TY - JOUR
AU1 - Issaoui,, Manel
AU2 - Delgado, Amélia, Martins
AU3 - Caruso,, Giorgia
AU4 - Micali,, Maria
AU5 - Barbera,, Marcella
AU6 - Atrous,, Hager
AU7 - Ouslati,, Amira
AU8 - Chammem,, Nadia
AB - Abstract Phenols or phenolics are a class of compounds that have one or more hydroxyl groups attached to a 6-carbon aromatic ring, they occur as plant secondary metabolites, having in common the antioxidant activity. Their average daily intake varies widely around the world. Many researchers consider coffee, tea, wine, cocoa products, fruits and vegetables as the main sources of polyphenols in different diets. However, spices and culinary herbs have been referred to as the foods richest in polyphenols. Despite spices and culinary herbs are used in small amounts as seasonings, their contribution to the dietary supply of phytonutrients should not be disregarded. A diet rich in a variety of polyphenols (and other phytonutrients) has potential health benefits, namely in the prevention of chronic diseases and cancer. In addition, flavor and color are the most important factors for the selection of food by consumers. A multitude of endogenous food compounds, including phenolics, are involved in food flavor. The presence of phenolic compounds in the food matrix has been mainly associated with the perception of bitter taste and tactile sensation of astringency. However, these compounds can also impact the color and aroma notes of fruits and vegetables. Thus, understanding the sensory impact of these substances and relationships with consumers’ approaches towards phenolic-rich fruits and vegetables may help find strategies to increase the consumption of such foods. A well-known example of a tasty, healthy and sustainable dietary model is the Mediterranean Diet. In this study, we summarize the dietary intake of some polyphenols from different dietary patterns around the world and the contribution of natural phenolic compounds to the flavor of food and beverages, in particularly those associated to the Mediterranean Diet. Polyphenols are phytonutrients, generally with antioxidant activity, which are typical of foods and beverages of plant origin. Polyphenols include, among others, simple phenols, phenolic acids, coumarins, flavonoids (flavanones, flavones and flavonols), as well as oligomers and polymers, such as tannins and lignin. They are mainly secondary metabolites, variable within botanic groups, species or even plant varieties, and are responsible for such traits as aroma, color, and antioxidant properties of plant foods. Polyphenols show highly diverse structures and over 500 different polyphenols have been identified in foods (1). Polyphenols are abundant in coffee, tea, cocoa products, wine (particularly red wine), spices, culinary herbs, onions, grapes, nuts, apples, and many other fruits and vegetables. It is important to note their beneficial effects on human health, namely in the prevention of chronic diseases, also known as non-communicable diseases (NCD). In addition to their known antioxidant properties, polyphenols may have other biological activities as presented by Saura-Calixto et al. (2) in affecting gene expression, cell signaling and cell adhesion. The scientific community has been paying more and more attention to the biological activities of polyphenols, namely to their mechanism of action, bioavailability and pharmacokinetics, thanks to their importance in the prevention of cancer and cardiovascular, inflammatory and neurodegenerative diseases, as well as to their contribution in lowering the risk of depression and cognitive decline during ageing (3). When used as nutraceuticals, natural phenolic compounds (NPC) are a good alternative to synthetic antioxidants. Industrialists and food technologists are considering or already using natural phyto-antioxidants in improving nutritional or technological features of food products, including increasing shelf-life. NPC may have myriad health benefits, even if just a small amount is absorbed in the body. Less than 10% of the total ingested amount is expected to be absorbed into the bloodstream, the remaining part will reach the colon where such compounds will be metabolized by gut bacteria, providing, in turn, a series of bioactive metabolites as well as direct health benefits through microbe-host interactions (2). Mounting evidence points to the paramount importance of gut bacteria in human health. Gut microbiota is now viewed as groups of symbionts that interact with many functions in our body, including our mood (2). We now know that gut microbiota can be modulated, at least to some extent, by food habits. Many of the previously called “antinutrients” have been found to be important in selecting and feeding some of these desirable microbial population groups. Nowadays such compounds tend to be named “phytonutrients”, a class in which phenols have been recently included (4). Biological properties of dietary polyphenols may depend on their absorption in the gut and their bioavailability (2). In this context, the Mediterranean Diet (MD), characterized by a high and varied consumption of plant foods, is known to prevent the risk of cardiovascular disease, at least in part, thanks to the high levels of polyphenols provided by this dietary pattern. Thus, the assessment of daily intake of polyphenols from a given dietary pattern, as well as their bioavailability will contribute to elucidating the importance of polyphenols to human health. The aim of this review is to present indicative figures on the intake of some types of polyphenols (flavonols, catechins, phenolic acids, flavanones, and flavan-3-ols) in different diets around the world. Despite taking a simplistic approach, this study aims at providing some guidance in respect to plant foods and their contribution in phytonutrients to the diet. In addition, the review summarizes the contribution of natural phenolic compounds to the flavor of food and beverages, in particularly those associated with the MD. Daily Intake of Polyphenols Around the World Dietary phenols do not have yet any official daily intake recommendations, although both health and structure-function claims have been granted to specific polyphenols present in foods and dietary supplements. As further exhibited below, in such cases, labels must explain the necessary daily intake of specific compound(s) so as to obtain the corresponding health claims according to Reg. (EC) No 1924/2006, articles 13 and 14, or of structure-function claims, in accordance with the Dietary Supplement Health and Education Act (DSHEA) statute of United States Federal legislation (1994). Recent research has demonstrated how important these compounds are in the modulation of gut microbiota. Mechanisms of action have been disclosed revealing how certain compounds (or their resulting microbial metabolites) influence important aspects of the functioning of the human body. As an example, in a recent study aiming at investigating possible relationships between normal intakes of dietary flavonoids and the risk of depression (considering total flavonoids and subclasses such as flavonols, flavones, flavanones, anthocyanins, flavan-3-ols, polymeric flavonoids, and proanthocyanidins), Chang et al. (5) found that women consuming noticeable amounts of flavonoids (mainly flavones and proanthocyanidins) had a lower risk of depression. Consumption of flavonoids has also been noted to slow down the decline of the cognitive function during ageing, according to a study by Letenneur et al. (3). Based on this research, older people (>65 years old) with a high dietary intake of flavonoids were found to have a better cognitive performance than those with a diet poorer in flavonoids. Estimations of dietary intakes of total polyphenols, in diverse world population samples, and with diverse food habits, can be found in the literature and are herein discussed. Kühnau was among one of the first authors to note the relevance of flavonoids in the diet, back in 1976. Kühnau (6) estimated the average daily intake of dietary flavonoids in the United States to be between 1 and 1.1 g/day. At the beginning of the 1990s, a study on the Dutch diet estimated the dietary intake of flavonols and flavones in the Netherlands to be considerably lower than the average value noted by the Kühnau review (6). Hertog et al. (7) reported intake values of 23 and 115 mg/day, respectively for flavonols and flavones in the Dutch population sample. Such variances may be explained by the different analytical methodologies and the way results were expressed. Thus, whereas the first study refers to total phenols (obtained by coarse analysis), the second and more recent study refers to specific classes of compounds (probably obtained by more specific analysis). Other studies report values in the same range. For example, a consumption of flavones and flavanones of the order of 26 ± 15 mg/day, also in the Netherlands (8), or 68 mg/day, in a publication related to the famous seven countries’ study by Ancel Keys (9). By the end of the 1990s, a team of researchers working on the Denmark diet registered daily intake values for flavones, flavonols and flavanones of approximately 28 mg/day (10). More recently, in 2000, research performed in Japan highlighted that the total mean intake values of flavonoids and isoflavones were 16.7 and 47.2 mg/day, respectively, for the studied population. The authors observed that the major source of flavonoids were onions (45.9%) and that of isoflavones was tofu (37.0%) (11). It is also noteworthy that different independent studies point to low levels and short diversification of polyphenol intake in the American/western diet. For example, consumption of flavan-3-ols ranging from 25–32 mg/day was recorded in post-menopausal women from Iowa, USA (12), whereas levels of 50–56 mg were recorded in the Netherlands for men and women (13) (strong inter-individual variations should be considered). Another study, conducted in 2007 in Spain, reported a mean daily intake of polyphenols (in a population with significant adherence scores to the Mediterranean dietary pattern) ranging from 2590 to 3016 mg/day, including both extractable and non-extractable polyphenols (2). The authors noted that the amount of non-extractable polyphenols, associated with the indigestible fraction, doubled that of extractable polyphenols. Based on this investigation, the highest fraction of dietary polyphenols (48%) were found to be bio-accessible in the small intestine, whereas the other fraction would probably be bio-accessible in the large intestine (2). After the digestion process, 10% of phytochemical compounds remained in the food matrix. Saura-Calixto et al. (2) explain that the sources of polyphenols in the studied population were cereals (793–1087 mg/day), vegetables (230–283 mg/day), legumes (238–275 mg/day), fruits (470–763 mg/day), nuts (102–121 mg/day), beverages (580–647 mg/day), and olive oil (5–11 mg/day). These data, although just indicative, are illustrative of the adequacy of the Mediterranean dietary pattern1 in supplying a wide diversity and quantity of polyphenols, a class of compounds including myriad molecules, many of which are exclusive to certain plant families, genera or species. A dedicated study was carried out in 2008 on Finnish adults to evaluate their daily intake of polyphenols (14). The authors estimated the dietary intake of polyphenols to be 863 ± 415 mg/day, in which phenolic acids were the dominant group of polyphenols (75% of total intake) followed by proanthocyanidins (14%), anthocyanidins, and other flavonoids (10%). Coffee and cereals were found to be the main contributors to the total polyphenol intake in the Finnish diet. In 2012, the “PREvencion con DIeta MEDiterranea” (PREDIMED) study shown estimations of quantitative intake levels of polyphenols and the corresponding main dietary sources in Spain. Based on this research, the daily intake of polyphenols by the Spanish group was approximately 820 ± 323 mg/day, consisting of 443 ± 218 mg/day flavonoids, 304 ± 156 mg/day phenolic acids, and 73 mg/day phenols from other groups. In terms of subclasses, hydroxycinnamic acids (Figure 1) are at the top of the list, with an average daily intake of about 276 ± 146 mg/day (1/3 of the total polyphenol intake), followed by flavanones (132 ± 125 mg/day) and proanthocyanidins (117 ± 81 mg/day). The PREDIMED study showed the main source of polyphenols to be fruits (>40%), with a total polyphenol intake of about 360 mg/day, of which 255 mg/day was flavonoids and 72 mg/day was phenolic acids (15). Non-alcoholic beverages (mainly coffee) ranked in second position, contributing 192 mg/day of total polyphenols, followed by vegetables (104 mg/day), alcoholic beverages (67 mg/day) and cereals (43 mg/day). Oils (mostly olive oil), cocoa products, nuts and seeds, as well as legumes (pulses), contributed all together to 53.6 mg/day of total polyphenols to the diet. The same database has been used by Pérez-Jiménez et al. (16) in order to evaluate the dietary intake of some polyphenols in French adults. These authors found that the mean total polyphenol intake in the French sample population was 1193 ± 510 mg/day (or 820 ± 335 mg/day when expressed as aglycone equivalents). Authors have remarked that non-alcoholic beverages ranked in first place as the food category supplying the highest level of total polyphenols (658 ± 426 mg/day). Coffee was found to be the main contributor (79%), followed by tea (17%). Fruits occupied the second position, providing 206 mg/day, in which apples were the major contributor (45%). The oil’s category (99% extra virgin olive oil) contributed only 4 ± 2 mg/day. Based on the same study, fruits were the richest food matrix in flavonoids (172 ± 130 mg/day), whereas phenolic acids dominated the polyphenolic fraction of non-alcoholic beverages. In general terms, coffee was found to be the major contributor of polyphenols to the diet of French adults, representing 44%. Figure 1. Open in new tabDownload slide Simple phenols from plant foods. The chemical structures of 4-hydroxycinnamic acid or p-coumaric acid and 4-hydroxybenzoic acid. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure (4, 16). Figure created by the authors. Figure 1. Open in new tabDownload slide Simple phenols from plant foods. The chemical structures of 4-hydroxycinnamic acid or p-coumaric acid and 4-hydroxybenzoic acid. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure (4, 16). Figure created by the authors. The intake of phenolic compounds in various European countries was evaluated by Zamora-Ros et al. (17). These authors found differences in the profile of ingested polyphenols, with highest levels of total phenolic acids daily intake observed in Denmark (around 1000 mg/day) and lowest levels observed in Greece (one order of magnitude less). These authors observed the main food matrix of phenolic acids to be coffee (55.3 -80.7% of the total phenolic acid intake) (Figure 1). These authors also referred fruits, vegetables and nuts to be the next relevant dietary sources of phenolic acids, after coffee. It should be noted that, as referred above, each plant species have a different polyphenolic profile and a varied diet is expected to correspond to the intake of a wide variety of phenolic compounds. Zamora-Ros et al. (17) remarked on the huge heterogeneity between the intake of phenolic acids between the north and the south of Europe, which they attributed to the different food habits. Data from the Polish arm of the “Health, Alcohol and Psychosocial factors In Eastern Europe” (HAPIEE) study demonstrated that the mean intake of polyphenols, by that population, was 1756.5 ± 695.8 mg/day (median value: 1662.5 mg/day), mainly from coffee (40%), tea (27%), and chocolate (8%). Fruits and vegetables were minor contributors of total polyphenols to the Polish diet. Further discrimination of relevant sources of particular polyphenols showed that, despite the lower intake of vegetables in Poland than in southern Europe (e.g., Spain, France), vegetable oils contributed hydroxycinnamic acids (705 mg/day) and olives supplied 0.4 mg/day of tyrosol (Figure 2) (18). Figure 2. Open in new tabDownload slide The chemical structure of tyrosol or 2-(4-hydroxyphenyl)ethanol), a phenol compound present in two of the traditional components (wine and virgin olive oil) of the Mediterranean Diet, and hydroxytyrosol, a phenolic phytochemical naturally occurring in virgin olive oil, with potential antioxidant, anti-inflammatory and cancer preventive activities. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure. Figure 2. Open in new tabDownload slide The chemical structure of tyrosol or 2-(4-hydroxyphenyl)ethanol), a phenol compound present in two of the traditional components (wine and virgin olive oil) of the Mediterranean Diet, and hydroxytyrosol, a phenolic phytochemical naturally occurring in virgin olive oil, with potential antioxidant, anti-inflammatory and cancer preventive activities. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure. Table 1 summarizes the above-mentioned and discussed studies. Since at least the 1970s researchers have been concerned about polyphenols in foods: to know their total concentration in foods, to discriminate the phenolic profile of specific food items, to understand their role and outcomes in the human body, and to estimate dietary intake levels. Although the presented values cannot be directly comparable (as they refer to different compounds, and different methodologies were used), they firstly reveal the global importance of coffee as a source of polyphenols. Table 1. Some studies concerning the dietary intake of phenols, from 1975 to 2013, in different parts of the world, referring to total phenols or subclasses. Flavonoids should be interpreted as the sum of flavonols and flavones. Data from (2, 6, 11, 15, 18, 19). Country . Daily intake . Studied phenols . Food Matrix . Method . Estimation . USA (6) 1 g/day Flavonoids USA diet – – Japan (11) Flavonoids: 16.7 mg/day Isoflavones: 47.2 mg/day Flavonoids and isoflavones Japanese diet – Food phytochemical composition table Spain (2) 2.59–3.016 g/day Total polyphenols Whole diet Folin-Ciocalteau procedure Spanish National Survey Food Consumption (2001) Finland (15) 863 ±415 mg/day Total polyphenols Major food sources of polyphenols Reversed-phase HPLC after alkaline and acid hydrolyses 48-h dietary recalls of 2007 Finnish adults Various European countries (18) Max in Denmark: men: 1265.5 mg/day women: 980.7 mg/day Min in Greece: men: 213.2 mg/day women: 158.6 mg/day Phenolic acid Food sources of phenolic acids – Phenol-Explorer database, http://phenol-explorer.eu/, and on 24-h recall occurrences Poland (19) 1.66 g/day Total polyphenols Whole diet – Phenol-Explorer database, http://phenol- explorer.eu/ Country . Daily intake . Studied phenols . Food Matrix . Method . Estimation . USA (6) 1 g/day Flavonoids USA diet – – Japan (11) Flavonoids: 16.7 mg/day Isoflavones: 47.2 mg/day Flavonoids and isoflavones Japanese diet – Food phytochemical composition table Spain (2) 2.59–3.016 g/day Total polyphenols Whole diet Folin-Ciocalteau procedure Spanish National Survey Food Consumption (2001) Finland (15) 863 ±415 mg/day Total polyphenols Major food sources of polyphenols Reversed-phase HPLC after alkaline and acid hydrolyses 48-h dietary recalls of 2007 Finnish adults Various European countries (18) Max in Denmark: men: 1265.5 mg/day women: 980.7 mg/day Min in Greece: men: 213.2 mg/day women: 158.6 mg/day Phenolic acid Food sources of phenolic acids – Phenol-Explorer database, http://phenol-explorer.eu/, and on 24-h recall occurrences Poland (19) 1.66 g/day Total polyphenols Whole diet – Phenol-Explorer database, http://phenol- explorer.eu/ Open in new tab Table 1. Some studies concerning the dietary intake of phenols, from 1975 to 2013, in different parts of the world, referring to total phenols or subclasses. Flavonoids should be interpreted as the sum of flavonols and flavones. Data from (2, 6, 11, 15, 18, 19). Country . Daily intake . Studied phenols . Food Matrix . Method . Estimation . USA (6) 1 g/day Flavonoids USA diet – – Japan (11) Flavonoids: 16.7 mg/day Isoflavones: 47.2 mg/day Flavonoids and isoflavones Japanese diet – Food phytochemical composition table Spain (2) 2.59–3.016 g/day Total polyphenols Whole diet Folin-Ciocalteau procedure Spanish National Survey Food Consumption (2001) Finland (15) 863 ±415 mg/day Total polyphenols Major food sources of polyphenols Reversed-phase HPLC after alkaline and acid hydrolyses 48-h dietary recalls of 2007 Finnish adults Various European countries (18) Max in Denmark: men: 1265.5 mg/day women: 980.7 mg/day Min in Greece: men: 213.2 mg/day women: 158.6 mg/day Phenolic acid Food sources of phenolic acids – Phenol-Explorer database, http://phenol-explorer.eu/, and on 24-h recall occurrences Poland (19) 1.66 g/day Total polyphenols Whole diet – Phenol-Explorer database, http://phenol- explorer.eu/ Country . Daily intake . Studied phenols . Food Matrix . Method . Estimation . USA (6) 1 g/day Flavonoids USA diet – – Japan (11) Flavonoids: 16.7 mg/day Isoflavones: 47.2 mg/day Flavonoids and isoflavones Japanese diet – Food phytochemical composition table Spain (2) 2.59–3.016 g/day Total polyphenols Whole diet Folin-Ciocalteau procedure Spanish National Survey Food Consumption (2001) Finland (15) 863 ±415 mg/day Total polyphenols Major food sources of polyphenols Reversed-phase HPLC after alkaline and acid hydrolyses 48-h dietary recalls of 2007 Finnish adults Various European countries (18) Max in Denmark: men: 1265.5 mg/day women: 980.7 mg/day Min in Greece: men: 213.2 mg/day women: 158.6 mg/day Phenolic acid Food sources of phenolic acids – Phenol-Explorer database, http://phenol-explorer.eu/, and on 24-h recall occurrences Poland (19) 1.66 g/day Total polyphenols Whole diet – Phenol-Explorer database, http://phenol- explorer.eu/ Open in new tab It is important to note that, despite the currently observed nutrition transition, the above displayed analysis (Table 1) shows that people from southern European countries tend to obtain dietary phenols from a larger variety of foods than people from northern Europe and the USA. Such inference is confirmed by Godos et al. (19): the total polyphenol intake is higher in consumers with higher adherence scores to the MD than in those with low adherence scores. These authors confirm the established MD benefits from a different angle. Health advantages may be mediated by high levels of polyphenols occurring in this eating pattern. Pérez-Jiménez et al. (16) have used the Phenol-Explorer tool to identify the 100 foods richest in polyphenols. The list refers to indicative values for total phenols of whole foods and the concentrations range from about 15 000 mg/100 g (cloves) to 10 mg/100 mL (rosé wine). The list should be interpreted with care, bearing in mind that only an estimate of total phenols is provided. The phenolic profile of foods is disregarded. Thus, based in this investigation, the three foods richest in total polyphenols (on the list) belong to the food group of seasonings (which includes 22 spices and culinary herbs) and are: cloves (15 188 mg/100 g), dried peppermint (11 960 mg/100 g) and star anise (5460 mg/100 g). Ripe table-olives rank high on the list, with an amount of 569 mg/100 g of total polyphenols. Extra virgin olive oil (62 mg/100 mL) and rapeseed oils (17 mg/100 mL) are the only edible fats present on the list (16). In short, the list of 100 foods richest in polyphenols is dominated by spices and culinary herbs. Their contribution to the dietary supply of phytonutrients should not be disregarded, in particular in such cuisines that make use of a large variety of herbs and spices, as in the cases of Oriental and Mediterranean cuisines. Nutritional and Health Benefits of Phenolic Compounds in Selected Vegetable Products It is well known that plant phenolics are the most important primary antioxidants in foods. It was also shown above that the MD provides adequate levels and variety of polyphenols, which are thought to be responsible for health benefits, namely those stated in health and nutritional claims (e.g., polyphenols from olive oil and walnuts). Consequently, phenolics may be hidden in MD food items, especially such compounds often claimed to have specific aromas and flavors (e.g. oleuropein, catechin, quercetin, eugenol). A selection of these foods, with a special attention to several flavored products, is herein presented. Cloves (Syzygium aromaticum), other spices, and culinary herbs Mediterranean meals are known to be simultaneously tasty and healthy, and spices contribute to such imprints. The natives of Mediterranean areas possess a rich culinary tradition based on the generous use of spices to season dishes. Cloves, dried peppermint, star anise, dried oregano, celery seeds, common sage, rosemary, spearmint, dried and fresh thyme, capers, sweet basil, curry, ginger, lemon verbena, cumin, cinnamon (powder and stick), caraway, Ceylon cinnamon, parsley, and marjoram, are all common seasoning ingredients in Mediterranean cuisine. Also relevant are coriander, containing the phytosterols stigmasterol and β-sitosterol, and saffron, containing safranal (a simple phenol that acts as anticonvulsant, and free radical scavenger) (20). Shan et al. (21) claimed that some spices should be considered as food ingredients, given the relatively large amounts that can be included in foods and the corresponding high levels of conveyed phenolics. Such is the case with of clove, cinnamon, oregano, sage, thyme, and rosemary. Pérez-Jiménez et al. (16) positioned cloves at the top of their list because it contained approximately 15 188 mg/100 g as total phenols (22). Other researchers reported their potentially strong antioxidant character (23). The Food and Drug Administration (FDA) and the World Health Organization (WHO) recognized cloves as safe and have established the concentration of 2.5 mg/kg of body weight (bw) as an acceptable daily intake in the human diet (24). Eugenol, or 4-allyl-2-methoxyphenol (Figure 3), is the principal bioactive compound of cloves (23, 25). It is a simple phenol(alkylbenzene) with molecular formula C10H12O2 (26). According to Phenol Explorer database version 3.62, eugenol content in cloves may vary from 9381.70 to 14 650.00 mg/100 g (22). Cloves also contain flavonoids, hydroxybenzoic acids, hydroxycinamic acids (Figure 1), and hydroxyphenylpropens. Cortès-Rojas et al. (23) and Bezerra et al. (25) have summarized, in two reviews, the main biological activities of cloves, as listed in Figure 4. Origanum vulgare, Salvia rosmarinus, and Thymus vulgaris, for which innumerous sub-species and regional varieties can be found to be among the most frequent culinary condiments used in Mediterranean cuisine. All of them are well placed in the list of the foods richest in total polyphenols (16, 22). Figure 3. Open in new tabDownload slide Chemical structures of eugenol - a naturally-occurring phenolic molecule found in several plants such as clove, cinnamon, and bay leaves -and rosmarinic acid, commonly found in species and culinary herbs. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure. Figure 3. Open in new tabDownload slide Chemical structures of eugenol - a naturally-occurring phenolic molecule found in several plants such as clove, cinnamon, and bay leaves -and rosmarinic acid, commonly found in species and culinary herbs. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure. Figure 4. Open in new tabDownload slide Summary of documented health promoting effects of: cloves (A), oregano (B), rosemary (C), and thyme (D). These food items contain the highest levels of total phenolic compounds according to Pérez-Jiménez et al. (17), and related contribution to healthy diets are relevant. The chemical structure of the most representative phenolic compound(s) in each case are shown, along with corresponding biological activity and health benefits. Figure 4. Open in new tabDownload slide Summary of documented health promoting effects of: cloves (A), oregano (B), rosemary (C), and thyme (D). These food items contain the highest levels of total phenolic compounds according to Pérez-Jiménez et al. (17), and related contribution to healthy diets are relevant. The chemical structure of the most representative phenolic compound(s) in each case are shown, along with corresponding biological activity and health benefits. The phenolic profile of oregano has been studied in depth by Gutiérrez-Grijalva et al. (27). Based on their investigation, the main phenols in oregano were found to be flavonoids (flavanones, flavones and flavonols) and phenolic acids. Reported therapeutic effects include: alleviation of inflammation-related diseases, respiratory and digestive disorders, headaches, rheumatism, and diabetes. Oregano’s phenolic fraction is also known by its potent antioxidant activity and potential anticancer protective effects (Figure 4) (27). In thyme, the dominant phenolic compounds are phenolic and rosmarinic acid (829 mg/100 g). Rosmarinic acid (Figure 3) is a powerful antioxidant (28) and has been identified in several herbs, namely in rosemary (987 mg/100 g), from which its name derives. Despite being used sparingly, spices supply relevant amounts of polyphenols to the diet, most particularly in Oriental and Mediterranean cuisines, where they are used abundantly. Thus, although herbs and spices are selected mainly according to sensorial aspects, they end up playing important roles in food preservation (due to their antimicrobial properties), as well as in nutrition, by supplying relevant quantities of a wide range of phytonutrients, some of which may still be unknown. Fortunately, spices are versatile, easy to add to dishes and can be incorporated into a wide variety of recipes in either fresh, dried or oil form. The use of abundant and diverse herbs and spices in seasoning is a healthy behavior because it helps improving the flavor and safety of dishes. In addition, it allows reducing the sodium content of meals while increasing the range of phytonutrients, thus contributing to the prevention of diseases and premature ageing. Figure 4 illustrates some documented features of herbs and spices commonly used in the Mediterranean cuisine, their representative phenolic compound(s) and health outcomes referred to in the literature (27–33). Greens and Other Vegetables Plants have their own specific secondary metabolites, and hence polyphenols vary widely among and within botanical families and genera, and much remains to be disclosed about polyphenols, including the fact that probably a large number of such natural compounds have not yet been identified. In general, phenolic compounds play a crucial role in defining the characteristics of fresh and processed plant food products. These secondary metabolites of plant metabolism contribute to the natural color (anthocyanins, flavonoid glycosides) or can give rise to brown oxidation products, due to air exposure, which may negatively affect the visual aspect of the food product (e.g., darkening in a juice). Polyphenols are also responsible for sensorial attributes, such as astringency and bitterness and almost invariably display antioxidant activity, making them valued as phytonutrients. Of these, o-diphenols perform better in chelating metal ions and in antagonizing free radicals (antioxidant activity). In addition, their structure allows substitutions, resulting in glucosides and terpenic-secoiridoid forms. They have a marked polarity, with consequent notable distribution in the aqueous phase. Olives can be considered one of the healthiest vegetables, due to their polyphenol profile. Among the various glucosides present in olives, oleuropein is noteworthy and is named after the plant Olea europaea. Oleuropein is an ester of 2-(3, 4-dihydroxyphenyl) ethanol (hydroxytyrosol) and has the oleosidic skeleton that is common to the secoiridoid glucosides of the Oleaceae, mainly in its aglycone form (Figure 5) (22, 34, 35). Oleuropein (secoiridoid glucoside and aglycone form) is the main compound responsible for the bitterness of olive fruits. Its degradation is related to the increase of hydrolytic enzymes, in particular glucosidases. Oleuropein level inversely correlates with the degree of maturation of the olive fruit. Hence oleuropein is present at a high level in the early stages of fruit maturation, reaching 14% of dry matter, decreasing with maturation. In some olive varieties, the level may reach zero when fruits become fully ripe, and color turns black. The decline in oleuropein coincides with the appearance and the increase of some other phenols such as tyrosol and hydroxytyrosol (Figure 2). Figure 5. Open in new tabDownload slide Structure of oleuropein aglycone, the most important phenolic compound present in olive cultivars, and quercetin, a flavonol from foods (ubiquitous in vegetables and most abundant in onions), which is reported to be a powerful free-radical scavenger and a potential anticancer agent, among other probable health benefits. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure. Figure 5. Open in new tabDownload slide Structure of oleuropein aglycone, the most important phenolic compound present in olive cultivars, and quercetin, a flavonol from foods (ubiquitous in vegetables and most abundant in onions), which is reported to be a powerful free-radical scavenger and a potential anticancer agent, among other probable health benefits. BKchem version 0.13.0, 2009 (http://bkchem.zirael.org/index.html) has been used for drawing this structure. Figure 6. Open in new tabDownload slide Summary of documented health promoting effects of olive oil and its contribution to a healthy diet are relevant. The chemical structure of the most representative phenolic compound(s) in each case are shown, along with corresponding biological activity and health benefits. Figure 6. Open in new tabDownload slide Summary of documented health promoting effects of olive oil and its contribution to a healthy diet are relevant. The chemical structure of the most representative phenolic compound(s) in each case are shown, along with corresponding biological activity and health benefits. Due to the presence of secoiridoids, and other phenols, the olive is a fruit that is not edible raw. Because of their strong bitter taste, olives must be “debittered” through extensive washing (taking advantage of the water solubility of these phenols), followed by reaction with alkali. These steps facilitate the elimination and degradation of oleuropein and other bitter compounds, which can be further hydrolyzed during microbial fermentation. The chemical hydrolysis of oleuropein in alkaline conditions produces hydroxytyrosol, elenolic acid, and glucose. Onion (Allium cepa) is one of the most widely planted and consumed vegetables around the world (36). Only red onions are in the list of 100 foods richest in polyphenols, diverging from other onion varieties. Red onion provides 50 mg/100 g of total phenols (16). The phenolic content and antioxidant capacity of red and yellow onions were compared (36) confirming the previous results of Pérez-Jiménez et al. (16). Thus, red onion is richer than yellow onion in antioxidant phenolics (36), namely flavonoids and phenolic acids including anthocyanins (responsible for the reddish-violet color) and flavanols. Quercetin is the main phenolic compound of onion. Shallot (Allium cepa var. aggregatum), also belonging to the onion family, provides 36 mg phenolics/100 g, mainly flavonoids (such as quercetin) and hydroxybenzoic acids. Globe artichoke heads (subspecies of Cynara cardunculus) provide about 436 mg/100 g of total polyphenols, of which 5-caffeoylquinic acid is the predominant bioactive phenolic compound; content of which may vary from 136 to 305 mg/100 g (20). Caffeoylquinic acid was reported to act as antioxidant, antibacterial, anticancer, and antihistaminic, by Miyamae et al. (37). From the category of the green leafy vegetables, Spinach (Spinacia oleracea) is noteworthy, providing 70 mg/100 g of total phenols, in which flavonols are the main subclass (16). This leafy green plant provides significant amounts of the specific flavonols, spinacetin and patuletin (38, 39). Non-Alcoholic Beverages Natural or traditional non-alcoholic beverages encompass Coffee (mostly a blend of Coffea arabica, and Coffea canephora, this last one known as “robusta”), tea (mainly green and black types), as well as herbal infusions, with the exclusion of fruit juices and cocoa-based products and drinks. Sodas and other processed non-alcoholic drinks are not herein included either, since generally sodas do not contribute positively to the diet. Coffee consumption being spread worldwide as a common source of phenols. Some epidemiological studies suggest that coffee may help prevent several non-communicable diseases (NCD), including type-2 diabetes mellitus, Parkinson's disease, cirrhosis and hepato-cellular carcinoma (26). The widespread belief that coffee negatively affects cardiovascular health is not scientifically supported. In fact, most prospective cohort studies point to the absence of significant correlation between coffee consumption and increased risk of cardiovascular disease (26). Filtered coffee offers more than 400 mg/100 g of total polyphenols (16) including a wide variety of compounds. The predominant polyphenol in coffee is chlorogenic acid, an ester of caffeic acid and quinic acid, and an intermediate in the synthesis of lignin. Chlorogenic acids relate to the subclass of tannins. A serving of 200 mL of filtered coffee contains between 70–350 mg of chlorogenic acid, which provides 35–175 mg of caffeic acid (26). Tea is a drink obtained from the infusion of the leaves of Camellia sinensis, originally from China and Japan. The Portuguese brought this plant to Europe from Japan in the sixteenth century. Although black tea is predominant in Europe, green tea is preferred in the south of the Mediterranean Sea. Green tea also originated from China, and spread to the Middle East and became very popular in Arabic countries (since the fifteenth century), where it still holds the status of a staple drink (20). To produce green tea, leaves are harvested and only slightly wilted, after which they are steamed for color fixation, and then shaped and dried. To produce black tea, leaves are wilted indoors, after which they undergo an oxidation process (a polyphenol oxidase-mediated oxidation) also called “fermentation,” before leaves are rolled or crushed and finally dried (20). Either black or green tea supply around 200 mg/100 g of total polyphenols (197 and 173 mg/100 g, respectively) (16). Both types of tea are rich in tannins and flavonoids. However, mainly due to the different processing, each type of tea presents a distinct polyphenol profile. Black tea primarily contains large polyphenols such as theaflavins, representing 60–70% of the polyphenolic fraction, whereas non-polymeric catechins represent 20–30% of the flavonoid fraction, in addition to many unidentified compounds (40). Both these polymeric catechins are potent antioxidants, and along with other tannins are responsible for color, aroma notes, and the astringency of black tea. Green tea contains higher levels of catechins than black tea, accounting for 30–40% of extractable solids and 80–90% of total flavonoids, with (-)-epigallocatechin-3-gallate (EGCG) as the predominant catechin (40, 41). Human studies on the bioavailability of green tea’s catechins reveal these compounds to be poorly absorbed, with less than 0.1% of ingested catechins appearing in the blood stream. Catechins, including EGCG and derivatives, are thought to interact with, and modulate, gut microbiota (24). In short, tea (green and black) is reported to have both anti-inflammatory and anticancer activities, and cardioprotective effects. Most of the health-promoting effects have been attributed to tea polyphenols, particularly to EGCG (18). The growing interest in the role of EGCG in health promotion and disease prevention is reflected by an exponential growth of research publications in this field. Herbal infusions are popular non-alcoholic drinks worldwide, originating from, and still related to, folk medicine. There are some scientifically-supported health benefits of herbal infusions, which are very popular in folk medicine as relaxing and anti-inflammatory agents. Most noteworthy examples are those of chamomile (flowers of Chamaemelum nobile), which contains remarkable amounts of 5-O-caffeoylquinic acid; balm (Melissa officinalis) existing in many varieties, from lemon balm to mint, and containing caftaric, caffeic, p-coumaric and ferulic acids, as well as luteolin, apigenin, quadranoside III, and rosmarinic acid in highly variable proportions; finally, lemon verbena (with the Verbenaceae family), which contains verbascoside (20, 26, 42, 43). Many other herbs are used in folk medicine, and much aspects of their composition, mode of action, etc. are still to be clarified. Dietary supplement manufacturers cannot legally make health claims without the approval of competent authorities; however, many companies have been globally promoting and disseminating unsubstantiated medical uses for botanical extracts, mainly commercialized as dietary supplements. Ongoing studies on both beneficial health effects and risk assessment are expected to shed some light on these alternative medicines. The main concerns are the concentrated plant extracts, although herbal infusions are also under the spotlight. The Phenolic Flavors of the MD As mentioned by Pandey and Rizvi (43), polyphenols may confer bitterness, astringency, color, flavor, odor and oxidative stability. The intensity of organoleptic properties depends on the phenolic structure and phenolic concentration; fruits such as grapes, apples, pears, cherries and berries exhibited a content up to 200–300 mg polyphenols/100 g of fresh weight, and the products manufactured from these plants still contain considerable amounts of polyphenols; i.e., a glass of red wine or a cup of tea or coffee contains about 100 mg polyphenols (16, 22), whereas a few edible olives, or 50–100 g of olive oil, may provide approximately 10 mg of polyphenols (44). As Panickar and Anderson (45) noted, the daily intake of polyphenols ranges from 100 mg/day to 1.0 g/day, which is much higher than with other classes of phytochemicals. With reference to the appreciated properties of polyphenols, the most interesting attributes are certainly flavor and aroma notes. Olive oils, especially extra-virgin and virgin types, are well researched: consequently, they can be used as examples when referring to phenolic flavors and aroma notes. In this ambit, the main group of phenolic compounds comprises hydroxytyrosol, tyrosol, caffeic acid, coumaric acid, and p-hydroxybenzoic acid (46). Phenols may be a biomarker of olive oil quality: the presence of hydroxytyrosol seems important, whereas tyrosol and some phenolic acids are indicators of mediocre quality. Their presence most probably will influence the judgment of selected and trained tasters, in accordance with International Olive Council (IOC) standards (47). Bitterness is a taste that is sensed by gustative papillae in the “V” region of the tongue that according to IOC is one of the assessed sensorial attributes, which is mainly found in olive oils obtained from green olives or olives turning color (47). Pungency is a tactile sensation perceived in whole of the mouth particularly in the throat, which according to IOC is a positive attribute that characterizes olive oils produced from the early harvested fruits dominated by olives that are still unripe (47). Thus, variegation in intensity of bitterness and pungency can be found. Oils made from riper fruits will have little to no bitterness, whereas oils made from greener fruits can be distinctly bitter. Pungency is a peppery sensation and a chemical irritation that can have different levels and for which the hotness of chili pepper, is a good example. It can vary from a very mild sensation to such an intensity that can make the consumer cough. In relation to the overall sensorial assessment, the IOC classifies the intensity of attributes of olive oils (OO) into three categories: robust, medium and delicate (47). Positive attributes, mainly bitter ness and pungency, are tightly bonded to the presence of polyphenols. Olive oil's taste intensity can be biting, mild or light. Olive oils with light or no bitter taste correspond to concentration lower than 220 mg phenols/kg (48). In addition, OO with a content varying from 220 to 340 mg/kg correspond to the slight bitter taste group, whereas bitter oils can reach 410 mg/kg. A really bitter OO may contain more than 410 mg/kg of phenolics. The implication and the role of each individual polyphenol in total bitterness are not yet clear. However, the intensity of bitter taste is reported to be correlated with the presence of polyphenols derived from the hydrolysis of oleuropein (49, 50). Conclusions Polyphenols, with their potential antioxidant activity, exhibit many beneficial effects on human health and prevention of NCD. Spices and culinary herbs were found to be the foods richest in polyphenols. Furthermore, coffee, tea, wine, cocoa products, fruits and vegetables were considered to be the main sources of polyphenols in different diets. However, their daily intake varied widely around the world. It is noteworthy that the MD provides high levels of polyphenols. Individuals from southern European countries (following a MD lifestyle) tend to obtain dietary phenols from a larger variety of foods than peoples from northern Europe and USA. These data may be useful to elucidate the effect of polyphenols on health. Moreover, polyphenols extracted from foods could be an alternative to synthetic antioxidants (widely used in cosmetics, pharmacology and in food industries). Thanks to the antioxidant potential of natural polyphenols, they are preferable food preservatives (e.g., in avoiding oxidation reactions). Further research is required to identify more polyphenols, to clarify their biological activities (particularly beyond antioxidant effects), their bioavailability and pharmacokinetics, in order to develop effective food supplements and to select healthy foods to include in particular diets. Polyphenols are omnipresent in the MD, configuring the sensorial proprieties of foods impacting color, taste (e.g., astringency and bitterness), in addition to nutritional and health benefits, which make them popular bioactive compounds. However, facing this popularity and the absence of an official daily intake, it is important to raise awareness of the need for official regulation of health claims (particularly in food supplements) and for the standardization of recommended daily intakes. It is also important to note that phenols are just one piece of the whole puzzle of dietary components that should be present in our dishes. The food system is related to several Sustainable Development Goals (SDG) involving hunger, health, climate change, natural resources and biodiversity. There is an urgent need to limit environmental damage and to cope with climate change, while safeguarding biodiversity (particularly of edible plants) and simultaneously providing a nutritious diet to a growing world population. In this sense the MD may provide a path to address United Nations sustainable development goals, because of its sustainable character, its encouragement of biodiversity and seasonality, its respect for small producers and local economies, and the ease of providing nutritious foods at affordable prices. That is, by preferring local and seasonal agricultural products, at least the costs of transportation and (cold) storage are expected to be significantly reduced (51, 52, 53, 54). Footnotes 1 Available online at the following web address: https://dietamediterranea.com/en/fundacion/download-pyramid/. 2 Available at the following web address: http://phenol-explorer.eu/. Acknowledgments The authors would like to give a sincere “thank you” to Carmelo Parisi, currently a student at the Liceo Scientifico Stanislao Cannizzaro, Palermo, Italy, for support and participation concerning the realization of chemical structures shown in this paper (Figures 1, 2, 3, and 5). Guest edited as a special report on “Characterization of Major Phenolic Compounds in Selected Foods by the Technological and Health Promotion Viewpoints” by Salvatore Parisi. References 1 Neveu V. , Perez-Jimeénez J., Vos F., Crespy V., du Chaffaut L., Mennen L., Knox C., Eisner R., Cruz J., Wishart D., Scalbert A. ( 2010 ) Database 2010, bap024. doi:10.1093/database/bap024 2 Saura-Calixto F. , Serrano J., Goñi I. ( 2007 ) Food Chem . 101 , 492 – 501 . doi:10.1016/j.foodchem.2006.02.006 Crossref Search ADS 3 Letenneur L. , Proust-Lima C., Le Gouge A., Dartigues J.F., Barberger-Gateau P. ( 2007 ) Am. J. Epidemiol . 165 , 1364 – 1371 . doi:10.1093/aje/kwm036 Crossref Search ADS PubMed 4 Delgado A.M. , Issaoui M., Chammem N. ( 2019 ) J. AOAC Int. 102 , 1356 – 1364 . doi:10.5740/jaoacint.19-0128 Crossref Search ADS PubMed 5 Chang S.C. , Cassidy A., Willett W.C., Rimm E.B., O'Reilly E.J., Okereke O.I. ( 2016 ) Am. J. Clin. Nutr. 104 , 704 – 714 . doi:10.3945/ajcn.115.1245456 Crossref Search ADS PubMed 6 Kühnau J. ( 1976 ) World Rev. Nutr. Diet. 24 , 117 – 191 Crossref Search ADS PubMed 7 Hertog M.G.L. , Hollman P.C.H., Katan M.B., Kromhout D. ( 1993 ) Nutr. Cancer 20 , 21 – 29 . doi:10.1080/01635589309514267 Crossref Search ADS PubMed 8 Keli S.O. , Hertog M.G.L., Feskens E.J.M., Kromhout D. ( 1996 ) Arch. Intern. Med. 154 , 637 – 642 . doi:10.1001/archinte.1996.00440060059007 Crossref Search ADS 9 Keys A. ( 1997 ) Nutrition 13 , 249 – 253 . doi: 10.1016/s0899-9007(96)00410-8 Crossref Search ADS PubMed 10 Leth T. , Justesen U. ( 1998 ) in Polyphenols in Foods , Amadò R., Andersson H., Bardocz S., Serra F. (Eds), Office for Official Publications of the European Communities , Brussels , pp 39 – 40 Google Scholar Google Preview OpenURL Placeholder Text WorldCat COPAC 11 Arai Y. , Watanabe S., Kimira M., Shimoi K., Mochizuki R., Kinae N. ( 2000 ) J. Nutr. 130 , 2243 – 2250 . doi:10.1093/jn/130.9.224 Crossref Search ADS PubMed 12 Arts I.C. , Hollman P.C.H., Bueno de Mesquita B.H., Feskens E.J., Kromhout D. ( 2001 ) Int. J. Cancer 92 , 298 – 302 . doi:10.1002/1097-0215(200102)9999:9999<::AID-IJC1187>3.0.CO;2-8 Crossref Search ADS PubMed 13 Arts I.C.W. , Hollman P.C.H., Feskens E.J.M., Bueno de Mesquita H.B., Kromhout D. ( 2001 ) Eur. J. Clin. Nutr. 55 , 76 – 81 . doi:10.1038/sj.ejcn.1601115 Crossref Search ADS PubMed 14 Ovaskainen M.-L. , Törrönen R., Koponen J.M., Sinkko H., Hellström J., Reinivuo H., Mattila P., ( 2008 ) J. Nutr . 138 , 562 – 566 . doi:10.1093/jn/138.3.562 Crossref Search ADS PubMed 15 Billingsley H.E. , Carbone S. ( 2018 ) Nutr. Diabetes. 8 , 13. doi:10.1038/s41387-018-0025-1 Crossref Search ADS PubMed 16 Pérez-Jiménez J. , Neveu V., Vos F., Scalbert A. ( 2010 ) Eur. J. Clin. Nutr . 64 , 112 – 120 . doi:10.1038/ejcn.2010.221 Crossref Search ADS 17 Zamora-Ros R. , Rothwell J.A., Scalbert A., Knaze V., Romieu I., Slimani N., Fagherazzi G., Perquier F., Touillaud M., Molina-Montes E., Huerta J.M., Barricarte A., Amiano P., Menéndez V., Tumino R., de Magistris M.S., Palli D., Ricceri F., Sieri S., Crowe F.L., Khaw K.-T., Wareham N.J., Grote V., Li K., Boeing H., Förster J., Trichopoulou A., Benetou V., Tsiotas K., Bueno-de-Mesquita H.B., Ros M., Peeters P.H.M., Tjønneland A., Halkjær J., Overvad K., Ericson U., Wallström P., Johansson I., Landberg R., Weiderpass E., Engeset D., Skeie G., Wark P., Riboli E., González C.A. ( 2013 ) Br. J. Nutr. 110 , 1500 – 1511 . doi:10.1017/S0007114513000688 Crossref Search ADS PubMed 18 Grosso G. , Stepaniak U., Topor-Mądry R., Szafraniec K., Pająk A. ( 2014 ) Nutrition 30 , 1398 – 1403 . doi:10.1016/j.nut.2014.04.012 Crossref Search ADS PubMed 19 Godos J. , Rapisarda G., Marventano S., Galvano F., Mistretta A., Grosso G. ( 2017 ) NFS J . 8 , 1 – 7 . doi:10.1016/j.nfs.2017.06.001 Crossref Search ADS 20 Delgado A.M. , Almeida M.D.V., Parisi S. ( 2017 ) Chemistry of the Mediterranean Diet , Springer International Publishing , New York , pp 59 – 137 and 209–239 Google Scholar Crossref Search ADS Google Scholar Google Preview WorldCat COPAC 21 Shan B. , Cai Y. Z., Sun M., Corke H. ( 2005 ) J. Agric. Food Chem. 53 , 7749 – 7759 . doi:10.1021/jf051513y Crossref Search ADS PubMed 22 Rothwell J.A. , Perez-Jimenez J., Neveu V., Medina-Remon A., M'Hiri N., Garcia-Lobato P., Manach C., Knox C., Eisner R., Wishart D.S., Scalbert A. ( 2013 ) Database 2013, bat070 – bat070 . doi:10.1093/database/bat070 23 Cortés-Rojas D.F. , de Souza C.R., Oliveira W.P. ( 2014 ) Asian Pac. J. Trop. Biomed . 4 , 90 – 96 . doi:10.1016/S2221-1691(14)60215-X Crossref Search ADS PubMed 24 Gulçiņ I. , Elmastas M., Aboul-Enein H.Y. ( 2012 ) Arab. J. Chem . 5 , 489 – 499 . doi:10.1016/j.arabjc.2010.09.016 Crossref Search ADS 25 Bezerra D.P. , Gadelha Militão G.C., de Morais M.C., de Sousa D.P. ( 2017 ) Nutrition 9 , 1367. doi:10.3390/nu9121367 26 National Center for Biotechnology Information (NCBI) ( 2018 ) Pub Chem Compound Database, https://pubchem.ncbi.nlm.nih.gov/ (accessed September 25, 2019) 27 Gutiérrez-Grijalva E.P. , Picos-Salas M.A., Leyva-López N., Criollo-Mendoza M.S., Vazquez-Olivo G., Heredia J.B. ( 2017 ) Plants 7 , 2. doi:10.3390/plants7010002 Crossref Search ADS 28 Javanmardi J. , Khalighi A., Kashi A., Bais H.P., Vivanco J.M. ( 2002 ) J. Agric. Food Chem. 50 , 5878 – 5883 . doi:10.1021/jf020487q Crossref Search ADS PubMed 29 Tapsell L.C. , Hemphill I., Cobiac L., Patch C.S., Sullivan D.R., Fenech M., Roodenrys S., Keogh J.B., Clifton P.M., Williams P.G., Fazio V.A., Inge K.E. ( 2006 ) Med. J. Aust . 185 , S1 – S24 Crossref Search ADS PubMed 30 Carlsen M.H. , Blomhoff R., Andersen L.F. ( 2011 ) Nutr. J. 10 , 50, 1 – 6 . doi:10.1186/1475-2891-10-50 Crossref Search ADS PubMed 31 Ghawi S.K. , Rowland I., Methven L. ( 2014 ) Appetite 81 , 20 – 29 . doi:10.1016/j.appet.2014.05.029 Crossref Search ADS PubMed 32 Opara E.I. , Chohan M. ( 2014 ) IJMS 15 , 19183 – 19202 . doi:10.3390/ijms151019183 Crossref Search ADS PubMed 33 Heimler D. , Isolani L., Vignolini P., Tombelli S., Romani A. ( 2007 ) J. Agric. Food Chem. 55 , 1724 – 1729 . doi:10.1021/jf0628983 Crossref Search ADS PubMed 34 Visioli F. , Galli C. ( 2002 ) Crit. Rev. Food Sci. Nutr . 42 , 209 – 221 . doi:10.1080/10408690290825529 Crossref Search ADS PubMed 35 Cicerale S. , Conlan X.A., Sinclair A.J., Keast R.S. ( 2008 ) Crit. Rev. Food Sci. Nutr . 49 , 218 – 236 . doi:10.1080/10408390701856223 Crossref Search ADS 36 Cheng A. , Chen X., Jin Q., Wang W., Shi Hi J., Liu Y. ( 2013 ) Czech J. Food Sci. 31 , 501 – 508 Crossref Search ADS 37 Miyamae Y. , Kurisu M., Han J., Isoda H., Shigemori H. ( 2011 ) Chem. Pharm. Bull. 59 , 502 – 507 . doi:10.1248/cpb.59.502 Crossref Search ADS PubMed 38 Enomoto T. , Nagasako-Akazome Y., Kanda T., Ikeda M., Dake Y. ( 2006 ) J. Investig. Allergol. Clin. Immunol. 16 , 283 – 289 PubMed 39 Choi S.H. , Liu W., Misra P., Tanaka E., Zimmer J.P., IttyIpe B., Bawendi M.G., Frangioni J.V. ( 2007 ) Nat. Biotechnol. 25 , 1165 – 1170 . doi:10.1038/nbt1340 Crossref Search ADS PubMed 40 Van Duynhoven J. , Vaughan E.E., van Dorsten F., Gomez-Roldan V., de Vos R., Vervoort J., van der Hooft J.J.J., Roger L., Draijer R., Jacobs D.M. ( 2013 ) Am. J. Clin. Nutr . 98 , 1631S – 1641S . doi:10.3945/ajcn.113.058263 Crossref Search ADS PubMed 41 Lambert J.D. , Elias R.J. ( 2010 ) Arch. Biochem. Biophys 501 , 65 – 72 . doi:10.1016/j.abb.2010.06.013 Crossref Search ADS PubMed 42 Srivastava J.K. , Pandey M., Gupta S. ( 2009 ) Life Sci . 85 , 663 – 669 . doi:10.1016/j.lfs.2009.09.007 Crossref Search ADS PubMed 43 Pandey K.B. , Rizvi S.I. ( 2009 ) Oxid. Med. Cell. Longev . 2 , 270 – 278 . doi:10.4161/oxim.2.5.9498 Crossref Search ADS PubMed 44 Boskou D. ( 2006 ) Trends Food Sci. Technol . 17 , 505 – 512 . doi:10.1016/j.tifs.2006.04.004 Crossref Search ADS 45 Panickar K.S. , Anderson R.A. ( 2011 ) IJMS 12 , 8181 – 8207 . doi:10.3390/ijms12118181 Crossref Search ADS PubMed 46 Montedoro G. , Bertuccioli M., Anichini F. ( 1978 ) in Flavor of Foods and Beverages , Charalampous G., Inglet G. (Eds), Academic Press , New York, NY , pp 247 – 281 Google Scholar Crossref Search ADS Google Scholar Google Preview WorldCat COPAC 47 IOOC ( 2018 ) Trade Standard Applying to Olive Oils and Olive Pomace Oils. COI/T.15/NC No 3, Rev. 12, June 2018. International Olive Council (IOOC), Madrid, Spain. http://www.internationaloliveoil.org/documents/viewfile/9708-norma-english (accessed on September 25, 2019) 48 Beltran G. , Ruano M.T., Jimenez A., Uceda M., Aguilera M.P. ( 2007 ) Eur. J. Lipid Sci. Technol. 108 , 193 – 197 . doi:10.1002/ejlt.200600231 Crossref Search ADS 49 Kiritsakis A.K. ( 1998 ) J. Am. Oil Chem. Soc. 75 , 673 – 681 . doi:10.1007/s11746-998-0205-6 Crossref Search ADS 50 Soler-Rivas C. , Espín J.C., Wichers H.J. ( 2000 ) J. Sci. Food Agric . 80 , 1013 – 1023 . doi:10.1002/(SICI)1097-0010(20000515)80:7<1013::AID-JSFA571>3.0.CO; 2-C Crossref Search ADS 51 United Nations, Sustainable Development Goals, ( 2011 ) https://www.un.org/sustainabledevelopment/sustainable-development-goals/ (accessed on January 25, 2020) 52 Food and Agriculture Organization of the United Nations (FAO) ( 2014 ) The Water-Energy-Food Nexus. A new approach in support of food security and sustainable agriculture, Rome http://www.fao.org/3/a-bl496e.pdf (accessed on January 25, 2020) OpenURL Placeholder Text WorldCat 53 United Nations Environment Programme (UNEP) ( 2019 ) Emissions Gap Report, Nairobi . http://www.unenvironment.org/emissionsgap (accessed on January 25, 2020) OpenURL Placeholder Text WorldCat 54 Tilman D , Clark M. ( 2014 ) Nature. 515 , 518 – 522 . doi:10.1038/nature13959 Crossref Search ADS PubMed © AOAC INTERNATIONAL 2020. All rights reserved. For permissions, please email: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
TI - Phenols, Flavors, and the Mediterranean Diet
JF - Journal of AOAC International
DO - 10.1093/jaocint/qsz018
DA - 2020-07-01
UR - https://www.deepdyve.com/lp/oxford-university-press/phenols-flavors-and-the-mediterranean-diet-UsCNQO7LSR
SP - 915
EP - 924
VL - 103
IS - 4
DP - DeepDyve
ER -