A study of the antioxidant properties of beers using electron paramagnetic resonance

Polak, Justyna; Bartoszek, M.; Stanimirova, I.

doi:10.1016/j.foodchem.2013.05.133

Cited by 32 publications

(26 citation statements)

References 29 publications

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“…In recent years, there has been a growing interest in the antioxidant properties of food products [1][2][3][4][5][6]. Various methods are used to study the antioxidant capacity of food products, Electronic supplementary material The online version of this article (doi:10.1007/s00217-017-2986-z) contains supplementary material, which is available to authorized users.…”

Section: Introductionmentioning

confidence: 99%

Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

Bartoszek

Polak

Chorążewski

2017

Eur Food Res Technol

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including tea; these methods are based on different mechanisms, using a variety of detection techniques and are therefore not standardized. Hence, the comparison of the antioxidant capacity values obtained in different laboratories is not possible. On the other hand, the antioxidant capacity values obtained in the same laboratory through the use of different methods and parameters are also not consistent, due to the use of different interactions. Therefore the research is leading to the modification of existing methods and new methods are constantly sought. Recently, an EPR method based on a new semi-empirical mathematical model were proposed [5]. This method allows for a quick and precise determination of the antioxidant capacity of food products. In this paper this method was applied to tea. Tea is one of the most widely consumed beverages in the world [7]. It is valued both for the taste and for the health benefits associated with its antioxidant content [1,[7][8][9][10]. All varieties of tea are produced from young, tender leaves of Camellia sinensis (L.) (family Theaceae). Through using a wide variety of methods, different types of tea are produced: unfermented (green and white), partially fermented (oolong) and fermented (black and red). Green tea is produced through treating the leaves with hot steam and subsequently drying them. In such conditions, polyphenol oxidation is inactivated, which prevents the oxidation of polyphenols. As a result, the raw material remains rich in flavonols such as: catechin, epicatechin, epigallocatechin, flavonoids and simple phenolic acids [7,11]. Fermentation is necessary in order to produce black tea. This process consists of enzymatic oxidation by endogenous polyphenol oxidases and peroxidases of tea polyphenols, namely colorless flavonols that are partially converted into theaflavins and thearubigins, responsible for the characteristic aroma and color of the black and oolong teas. About 75% of the catechin contained in leaves undergoes enzymatic oxidation [12]. AbstractThe antioxidant properties of different types of tea-green, black and earl grey-were investigated using the EPR spectroscopy method based on a new semi-empirical mathematical model and on a single EPR spectroscopy measurement. The obtained values of the antioxidant capacity were correlated with the bioactive ingredient content identified through the NMR spectroscopy. Moreover, an attempt was made to determine what impact on the antioxidant properties of tea does adding sugar, milk, lemon and honey have. All studied teas exhibited antioxidant properties. The best DPPH free radical scavengers were green teas. Adding sugar, milk and lemon juice to tea did not significantly impact the antioxidant properties of the infusion; adding honey, however, caused an increase in the total antioxidant capacity of the infusion. The aromatic proton content correlates positively with the antioxidant capacity value.

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Section: Introductionmentioning

confidence: 99%

Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

Bartoszek

Polak

Chorążewski

2017

Eur Food Res Technol

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“…The intensity of the EPR signal decreases with increasing concentrations of extracts or reference compounds, which results in an increase of the percentage of radical inhibition (T [%]). The percentage of radical inhibition was calculated using the following equation :

T (%) = [(I_{0} - I) / I_{0}] \times 100

where I 0 is the intensity of the EPR spectrum of or ABTS •+ (a control sample), and I is the intensity of the EPR spectrum obtained with the mixture of ABTS •+ in the presence of the extract or the reference compound.…”

Section: Methodsmentioning

confidence: 99%

Section: Epr Spectroscopymentioning

confidence: 99%

Capillary electrophoresis, high‐performance liquid chromatography, and thin‐layer chromatography analyses of phenolic compounds from rapeseed plants and evaluation of their antioxidant activity

Huang

Jansen

Frédérich

et al. 2018

J of Separation Science

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Rapeseed plants, known for oil production, are also known to contain phenolic compounds such as phenolic acids and flavonoids, with potential antioxidant and anticancer activities. The separation and identification of 11 phenolic acids in rapeseed extracts (including leaves, flowers, Chinese seeds, Belgian seeds, and cake) by capillary electrophoresis were investigated. The results were compared with those obtained with high‐performance liquid chromatography and thin‐layer chromatography and showed that the capillary electrophoresis technique offers several advantages for the identification of phenolic compounds in various rapeseed extracts. The antioxidant activity of rapeseed extracts and reference compounds was evaluated using four different approaches, namely, 2,2′‐azinobis‐ (3‐ethylbenzohiazoline‐6‐sulfonic acid assay, free radical 2,2‐diphenyl‐1‐picrylhydrazyl assay, electron paramagnetic resonance spectroscopy and the measurement of the total polyphenol content. The contents of total polyphenols in the tested extracts were ranging between 5.4 and 21.1% m/m and ranked as follows: Chinese seeds ˃ Belgian seeds ˃ Flowers ˃ Cake ˃ Leaves.

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“…The EPR signal is reduced after the addition of radicals in oil because of the reduction of the radicals from the antioxidant food components, and the antioxidant activity can be calculated from Eq. (3) or more complicate mathematical equations [85][86][87][88][89].…”

Section: Addition Of Radicalsmentioning

confidence: 99%

EPR Methods Applied on Food Analysis

Drouza¹,

Spanou²,

Keramidas³

2019

Topics From EPR Research

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An overview of the different methodologies developed so far for the investigation of paramagnetic species in foods is presented. Electron paramagnetic resonance spectroscopy (EPR), also known as electron spin resonance spectroscopy (ESR), is the primary technique toward the development of methods for the exploration of EPR-sensitive species, such as free radicals, reactive oxygen species (ROS), nitrogen reactive species (NRS), and C-centered radicals and metal ions. These methods aim for: (a) quantification of radical species, (b) exploration of redox chemical reaction mechanisms in foods, (c) assessment of the antioxidant capacity of food, and (d) food quality, stability, and food shelf life. For these purposes, different radical initiations and detections have been used in foods depending on both the chemistry of the target system and the kind of information required, listed in: the induction of radicals by (a) microwave, UV, or γ-radiation; (b) heating; (c) addition of metals; and (d) use of oxidants.

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A study of the antioxidant properties of beers using electron paramagnetic resonance

Cited by 32 publications

References 29 publications

Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

Capillary electrophoresis, high‐performance liquid chromatography, and thin‐layer chromatography analyses of phenolic compounds from rapeseed plants and evaluation of their antioxidant activity

EPR Methods Applied on Food Analysis

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