHT and ZDDP have a synergistic effect on the high temperature performance of the PFPE grease due to their different antioxidant mechanisms.

Social implications

In this paper, the problems related to PFPE grease are studied, which has a certain guiding effect on the industrial application of fluorine grease and the related formulation design.

Originality/value

In this paper, the properties of PFPE grease under different lubricating condition were studied. The synergistic lubrication effect of antioxidant and ZDDP are discussed. It provides experimental and theoretical support for reducing the content of ZDDP and improving the performance of additives.

Details

Industrial Lubrication and Tribology, vol. 73 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 11 September 2020

Seok Shin Tan, Seok Tyug Tan and Chin Xuan Tan

Salak (Salacca zalacca) is an underutilised fruit. The bioactivities of this fruit have rarely been studied scientifically. Thus, the present study aimed to determine the…

Abstract

Purpose

Salak (Salacca zalacca) is an underutilised fruit. The bioactivities of this fruit have rarely been studied scientifically. Thus, the present study aimed to determine the antioxidant activity of extracts derived from the peel, fruit and kernel of the Salak fruit, as well as the hypoglycemic and anti-hypertensive properties of Salak peel extracts.

Design/methodology/approach

The peel, fruit and kernel of the Salak were extracted using distilled water, methanol and ethanol. Antioxidant activities, angiotensin-converting enzyme (ACE) and alpha-amylase inhibition properties of the extracts were estimated via in vitro standard methods. Besides, the total phenolic content (TPC) and total flavonoid content (TFC) of the extracts were also determined in the present study. The antioxidant activities of different parts of Salak extracts were determined by ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) methods. Percent of radical scavenging properties were calculated via DPPH assay. The hypoglycemic and anti-hypertensive properties of Salak peel were evaluated using alpha-amylase inhibition and ACE assays, respectively.

Findings

Fruit extracts of Salak in methanol were found to exhibit the highest TPC (10.27 ± 0.12 mg GAE/g), TFC (11.04 ± 0.89 mg CE/g) and antioxidant properties amongst all samples whereby the TPC and TFC were strongly correlated with antioxidant activities. On the other hand, distilled water extracted Salak kernel showed to have the lowest TPC (0.53 ± 0.05 mg GAE/g), TFC (0.37 ± 0.01 mg CE/g) and antioxidant properties amongst all the Salak extracts. Peel extracts exhibit comparable antioxidant activities with fruit extracts in the current findings. In addition, peel extracts indicated some extend of ACE and alpha-amylase inhibition activities regardless of the solvents used. Methanol and ethanol peel extracts indicated no significant difference (p < 0.05) ACE (98%) and alpha-amylase (90%) inhibition activities. However, distilled water extracted Salak peel showed significantly lower ACE and alpha-amylase inhibition in comparison to methanol and ethanol peel extracts.

Originality/value

The present findings suggested that the fruit of Salak exhibits the highest antioxidant properties, followed by the peel and lastly, the kernel, which shows the lowest antioxidant properties amongst all the samples. The results also indicated that the peel extracts have ACE and alpha-amylase inhibition activities.

Details

British Food Journal, vol. 122 no. 10
Type: Research Article
ISSN: 0007-070X

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Article
Publication date: 21 September 2020

Paulina Górska, Ilona Górna and Juliusz Przysławski

This study aims to analyze the antioxidant properties of the Mediterranean diet and describe methods that are used in clinical studies to assess its role in reducing…

Abstract

Purpose

This study aims to analyze the antioxidant properties of the Mediterranean diet and describe methods that are used in clinical studies to assess its role in reducing oxidative stress.

Design/methodology/approach

The review presents the results of interventional and observational clinical trials aimed at assessing the influence of the Mediterranean diet on the level of enzymatic and non-enzymatic antioxidants, as well as the total blood antioxidant capacity.

Findings

The Mediterranean diet as a varied diet can be a better way to provide antioxidants to the body than supplements. Individual compounds administered in an isolated form can give the opposite effect to the expected, stimulating oxidative stress. The administration of antioxidants in the form of supplements instead of a varied diet is also associated with a lack of synergism of action. In studies on the importance of the Mediterranean diet in the reduction of oxidative stress, single markers are used to measure oxidative damage, the activity of enzymatic antioxidants and the concentration of individual non-enzymatic antioxidants. At the same time, the need to find markers that would assess the level of oxidative stress and the body’s antioxidant capacity more comprehensively is emphasized.

Practical implications

It should be taken into account that differences between in vivo and in vitro results may result from the fact of various factors, including genetic, smoking, intestinal microflora or diet composition. It is also necessary to answer the question about which marker or set of markers could in the most comprehensive way to assess the level of oxidative stress and the body’s antioxidant capacity.

Originality/value

The literature review shows not only the source of antioxidants in the Mediterranean diet. This paper also presents a critical approach to markers that allow the assessment of the antioxidant properties of the diet.

Details

Nutrition & Food Science , vol. 51 no. 4
Type: Research Article
ISSN: 0034-6659

Keywords

Open Access
Article
Publication date: 19 May 2020

Nobuhle Sharon Lungu, Anthony Jide Afolayan, Ronald Sylvester Thomas and Emrobowansan Monday Idamokoro

The objective of the study was to assess consumer exposure to warmed-over flavour, their eating habits with respect to pre-cooked stored meats, awareness of antioxidants

Abstract

Purpose

The objective of the study was to assess consumer exposure to warmed-over flavour, their eating habits with respect to pre-cooked stored meats, awareness of antioxidants and attitudes towards the use of natural antioxidants as preservatives in meat and meat products.

Design/methodology/approach

A total of 238 Check-All-That-Apply (CATA) design questionnaires were used to gather information from the University of Fort Hare community in the Eastern Cape province of South Africa.

Findings

The majority of the respondents had been exposed to warmed-over flavour before. More than half of the respondents did not know about antioxidants. Respondents were in support of the use of natural antioxidants in meat and meat products.

Research limitations/implications

The study mainly captured consumer habits based on living arrangements. Age influence could not be extrapolated due to the nature of the population, which was being studied. The population was limited to the University community, which is mainly made up of not so widely spread age groups and more or less similar levels of education. As a result, the findings and conclusions may not be a true reflection of the general public consumers in terms of age, level of education and employment status.

Originality/value

This research presents an original insight into consumer habits concerning the purchasing and storage of pre-cooked meat and meat products. The study revealed that most consumers nowadays prefer ready-to-eat or pre-cooked meat and meat products due to convenience. The warmed-over flavour is common in pre-cooked meats. The findings suggests that the meat industry has to improve the shelf-life of pre-cooked foods such that warmed-over flavour development is delayed to fit into the current consumer habits. In recent years there has been a growing interest in the use of natural antioxidants to improve shelf-life of muscle foods. However, there is a dearth of information on consumer attitudes towards the use of natural antioxidants as preservatives. This study reveals that consumers are willing to try products formulated using natural antioxidants.

Details

British Food Journal, vol. 122 no. 9
Type: Research Article
ISSN: 0007-070X

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Article
Publication date: 9 May 2016

Maryam Sardarodiyan and Ali Mohamadi Sani

The study aims to describe the main classes of antioxidants existing in fruit, beverages, vegetables and herbs and the different extraction and application of antioxidants

Abstract

Purpose

The study aims to describe the main classes of antioxidants existing in fruit, beverages, vegetables and herbs and the different extraction and application of antioxidants in food. Oxidative degradation of lipids, especially induced by reactive oxygen species, leads to quality deterioration of foods and cosmetics and could have harmful effects on health. A major challenge is to develop tools to assess the antioxidant capacity and real efficacy of these molecules. Recently, many review papers regarding antioxidants from different sources and different extraction and quantification procedures have been published. However, none of them has all the information regarding antioxidants (sources, extraction and application in food).

Design/methodology/approach

This paper tries to take a different perspective on antioxidants for the new researcher involved in this field.

Findings

Antioxidants from fruit, vegetables and beverages play an important role in human health, for example, preventing cancer and cardiovascular diseases and lowering the incidence of different diseases. A number of plant products act as scavengers of free radical species and so have been classified as antioxidants. Antioxidants are an important group of food additives that have the ability to protect against detrimental change of oxidizable nutrients and consequently they extend shelf-life of foods.

Research limitations/implications

Most of the antioxidants present in foods are phenolic and polyphenolic compounds, but their efficacy in food for the prevention of oxidation or in the body for dealing with oxidative stress and its consequences depends on different factors.

Originality/value

This study collected the last finding in the field of sources and applications of natural antioxidants.

Details

Nutrition & Food Science, vol. 46 no. 3
Type: Research Article
ISSN: 0034-6659

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Article
Publication date: 29 April 2014

Khlood S. Abdel Zaher, R.H. Swellem, Galal A.M. Nawwar, Fathy M. Abdelrazek and Salwa H. El-Sabbagh

The purpose of this paper is to study the efficiency of lignin/silica and calcium lignate/calcium silicate as natural antioxidants in styrene-butadiene rubber (SBR…

Abstract

Purpose

The purpose of this paper is to study the efficiency of lignin/silica and calcium lignate/calcium silicate as natural antioxidants in styrene-butadiene rubber (SBR) vulcanizates.

Design/methodology/approach

It has been found that thermal aging data of the aged sample revealed that SBR vulcanizate undergoes crosslink reactions that lead to embrittlement and ultimately failure. Incorporation of lignin/silica or calcium lignate/calcium silicate, however, resulted in significant improvement of the degradation profile of the vulcanizates at 90±1°C. Loss of tensile strength and flexibility during aging of the SBR compounds with 8 phr lignin/silica or calcium lignate/calcium silicate was mild relative to unfilled polymer, indicating a restricted degradation due to the presence of the investigated compounds. The results obtained revealed that the investigated compounds are good antioxidant, and the evaluation was confirmed by physico-mechanical properties of the vulcanizates, FT-IR spectroscopy, transmission (TEM) and scanning (SEM) electron microscope.

Findings

It was noticed that SBR vulcanizates having 8 phr of lignin/silica or calcium lignate/calcium silicate exhibited the best mechanical properties in comparison with other concentrations (1, 2, 4, 6 and 10 phr). Also, results revealed that the lignin/silica derivatives are efficient antioxidants in SBR vulcanizates compared to vulcanizates containing conventional antioxidants used in rubber industry, namely polymerized 2,2,4-trimethyl-1, 2-dihydroquinoline (TMQ), and N-isopropyl-N'-phenyl-P-phenylenediamine (IPPD).

Research limitations/implications

All these results indicated that lignin/silica and calcium lignate/calcium silicate in SBR had good heat resistance and aging resistance, calcium lignate/calcium silicate has an application limitation as not all vulcanizates need to use CaCO3/calcium salts.

Practical implications

Lignin is usually seen as a waste product of pulp and paper industry and is often used as fuel for the energy balance of the pulping process. It is simple isolation along with silica from rice straw and using it as an antioxidant added further practical utility for this waste.

Originality/value

The importance of lignin/silica derivatives is arisen from their biodegradability and their ease availability from rice straw black liquor.

Details

Pigment & Resin Technology, vol. 43 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 4 December 2019

Jaísa Oliveira Chaves, Angelica Maria de Freitas Fernandes, Paola Machado Parreiras, Gustavo Silveira Breguez, Maria Cristina Passos, Luciana Rodrigues da Cunha and Camila Carvalho Menezes

The purpose of this paper is to evaluate the effect of different times and freezing temperatures on the antioxidant activity of raw human milk (HM) and the impact of light…

Abstract

Purpose

The purpose of this paper is to evaluate the effect of different times and freezing temperatures on the antioxidant activity of raw human milk (HM) and the impact of light by different packaging on retinol level and the antioxidant activity of pasteurized HM.

Design/methodology/approach

Donor milks were homogenized to form the pool of the experimental study characterized by the evaluation of the effects of time (0, 2, 4, 8 and 15 days) freezing temperatures (−3°C, −8°C and −18°C) and the interference of the type of packaging on the antioxidant activity and retinol levels of HM.

Findings

The existing studies do not reveal the real impact of HM storage conditions adopted by human milk banks (HMB) in Brazil on their compounds, mainly in relation to the effects of temperature and freezing time and the incidence of light on retinol levels and antioxidant activity. In view of the already documented importance of these compounds for the growth, development and health of children, it is extremely important to assess their stability according to the procedures adopted by the banks. It has been observed in this study that lower freezing temperatures (−18°C) further preserve the antioxidant activity. It was found that the amber and transparent vials wrapped with aluminum foil allowed for greater retinol stability of HM, with values of 2.501±0.757 µmol/L and 4.991±0.825 µmol/L, respectively. On the contrary, there was no significant influence on antioxidant activity.

Originality/value

It is suggested that HMB store milk at lower temperatures and use glass jars that block the passage of light.

Details

British Food Journal, vol. 122 no. 2
Type: Research Article
ISSN: 0007-070X

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