Methods available for the measurement of antioxidant capacity are reviewed, presenting the general chemistry underlying the assays, the types of molecules detected, and the most important advantages and shortcomings of each method. This overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. From evaluation of data presented at the First International Congress on Antioxidant Methods in 2004 and in the literature, as well as consideration of potential end uses of antioxidants, it is proposed that procedures and applications for three assays be considered for standardization: the oxygen radical absorbance capacity (ORAC) assay, the Folin-Ciocalteu method, and possibly the Trolox equivalent antioxidant capacity (TEAC) assay. ORAC represent a hydrogen atom transfer (HAT) reaction mechanism, which is most relevant to human biology. The Folin-Ciocalteu method is an electron transfer (ET) based assay and gives reducing capacity, which has normally been expressed as phenolic contents. The TEAC assay represents a second ET-based method. Other assays may need to be considered in the future as more is learned about some of the other radical sources and their importance to human biology.

https://faculty.missouri.edu/~glaserr/3700s14/Antioxidant-Capacity_jf0502698.pdf

Standardized Methods for the Determination of Antioxidant Capacity and Phenolics in Foods and Dietary Supplements

Biodegradation aspects of Polycyclic Aromatic Hydrocarbons (PAHs): A review

While use of synthetic antioxidants (such as butylated hydroxytoluene and butylated hydroxyanisole) to maintain the quality of ready-to-eat food products has become commonplace, consumer concern regarding their safety has motivated the food industry to seek natural alternatives. Phenolic antioxidants can inhibit free radical formation and/or interrupt propagation of autoxidation. Fat-soluble vitamin E (α-tocopherol) and water-soluble vitamin C (L-ascorbic acid) are both effective in the appropriate matrix. Plant extracts, generally used for their flavoring characteristics, often have strong H-donating activity thus making them extremely effective antioxidants. This antioxidant activity is most often due to phenolic acids (gallic, protocatechuic, caffeic, and rosmarinic acids), phenolic diterpenes (carnosol, carnosic acid, rosmanol, and rosmadial), flavonoids (quercetin, catechin, naringenin, and kaempferol), and volatile oils (eugenol, carvacrol, thymol, and menthol). Some plant pigments (anthocyanin and anthocyanidin) can chelate metals and donate H to oxygen radicals thus slowing oxidation via 2 mechanisms. Tea and extracts of grape seeds and skins contain catechins, epicatechins, phenolic acids, proanthocyanidins, and resveratrol, all of which contribute to their antioxidative activity. The objective of this article is to provide an overview of natural antioxidants, their mechanisms of action, and potential applications.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1541-4337.2011.00156.x

Natural antioxidants: sources, compounds, mechanisms of action, and potential applications

Recently, there has been growing interest in research into the role of plant-derived antioxidants in food and human health. The beneficial influence of many foodstuffs and beverages including fruits, vegetables, tea, coffee, and cacao on human health has been recently recognized to originate from their antioxidant activity. For this purpose, the most commonly methods used in vitro determination of antioxidant capacity of food constituents are reviewed and presented. Also, the general chemistry underlying the assays in the present paper was clarified. Hence, this overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. In addition, the most important advantages and shortcomings of each method were detected and highlighted. The chemical principles of these methods are outlined and critically discussed. The chemical principles of methods of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS·+) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radical scavenging, Fe3+–Fe2+ transformation assay, ferric reducing antioxidant power (FRAP) assay, cupric ions (Cu2+) reducing power assay (Cuprac), Folin-Ciocalteu reducing capacity (FCR assay), peroxyl radical scavenging, superoxide anion radical (O
 2
 ·−
 ) scavenging, hydrogen peroxide (H2O2) scavenging, hydroxyl radical (OH·) scavenging, singlet oxygen (1O2) quenching assay and nitric oxide radical (NO·) scavenging assay are outlined and critically discussed. Also, the general antioxidant aspects of main food components were discussed by a number of methods which are currently used for detection of antioxidant properties food components. This review consists of two main sections. The first section is devoted to main components in the foodstuffs and beverages. The second general section is some definitions of the main antioxidant methods commonly used for determination of antioxidant activity of components in the foodstuffs and beverages. In addition, there are given some chemical and kinetic basis and technical details of the used methods.

Antioxidant activity of food constituents: an overview

Significance of biogenic amines to food safety and human health

The antioxidant activity of a methanolic extract of Ocimum basilicum L. (sweet basil) was examined using different in vitro assay model systems. The crude extract was fractionated on a Sephadex LH-20 column, and six fractions were identified. The DPPH scavenging assay system and the oxidation of the soy phosphotidylcholin liposome model system were used to evaluate the antioxidant activity of each fraction. Fraction IV showed the strongest activity followed by fractions V and VI. Phenolic compounds responsible for the antioxidative activity of the fractions were characterized by atmospheric pressure chemical ionization liquid chromatography-mass spectrometry. The major antioxidant compound in fraction IV was confirmed as rosmarinic acid by (1)H NMR and characteristic fragmentations in the mass spectrum. Moreover, the native of antioxidant activity of rosmarinic acid in the liposome system was examined. The results showed that one rosmarinic acid can capture 1.52 radicals, and furthermore, the existence of a synergistic effect between alpha-tocopherol and rosmarinic acid was revealed.

Phenolics Composition and Antioxidant Activity of Sweet Basil (Ocimum basilicum L.)

The importance of peroxide value in assessing food quality and food safety

The treatment of α-tocopherol-rosemary mixture (0.05%+ 0.02%) had the strongest antioxidant activity among the antioxidants tested in sardine oil model system and frozen-crushed fish meat. In sardine oil, it delayed the onset of oxidation 5 days longer than either α-tocopherol or rosemary extract alone, and its antioxidant activity was comparable to that of BHA. It was found that the α-tocopherol in sample of mixture treatment remained 5 days longer than in sample of α-tocopherol. In frozen-crushed bonito meat, the thiobarbituric acid value (TBA) in sample of mixture treatment was the lowest among antioxidant treatments. the analysis of the ratio of EPA + DHA/16:0 during the storage also showed that the ratio in sample of mixture treatment was about 10% higher than that in sample of α-tocopherol. This suggested that oxidation of polyunsaturated fatty acid was inhibited. the treatment of α-tocopherol-rosemary mixture also caused less triglyceride hydrolysis than either a-tocopherol or rosemary extract alone. A synergistic effect between α-tocopherol and rosemary extract was observed.

THE SYNERGISTIC ANTIOXIDANT EFFECT of ROSEMARY EXTRACT and α-TOCOPHEROL IN SARDINE OIL MODEL SYSTEM and FROZEN-CRUSHED FISH MEAT

By using a 500 MHz proton nuclear magnetic resonance (1H NMR) spectrometer we have developed a quantitative method for determining the contents of docosahexaenoic acid (DHA) in fish oils (mg/g), the molar proportions (mol%) of DHA to all other fatty acids composing the fish oils, and the molar proportions of total n-3 fatty acids to all other non-n-3 fatty acids in the fish oils. After examining the suitability of ethylene glycol dimethyl ether (EGDM), methanol, and 1,4-dioxane as internal standards, experimental conditions were optimized by mainly using EGDM as an internal standard. By setting the pulse repetition time at 30 s, five times longer than the longest T 1 of the 1H NMR signals of fish oils, good reproductibility of data and analytical times less than 10 min were achieved. The use of the internal standard also allowed us to quantify DHA on a weight basis (mg/g). Verification of the method was carried out in an interlaboratory study between Japan and Norway on bonito, tuna, and salmon oils. The relative errors in the 1H NMR data between Japan and Norway were 0.57–5.29% for quantification of DHA, 0.7–2.09% for the molar proportion of DHA, and 0.1–1.41% for the molar proportion of total n-3 fatty acids. Good agreement was observed between the 1H NMR data and those obtained by gas chromatography (GC). The sample preparation before 1H NMR measurements required only two steps: sample weighing and preparation of an internal standard solution. Based on the high reproducibility, simplicity of the procedure, and clarity of principle, the proposed 1H NMR method was judged to be a promising alternative to the GC method in quantification of DHA and n-3 fatty acids in fish oils.

Nondestructive quantitative determination of docosahexaenoic acid and n-3 fatty acids in fish oils by high-resolution 1H nuclear magnetic resonance spectroscopy.

Influence of commercial dietary fatty acids on polyunsaturated fatty acids of cultured freshwater fish and comparison with those of wild fish of the same species

Shun Wada

Papers

Phenolics Composition and Antioxidant Activity of Sweet Basil (Ocimum basilicum L.)

The importance of peroxide value in assessing food quality and food safety

THE SYNERGISTIC ANTIOXIDANT EFFECT of ROSEMARY EXTRACT and α-TOCOPHEROL IN SARDINE OIL MODEL SYSTEM and FROZEN-CRUSHED FISH MEAT

Nondestructive quantitative determination of docosahexaenoic acid and n-3 fatty acids in fish oils by high-resolution 1H nuclear magnetic resonance spectroscopy.

Influence of commercial dietary fatty acids on polyunsaturated fatty acids of cultured freshwater fish and comparison with those of wild fish of the same species