Phenols, Flavors, and the Mediterranean Diet.

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.

Review of the Role of Fluid Dairy in Delivery of Polyphenolic Compounds in the Diet: Chocolate Milk, Coffee Beverages, Matcha Green Tea, and Beyond.

Dairy-based functional beverages have been a growing segment as consumer demands for health foods have shifted focus from simply enhancing lifespan to protecting health. Green tea is often limited in use because of poor bioavailability and disagreeable taste. However, milk is considered an ideal platform for the delivery of active polyphenolic compounds in green tea. Furthermore, the antioxidant enzymatic activity and antioxidant index of polyphenols in green tea have been known to be protected through interaction with dairy proteins inside the unstable intestinal environment. In addition, consumption of green tea infused with milk has been found to have a significant impact on reducing skin wrinkles and roughness in elderly subjects, through a decrease in lipid peroxidation and a concomitant reduction in oxidative stress. A similar affinity has been observed between antioxidants in coffee and milk proteins. Dark chocolate has been known to contain significant phenolic content and antioxidant activity. The activation of protein complex NF-κB, which is responsible for cell survival, was found to be significantly reduced upon consumption of cocoa with water, whereas consuming cocoa with milk had no effect on the bioavailability of the phenolic compounds in cocoa. The popularity of dairy as the source for polyphenol fortified beverages in the diet will be dictated by optimization of the technology for maximizing the bioavailability of the antioxidants.

Analysis of Main and Healthy Phenolic Compounds in Foods.

Background: In the last few decades, the media has been overwhelming the consumer with various dietary requirements that some of which lead to no avail. On the other hand, the Mediterranean diet, which stems from a very ancient lore, stands as one of the most effective diets whose conspicuous and positive results are still impacting the lives of many Mediterranean locals. The "Mediterranean Diet" is an umbrella term that is used to denote a plethora of natural ingredients used in the culinary tradition of the region, and which comprises but is not limited to olive oil, cereals, wine, fruits, dried fruits, and spices. MD components are known for being rich in antioxidant compounds. Polyphenols belong to the category of antioxidants that occur in the above-mentioned Mediterranean foods. Objective: The current review aims at presenting main classes of phenols from plant foods, their role as dietary components, and an overview on analytical methods for their extraction from food matrices, their separation, detection and quantification. Conclusions: The discrimination of phenols is not an easy matter, and several methods are described in the literature, mainly chromatographic methods, which are herein reviewed. In short, phenols are mainly found in vegetable foods in which the Mediterranean Diet is rich. The health effects of some phenols and analytical methods are herein revised. Highlights: Phenols or Phenolics is a designation corresponding to compounds that have one or more hydroxyl groups attached to a 6-carbon aromatic ring. Phenols in foods occur mainly as secondary metabolites of vegetables, often found in polymeric forms (polyphenols). Phenols from foods are mainly simple phenols (e.g., caffeic acid), flavonoids, the most varied and ubiquitous class (e.g., catechin, quercetin), stilbenes (resveratrol), lignans, and tannins. In addition to the wide range of polyphenols present in foods, the compounds are quantitatively and qualitatively distributed in a heterogenous way in the different compartments of the food matrix. This structural and compartmental diversity leads to an important variability of the physicochemical properties impacting otherwise the extraction of phenols. Total phenols are determined by the Folin Cioucalteau method, as described in European Pharmacopeaea.

Food Crises and Food Safety Incidents in European Union, United States, and Maghreb Area: Current Risk Communication Strategies and New Approaches.

Globalization has created a dynamic market, which has dramatically intensified interchanges of goods and information as well as the flow of people among nations. This international phenomenon offers the consumer a choice between a wide variety of foods from diverse locations. However, there are challenges to improving food security and safety on a global scale; the major question is how food safety can be guaranteed while increasing the complexity of food supply chains. A food produced in a certain location usually contains ingredients, additives, and preservatives from different and distant origins. Although countries take several food control measures, their institutional and regulatory frameworks diverge widely, as do the definitions of food crisis, food incidents, and risk management approaches. The present review discusses some past food safety issues and lessons learned. Convergences and differences in the regulatory framework of food control agencies in different regions of the world are herein revealed. Emerging risks are also discussed, particularly the spread of antibiotic resistance in the food chain and the environment, as well as the rise of new antibiotic-resistant pathogenic strains with broader tolerance to environmental factors.

Anti-Acanthamoeba activity of Tunisian Thymus capitatus essential oil and organic extracts.

Acanthamoeba species are free-living amoebae widely distributed in the environment and which cause serious human infections. The treatment of Acanthamoeba infections is always very difficult and not constantly effective. More efficient drugs against Acanthamoeba must be developed and medicinal plants can be useful in this case. Our research focused on the examination of the anti-Acanthamoeba activity of the essential oil and the ethanolic-aqueous extract from Thymus capitatus L. The essential oil showed best activity with an IC50 of 2.73 µg/ml. The conducted Bio-guided fractionation of thyme extract result to the identification of two active compounds against the trophozoite stage of Acanthamoeba: thymol and 2,3-dihydroxy-p-cymene. The results have clearly shown that the investigated products may be successfully used against Acanthamoeba infections. These molecules that are found in plants may be an alternative for the development of new drugs.

Advanced oxidation process and biological treatments for table olive processing wastewaters: constraints and a novel approach to integrated recycling process: a review.

Table olive processing wastewaters constitute a dangerous environmental problem in the Mediterranean countries because of their large volumes, high organic matter and salt concentration. The quantity and the characteristics of wastewaters produced, and thus, their environmental impact, varied depending on the season, varieties, soil and process employed. Several chemicals, biological and combined technologies have proven effective at bringing down organic pollution and toxicity of these effluents. Advanced oxidation processes have recognized as highly efficient treatments for the degradation of organic matter. Nonetheless, complete mineralization is generally expensive without salt removal. Biological processes are the most environmentally compatible and least-expensive treatment methods, but these operations do not always provide satisfactory results. This article surveys the current available technologies and suggests an effective, cheaper alternative for the recycling and the valorization of green table olives wastewaters.

Combined effect of carnosol, rosmarinic acid and thymol on the oxidative stability of soybean oil using a simplex centroid mixture design.

BACKGROUND: Oxidation taking place during the use of oil leads to the deterioration of both nutritional and sensorial qualities. Natural antioxidants from herbs and plants are rich in phenolic compounds and could therefore be more efficient than synthetic ones in preventing lipid oxidation reactions. This study was aimed at the valorization of Tunisian aromatic plants and their active compounds as new sources of natural antioxidant preventing oil oxidation. RESULTS: Carnosol, rosmarinic acid and thymol were isolated from Rosmarinus officinalis and Thymus capitatus by column chromatography and were analyzed by nuclear magnetic resonance. Their antioxidant activities were measured by DPPH, ABTS and FRAP assays. These active compounds were added to soybean oil in different proportions using a simplex-centroid mixture design. Antioxidant activity and oxidative stability of oils were determined before and after 20 days of accelerated oxidation at 60 °C. CONCLUSION: Results showed that bioactive compounds are effective in maintaining oxidative stability of soybean oil. However, the binary interaction of rosmarinic acid and thymol caused a reduction in antioxidant activity and oxidative stability of soybean oil. Optimum conditions for maximum antioxidant activity and oxidative stability were found to be an equal ternary mixture of carnosol, rosmarinic acid and thymol. © 2016 Society of Chemical Industry.

Influence of Tunisian aromatic plants on the prevention of oxidation in soybean oil under heating and frying conditions.

The aim of this study was to improve the oxidative stability of soybean oil by using aromatic plants. Soybean oil flavored with rosemary (ROS) and soybean oil flavored with thyme (THY) were subjected to heating for 24h at 180°C. The samples were analyzed every 6h for their total polar compounds, anisidine values, oxidative stability and polyphenols content. The tocopherols content was determined and volatile compounds were also analyzed. After 24h of heating, the incorporation of these plants using a maceration process reduced the polar compounds by 69% and 71% respectively, in ROS and THY compared to the control. Until 6h of heating, the ROS kept the greatest oxidative stability. The use of the two extracts preserves approximately 50% of the total tocopherols content until 18h for the rosemary and 24h for the thyme flavored oils. Volatile compounds known for their antioxidant activity were also detected in the formulated oils. Aromatic plants added to the soybean oil improved the overall acceptability of potato crisps (p<0.05) until the fifteenth frying.

Activity of olive leaf extracts against the promastigote stage of Leishmania species and their correlation with the antioxidant activity.

Leishmaniasis is one of the neglected tropical diseases in terms of drug discovery and development. Furthermore, the chemotherapy used to treat this disease has been proved to be highly toxic and to present resistance issues. As consequent, the need for novel leishmanicidal molecules has notably increased in the recent years. In the present work an attempt was made to evaluate the antioxidant and leishmanicidal activities besides presence of compounds in leaf extracts of 5 different Tunisian olive tree varieties, used as traditional medicine in this country. The concentration of extracts needed to inhibit 50% of the parasitic growth (IC50) was estimated using different Leishmania strains. All tested extracts showed an inhibitory effect on the parasite growth with IC50 ranging from 2.130±0.023 to 71.570±4.324µg/ml, respectively for the methanolic extracts of Limouni and Zarrazi against Leishmania donovani. In fact, this activity was significantly affected by the olive cultivar and the tested Leishmania strain. Furthermore, the activities against both Leishmania tropica and major species were correlated to the total phenolic compounds. These results could suggest that olive leaf extract could carry potential new compounds for the development of novel drugs against Leishmaniasis.

Activity assessment of Tunisian olive leaf extracts against the trophozoite stage of Acanthamoeba.

The olive tree (Olea europaea, Oleaceae) has historically provided huge economic and nutritional benefits to the Mediterranean basin. In fact, olive leaf extracts have also been used by native people of this area in folk medicine to treat fever and other diseases such as malaria. Recently, several studies have focused on the extraction of high-added-value compounds from olive leaves. However, no previous studies have been developed in order to evaluate the activity of these extracts against Acanthamoeba. In the present work, olive leaf extracts from five different Tunisian varieties of olive trees (Chemlali Tataouine, Zarrazi, Toffehi, Dhokkar, and Limouni) were obtained by using three different solvents, and their activity against the trophozoite stage of Acanthamoeba castellanii Neff was screened. The IC50/96 h (50% parasite growth inhibition) was chosen as the appropriate and comparable data to give as previously described. It could be observed that the amoebicidal activity was dose dependent. Trophozoite growth was inhibited by all the tested extracts with IC50 ranging from 8.234 ± 1.703 µg/ml for the alcoholic mixture of the Dhokkar extract to 33.661 ± 1.398 µg/ml for the methanolic extract of the Toffehi variety. The activity in fact was affected especially by the tested variety and not by the solvent extraction, the Dhokkar variety being the most active one as mentioned above.

Characterization of Lactobacillus isolates from fermented olives and their bacteriocin gene profiles.

Near one hundred isolates of Lactobacillus paraplantarum, Lactobacillus pentosus and Lactobacillus plantarum from table olives were studied. Strains were genotyped by rep-PCR. Although the technique failed to differentiate some isolates at the species level, it proved a robust and easy procedure that could be useful for distinguishing between related strains of L. paraplantarum, L. pentosus and L. plantarum from a large pool of unrelated strains of these species. A PCR-based screening revealed the presence of the plantaricin encoding genes plnA, plnB, plnC, plnD, plnE/F, plnF, plnI, plnJ, plnK, plnG and plnN in most isolates of the three species. Sequences of bacteriocin genes present in L. paraplantarum and L. pentosus were homologous to L. plantarum genes. Through a discriminating analysis of the bacteriocin gene profiles, it was possible to establish a relationship between the origin of isolation and the LAB isolates, regardless of species.