Prebiotics and lipid metabolism.

Prebiotics are defined as nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth or the activity of one or a limited number of bacteria (bifidobacteria, lactobacilli) in the colon. Dietary fructans are nutritionally interesting oligosaccharides that strictly conform to the definition of prebiotics and (in view of experimental studies in animals and of less numerous studies in humans) exhibit interesting serum or hepatic lipid lowering properties. Other nondigestible/fermentable nutrients, which also modulate intestinal flora activity, exhibit cholesterol or triglyceride lowering effects. Are changes in intestinal bacterial flora composition or fermentation activity responsible for those effects? What is the future of prebiotics in the nutritional control of lipidaemia and cardiovascular disease risk in humans? Those questions only receive partial response in the present review because studies of the systemic effects of prebiotics are still in their infancy, and require fundamental research devoted to elucidating the biochemical and physiological events that allow prebiotics to exert systemic effects on lipid metabolism.     

Prebiotics in foods

A wealth of information has been gathered over the past 15 years on prebiotics through experimental, animal and human studies, with the aim to understand the mechanism of actions and elucidate their beneficial health effects to the human host. Significant amount of evidence exists for their ability to increase the bioavailability of minerals and stimulate the immune system, although there is less clear evidence so far for their prophylactic or therapeutic role in gastrointestinal infections. Moreover, the effect of the food delivery vehicle on the efficacy of prebiotics is an area that has been hardly investigated. Besides their beneficial effects, prebiotics influence the textural and organoleptic properties of the food products, such as dairy and baked products. To do this however, they need to be stable during food processing, in particular under conditions of high temperature and low pH.     

Prebiotics and synbiotics: towards the next generation

Recent research in the area of prebiotic oligosaccharides and synbiotic combinations with probiotics is leading towards a more targeted development of functional food ingredients. Improved molecular techniques for analysis of the gut microflora, new manufacturing biotechnologies, and increased understanding of the metabolism of oligosaccharides by probiotics are facilitating development. Such developments are leading us to the time when we will be able to rationally develop prebiotics and synbiotics for specific functional properties and health outcomes.     

Prebiotics and calcium bioavailability

A prebiotic substance has been defined as a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon. Therefore, compared to probiotics, which introduce exogenous bacteria into the colonic microflora, a prebiotic aims at stimulating the growth of one or a limited number of the potentially health-promoting indigenous micro-organisms, thus modulating the composition of the natural ecosystem. In recent years, increasing attention has been focussed on the possible beneficial effects of prebiotics, such as enhanced resistance to invading pathogens, improved bowel function, anti-colon cancer properties, lipid lowering action, improved calcium bioavailability, amongst others. The objective of this review is to critically assess the available data on the effects of prebiotics on calcium bioavailability, and place it in the context of human physiology and, when possible, explain the underlying cellular and molecular mechanisms. The review will also try to highlight future areas of research that may help in the evaluation of prebiotics as potential ingredients for functional foods aimed at enhancing calcium bioavailability and protecting against osteoporosis.     

Bacterial,SCFA and gas profiles of a range of food ingredients following in vitro fermentation by human colonic microbiota

It is now apparent that there is a strong link between health and nutrition and this can be seen clearly when we talk of obesity. The food industry is trying to capitalise on this by adapting high sugar/fat foods to become healthier alternatives. In confectionery food ingredients can be used for a range of purposes including sucrose replacement. Many of these ingredients may also evade digestion in the upper gut and be fermented by the gut microbiota upon entering the colon. This study was designed to screen a range of ingredients and their activities on the gut microbiota. In this study we screened a range of these ingredients in triplicate batch culture fermentations with known prebiotics as controls. Changes in bacteriology were monitored using FISH. SCFA were measured by GC and gas production was assessed during anaerobic batch fermentations. Bacterial enumeration showed significant increases (P ≤ 0.05) in bifidobacteria and lactobacilli with polydextrose and most polyols with no significant increases in Clostridium histolyticum/perfringens. SCFA and gas formation indicated that the substrates added to the fermenters were being utilised by the gut microbiota. It therefore appears these ingredients exert some prebiotic activity in vitro. Further studies, particularly in human volunteers, are necessary.     

Application of Microencapsulated Synbiotics in Fruit-Based Beverages

In the last years, demand for functional products containing both prebiotics and probiotics (known as synbiotic) has increased, which stimulated their incorporation into other food matrices than milk-based ones. Synbiotics improve gut functionality as well as respond to the increasing demand of consumers who have become aware of the health benefits of a proper diet. The most important criterion for preserving consumer acceptance in such products is maintaining the minimum viability and activity of probiotics from the beginning of production to the end of shelf-life. For their viability, fixation and multiplying within the host, several solutions have been proposed including the fortification with prebiotics and microencapsulation of prebiotics along with probiotics. The challenge of microencapsulation is to protect the probiotic cells in foods that are not usually considered their vehicle, such as fruit matrices. It is generally known that different prebiotics may exert different degrees of protection on the entrapped bacteria cells. For food products, such as fruit beverages, few works exist that investigate the functionality of synbiotic microcapsules in protecting the survivability of probiotic cells during processing and storage. This article provides an overview of this novel trend based on a review of relevant literature. The article summarizes the synbiotic concept, challenges for synbiotic formulation in fruit beverages, and future perspectives.

     

The potential of microalgae and their biopolymers as structuring ingredients in food: A review

Microalgae are considered promising functional food ingredients due to their balanced composition, containing multiple nutritional and health-beneficial components. However, their functionality in food products is not limited to health aspects, since microalgae can also play a structuring role in food, for instance as a texturizing ingredient. Photoautotrophic microalgae are actually rich in structural biopolymers such as proteins, storage polysaccharides, and cell wall related polysaccharides, and their presence might possibly alter the rheological properties of the enriched food product. A first approach to benefit from these structural biopolymers consists of isolating the cell wall related polysaccharides for use as food hydrocolloids. The potential of extracted cell wall polysaccharides as food hydrocolloids has only been shown for a few microalgae species, mainly due to an enormous diversity in molecular structure and composition. Nevertheless, with intrinsic viscosities comparable or higher than those of commercial thickening agents, extracellular polysaccharides of red microalgae and cyanobacteria could be a promising source of novel food hydrocolloids. A more sustainable approach would be to incorporate the whole microalgal biomass into food products, to combine health benefits with potential structuring benefits, i.e. providing desired rheological properties of the enriched food product. If microalgal biomass would act as a thickening agent, this would actually reduce the need for additional texturizing ingredients. Even though only limitedly studied so far, food processing operations have been proven successful in establishing desired microstructural and rheological properties. In fact, the use of cell disruption techniques allows the release of intracellular compounds, which become available to create strong particle aggregates resulting in an improved viscosity and network structure. Food processing operations might not only be favorable in terms of rheological properties, but also for enhancing the bioaccessibility of several bioactive compounds. However, this research area is only very scarcely explored, and there is a demand for more standardized research studies to draw conclusions on the effect of processing on the nutritional quality of food products enriched with microalgae. Even though considered as promising food ingredients, some major scientific challenges have been pointed out throughout this review paper for the successful design of microalgal based food products.     

Analysis of Food Pairing in Regional Cuisines of India

Any national cuisine is a sum total of its variety of regional cuisines, which are the cultural and historical identifiers of their respective regions. India is home to a number of regional cuisines that showcase its culinary diversity. Here, we study recipes from eight different regional cuisines of India spanning various geographies and climates. We investigate the phenomenon of food pairing which examines compatibility of two ingredients in a recipe in terms of their shared flavor compounds. Food pairing was enumerated at the level of cuisine, recipes as well as ingredient pairs by quantifying flavor sharing between pairs of ingredients. Our results indicate that each regional cuisine follows negative food pairing pattern; more the extent of flavor sharing between two ingredients, lesser their co-occurrence in that cuisine. We find that frequency of ingredient usage is central in rendering the characteristic food pairing in each of these cuisines. Spice and dairy emerged as the most significant ingredient classes responsible for the biased pattern of food pairing. Interestingly while individual spices contribute to negative food pairing, dairy products on the other hand tend to deviate food pairing towards positive side. Our data analytical study highlighting statistical properties of the regional cuisines, brings out their culinary fingerprints that could be used to design algorithms for generating novel recipes and recipe recommender systems. It forms a basis for exploring possible causal connection between diet and health as well as prospection of therapeutic molecules from food ingredients. Our study also provides insights as to how big data can change the way we look at food.     

Lignocellulose derived functional oligosaccharides: production,properties, and health benefits

Abstract

Lignocellulosic biomass (LB) is the renewable feedstock for the production of fuel/energy, feed/food, chemicals, and materials. LB could also be the versatile source of the functional oligosaccharides, which are non-digestible food ingredients having numerous applications in food, cosmetics, pharmaceutical industries, and others. The burgeoning functional food demand is expected to be more than US$440 billion in 2022. Because of higher stability at low pH and high temperature, oligosaccharides stimulate the growth of prebiotic bifidobacteria and lactic acid bacteria. Xylooligosaccharides (XOS) are major constituents of oligosaccharides consisting of 2–7 xylose monomeric units linked via β-(1,4)-linkages. XOS can be obtained from various agro-residues by thermochemical pretreatment, enzymatic or chemoenzymatic methods. While thermochemical methods are fast, reproducible, enzymatic methods are substrate specific, costly, and produce minimum side products. Enzymatic methods are preferred for the production of food grade and pharmaceutically important oligosaccharides. XOS are potent prebiotics having antioxidant properties and enhance the bio-adsorption of calcium and improving bowel functions, etc. LB can cater to the increasing demand of oligosaccharides because of their foreseeable amount and the advancements in technology to recover oligosaccharides. This paper summarizes the methods for oligosaccharides production from LB, classification, and benefits of oligosaccharides on human health.     

Yeast cells for encapsulation of bioactive compounds in food products: A review

Nowadays bioactive compounds have gained great attention in food and drug industries owing to their health aspects as well as antimicrobial and antioxidant attributes. Nevertheless, their bioavailability, bioactivity, and stability can be affected in different conditions and during storage. In addition, some bioactive compounds have undesirable flavor that restrict their application especially at high dosage in food products. Therefore, food industry needs to find novel techniques to overcome these problems. Microencapsulation is a technique, which can fulfill the mentioned requirements. Also, there are many wall materials for use in encapsulation procedure such as proteins, carbohydrates, lipids, and various kinds of polymers. The utilization of food-grade and safe carriers have attracted great interest for encapsulation of food ingredients. Yeast cells are known as a novel carrier for microencapsulation of bioactive compounds with benefits such as controlled release, protection of core substances without a significant effect on sensory properties of food products. Saccharomyces cerevisiae was abundantly used as a suitable carrier for food ingredients. Whole cells as well as cell particles like cell wall and plasma membrane can act as a wall material in encapsulation process. Compared to other wall materials, yeast cells are biodegradable, have better protection for bioactive compounds and the process of microencapsulation by them is relatively simple. The encapsulation efficiency can be improved by applying some pretreatments of yeast cells. In this article, the potential application of yeast cells as an encapsulating material for encapsulation of bioactive compounds is reviewed.     

Review: Insects and former foodstuffs for upgrading food waste biomasses/streams to feed ingredients for farm animals

The increasing global need to find alternative protein/energy sources has triggered research in the field of non-conventional feed ingredients, with insects and former foodstuffs being the most promising. Insects contain high level of protein and fat, whereas former foodstuffs contain high energy in the form of carbohydrates and fats; therefore, both should be considered as promising alternative feed ingredients for livestock production. In addition to the nutritional value, they also represent a way by which food waste biomasses/streams can be upgraded to valuable feed ingredients. This review outlines the main nutritional and safety issues of insects and former foodstuffs, and also considers the legal framework involved. The importance of the type of insect metamorphosis and tailored substrates that could lead to the production of a premium feed is also described. This is also the first time that a review discusses the nutritional quality of former foodstuffs. Energy and the main nutrient content of former foodstuff are compared with the composition of common cereals as the principal energy sources in animal feed. For both ingredients a critical review of the safety issues is provided. Based on the current data available, both insects and former foodstuffs have an excellent potential use as alternative feed ingredients for livestock production. When produced in line with the criteria set by major feed/food authorities, they are characterized by high quality and safety standards. This makes them comparable to other feed materials and ingredients currently available on the market, although their full nutritional, functional, safety and sustainability evaluation cannot be considered complete.     

Nanoliposomes and their applications in food nanotechnology

Food nanotechnology involves the utilization of nanocarrier systems to stabilize the bioactive materials against a range of environmental and chemical changes as well as to improve their bioavailability. Nanoliposome technology presents exciting opportunities for food technologists in areas such as encapsulation and controlled release of food materials, as well as the enhanced bioavailability, stability, and shelf-life of sensitive ingredients. Liposomes and nanoliposomes have been used in the food industry to deliver flavors and nutrients and, more recently, have been investigated for their abilityto incorporate antimicrobials that could aid in the protection of food products against microbial contamination. In this paper, the main physicochemical properties of liposomes and nanoliposomes are described and some of the industrially applicable methods for their manufacture are reviewed. A summary of the application of nanoliposomes as carrier vehicles of nutrients, nutraceuticals, enzymes, food additives, and food antimicrobials is also presented.     

Nanoliposomes and Their Applications in Food Nanotechnology

Food nanotechnology involves the utilization of nanocarrier systems to stabilize the bioactive materials against a range of environmental and chemical changes as well as to improve their bioavailability. Nanoliposome technology presents exciting opportunities for food technologists in areas such as encapsulation and controlled release of food materials, as well as the enhanced bioavailability, stability, and shelf-life of sensitive ingredients. Liposomes and nanoliposomes have been used in the food industry to deliver flavors and nutrients and, more recently, have been investigated for their ability to incorporate antimicrobials that could aid in the protection of food products against microbial contamination. In this paper, the main physicochemical properties of liposomes and nanoliposomes are described and some of the industrially applicable methods for their manufacture are reviewed. A summary of the application of nanoliposomes as carrier vehicles of nutrients, nutraceuticals, enzymes, food additives, and food antimicrobials is also presented.     

Enzymes for the biocatalytic production of rare sugars

Carbohydrates are much more than just a source of energy as they also mediate a variety of recognition processes that are central to human health. As such, saccharides can be applied in the food and pharmaceutical industries to stimulate our immune system (e.g., prebiotics), to control diabetes (e.g., low-calorie sweeteners), or as building blocks for anticancer and antiviral drugs (e.g., L: -nucleosides). Unfortunately, only a small number of all possible monosaccharides are found in nature in sufficient amounts to allow their commercial exploitation. Consequently, so-called rare sugars have to be produced by (bio)chemical processes starting from cheap and widely available substrates. Three enzyme classes that can be used for rare sugar production are keto-aldol isomerases, epimerases, and oxidoreductases. In this review, the recent developments in rare sugar production with these biocatalysts are discussed.     

Bacterial metabolism and health-related effects of galacto-oligosaccharides and other prebiotics

Most studies involving prebiotic oligosaccharides have been carried out using inulin and its fructo-oligosaccharide (FOS) derivatives, together with various forms of galacto-oligosaccharides (GOS). Although many intestinal bacteria are able to grow on these carbohydrates, most investigations have demonstrated that the growth of bifidobacteria, and to a lesser degree lactobacilli, is particularly favoured. Because of their safety, stability, organoleptic properties, resistance to digestion in the upper bowel and fermentability in the colon, as well as their abilities to promote the growth of beneficial bacteria in the gut, these prebiotics are being increasingly incorporated into the Western diet. Inulin-derived oligosaccharides and GOS are mildly laxative, but can result in flatulence and osmotic diarrhoea if taken in large amounts. However, their effects on large bowel habit are relatively minor. Although the literature dealing with the health significance of prebiotics is not as extensive as that concerning probiotics, considerable evidence has accrued showing that consumption of GOS and FOS can have significant health benefits, particularly in relation to their putative anti-cancer properties, influence on mineral absorption, lipid metabolism, and anti-inflammatory and other immune effects such as atopic disease. In many instances, prebiotics seem to be more effective when used as part of a synbiotic combination.     

In vitro evaluation of the prebiotic effect of red and white grape polyphenolic extracts

Nowadays, the strong relationship between diet and health is well known. Although the primary role of diet is to provide nutrients to fulfill metabolic requirements, the use of foods to improve health and the state of well-being is an idea increasingly accepted by society in the last three decades. During the last years, an important number of scientific advances have been achieved in this field and, although in some situations, it is difficult to establish a distinction between “harmful” and “good” bacteria, experts agree in classifying the genera Bifidobacterium and Lactobacillus as beneficial bacteria. Thus, several strategies can be used to stimulate the proliferation of these beneficial intestinal bacteria, being one of them the consumption of prebiotics. The development of new prebiotics, with added functionality, is one of the most serious challenges shared not only by the scientific community but also by the food industry. The objective of this work was to evaluate the potential prebiotic effect of red and white grape residues, both obtained during the winemaking process. For such purpose, an in vitro study with pure cultures of Lactobacillus and Bifidobacterium was first conducted. Secondly, a study with mixed cultures using human fecal inocula was carried out in a simulator of the distal part of the colon. The obtained results showed an increase in the Lactobacillus and Bifidobacterium population, indicating that these ingredients are serious candidates to be considered as prebiotics.     

Do cereal mixed-linked β-glucans possess immune-modulating activities?

β-glucans are known for their immune-modulating properties. However, the heterogeneity of these glucose polymers makes a distinction between the different sources and structures necessary-a fact that has been little allowed for in the literature. We have focused on β-glucans from cereals as they are already used as functional food ingredients due to their established cholesterol lowering effect. Cereal β-glucans have shown in vitro activity on cytokine secretion, phagocytic activity and cytotoxicity of isolated immune cells, and activation of the complement system. Animal studies suggest a possible protective effect against an intestinal parasite, against bacterial infection, and a synergistic effect in antibody-dependent cellular cytotoxicity. Animal studies have shown activity of orally applied cereal β-glucans indicating uptake or interaction with cells of the gastrointestinal tract. However, uptake is still debated, interaction with intestinal epithelial cells has been suggested but not clarified, and mechanisms of action remain largely unknown. So far, cereal β-glucans have not shown immune modulation in the few conducted human studies and further studies are needed to clarify their effect.     

The Leap of Inulin Fructans from Food Industry to Medical Application

As a dietary supplement, the efficacy of prebiotics has become a hot issue in recent years. Inulin is one of internationally recognized prebiotics and belongs to a group of non-digestible and fermentable carbohydrates. Currently, the food industry is increasingly using prebiotic inulin as a health-promoting substrate, not just as food supplement. In addition, inulin has also shown great promise in the treatment of various diseases. This article reviews the application of inulin in the food industry and summarizes physiological function of inulin. Through the review and prospect of the research on obesity, diabetes and mental illness, it provides the theoretical basis for the joint development of inulin in food industry and medical application.     

Survival and therapeutic potential of probiotic organisms with reference to Lactobacillus acidophilus and Bifidobacterium spp

The present paper provides an overview on the use of probiotic organisms as live supplements, with particular emphasis on Lactobacillus acidophilus and Bifidobacterium spp. The therapeutic potential of these bacteria in fermented dairy products is dependent on their survival during manufacture and storage. Probiotic bacteria are increasingly used in food and pharmaceutical applications to balance disturbed intestinal microflora and related dysfunction of the human gastrointestinal tract. Lactobacillus acidophilus and Bifidobacterium spp. have been reported to be beneficial probiotic organisms that provide excellent therapeutic benefits. The biological activity of probiotic bacteria is due in part to their ability to attach to enterocytes. This inhibits the binding of enteric pathogens by a process of competitive exclusion. Attachment of probiotic bacteria to cell surface receptors of enterocytes also initiates signalling events that result in the synthesis of cytokines. Probiotic bacteria also exert an influence on commensal micro-organisms by the production of lactic acid and bacteriocins. These substances inhibit growth of pathogens and also alter the ecological balance of enteric commensals. Production of butyric acid by some probiotic bacteria affects the turnover of enterocytes and neutralizes the activity of dietary carcinogens, such as nitrosamines, that are generated by the metabolic activity of commensal bacteria in subjects consuming a high-protein diet. Therefore, inclusion of probiotic bacteria in fermented dairy products enhances their value as better therapeutic functional foods. However, insufficient viability and survival of these bacteria remain a problem in commercial food products. By selecting better functional probiotic strains and adopting improved methods to enhance survival, including the use of appropriate prebiotics and the optimal combination of probiotics and prebiotics (synbiotics), an increased delivery of viable bacteria in fermented products to the consumers can be achieved.     

Consumers' hedonic liking of different labeled and conventional food products in Slovenia

In recent years, like others in Europe, the Slovenian government has introduced national and European quality schemes and launched a campaign to inform consumers and boost demand for local products. Very few studies consider consumers' hedonic liking of different food products labeled with Protected Designation of Origin (PDO)/Protected Geographical Indication (PGI) indications. This study therefore aims to fill this research gap and identify whether information affects the hedonic liking of various typical Slovenian PDO/PGI‐labeled products compared to their alternative conventional food products, whether Slovenian consumers like different typical Slovenian PDO/PGI‐labeled food products relative to their conventional food products, and which food products they sensorically prefer. The study findings show consumer hedonic liking is identical for all PDO/PGI‐labeled regional products, yet their sensory preferences reveal some significant differences between the analyzed products by age, gender, and education. Accordingly, studies should employ different sensory analyses for different food products and not generalized consumer hedonic liking/preference based on just one food product.

Practical applications

The finding that consumers do not hold hedonic preferences for either PDO/PGI‐labeled or conventional products when both informed and blind has significant implications for the Slovenian government, the marketers of labeled products and consumer policy aiming to promote better labeled products. For transition countries like Slovenia that have recently introduced food products labeling meeting EU standard but have a relatively small food industry based on local ingredients, traditional recipes, and production methods, our findings reveal the need to extend and intensify promotion and communication activities that highlight the guaranteed quality and use of local ingredients to boost consumers' preferences for PDO/PGI‐labeled products like cheese, ham, and honey.