Extraction and analysis of polyphenols: recent trends

In recent years, there has been an increasing interest in diets rich in fruits and vegetables and this is mostly due to their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. This is mainly due to the presence of bioactive compounds, such as polyphenols, carotenoids, among others. Polyphenols are one of the main classes of secondary metabolites derived from plants offering several health benefits resulting in their use as functional foods. Prior to the use of these polyphenols in specific applications, such as food, pharmaceutical, and the cosmetic industries, they need to be extracted from the natural matrices, then analyzed and characterized. The development of an efficient procedure for the extraction, proper analysis, and characterization of phenolic compounds from different sources is a challenging task due to the structural diversity of phenolic compounds, a complex matrix, and their interaction with other cellular components. In this light, this review discusses different methods of extraction, analysis, and the structural characterization of polyphenolic compounds.     

Arbuscular mycorrhizal fungi affect glucosinolate and mineral element composition in leaves of Moringa oleifera

Moringa is a mycorrhizal crop cultivated in the tropics and subtropics and appreciated for its nutritive and health-promoting value. As well as improving plant mineral nutrition, arbuscular mycorrhizal fungi (AMF) can affect plant synthesis of compounds bioactive against chronic diseases in humans. Rhizophagus intraradices and Funneliformis mosseae were used in a full factorial experiment to investigate the impact of AMF on the accumulation of glucosinolates, flavonoids, phenolic acids, carotenoids, and mineral elements in moringa leaves. Levels of glucosinolates were enhanced, flavonoids and phenolic acids were not affected, levels of carotenoids (including provitamin A) were species-specifically reduced, and mineral elements were affected differently, with only Cu and Zn being increased by the AMF. This study presents novel results on AMF effects on glucosinolates in leaves and supports conclusions that the impacts of these fungi on microelement concentrations in edible plants are species dependent. The nonspecific positive effects on glucosinolates and the species-specific negative effects on carotenoids encourage research on other AMF species to achieve general benefits on bioactive compounds in moringa.     

Plants Probiotics as a Tool to Produce Highly Functional Fruits: The Case of Phyllobacterium and Vitamin C in Strawberries

The increasing interest in the preservation of the environment and the health of consumers is changing production methods and food consumption habits. Functional foods are increasingly demanded by consumers because they contain bioactive compounds involved in health protection. In this sense biofertilization using plant probiotics is a reliable alternative to the use of chemical fertilizers, but there are few studies about the effects of plant probiotics on the yield of functional fruits and, especially, on the content of bioactive compounds. In the present work we reported that a strain of genus Phyllobacterium able to produce biofilms and to colonize strawberry roots is able to increase the yield and quality of strawberry plants. In addition, the fruits from plants inoculated with this strain have significantly higher content in vitamin C, one of the most interesting bioactive compounds in strawberries. Therefore the use of selected plant probiotics benefits the environment and human health without agronomical losses, allowing the production of highly functional foods.     

Nutraceuticals: facts and fiction

Epidemiological studies show a link between the consumption of plant-derived foods and a range of health benefits. These benefits have been associated, at least partially, to some of the phytochemical constituents, and, in particular, to polyphenols. In the last few years, nutraceuticals have appeared in the market. These are pharmaceutical forms (pills, powders, capsules, vials, etc.) containing food bioactive compounds as active principles. The bioactive phytochemicals have become a very significant source for nutraceutical ingredients. Scientific research supports the biological activity of many of these food phytochemicals, but the health claims attributed to the final marketed nutraceutical products have often little or doubtful scientific foundation. This is due to the fact that a lot of the scientific evidence is derived from animal testing and in vitro assays, whereas human clinical trials are scarce and inconclusive. Some key issues such as bioavailability, metabolism, dose/response and toxicity of these food bioactive compounds or the nutraceuticals themselves have not been well established yet. Amongst the phytochemicals, several groups of polyphenols (anthocyanins, proanthocyanidins, flavanones, isoflavones, resveratrol and ellagic acid) are currently used in the nutraceutical industry. In this report, we have reviewed the most recent scientific knowledge on the bioavailability and biological activity of these polyphenols ('fact'), as well as the health claims (which are not always supported by scientific studies) ascribed to the polyphenols-containing nutraceuticals ('fiction'). The in vitro antioxidant capacity, often used as a claim, can be irrelevant in terms of in vivo antioxidant effects. Bioavailability, metabolism, and tissue distribution of these polyphenols in humans are key factors that need to be clearly established in association to the biological effects of these polyphenols-containing nutraceuticals. The future trends of phytochemistry research regarding nutraceuticals are discussed.     

Effect of domestic processing on bioactive compounds

Nowadays, most of the consumed foods are rarely ready for direct consumption. Food can be purchased at the local supermarket as fresh raw product such as meat, fruit, fish etc. or as manufactured product after an industrial processing (canned meat, dried fish, packed fruit etc.). But later on, both food types are usually submitted to culinary treatments which will transform the selected food into a cooked dish ready to eat. Domestic methods of food processing have been developed over the centuries to make the final product more attractive in flavour, appearance, taste and consistency. But, until the last centuries, none of the gourmets realize that at the same time, the cooking process was making their foods more digestible, microbiologically safer and more or less nutritive depending on the selected cooking technology. Besides consumer preferences, the selected cooking method is an important factor affecting not only the food chemical composition, but also the intake of bioactive compounds under normal dietary conditions. Therefore, in this work, the different culinary treatments and domestic cooking methods will be compared to define the optimal process to reduce the degradation of biologically active metabolites present in foods commonly consumed as an elaborated dish. Compounds such as carotenoids, glucosinolates, flavonoids and other phenolic compounds, ω-3 fatty acids, tocopherols, phytosterols, etc. have been pointed as bioactive compounds beneficial for human health. Apparently, they are able to prevent cardiovascular diseases (CVD), tumour formation, hiper-cholesterolemia in blood and other deleterious disorders. An adequate domestic practice might help to increase in taking of those functional molecules enhancing their functionality and reducing the risk of chronic diseases.     

Functional relevance and health benefits of soymilk fermented by lactic acid bacteria

The growing interest of consumers towards nutritionally enriched, and health promoting foods, provoke interest in the eventual development of fermented functional foods. Soymilk is a growing trend that can serve as a low-cost non-dairy alternative with improved functional and nutritional properties. Soymilk acts as a good nutrition media for the growth and proliferation of the micro-organism as well as for their bioactivities. The bioactive compounds produced by fermentation of soymilk with lactic acid bacteria (LAB) exhibit enhanced nutritional values, and several improved health benefits including antihypertensive, antioxidant, antidiabetic, anticancer and hypocholesterolaemic effects. The fermented soymilk is acquiring a significant position in the functional food industry due to its increased techno-functional qualities as well as ensuring the survivability of probiotic bacteria producing diverse metabolites. This review covers the important benefits conferred by the consumption of soymilk fermented by LAB producing bioactive compounds. It provides a holistic approach to obtain existing knowledge on the biofunctional attributes of fermented soymilk, with a focus on the functionality of soymilk fermented by LAB.     

Review: Chestnut and quebracho tannins in pig nutrition: the effects on performance and intestinal health

Natural extracts are frequently adopted as a valuable alternative to antibiotics in intensive animal farming. Their diverse bioactive constituents such as phytosterols, glucosinolates, carotenoids and polyphenols have shown antioxidant, anti-inflammatory and antibacterial effects. Tannins are the largest class of polyphenol compounds of plant extracts, which can be classified into two hydrolysable or condensed subgroups. Poultry and swine nutrition are the most important sectors in which tannins have been used, firstly adopting tannin-rich feedstuffs and more recently, using tannin extracts from different plants. Several commercial products are available containing tannins extracted from the European chestnut tree (Castanea sativa Mill.) and the American quebracho (Schinopsis spp.). Tannins extracted from these plants have been applied on intensive swine farms due to their ability to improve animal performance and health. These positive and prominent effects are frequently associated with the antinutritional effects in reducing feed palatability, digestibility and protein utilization of feed. Some criticisms and contrasting results regarding pig performance and intestinal health have been reported. This paper provides an overview of the effects of chestnut and quebracho tannins on growth performance and intestinal health of pigs in order to clarify the appropriate dosage and response in the various physiological stages.     

Sorghum: Nutritional Factors,Bioactive Compounds,Pharmaceutical and Application in Food Systems: A Review

After wheat, rice, maize, and barley, sorghum is the fifth most widely grown cereal on the planet. Due to its high production, drought resistance, and heat tolerance, this crop is replacing maize in some areas. Sorghum is available in a variety of colors, including cream, lemon-yellow, red, and even black. The principal grain anatomical components are pericarp, germ or embryo and endosperm. This review provides an overview of key sorghum grain components, including starches, fiber, proteins, lipids, and vitamins. Also, we summarized phenolic compounds, flavonoids, tannins, carotenoids, vitamin E, amines, Policosanols and Phytosterols in sorghum grains. Sorghum is used to manufacture bread and porridge, and it provides a significant source of energy and nutrition for humans; sorghum is extensively farmed for animal feed. However, because the natural components in sorghum are useful in the development of healthy and functional foods, sorghum farming for both biofuel production and human consumption is gaining popularity. Pigmented sorghum grain is high in antioxidants such as polyphenols, primarily tannins, which have a variety of health benefits, including antiproliferative properties linked to the prevention of certain cancers, antioxidant activities linked to the prevention of diseases linked to oxidative stress, and anti-inflammatory effects, as well as improving glucose metabolism. Because these chemicals cannot be assimilated, their application in the food business has been limited, as sorghum is regarded as a lownutritional grain due to the presence of anti-nutritional components such as strong tannins, which form complexes with proteins and iron, limiting their digestibility. This review aims to show the utilization of sorghum as a source of bioactive chemicals and the value they bestow on human health due to the general biological potential it possesses.     

Putting microbes to work: dairy fermentation, cell factories and bioactive peptides. Part II: bioactive peptide functions

A variety of milk-derived biologically active peptides have been shown to exert both functional and physiological roles in vitro and in vivo, and because of this are of particular interest for food science and nutrition applications. Biological activities associated with such peptides include immunomodulatory, antibacterial, anti-hypertensive and opioid-like properties. Milk proteins are recognized as a primary source of bioactive peptides, which can be encrypted within the amino acid sequence of dairy proteins, requiring proteolysis for release and activation. Fermentation of milk proteins using the proteolytic systems of lactic acid bacteria is an attractive approach for generation of functional foods enriched in bioactive peptides given the low cost and positive nutritional image associated with fermented milk drinks and yoghurt. In Part II of this review, we focus on examples of milk-derived bioactive peptides and their associated health benefits, to illustrate the potential of this area for the design and improvement of future functional foods.     

Integrated Text Mining and Chemoinformatics Analysis Associates Diet to Health Benefit at Molecular Level

Awareness that disease susceptibility is not only dependent on genetic make up, but can be affected by lifestyle decisions, has brought more attention to the role of diet. However, food is often treated as a black box, or the focus is limited to few, well-studied compounds, such as polyphenols, lipids and nutrients. In this work, we applied text mining and Naïve Bayes classification to assemble the knowledge space of food-phytochemical and food-disease associations, where we distinguish between disease prevention/amelioration and disease progression. We subsequently searched for frequently occurring phytochemical-disease pairs and we identified 20,654 phytochemicals from 16,102 plants associated to 1,592 human disease phenotypes. We selected colon cancer as a case study and analyzed our results in three directions; i) one stop legacy knowledge-shop for the effect of food on disease, ii) discovery of novel bioactive compounds with drug-like properties, and iii) discovery of novel health benefits from foods. This works represents a systematized approach to the association of food with health effect, and provides the phytochemical layer of information for nutritional systems biology research.     

Solid Lipid Nanoparticles as Delivery Systems for Bioactive Food Components

The inclusion of bioactive compounds, such as carotenoids, omega-3 fatty acids, or phytosterols, is an essential requisite for the production of functional foods designed to improve the long-term health and well-being of consumers worldwide. To incorporate these functional components successfully in a food system, structurally sophisticated encapsulation matrices have to be engineered, which provide maximal physical stability, protect ingredients against chemical degradation, and allow for precise control over the release of encapsulated components during mastication and digestion to maximize adsorption. A novel encapsulation system initially developed in the pharmaceutical industries to deliver lipophilic bioactive compounds is solid lipid nanoparticles (SLN). SLN consist of crystallized nanoemulsions with the dispersed phase being composed of a solid carrier lipid–bioactive ingredient mixture. Contrary to larger colloidal solid lipid particles, specific crystal structures can be “dialed-in” in SLN by using specific surfactant mixtures and ensuring that mean particle sizes are below 100–200 nm. Moreover, in SLN, microphase separations of the bioactive compound from the solidifying lipid matrix can be prevented resulting in an even dispersion of the encapsulated compound in the solid matrix thereby improving chemical and physical stability of the bioactive. In this review article, we will briefly introduce the structure, properties, stability, and manufacturing of solid lipid particles and discuss their emerging use in food science.     

Encapsulation systems for the delivery of hydrophilic nutraceuticals: Food application

Increased health risk associated with the sedentary life style is forcing the food manufacturers to look for food products with specific or general health benefits e.g. beverages enriched with nutraceuticals like catechin, curcumin rutin. Compounds like polyphenols, flavonoids, vitamins are the good choice of bioactive compounds that can be used to fortify the food products to enhance their functionality. However due to low stability and bioavailability of these bioactives (both hydrophobic and hydrophilic) within the heterogeneous food microstructure and in the Gastro Intestinal Tract (GIT), it becomes extremely difficult to pass on the real health benefits to the consumers.Recent developments in the application of nano-delivery systems for food product development is proving to be a game changer which has raised the expectations of the researchers, food manufacturers and consumers regarding possibility of enhancing the functionality of bioactives within the fortified food products. In this direction, nano/micro delivery systems using lipids, surfactants and other materials (carbohydrates, polymers, complexes, protein) have been fabricated to stabilize and enhance the biological activity of the bioactive compounds.In the present review, current status of the various delivery systems that are used for the delivery of hydrophilic bioactives and future prospects for using other delivery systems that have been not completely explored for the delivery of hydrophilic bioactives e.g. niosomes; bilosomes, cubosomes are discussed.     

Phenolic phytochemicals and bone

Concerning the prevention of osteoporosis, recognized as a major public health problem, nutrition may appear as an alternative strategy for optimizing health skeleton. The importance of adequate calcium and vitamin D intakes for bone health is now well documented. But, in addition to essential macro- and micronutrients, human diet contains a complex array of non-nutrient natural bioactive molecules, namely the phytochemicals that may act and protect bone. Among phytochemicals, emphasis has been so far placed upon polyphenols. Indeed, subsequent epidemiological studies have suggested associations between long-term consumption of diets rich in polyphenols and protection against chronic diseases. With respect to human health, flavonoids are the most extensively studied polyphenols. These compounds may be partly responsible for some of the positive links found between fruit and vegetables intake and higher bone mineral density in adults and children. However, no long-term intervention studies in humans have investigated the effect of specific phenolic phytochemicals on the prevention of bone loss in postmenopausal women, except for phytoestrogens (soy isoflavones, lignans). Besides, in animal models of postmenopausal osteoporosis, consumption of some dietary flavonoids has been shown to prevent ovariectomy-induced bone loss. Finally, few in vitro experiments with bone cells have reported cellular and molecular mechanisms of phytochemicals involved in bone metabolism. To date, investigations providing some evidence of a positive impact of some phytochemicals on bone metabolism are accumulating but further studies, notably clinical trials, are needed to explore the various bioactivities offered by such compounds. Anyway, it can be postulated that increased consumption of plant-derived foods, especially fruit and vegetables, may be positive in the prevention of osteoporosis.     

Functional relationship of vegetable colors and bioactive compounds: Implications in human health

Vegetables are essential protective diet ingredients that supply ample amounts of minerals, vitamins, carbohydrates, proteins, dietary fiber, and various nutraceutical compounds for protection against various disease conditions. Color is the most important quality parameter for the farmers to access the harvest maturity while for the consumer's reliable indices to define acceptability or rejection. The colored vegetables contain functional compounds like chlorophylls, carotenoids, betalains, anthocyanins, etc. well recognized for their antioxidant, antimicrobial, hypolipidemic, neuroprotective, antiaging, diuretic, and antidiabetic properties. Recently, there has been a shift in food consumption patterns from processed to semi-processed or fresh fruits and vegetables to ensure a healthy disease-free life. This shifted the focus of agriculture scientists and food processors from food security to nutrition security. This has resulted in recent improvements to existing crops like blue tomato, orange cauliflower, colored and/or black carrots, with improved color, and thus enriched bioactive compounds. Exhaustive laboratory trials though are required to document and establish their minimum effective concentrations, bioavailability, and specific health benefits. Efforts should also be directed to breed color-rich cultivars or to improve the existing varieties through conventional and molecular breeding approaches. The present review has been devoted to a better understanding of vegetable colors with specific health benefits and to provide in-hand information about the effect of specific pigment on body organs, the effect of processing on their bioavailability, and recent improvements in colors to ensure a healthy lifestyle.     

Improving the oral bioavailability of beneficial polyphenols through designed synergies

A substantial and growing consumer demand exists for plant-based functional foods that improve general health and wellbeing. Amongst consumed phytochemicals, the polyphenolic compounds tend to be the most bioactive. Many commonly consumed polyphenols have been shown to have specific and potent health-promoting activities when assessed by high-throughput in vitro assays and when administered to experimental animals by injection. However, very few have been shown to have any beneficial effects in animals or man when orally consumed, because of the poor bioavailability exhibited by most polyphenols following the ingestion. Consumed polyphenols, like most pharmaceuticals, are regarded as xenobiotics by the body and must overcome many barriers, including extensive enzymatic and chemical modification during digestion and absorption, to reach their site(s) of action. This is especially true for polyphenols targeting the brain, which is protected by the tightly regulated blood–brain barrier. Interestingly, many polyphenols are also known to specifically modify some of the metabolic and transport processes that govern bioavailability. Therefore, the opportunity exists to increase the bioactivity of beneficial polyphenols by designing specific synergistic interactions with polyphenols that improve their oral bioavailability. This hypothesis and review paper will discuss some of the endogenous systems that limit the bioavailability of ingested polyphenols to the body and the brain, and the means by which bioavailability may be improved by specifically designing synergies between orally consumed polyphenols.     

Floral Pollen Bioactive Properties and Their Synergy in Honeybee Pollen

Honeybee pollen (HBP) is a mixture of floral pollen collected by honeybees near the hive. It is characterized by a composition rich in phenolic compounds, carotenoids and vitamins that act as free radicals scavengers, conferring antioxidant and antibacterial capacity to the matrix. These bioactive properties are related to the botanical origin of the honeybee pollen. Honeybee pollen samples were collected from different geographical locations in central Chile, and their total carotenoid content, polyphenols profile by HPLC/MS/MS, DPPH radical scavenging capacity, and antimicrobial capacity against S. pyogenes, E. coli, S. aureus, and P. auriginosa strains were evaluated. Our results showed a good carotenoids content and polyphenols composition, while antioxidant capacity presented values between 0–95 % for the scavenging effect related to the botanical origin of the samples. Inhibition diameter for the different strains presented less variability among the samples, Furthermore, binary mixtures representing the two most abundant species in each HBP were prepared to assess the synergy effect of the floral pollen (FP) present in the samples. Data shows an antagonist effect was observed when assessing the carotenoid content, and a synergy effect often presents for antimicrobial and antioxidant capacity for bee pollen samples. The bioactive capacities of the honeybee pollen and their synergy effect could apply to develop new functional ingredients for the food industry.     

Flesh Color Diversity of Sweet Potato: An Overview of the Composition,Functions, Biosynthesis,and Gene Regulation of the Major Pigments

Sweet potato is a multifunctional root crop and a source of food with many essential nutrients and bioactive compounds. Variations in the flesh color of the diverse sweet potato varieties are attributed to the different phytochemicals and natural pigments they produce. Among them, carotenoids and anthocyanins are the main pigments known for their antioxidant properties which provide a host of health benefits, hence, regarded as a major component of the human diet. In this review, we provide an overview of the major pigments in sweet potato with much emphasis on their biosynthesis, functions, and regulatory control. Moreover, current findings on the molecular mechanisms underlying the biosynthesis and accumulation of carotenoids and anthocyanins in sweet potato are discussed. Insights into the composition, biosynthesis, and regulatory control of these major pigments will further advance the biofortification of sweet potato and provide a reference for breeding carotenoid- and anthocyanin-rich varieties.     

Functional genomics of UV radiation responses in human cells

Functional foods are "foods and beverages with claimed health benefits based on scientific evidence". Health claims need to be substantiated scientifically. The future of functional foods will heavily rely on proven efficacy in well-controlled intervention studies with human volunteers. In order to have the maximum output of human trials, improvements are needed with respect to study design and optimization of study protocols. Efficacy at realistic intake levels needs to be established in studies with humans via the use of suitable biomarkers, unless the endpoint can be measured directly. The human body is able to deal with chemical entities irrespective of their origin, and the pharmaceutical terms "absorption, distribution, metabolism and excretion" have their equivalent when biomarkers are concerned. Whereas only "diurnal variation" or "circadian rhythm" is sometimes considered, little attention is paid to "kinetics of biomarkers". "Kinetics of biomarkers" comprises "formation, distribution, metabolism and excretion". However, this is at present neither an established science nor common practice in nutrition research on functional foods. As a consequence, sampling times and matrices, for example, are chosen on the basis of historical practice and convenience (for volunteers and scientists) but not on the basis of in depth insight. The concept of kinetics of biomarkers is illustrated by a variety of readily comprehensible examples, such as malaria, cholesterol, polyphenols, glutathione-S-transferase alpha, F2-isoprostanes, interleukin-6, and plasma triacylglycerides.     

Preventive and therapeutic aspects of fermented foods

In recent times, the status of some fermented foods which are considered as functional foods that confer health benefits in certain disease conditions has grown rapidly. The health benefits of fermented foods are due to the presence of probiotic microbes and the bioactive compounds formed during fermentation. Microbes involved and metabolites produced by them are highly species specific and contribute to the authenticity of the fermented foods. Several studies pertaining to the effect of fermented foods on various disease conditions have been conducted in recent years using both animal models and clinical trials on humans. This review focuses on the impact of fermented foods on conditions such as diabetes, cardiovascular disease, obesity, gastrointestinal disorder, cancer and neurodegenerative disorders.