Special Issue: Phenolic Profiling and Antioxidant Capacity in Agrifood Products (original) (raw)
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Phenolic compounds, ubiquitous in plants are an essential part of the human diet, and are of considerable interest due to their antioxidant properties. These compounds posses an aromatic ring bearing one or more hydroxyl groups and their structures may range from that of a simple phenolic molecule to that of a complex high-molecular weight polymer. Flavonoids, which bear the C 6 -C 3 -C 6 structure, account for more than half of the over eight thousand different phenolic compounds. The antioxidant activity of phenolic compounds depends on the structure, in particular the number and positions of the hydroxyl groups and the nature of substitutions on the aromatic rings. Fruits, vegetables and beverages are the major sources of phenolic compounds in the human diet. The food and agricultural products processing industries generate substantial quantities of phenolics-rich by-products, which could be valuable natural sources of antioxidants. Some of these by-products have been the subject of investigations and have proven to be effective sources of phenolic antioxidants. When tested in edible oils, and in fish, meat and poultry products, phenolic-rich extracts have shown antioxidant activities comparable to that of synthetic antioxidants. Practical aspects of extraction and production of sufficient amounts of natural antioxidants from most of these sources remain to be elucidated.
Food Chemistry, 2006
Phenolic compounds, ubiquitous in plants are an essential part of the human diet, and are of considerable interest due to their antioxidant properties. These compounds posses an aromatic ring bearing one or more hydroxyl groups and their structures may range from that of a simple phenolic molecule to that of a complex high-molecular weight polymer. Flavonoids, which bear the C 6-C 3-C 6 structure, account for more than half of the over eight thousand different phenolic compounds. The antioxidant activity of phenolic compounds depends on the structure, in particular the number and positions of the hydroxyl groups and the nature of substitutions on the aromatic rings. Fruits, vegetables and beverages are the major sources of phenolic compounds in the human diet. The food and agricultural products processing industries generate substantial quantities of phenolics-rich by-products, which could be valuable natural sources of antioxidants. Some of these by-products have been the subject of investigations and have proven to be effective sources of phenolic antioxidants. When tested in edible oils, and in fish, meat and poultry products, phenolic-rich extracts have shown antioxidant activities comparable to that of synthetic antioxidants. Practical aspects of extraction and production of sufficient amounts of natural antioxidants from most of these sources remain to be elucidated.
The hidden face of food phenolic composition
Archives of Biochemistry and Biophysics, 2010
Plant polyphenols are extremely diverse, due to the occurrence of several basic structures, numerous substitutions and, for some groups, of polymers (tannins). Plant polyphenol composition depends on the plant species and organ, with some molecules specific of particular plant families while others are ubiquitous. The polyphenol content is classically assessed by global analysis methods, which lack specificity and accuracy. These methods have been replaced with high performance liquid chromatography (HPLC), that enables accurate determination of individual molecules, provided they can be unambiguously identified and calibration curves can be established. However, HPLC analysis is restricted to simple compounds and difficult to apply in the case of complex extracts. Further difficulties encountered in the case of polymers include irreversible adsorption on the stationary phases. Proanthocyanidin analysis by HPLC after acid-catalysed depolymerisation in the presence of a nucleophile permits to overcome these problems and shows that proanthocyanidins predominate in the polyphenol composition of most plants. Large varietal differences in tannin quantitative and qualitative composition were observed for all plant species studied. Moreover, analysis is usually performed after extraction, which may lead to significant underestimation of the polyphenol content, since a large proportion is not extracted by usual solvents. This may be due to covalent binding to other plant constituents and to non-covalent adsorption on plant solids. Such matrix effect also influences the taste perception of polyphenols and their fate in the digestive tract, from in-mouth interactions with salivary proteins to their metabolism by colon microflora, with potential influence on bioavailability.
Antioxidant activity of some foods containing phenolic compounds
International Journal of Food Sciences and Nutrition, 2001
This study was designed to determine the total phenols (TP) and total antioxidant activity (TAA) of some liquid and solid plant foods that are commonly consumed in Turkey. Total phenols were analysed according to the Folin-Ciocalteu method and antioxidant activities of these compounds in aqueous phase were assessed by measuring their direct ABTSradical scavenging abilities. Total phenols varied from 68 to 4162 mg/l for liquid foods and from 735 to 3994 mg/kg for solid foods. TAA of liquid and solid foods ranged between 0.61-6.78 mM and 0.63-8.62 mM, respectively. Total antioxidant activities of foods were well correlated with total phenols (r 2 = 0.95). According to content of total phenols per serving, liquid foods were in the order of black tea > instant coffee > coke > red wine > violet carrot juice > apricot nectar > Turkish coffee > grape molasses > sage > white wine > linden flower, and solid foods were in the order of red grape > raisins > tarhana > dried black plum > dried apricot > grape > fresh paprika > fresh black plum > Urtica sp. > cherry > fresh apricot > paprika pickle > paprika paste.
Plant Origin Phenolics as Prospective Antioxidants: State-of-Art for Application
Proceedings of the 1st International Symposium Innovations in Life Sciences (ISILS 2019), 2019
In the recent years there is a growing demand for plant origin antioxidants, due to their potential therapeutic value and low level of side effects. Among the plant origin substances, the metabolites with antioxidant activity are the widely used which are mainly belong to the phenolic group of compounds as well as carotenoids and vitamins. These natural antioxidants act via different mechanisms: they can decrease the level of oxidative damage in cells directly reacting with free radicals or indirectly-by inhibition the activity and expression of free radical generating enzymes or enhancing the activity or expression of intracellular antioxidant defense enzymes. The manuscript is focused on the main group of phenolics which can be used in pharmacological, food and other areas.
Health promoting and sensory properties of phenolic compounds in food
Revista Ceres, 2014
Phenolic compounds have been extensively studied in recent years. The presence of these compounds in various foods has been associated with sensory and health promoting properties. These products from the secondary metabolism of plants act as defense mechanisms against environmental stress and attack by other organisms. They are divided into different classes according to their chemical structures. The objective of this study was to describe the different classes of phenolic compounds, the main food sources and factors of variation, besides methods for the identification and quantification commonly used to analyze these compounds. Moreover, the role of phenolic compounds in scavenging oxidative stress and the techniques of in vitro antioxidant evaluation are discussed. In vivo studies to evaluate the biological effects of these compounds and their impact on chronic disease prevention are presented as well. Finally, it was discussed the role of these compounds on the sensory quality ...
Phenolics in Foods: Extraction, Analysis and Measurements
Phenolic Compounds - Natural Sources, Importance and Applications, 2017
The increasing consumers demands to acquire healthier fruits and vegetables as well as the urgency in looking to natural compounds with antioxidant activity and enhanced antimicrobial activity against antibiotic-resistant pathogenic bacterial strains have encouraged a quick expansion of research studies about enhanced phenolic extraction and identification methods. Considering the importance of phenolics as natural compounds with antioxidant and antimicrobial activity, this chapter aims to present the most updated information about extraction methods, ranging from the traditional to the most advanced processes, as well as the access to the modern methods used in the identification and quantification of phenolics. The main goal of this chapter is to provide the reader with a broad view on the different protocols used to extract, identify and quantify phenolic compounds from different kinds of foods, including fruits and vegetables.
Determination of phenolic compounds and their antioxidant activity in fruits and cereals
Talanta, 2007
Three methods, FCM (with Folin-Ciocalteu reagent), PBM (Price and Butler) and AAPM (with 4-aminoantipyrine) for assessment of phenolic compounds and three commonly used methods, TEAC (Trolox equivalent antioxidant capacity), DPPH (with diphenyl-picrylhydrazyl radical), and FRAP (ferric reducing antioxidant power) for evaluation of antioxidant capacity, were modified to a semimicroscale (total volume 1ml) with minimum consumption (to 100mul) of a sample and thereby applicable for fast screening. Appropriate standards and extracts of 17 kinds of fruit and six kinds of cereal were assessed for total content of phenolic compounds and total antioxidant capacity by each of these methods. The results of analyses of commonly used standards (gallic, caffeic and ferulic acids, (+)-catechin, Trolox, fenol and FeSO(4)) for these methods and identical plant extract showed different reactivity of principal reagent of the methods with individual standards and therefore with phenolic substances of ...