Factors Affecting the Bioaccessibility and Bioavailability of Bioactive Compounds

Bioactive compounds are found in fruits, vegetables and whole grains. They include an extremely heterogeneous class of compounds (polyphenolic compounds, carotenoids, tocopherols, phytosterols and organosulfur compounds) with different chemical structures (hydrophilic or lipophilic), distribution in nature (specific to vegetable species or ubiquitous), range of concentrations both in foods and in the human body, possible site of action, effectiveness against oxidative species, and specificity and biological action.

Several factors interfere with the bioavailability of antioxidants, such as food source and chemical interactions with other phytochemicals and biomolecules present in the food include some of the factors interfering with the bioavailability of bioactive compounds. For example, fruit antioxidants are commonly mixed with different macromolecules such as carbohydrates, lipids, and proteins to form the food matrix. In plant tissue, carbohydrates are the major compounds found, mainly in free and conjugated forms.

After consumption, the nutrients that are present in a food or drink are released, absorbed into the bloodstream and transported to their target tissues. Different nutrients differ in their bioavailability, which means that they are not utilized to the same extent. Release of the nutrient from the food matrix, effects of digestive enzymes in the intestine, binding and uptake by the intestinal mucosa, transfer across the gut wall to the blood or lymphatic circulation, systemic distribution and deposition, metabolic and functional use, excretion can affect nutrient bioavailability. It is mediated by external (e.g. characteristics of the food matrix, chemical form of the nutrient etc) and consumer internal (e.g. gender, age, nutrient status and life stage) factors. The bioavailability of macronutrients (carbohydrates, proteins and fats) is usually very high, e.g. more than 90% of the amount ingested.

Read full article in my Elsevier Scitech Connect Blog.

“Olive Mill Waste” Book Presentations & Author Team Acknowledgments

After its launch five months ago, the Olive Mill Waste book is continuously raising interest among researchers, academics, students, professionals and industrial partners activated in the field.

Trying to catch up with colleagues, meet our audience as well as explain in details the key features and hints of the book, an online book presentation was organized on 4th April 2017 by ISEKI Food Association (IFA) watched live by hundreds of colleagues around the world. A recording of this book presentation can be viewed in the following video:

https://www.youtube.com/watch?v=UIRd-wUpBZo&t=10s

Authors’ Team Acknowledgments

All these activities are organized by the FWR Group and volunteering actions of experts in the field. Therefore, I would like to take this opportunity to thank all group members and authors’ team for their fruitful collaboration and high quality work in bringing together different topics and technologies in an integral and comprehensive text.

Read full article here.

Presentation of “Nutraceutical and Functional Food Components” & Author Team Acknowledgments

After its launch five months ago, the Nutraceutical and Functional Food Components book is continuously raising interest among researchers, academics, students, professionals and industrial partners activated in the field.

While trying to catch up with colleagues, meet our audience as well as explain the key features and hints in detail, we also developed an online book presentation which was organized on 22th March 2017 by ISEKI Food Association (IFA). It was watched live by hundreds of colleagues around the world and a recording of it can be viewed here.

Authors’ Team Acknowledgments

I would like to take this opportunity to thank all authors for their fruitful collaboration and high quality work in bringing together different topics, approaches and strategies in an integral and comprehensive text. Some information about their background, expertise and contribution can be seen here.

Is Olive a Medicine?

                                                                   Photo Source: Pixabay

Olive oil, the production of olive fruit extraction, is the pillar of Mediterranean diet and its consumption is well known to provide multiple benefits to our health (e.g. for the cardiovascular system). Olive oil is nowadays highlighted and marketed as a “superfood” for human health not only due to its lipid profile (e.g. high oleic acid and low saturates), but also due to its high content in micronutrients such as squalene and polyphenols. The latter powerful antioxidants are in many cases advertised almost as an “elixir” that promise to relieve us against multiple diseases and health problems. Which of these advertised health claims have a scientific basis and how many of them are promises or just guesses?

Over the last two decades, olive oil has concentrated scientific attention not only in the Mediterranean area, but all around the world due to its beneficial effects in human health. This trend is mainly driven by its content in polyphenols. Hydroxytyrosol, tyrosol, oleuropein, eleocanthal, oleacein and other polyphenols with exotic names may not being well known to general public yet, but they already appear in the product labels in the shelves of supermarkets and pharmacies, promising to provide multiple benefits to consumers.

Polyphenols pass from the olive tree to olive fruit, olive oil and olive processing by-products (olive tree leaves and olive mill wastewater). Recent biochemical, pharmacological and other studies have shown that polyphenols possess strong radical scavenging capacities and can play an important role in protecting against oxidative damages and cellular aging. By far the most investigated olive oil polyphenol is hydroxytyrosol. Studies have been conducted in both cells and animals, whereas its antioxidant effect is nowadays taken for granted. Besides, hydroxytyrosol is currently in early clinical trials as a dietary supplement for patients with multiple sclerosis and as a measure preventing breast cancer in women with a relevant genetic predisposition. Oleuropein, which is mainly contained in the olive tree leaves, has also been investigated a lot. Oleocanthal, a tyrosol derivative whose ant-inflammatory role found similar to that of the drug ibuprofen in 2005, have also shown important bioactivities (e.g. against Alzheimer’s disease, several cancers etc), although most studies have been performed in cells and few of them in animals; thus it has not yet been fully evaluated.

Despite the so far promising results, the main weakness for these investigations is that their outcomes are to a great extent not systematically addressed. Olive oil is an extremely complex mixture of ingredients and thus it is not clear if findings based on experiments conducted with free compounds (e.g. hydroxytytorosol and oleuropein that exist in minute quantities in olive oil) can be extended to actual major constituents and olive oil (a natural product with great variability in composition). The problem of the levels of individual bioactive compounds in olive oil and the possible combined effects of various classes of bioactive compounds have not yet answered. In addition, the vast majority of the available studies have so far been conducted either in vitro or in vivo. Very few of them have been performed to reliable clinical trials in humans. The latter constitute the necessary test to prove the efficacy and safety of a component.

Read full article in my Elsevier SciTech Connect Blog.

What is the Difference Between Bioavailability Bioaccessibility and Bioactivity of Food Components?

The preparation of foods fortified with functional components requires integration of diverse aspects under evaluation. These include selecting of the appropriate source, detecting the bioactive compounds, applying separation and recovery techniques, performing toxicological assessments and finally making stability, activity and bioaccessibility measurements. At this point, it is important to define carefully the terms “bioavailability”, “bioaccessibility” and “bioactivity” (Figure 1) that are often used indistinctly to express similar functions.

Bioavailability includes gastrointestinal (GI) digestion, absorption, metabolism, tissue distribution, and bioactivity.  However, it has several meanings depending on the research area used to. For instance, from a pharmacological point of view, bioavailability is the rate and extent to which the therapeutic moiety is absorbed and becomes available at the drug action site. From the nutritional point of view (that is of particular interest in the current book), bioavailability refers to the fraction of the nutrient that is stored or being available in physiological functions. It is a key term for nutritional effectiveness, as not all the amounts of bioactive compounds are used effectively by the organism. For example, when different foods come in contact with the mouth or digestive tract, various interactions may take place affecting phytochemical bioavailability (e.g. fat enhances quercetine bioavailabilty in meals). Therefore, bioavailability expresses the fraction of ingested nutrient or bioactive compound that reaches the systemic circulation and ultimately utilized.

Before becoming bioavailable, bioactive compounds must be released from the food matrix and modified in the GI tract. Thus, bioavailability includes the term bioaccessibility. Indeed, it is important to analyze whether the digestion process affects bioactive compounds and their stability, before concluding on any potential health effect. Bioaccessibility is defined as the quantity of a compound that is released from its matrix in the gastrointestinal tract, becoming available for absorption (e.g. enters the blood stream). This term includes digestive transformations of foods into material ready for assimilation, the absorption/assimilation into intestinal epithelium cells as well as the presystemic, intestinal and hepatic metabolism. However, beneficial effects of unabsorbed nutrients such as calcium binding of bile salts in the tract are missed by definitions based on absorption. Bioaccessibility is usually evaluated by in vitro digestion procedures, generally simulating gastric and small intestinal digestion, sometimes followed by Caco-2 cells uptake.

Read full article in my SciTech Connect Blog.

Nutraceuticals and Functional Components in Nutrition and Food Products

Foods contain major and minor components as well as bioactive compounds (e.g. antioxidants, peptides, carbohydrates, lipids, glucosinolates) that are of primary importance for human nutrition. Consequently, their importance has initiated a surge of research and product development in the food industry. In order to adapt to these consumer drivers and enhance the physiological functionality of inherent nutrients, the food industry is developing the so-called “functional foods”.

The latest term was born in Japan. Indeed, Japanese were the first to observe that food could have a role beyond gastronomic pleasure and nutrient supply to the human organism. Japan is the first country to legislate these products in the FOSHU (Foods of Specified Health Use) legislation, whereas it has the highest number of functional foods on the market. Europe and the American countries incorporated later this concept.

The American Dietetic Association (ADA) classified in 2004 all food as functional at some physiological level, pointing out that “the term functional food should not be used to imply that there are good and bad foods“. In addition, it denotes that “all food can be incorporated into a healthful eating plan ─ the key being moderation and variety“. Whole foods like fruits and vegetables represent the simplest example of functional foods since they are rich in bioactive compounds that protect body’s cells against oxidative damage and reduce the risk of developing certain cancers.

Read full article in my SciTech Connect Blog.

How do Emerging Processing Technologies Affect Nutraceuticals and Functional Food Components?

Foods contain major and minor components as well as bioactive compounds that are of primary importance for human nutrition. The importance of these compounds accelerated the development of innovations in the food industry, generating the so-called “functional foods” and “nutraceuticals“. Whole foods like fruits and vegetables represent the simplest example of functional foods, as they are rich in bioactive compounds and have a well-established protective role against the development of diseases.

Nutraceuticals represent any substance that provides medical or health benefits, including the prevention and treatment of diseases. Contrarily to functional foods, nutraceuticals are commodities derived from foods used in the medicinal form of pills or capsules. The preparation of foods fortified with functional components requires integration of diverse aspects under evaluation. These include for instance separation techniques, toxicological assessments, stability and activity tests.

On the other hand, processing has an impact on the final food products. Applied technologies may influence the content and effectiveness of nutrients, e.g. loss of bioactive compounds or diminution of their functionality typically increases more and more as foods are processed, stored and transported.

Novel, non-thermal technologies (e.g. ultrasounds, high-hydrostatic pressure, pulsed electric field, high voltage electrical discharge, cold plasma) promise to treat foods without destroying the nutritional components and sensorial characteristics that are normally affected during heat treatment. The latest techniques are today applied in both research institutes and food industries, promising to shorten processing times, control Maillard reactions, improve products’ quality and enhance functionality. The implementation of these technologies together with other trends and practices of the food industry (e.g. nanoencapsulation, food waste recovery, emerging need for innovations etc.) have brought new developments, data and state of the art in the field.

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