Antioxidant Capacity Of Foods Research Articles

The Total Antioxidant Capacity Of Foods: A Reappraisal. Application To Commercial Orange Juices.

The Total Antioxidant Capacity Of Foods: A Reappraisal. Application To Commercial Orange Juices.

An apple plus a Brazil nut a day keeps the doctors away: antioxidant capacity of foods and their health benefits.

Antioxidant-rich foods scavenge free radicals and other reactive species, decreasing the risk of different non-communicable chronic diseases. The objective of this study was to review the content of total antioxidant capacity of commonly foods comparing with experimental data and to explore the health benefits due to foods with moderate to high TAC. The TAC was analytically measured using the "Total Antioxidant Capacity" (NX2332) test from Randox® (UK) by spectrometry at 600 nm. Brazil nut (Bertholletia excelsa), "guaraná" (Paullinia cupana Kunth) powder, ready to drink boiled coffee (Coffea arabica L.), and milk chocolate (made from seeds of Theobroma cacao) had the highest TAC values, followed by collard greens (Brassica oleracea L.), beets (Beta vulgaris L.), apples (Malus domestica Borkh.), bananas (Musa paradisiaca), common beans (Phaseolus vulgaris), oranges (Citrus sinensis (L.) Osbeck), onions (Allium cepa L.), and lettuce (Lactuca sativa L.). Other foods also showed antioxidant capacity. The binomial antioxidant capacity of foods and health was extensively discussed according to science literature. Based on the high TAC content of Brazil nuts, guaraná, coffee, chocolate, collard greens, apples, beets, beans, oranges, onions and other foods, their regular dietary intake is strongly recommended to reduce the risk of chronic non-communicable diseases.

Matching in Vitro Bioaccessibility of Polyphenols and Antioxidant Capacity of Soluble Coffee by Boosted Regression Trees.

The aim of this study was to evaluate changes in polyphenol profile and antioxidant capacity of five soluble coffees throughout a simulated gastro-intestinal digestion, including absorption through a dialysis membrane. Our results demonstrate that both polyphenol content and antioxidant capacity were characteristic for each type of studied coffee, showing a drop after dialysis. Twenty-seven compounds were identified in coffee by HPLC-MS, while only 14 of them were found after dialysis. Green+roasted coffee blend and chicory+coffee blend showed the highest and lowest content of polyphenols and antioxidant capacity before in vitro digestion and after dialysis, respectively. Canonical correlation analysis showed significant correlation between the antioxidant capacity and the polyphenol profile before digestion and after dialysis. Furthermore, boosted regression trees analysis (BRT) showed that only four polyphenol compounds (5-p-coumaroylquinic acid, quinic acid, coumaroyl tryptophan conjugated, and 5-O-caffeoylquinic acid) appear to be the most relevant to explain the antioxidant capacity after dialysis, these compounds being the most bioaccessible after dialysis. To our knowledge, this is the first report matching the antioxidant capacity of foods with the polyphenol profile by BRT, which opens an interesting method of analysis for future reports on the antioxidant capacity of foods.

Mechanism of Pyrogallol Red Oxidation Induced by Free Radicals and Reactive Oxidant Species. A Kinetic and Spectroelectrochemistry Study

Pyrogallol red (PGR) presents high reactivity toward reactive (radical and nonradical) species (RS). This property of PGR, together with its characteristic spectroscopic absorption in the visible region, has allowed developing methodologies aimed at evaluating the antioxidant capacity of foods, beverages, and human fluids. These methods are based on the evaluation of the consumption of PGR induced by RS and its inhibition by antioxidants. However, at present, there are no reports regarding the degradation mechanism of PGR, limiting the extrapolation to how antioxidants behave in different systems comprising different RS. In the present study, we evaluate the kinetics of PGR consumption promoted by different RS (peroxyl radicals, peroxynitrite, nitrogen dioxide, and hypochlorite) using spectroscopic techniques and detection of product by HPLC mass spectrometry. The same pattern of oxidation and spectroscopic properties of the products is observed, independently of the RS employed. Mass analysis indicates the formation of only one product identified as a quinone derivative, excluding the formation of peroxides or hydroperoxides and/or chlorinated compounds, in agreement with FOX's assays and oxygen consumption experiments. Cyclic voltammetry, carried out at different pH's, shows an irreversible oxidation of PGR, indicating the initial formation of a phenoxy radical and a second charge transfer reaction generating an ortho-quinone derivative. Spectroelectrochemical oxidation of PGR shows oxidation products with identical UV-visible absorption properties to those observed in RS-induced oxidation.

Electrochemical Biosensors for the Determination of the Antioxidant Capacity in Foods and Beverages Based on Reactive Oxygen Species

Reactive oxygen species (ROS) are very unstable molecules generated during the metabolism. They can be produced in excess, contributing to cellular dysfunctions. Antioxidants are substances that play an important role as a health-protecting factor, limiting the lesions caused by ROS. Two kinds of electrochemical biosensors based on ROS have been described to evaluate the antioxidant capacity in the food industry. The first one involves hydroxyl radicals and studies their effect on DNA alterations. The second one consists of the superoxide radicals scavenging ability, radicals being essentially generated by the xanthine/xanthine oxidase system. These sensors are commonly based on either cytochrome c or superoxide dismutase, even though recent strategies are emerging. Whatever the involved ROS, all the described biosensors possess similar advantages such as simplicity, rapidity and low cost and are successfully applied for the assessment of antioxidant properties in various foods, additives or beverages. Keywords: Antioxidant Capacity, Beverages, Biosensors, Food, Hydroxyl Radicals, Reactive Oxygen Species, Superoxide Radicals

Solvent effects on total antioxidant capacity of foods measured by direct QUENCHER procedure

This study aimed to investigate the effects of solvent composition of different radicals (ABTS, DPPH) on measured total antioxidant capacity (TAC) of foods determined by the QUENCHER procedure. The working solutions of ABTS radical were prepared in the mixture of water–ethanol with different volume ratios (0:100, 25:75, 50:50, 75:25, 100:0). The solvent composition had a significant effect on the measured antioxidant capacity of various food matrices including cereals, fruits and vegetables, pulses and nuts (p<0.05). The use of ethanol alone gave the lowest values during measurement while introducing water to ethanol significantly improved the levels of antioxidant capacity. These results suggested that the mixture of water–ethanol (50:50, v/v) may be the most appropriate solution for standardizing the TAC database of foods tested by the QUENCHER procedure. The need of water is due to its ability to open the structure enabling better access of radicals to functional ends of the food matrices.

Antioxidant activity of food constituents: relevance for the risk of chronic human diseases

The relevance of antioxidative food constituents and the risk of developing several chronic human diseases have long been discussed. For example, the consumption of fruits and vegetables has been associated with a reduced risk of coronary atherosclerosis. This may be caused by the antioxidative activity of phenolics and flavonoids that inhibit the oxidation of low-density lipoprotein cholesterol. The editors are pleased that Ilhami Gulcin from Ataturk University in Erzurum, Turkey, has accepted our invitation to review this important but controversial topic (Gulcin 2012; this issue). The comprehensive review focuses on the methods commonly used for determination of the antioxidative capacity of food constituents. What is the chemistry underlying the assays? What are their limitations? How can they be used for developing standardized methods for characterizing the antioxidant capacity of food? Oxidative stress represents a cutting-edge topic of both this and other journals (Yen et al. 2011; Wang et al. 2011; Stewart et al. 2011a, b; Stewart et al. 2010; Barcelos et al. 2011; Michalowicz 2010; Bolt and Hengstler 2010; Bolt et al. 2011; Hardelauf et al. 2011; Cadenas et al. 2010; Hoehme et al. 2010; Schumann et al. 2009). The current review of Gulcin (2012) is a must-read for everybody interested in a critical discussion of the chemical principles underlying the most commonly used methods in this field of research. References

In Vitro 항산화능 측정법에 대한 특징 분석과 채소.과일 시료에 대한 적용 사례 고찰

건강한 삶에 대한 현대인의 관심이 나날이 고조되고 있으며, 이에 따라 노화와 질병의 예방에 효과가 있는 항산화제의 연구가 활발히 이루어지고 있다. 특히 천연물이나 식품을 소재로 한 식이성 항산화제에 대한 연구는 꾸준히 증가하고 있는 추세이며, 천연물의 소재나 연구 분야의 폭이 매우 넓다. 따라서 다양한 식품 소재의 항산화능을 조사할 수 있는 측정법의 중요성이 크게 부각되고 있다. 현재 약용 식물이나 상용 채소, 과일을 시료로 하여 여러 가지 radical이나 target molecule에 대한 항산화능을 측정할 수 있는 다수의 생체외(in vitro) 측정법이 사용되고 있다. 이에 본 총설에서는 널리 사용되고 있는 항산화능 측정법의 특징을 분석하고 적용 사례를 검토하였다. 식품의 구성 성분은 단일물질이 아닌 복합체로 구성되어 있으므로 하나의 측정법으로 항산화능을 평가할 수가 없다. 그러므로 채소와 과일을 포함한 여러가지 식물성 식품 추출물의 항산화 활성을 정확히 측정하기 위해서는 각 실험에 사용되는 radical과 기전(mechanism), 실험 조건(온도, pH, 실험기기, 시료추출방법, 소요 시간, 비용) 등을 고려하여 적절히 수행되어야 할 것이다. 그러나 이들 측정법의 다양성과 사용 단위의 차이로 인해 각 시료의 항산화능을 객관적으로 비교하는데 어려움이 있는 실정이다. 따라서 향후 항산화능 측정법의 표준화와 표현 단위의 통일이 절실히 요구된다. 또한 in vitro에서 항산화능을 나타내는 채소, 과일 등의 생체 내 활성은 다양한 biomechanism과 polymerphism으로 인해 그 효과를 예측하기가 매우 어렵다. 따라서 in vitro에서의 항산화능 screening 결과를 바탕으로 in vivo에서의 그 효과를 검증하는 연구가 부가적으로 시행되어야 할 것이라 사료된다.

Nutritional composition and bioactive properties of commonly consumed wild greens: Potential sources for new trends in modern diets

Beyond the composition of the usual macronutrients and micronutrients, it is important to provide information on the composition of bioactive compounds and antioxidant capacity of foods, particularly of wild species to regain them for nowadays' dietary habits. Many greens are known as excellent sources of natural antioxidants, and consumption of fresh plants in the diet may contribute to the daily antioxidant intake. In the present study five leafy wild greens traditionally consumed ( Borago officinalis, Montia fontana, Rorippa nasturtium-aquaticum, Rumex acetosella, Rumex induratus) were studied in order to document macronutrient, micronutrient and non-nutrient composition. R. induratus revealed the highest levels of sugars, ascorbic acid, tocopherols, lycopene, chlorophylls, flavonoids, and one of the highest antioxidant activity expressed as DPPH scavenging activity, β-carotene bleaching inhibition, and TBARS formation inhibition. R. nasturtium-aquaticum showed the healthier PUFA/SFA and n-6/n-3 ratios, and B. officinalis proved to be a source of γ-linolenic acid and other fatty acids from n-6 series that are precursors of mediators of the inflammatory response. The nutritional characteristics and antioxidant potential of these wild greens require reconsideration of their role in traditional as well as in contemporary diets. Furthermore, their extracts might find applications in the prevention of free radical-related diseases, as functional food formulations.

Long-Wavelength Fluorimetric Determination of Food Antioxidant Capacity Using Nile Blue as Reagent

A method for the determination of the antioxidant capacity using long-wavelength fluorescence measurements is described for the first time. This method is a modification of the conventional oxygen radical absorbance capacity (ORAC) method that uses fluorescein or phycoerythrin and the generator of peroxyl radicals, 2,2'-azo-bis-(2-methylpropionamidine) dihydrochloride (AAPH). The long-wavelength fluorophor nile blue is proposed as an analytical reagent alternative to these conventional fluorophores. Kinetic curves have been obtained by monitoring the fluorescence variation (λex, 620; λem, 680 nm) with time, using the 96-well microplate format. The vitamin E analogue 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) has been chosen as the model analyte, and the normalized area under the decay curve has been used as the analytical parameter. The dynamic range of the calibration curve is 0.8-8.0 μM, and the detection limit is 0.45 μM. The precision of the method, expressed as relative standard deviation and assayed using 1 and 5 μM Trolox concentrations, was 5.6 and 2.9%, respectively. The method has been applied to the analysis of fruit juices and wines, obtaining results that did not differ significantly from those provided using the ORAC method with fluorescein as reagent.

Evaluation of Oxygen Radical Absorbance Capacity in Kampo Medicine

Antioxidant capacity of food has come to be shown in terms of oxygen radical absorbance capacity (ORAC) mainly on vegetables or fruit. However, the evaluation of Kampo in terms of ORAC has not yet been accomplished. It is important that such an investigation is also conducted for Kampo medicine. We measured the ORAC value of almost all the available Kampo formulas used in the Japanese National health insurance system and examined the ORAC value both for the daily prescription, and also the crude herb ingredients. The ORAC value of Kampo medicine ranged 4.65–5913 units/day. The ORAC value was high in Kampo formulas including Rhei Rhizoma, and was relatively high in Kampo formulas including anti-inflammatory herbs other than Rhei Rhizoma. The ORAC value was also high in Kampo formulas including crude herbs that have relaxation effects. The ORAC value of a crude herb would seem to not be fixed but be dependent on combination with other crude herbs from the comparison of different herbs added to the basic Kampo medicine. These results suggest variability and complexity of the antioxidant capacity of Kampo medicine within the similar range of food. On the other hand, investigation of the compound changes of various crude herbs with ORAC may lead to the elucidation of the action mechanism of Kampo medicine.

MICROWAVE AND TRADITIONAL COOKING METHODS: EFFECT OF COOKING ON ANTIOXIDANT CAPACITY AND PHENOLIC COMPOUNDS CONTENT OF SEVEN VEGETABLES

ABSTRACT The effect of microwave, boiling and pressure cooking on total antioxidant capacity and total phenolics content of seven vegetables were studied. Total phenolics in raw and cooked vegetables were determined by the Folin–Ciocalteu method, whereas the total antioxidant capacity of vegetables extracts was evaluated using the Crocin method. After boiling, four out of seven vegetables (cauliflower, peas, spinach and Swiss chard) showed a significant decrease in their total phenolic content (P < 0.05). No decrease or a smaller decrease was observed for these four vegetables (P < 0.05) after pressure cooking and/or microwaving than after boiling. The total antioxidant capacity of potato and Swiss chard was not significantly affected by cooking procedures, whereas it decreased for spinach and peas, and it increased for tomato and carrots (P < 0.05). In addition, there was a statistically significant correlation between total phenolic content and total antioxidant capacity in cooked and uncooked vegetables, but the strength of the correlation increased when separating carotenoid-poor from carotenoid-rich vegetables. PRACTICAL APPLICATIONS All guidelines for a healthy nutrition include recommendation for increasing the consumption of fruit and vegetables also because of their phenolic compounds content and antioxidant capacity. However, all studies correlating antioxidants consumption and health benefits relate food consumption studies with antioxidant capacity of foods, neglecting to consider the chemical composition changes that may occur during cooking. This study provides data in order to better understand the implication on the total antioxidant capacity of foods due to different cooking approaches.

Comparison of ABTS/DPPH assays for the detection of antioxidant capacity in foods

The present study aimed to evaluate two different spectrophotometric assays for detection of vitamin C equivalent antioxidant capacity (VCEAC) of foods. Fifty popular, antioxidant‐rich fruits, vegetables and beverages in the U.S. diet were analyzed for their 2,2′‐azino‐bis‐3‐ethylbenzthiazoline‐6‐sulphonic acid (ABTS) anion radical scavenging activity (ABTS assay) and their ability to reduce 1,1‐diphenyl‐2picrylhydrazyl (DPPH) radical (DPPH assay). The highest VCEAC was detected for strawberry with 520.7 ± 39.3 mg vitamin C equivalent (VCE)/100 g by DPPH assay and for blueberry with 476.6 ± 28.9 mg VCE/100 g by ABTS assay. Although the order differed slightly, both assays identified the same top ten VCEAC food items in the U.S. diet based on fresh weight as blueberry, plum, strawberry, red cabbage, red wine, grape, cherry, green tea, broccoli and apple. VCEAC of 50 food items detected by ABTS assay showed a strong positive relationship with VCEAC measured by DPPH assay (r = 0.886, p&lt;0.001). VCEAC detected by ABTS assay demonstrated a stronger positive association with the USDA database for the oxygen radical absorbance capacity (ORAC) (r = 0.473, p &lt; 0.01). ABTS assay was superior to DPPH assay in reflecting the antioxidant levels of foods containing hydrophilic, lipophilic, high‐moisture, or high‐pigmented nutrients. Hence, ABTS assay may be more useful than DPPH assay in detecting VCEAC in foods.Grant Funding Source: Supported by Beginning Grant in Aid (BGIA) No. 0865092E from the American Heart Association and University of Connecticut Faculty Large Grant

Dietary Total Antioxidant Capacity: A Novel Indicator of Diet Quality in Healthy Young Adults

Background: Overall diet quality measurements have been suggested as a useful tool to assess diet-disease relationships. Oxidative stress has been related to the development of obesity and other chronic diseases. Furthermore, antioxidant intake is being considered as protective against cell oxidative damage and related metabolic complications.Objective: To evaluate potential associations between the dietary total antioxidant capacity of foods (TAC), the energy density of the diet, and other relevant nutritional quality indexes in healthy young adults.Methods: Several anthropometric variables from 153 healthy participants (20.8 ± 2.7 years) included in this study were measured. Dietary intake was assessed by a validated food-frequency questionnaire, which was also used to calculate the dietary TAC and for daily energy intake adjustment.Results: Positive significant associations were found between dietary TAC and Mediterranean energy density hypothesis–oriented dietary scores (Mediterranean Diet Score, Alternate Mediterranean Diet Score, Modified Mediterranean Diet Score), non-Mediterranean hypothesis–oriented dietary scores (Healthy Eating Index, Alternate Healthy Eating Index, Diet Quality Index-International, Diet Quality Index-Revised), and diversity of food intake indicators (Recommended Food Score, Quantitative Index for Dietary Diversity in terms of total energy intake). The Mediterranean Diet Quality Index and Diet Quality Index scores (a Mediterranean and a non–Mediterranean hypothesis–oriented dietary score, respectively), whose lower values refer to a higher diet quality, decreased with higher values of dietary TAC. Energy density was also inversely associated with dietary TAC.Conclusion: These data suggest that dietary TAC, as a measure of antioxidant intake, may also be a potential marker of diet quality in healthy subjects, providing a novel approach to assess the role of antioxidant intake on health promotion and diet-based therapies.

ANTIOXIDANT STATUS IN VIVO: THE CASE FOR REGULAR CONSUMPTION OF ANTIOXIDANT RICH FRUITS AND VEGETABLES

ANTIOXIDANT STATUS IN VIVO: THE CASE FOR REGULAR CONSUMPTION OF ANTIOXIDANT RICH FRUITS AND VEGETABLES

Antioxidant Activity in Variously Prepared Elderberry Foods and Supplements

Antioxidant capacity of foods and food supplements based on berries and flowers of medicinal plant elderberry (&lt;I&gt;Sambucus nigra&lt;/I&gt; L.) was assessed. Reducing properties of the samples and extracts were evaluated using amperometric detection at working electrode potential –0.8 V after HPLC separation. Moreover, antiradical activity of selected samples was determined by the means of spectrophotometric DPPH radical scavenging method. Electrochemical activity (EA) of fresh juice pressed from elder fruits amounted to 0.71 g AAE/l with anthocyanins as minor contributors (10.2%). Catechins and phenolic acids were the major active groups. During production of elder berry spread, even more than 90% of the EA compounds found in raw elder berry material can be destroyed. Comparable activity may be found also in the products from elder flowers. Although elder blossom syrups possessed similar EA regardless of the technology used (0.033–0.054 g AAE/kg), their chromatographic patterns were often very different. For example, no flavonols were present in the syrups, if traditional preparation comprising 24-h maceration with citric acid was applied. Analyzing the chromatographic patterns, one can distinguish different base materials and technology, which can be used for the authenticity confirmation. Herbal infusions from elder flowers, which contain more flavonols than are in syrups, were 16–27 times richer in EA than drinks prepared from the syrups after recommended dilution. Only the syrup designed for preventing and treating upper-respiratory viral infections showed the EA (0.09 g AAE/kg) comparable to that of herbal infusion (0.13 g AAE/l).

AtMYB12 regulates caffeoyl quinic acid and flavonol synthesis in tomato: expression in fruit results in very high levels of both types of polyphenol

Plant polyphenolics exhibit a broad spectrum of health-promoting effects when consumed as part of the diet, and there is considerable interest in enhancing the levels of these bioactive molecules in plants used as foods. AtMYB12 was originally identified as a flavonol-specific transcriptional activator in Arabidopsis thaliana, and this has been confirmed by ectopic expression in tobacco. AtMYB12 is able to induce the expression of additional target genes in tobacco, leading to the accumulation of very high levels of flavonols. When expressed in a tissue-specific manner in tomato, AtMYB12 activates the caffeoyl quinic acid biosynthetic pathway, in addition to the flavonol biosynthetic pathway, an activity which probably mirrors that of the orthologous MYB12-like protein in tomato. As a result of its broad specificity for transcriptional activation in tomato, AtMYB12 can be used to produce fruit with extremely high levels of multiple polyphenolic anti-oxidants. Our data indicate that transcription factors may have different specificities for target genes in different plants, which is of significance when designing strategies to improve metabolite accumulation and the anti-oxidant capacity of foods.

Antioxidant Activity of Proteins and Peptides

Proteins can inhibit lipid oxidation by biologically designed mechanisms (e.g. antioxidant enzymes and iron-binding proteins) or by nonspecific mechanisms. Both of these types of antioxidative proteins contribute to the endogenous antioxidant capacity of foods. Proteins also have excellent potential as antioxidant additives in foods because they can inhibit lipid oxidation through multiple pathways including inactivation of reactive oxygen species, scavenging free radicals, chelation of prooxidative transition metals, reduction of hydroperoxides, and alteration of the physical properties of food systems. A protein's overall antioxidant activity can be increased by disruption of its tertiary structure to increase the solvent accessibility of amino acid residues that can scavenge free radicals and chelate prooxidative metals. The production of peptides through hydrolytic reactions seems to be the most promising technique to form proteinaceous antioxidants since peptides have substantially higher antioxidant activity than intact proteins. While proteins and peptides have excellent potential as food antioxidants, issues such as allergenicity and bitter off-flavors as well as their ability to alter food texture and color need to be addressed.

An Integrated Approach to Evaluate Food Antioxidant Capacity

Many methods are available for determining food antioxidant capacity, which is an important topic in food and nutrition research and marketing. However, the results and inferences from different methods may vary substantially because each complex chemical reaction generates unique values. To get a complete and dynamic picture of the ranking of food antioxidant capacity, relative antioxidant capacity index (RACI), a hypothetical concept, is created from the perspective of statistics by integrating the antioxidant capacity values generated from different in vitro methods. RACI is the mean value of standard scores transformed from the initial data generated with different methods for each food item. By comparing the antioxidant capacity of 20 commonly consumed vegetables in the U.S. market that were measured with 7 chemical methods, we demonstrated that the RACI correlated strongly with each method. The significant correlation of RACI with an independent data set further confirmed that RACI is a valid tool to assess food antioxidant capacity. The key advantage of this integrated approach is that RACI is in a numerical scale with no units and has consistent agreement with chemical methods. Although it is a relative index and may not represent a specific antioxidant property of different food items, RACI provides a reasonably accurate rank of antioxidant capacity among foods. Therefore, it can be used as an integrated approach to evaluate food antioxidant capacity.

Food antioxidant capacity determined by chemical methods may underestimate the physiological antioxidant capacity

Antioxidant capacity assays are of growing interest in the study of dietary antioxidant properties since they are able to analyse a complex mixture of antioxidants and its synergistic interactions. However, most of the antioxidant capacity assays in the literature are limited by the antioxidant extraction technique, since some antioxidants may remain associated in the extraction residues. The objective of this work was to compare an in vitro physiological procedure for antioxidant extraction with a methanol/acetone/water extraction (chemical procedure). Enzymatic digestions and in vitro colonic fermentations were used on solid plant foods daily consumed in the Spanish diet to estimate the total antioxidant capacity released during the entire digestion process. The in vitro physiological procedure yielded a higher antioxidant capacity than the chemical procedure (7000 and 900 μmol trolox equivalents measured by ABTS, respectively). Our results suggest that determination of antioxidant capacity in food chemical extracts may underestimate the real antioxidant capacity that may be in close contact with the intestinal lumen.