Food Science & Technology · Product, Health & Industry · also Nutraceuticals, Functional Foods, Health Foods, Probiotics and Prebiotics
Foods and ingredients with health benefits beyond basic nutrition: bioactive compounds, probiotics and prebiotics, dietary fibre, omega-3 fatty acids, plant sterols and polyphenols, foods for special dietary uses, the evidence needed for health claims and how claims are regulated in different countries.
In the exams: GATE XE-G Section 1 (nutraceuticals); ICAR AICE 35.a Unit 8 (nutraceutical and functional foods) and 37 Unit 6
Functional foods and nutraceuticals are foods and food-derived products that are marketed for a health benefit beyond basic nutrition: a yoghurt with a probiotic strain, a spread with plant sterols, an oat cereal with a cholesterol claim, omega-3 capsules, a protein drink for older adults, a formula for a child with a metabolic disorder. The field sits where food technology meets nutrition science, medicine and law. The technologist's job is to identify the active component, deliver it in a stable, bioavailable form in a food people will eat, and support any claim with evidence strong enough to satisfy a regulator.
This manual covers definitions and the main classes of bioactive compounds; probiotics, prebiotics and the gut microbiome; dietary fibre; omega-3 fatty acids and structured lipids; bioactive peptides; foods for special dietary and medical purposes, including infant and elderly products; the technology of delivering bioactives; and, throughout and in the last two chapters, how evidence is graded and how claims are regulated in different countries. The chemistry of food constituents is in food-chemistry-major-constituents, probiotic dairy products in depth in the Dairy Technology track's probiotics-functional-dairy, plant protein ingredients in pulses-oilseeds-plant-proteins, and additives, sweeteners and hydrocolloids in food-additives-ingredients. Those subjects are referred to, not repeated.
A note on evidence runs through the whole subject. Many compounds show striking effects in cell or animal studies that are not confirmed in people, and many marketed products make claims that regulators have rejected. A health claim may be made only when the relevant authority permits it, and the strength of the science behind it varies from well-established (for example plant sterols and LDL cholesterol) to weak or absent. This manual states claims as regulated and evidence-graded, and the regulation differs between countries. The subject is examined in postgraduate food science entrance examinations, research fellowship and doctoral entrance examinations, and nutrition-oriented papers in many countries.
There is no single worldwide legal definition of a functional food. The idea took regulatory form in Japan, which in 1991 introduced Foods for Specified Health Uses (FOSHU), foods approved individually to carry a stated health effect. In general use, a functional food is a food, similar in appearance to conventional foods and eaten as part of a normal diet, that has been shown to have a physiological benefit or to reduce the risk of disease beyond basic nutrition. It may be a whole food (oats, tomatoes), a fortified or enriched food (milk with added vitamin D), or a food formulated around a bioactive ingredient (a sterol-enriched spread).
The term nutraceutical, coined in 1989 by combining nutrition and pharmaceutical, refers to a food or part of a food that provides medical or health benefits, often presented in concentrated or dose form. A dietary supplement, in the legal sense used in the United States since the Dietary Supplement Health and Education Act of 1994, is a product taken by mouth that contains a dietary ingredient, such as a vitamin, mineral, herb, amino acid or concentrate, intended to supplement the diet and sold in forms such as tablets, capsules and powders. In the European Union these are food supplements, in Canada natural health products, and in several other countries health supplements or nutraceuticals under national food law. The boundaries between food, supplement and medicine are drawn differently in each jurisdiction, and the category a product falls into determines what it may contain and what it may claim.
Classification has practical consequences. A medicine treats, cures or prevents a disease and must be authorised on evidence of safety, quality and efficacy; a food or supplement may not claim to treat or cure disease, but in many jurisdictions may carry approved claims about nutrition, normal body function or the reduction of a disease risk factor. If a product's claims or composition cross into medicinal territory, regulators may treat it as an unauthorised medicine. Botanicals are a frequent problem: the same plant extract may be a traditional herbal medicine in one country and a food supplement in another.
Novel ingredients that were not eaten widely before a cut-off date need pre-market approval as novel foods in the European Union and some other jurisdictions, and new dietary ingredients need a notification in the United States. Safety comes first: a functional ingredient must be safe at the intended intake for the whole population likely to consume it, including people who eat several fortified products, and toxicity at high doses (for example vitamin A, iron or some botanicals) is a real concern. For the general framework of food law, see food-law-regulatory-affairs.
Polyphenols are a large family of plant compounds with phenolic rings. Flavonoids are the largest group: flavanols (catechins in tea and cocoa, proanthocyanidins), flavonols (quercetin), flavanones (hesperidin in citrus), anthocyanins (berries), and isoflavones (genistein and daidzein in soy), which have weak oestrogen-like activity. Other groups include phenolic acids (chlorogenic acid in coffee), stilbenes (resveratrol) and lignans (in flaxseed). Polyphenols are antioxidants in the test tube, but antioxidant capacity measured in vitro does not predict effects in the body; most polyphenols are poorly absorbed, extensively metabolised in the gut wall, liver and by colonic bacteria, and present in blood at low concentrations. Their possible effects are now thought to act more through cell signalling and the gut microbiota than through direct antioxidant action. Approved health claims for polyphenols are few; one example in the EU concerns cocoa flavanols and normal blood flow, at a specified intake.
Carotenoids are fat-soluble pigments. β-Carotene and some others are provitamin A. Lutein and zeaxanthin accumulate in the macula of the eye; lycopene gives tomatoes their colour. Carotenoids are better absorbed from cooked foods eaten with fat. High-dose β-carotene supplements increased lung cancer risk in smokers in large trials, a lesson that isolated compounds in high doses can behave differently from foods.
Phytosterols and their saturated forms, phytostanols, are plant compounds structurally similar to cholesterol. Added to foods, usually as esters in spreads, yoghurts and milks, they reduce the absorption of cholesterol from the gut and lower blood LDL cholesterol. This is one of the best-established functional food effects: authorised claims in the European Union and elsewhere state that an intake of about 1.5–3 g per day lowers LDL cholesterol by roughly 7–10% within two to three weeks, and products must carry statements that they are intended for people who want to lower blood cholesterol and are not nutritionally appropriate for young children or pregnant and breastfeeding women. If a spread supplies 0.8 g of plant sterols per 10 g serving, 2.5 servings provide 2 g.
Other bioactive groups include glucosinolates in cruciferous vegetables, which are converted by the enzyme myrosinase to isothiocyanates such as sulforaphane; organosulphur compounds in garlic and onion; curcumin from turmeric, notable for its very low oral bioavailability; and bioactive peptides, treated in a later chapter. For each, the questions are the same: how much is present, how much is absorbed, what does it do at realistic intakes in humans, and what is the evidence.
Turning a bioactive compound into a credible product involves several decisions. The first is the source: a whole food, a standardised extract with a defined content of a marker compound, or a purified or synthetic compound. Extracts vary with plant variety, growing conditions and extraction method, so specifications must define the content of active or marker compounds and limits for contaminants such as pesticide residues, heavy metals and solvent residues. The second is the dose: the amount used in successful human studies, not the amount that is convenient or cheap, and it must be achievable in a normal serving without unacceptable taste. The third is the food matrix: fat, fibre, protein and processing all change release and absorption, so a dose effective in a capsule may not be effective in a biscuit. The fourth is safety at the intended intake, including interactions with medicines, which is a known issue for some botanicals such as St John's wort and grapefruit constituents. Finally, the claim must match what the evidence shows and what the regulator allows. A product team that works through these steps before launch avoids most of the failures seen in the market.
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host; this wording comes from an FAO/WHO expert consultation and was refined by the International Scientific Association for Probiotics and Prebiotics (ISAPP). Three conditions follow: the organisms must be alive at the time of consumption, there must be enough of them, and a health benefit must have been shown. Most probiotic strains belong to the lactic acid bacteria and bifidobacteria, together with the yeast Saccharomyces boulardii. In 2020 the genus Lactobacillus was split into many new genera, so Lactobacillus rhamnosus is now Lacticaseibacillus rhamnosus, Lactobacillus plantarum is Lactiplantibacillus plantarum, and so on; labels and literature use both old and new names.
Probiotic effects are strain-specific: a benefit shown for one strain cannot be assumed for another strain of the same species. Products must therefore name the strain, and evidence must come from studies of that strain at the dose delivered. The best-supported uses include reducing the risk of antibiotic-associated diarrhoea and treating some acute infectious diarrhoea in children with particular strains; evidence for many other claimed effects is weaker. In the European Union no probiotic health claim had been authorised, and even the word 'probiotic' is treated as an implied health claim in many member states, while other jurisdictions permit it with conditions.
A prebiotic is, in the ISAPP definition, a substrate that is selectively utilised by host microorganisms, conferring a health benefit. The established prebiotics are fructans (inulin and fructo-oligosaccharides from chicory and other sources) and galacto-oligosaccharides (GOS), made from lactose by β-galactosidase; human milk oligosaccharides such as 2'-fucosyllactose act similarly in infants and are now produced by fermentation for infant formula. Selectivity, the stimulation mainly of beneficial groups such as bifidobacteria, distinguishes prebiotics from fibres in general. Large doses cause flatulence and bloating.
A synbiotic is a mixture of live microorganisms and substrates selectively used by host microorganisms that confers a health benefit; a complementary synbiotic combines a probiotic and a prebiotic that each work independently, while a synergistic synbiotic contains a substrate chosen to be used by the co-administered microorganism. A postbiotic, a newer concept, is a preparation of inanimate microorganisms and/or their components that confers a health benefit; heat-killed cells and cell fractions are examples. Postbiotics avoid the challenge of keeping cells alive but still need evidence of benefit.
The main technical challenge is viability. Probiotic numbers decline during processing and storage because of heat, oxygen (especially for anaerobic bifidobacteria), low pH, water activity and interaction with other ingredients and starter cultures; they must also survive stomach acid and bile to reach the intestine. Products are formulated to deliver a stated number of colony-forming units (cfu) per serving at the end of shelf life, not at manufacture. If a product must deliver 10^9 cfu in a 200 g serving, it needs 5 × 10^6 cfu/g at the end of shelf life; if one log of viability is lost in storage, it must contain about 5 × 10^7 cfu/g when made.
Approaches to improve survival include selecting robust strains, adding cells after heat treatment, oxygen-barrier packaging, microencapsulation in alginate or other matrices, cold-chain storage, and freeze-dried powders in low water activity products such as capsules. Viable counts are verified by plate counts on selective media, and increasingly by flow cytometry and strain-specific molecular methods. Dairy probiotic products in depth are covered in the Dairy Technology track's probiotics-functional-dairy.
Dietary fibre is defined by Codex Alimentarius as carbohydrate polymers with ten or more monomeric units that are not hydrolysed by the endogenous enzymes of the human small intestine, belonging to naturally occurring edible polymers, polymers obtained from raw material by physical, enzymatic or chemical means with a demonstrated physiological benefit, or synthetic polymers with such a benefit; national authorities decide whether carbohydrates of three to nine units are included. Fibre includes cellulose, hemicelluloses, pectins, β-glucans, gums, resistant starch, inulin and resistant oligosaccharides, with lignin often counted alongside.
Fibres differ in physiological effect. Viscous soluble fibres such as oat and barley β-glucan, psyllium and guar gum slow gastric emptying and nutrient absorption and lower blood cholesterol by binding bile acids and reducing their reabsorption; authorised claims link oat β-glucan, at about 3 g per day, to lowering blood cholesterol, so a product supplying it needs, for example, 75 g of an oat ingredient containing 4% β-glucan. Insoluble fibres such as wheat bran increase faecal bulk and speed intestinal transit. Resistant starch, starch that escapes digestion, comes in several types: physically inaccessible (RS1), raw granules (RS2), retrograded (RS3), chemically modified (RS4) and amylose–lipid complexes (RS5). Methods of fibre analysis are covered in food-analysis.
Fibre that reaches the colon is fermented by the gut microbiota, the community of trillions of bacteria and other microorganisms living mainly in the large intestine. The main products are the short-chain fatty acids acetate, propionate and butyrate, together with gases. Butyrate is the preferred energy source of colonocytes and is linked to gut barrier function; propionate is used mainly by the liver; acetate enters the general circulation. Different fibres support different microbes, so diet shapes the composition and activity of the microbiota.
Research has linked the microbiota with many conditions, but much of the evidence is associative, from studies comparing people or from animal models, and causal effects in humans are harder to show. A 'healthy microbiome' has not been defined in a way that a product could target, so claims to 'balance' or 'improve' the microbiome are generally not permitted without evidence of a specific health benefit. Practical messages are better supported: most populations eat less fibre than recommended, and increasing intake of fibre-rich whole foods has well-established benefits for bowel function and is associated with lower risk of several chronic diseases.
Adding fibre to everyday foods is one of the most practical functional food strategies, because most populations fall short of recommended intakes. Each fibre brings technical consequences. Inulin and oligofructose add sweetness and solubility and can replace some sugar and fat, but large amounts cause flatulence. Oat and barley β-glucans give viscosity, which is responsible for their cholesterol effect but thickens beverages and changes dough. Resistant starch has little effect on texture and taste and suits bread, pasta and snacks. Bran and other insoluble fibres absorb water and can make baked products dry, dense and gritty unless particle size and water addition are adjusted. Psyllium forms strong gels and is used in gluten-free bread. Processing can reduce the molecular weight of β-glucan by enzymes or heat and so weaken its effect, which is why authorised claims often specify the form and quantity of β-glucan in the final product. Nutrition claims such as 'source of fibre' or 'high fibre' require minimum contents set by each jurisdiction, and the analytical method used must measure the fibres actually added, because older methods miss low-molecular-weight fibres such as inulin.
Omega-3 (n-3) fatty acids have their first double bond three carbons from the methyl end. α-Linolenic acid (ALA, 18:3 n-3) is essential and comes from plant oils such as flaxseed, rapeseed (canola), soybean and walnut. The long-chain omega-3s eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) come mainly from fish and seafood, ultimately from marine microalgae; human conversion of ALA to EPA and especially to DHA is limited. DHA is a major structural fatty acid of the brain and retina and is added to infant formula. EPA and DHA at sufficient intakes lower blood triglycerides, and authorised claims in several jurisdictions relate them to normal heart function, normal blood pressure or triglyceride levels at specified intakes, and DHA to normal brain function and vision. Large trials of fish oil supplements for preventing cardiovascular events have given mixed results, so claims are framed carefully.
Sources for fortification and supplements include refined fish oil, concentrated ethyl-ester or re-esterified triglyceride forms, krill oil, and algal oils from cultivated microalgae such as Schizochytrium, which supply DHA (and some EPA) without fish and suit vegetarians. A capsule of 1 g fish oil containing 18% EPA and 12% DHA supplies 300 mg EPA plus DHA.
Long-chain polyunsaturated fatty acids oxidise very readily, giving fishy and painty off-flavours at low levels of oxidation and potentially harmful products. Oxidation is measured by peroxide value (primary products), anisidine value (secondary products) and their combination as the TOTOX value, with industry quality standards setting maxima. Fortifying foods with omega-3 oils therefore needs high-quality, freshly refined oil, antioxidants such as tocopherols, rosemary extract or ascorbyl palmitate, exclusion of oxygen and light, protection from pro-oxidant metals, and often microencapsulation in spray-dried powders with protein and carbohydrate walls. Products such as milk, bread, spreads and juices have been fortified successfully when these precautions are taken; failure shows quickly as a fishy taste. Sensory testing by trained panels, and storage trials in the final pack under realistic temperatures, are the only reliable way to set the shelf life of an omega-3 fortified product, because the threshold for fishy flavour is far below the levels that analytical oxidation indices flag as a problem. Fortification levels are therefore often limited by taste rather than by cost or technology.
Structured lipids are triacylglycerols whose fatty acid composition or position on the glycerol backbone has been changed, chemically or enzymatically, to give a nutritional or functional property. Enzymatic interesterification with sn-1,3-specific lipases can place chosen fatty acids at the outer positions while keeping the fatty acid at the middle (sn-2) position. One example is human milk fat substitutes: in human milk fat, palmitic acid is mainly at the sn-2 position, which improves its absorption and reduces the formation of insoluble calcium soaps in the infant gut; structured OPO lipids (1,3-dioleoyl-2-palmitoylglycerol) are made to imitate this for infant formula. Medium- and long-chain triacylglycerols combine medium-chain fatty acids, which are absorbed and oxidised rapidly, with long-chain essential fatty acids, and are used in clinical nutrition. Diacylglycerol oils were marketed for body-fat claims in some countries. The chemistry of fat modification is covered in fats-oils-technology. Structured lipids must meet the same safety and labelling rules as other fats and, where new, may need novel food approval. Their production cost is higher than that of conventional oils, so they are used where a specific nutritional or clinical benefit justifies it, mainly in infant formula and medical nutrition.
Bioactive peptides are specific protein fragments, usually 2–20 amino acids long, that are inactive within the parent protein but can have physiological effects when released. They are released by gastrointestinal digestion, by fermentation with proteolytic cultures, or by controlled enzymatic hydrolysis of proteins from milk, egg, fish, meat, soy, cereals and other sources. Reported activities include inhibition of angiotensin-converting enzyme (ACE), which is relevant to blood pressure; antioxidant, antimicrobial and immunomodulating effects; mineral binding; and opioid-like activity. The best-known examples are the lactotripeptides valine-proline-proline (VPP) and isoleucine-proline-proline (IPP), formed in milk fermented with Lactobacillus helveticus, which inhibit ACE in vitro and lowered blood pressure modestly in some human trials, and casein phosphopeptides, which bind calcium and keep it soluble.
The weak point is again evidence in humans. Many peptides active in vitro are broken down in the gut or poorly absorbed, and effects in trials are small and inconsistent; regulators have rejected many peptide claims, including, in the European Union, a blood pressure claim for lactotripeptides.
Protein hydrolysates are made by treating proteins with proteases, often in sequence, under controlled pH, temperature and time. The extent of hydrolysis is expressed as the degree of hydrolysis (DH), the percentage of peptide bonds cleaved: DH = h ÷ h_tot × 100, where h is the number of bonds cleaved and h_tot the total number of peptide bonds, both usually in milliequivalents per gram of protein. A hydrolysate with h = 2.4 meq/g from a protein with h_tot = 8.0 meq/g has a DH of 30%. DH is followed during production by the pH-stat method or by measuring free amino groups.
Hydrolysis changes function. Low DH improves solubility, emulsifying and foaming properties; high DH gives small peptides that are rapidly absorbed, used in sports and clinical nutrition, and reduces allergenicity, which is why extensively hydrolysed whey or casein formulas are used for infants with cow's milk protein allergy (partially hydrolysed formulas are not suitable for diagnosed allergy). A common technical problem is bitterness from peptides with exposed hydrophobic amino acids, especially at proline and leucine-rich sequences; it is reduced by choosing enzymes, by exopeptidases that trim terminal hydrophobic residues, by debittering with activated carbon, or by masking. Plant protein hydrolysates are covered alongside plant proteins in pulses-oilseeds-plant-proteins.
Foods for special dietary uses are processed or formulated to meet particular dietary requirements arising from a physical or physiological condition, a disease or a disorder. Gluten-free foods for people with coeliac disease are the most widespread example; Codex sets the threshold for 'gluten-free' at not more than 20 mg/kg of gluten, a value adopted by many countries, and the challenge for the technologist is to replace the structure-forming function of gluten in bread and pasta with starches, hydrocolloids, proteins and enzymes, while avoiding cross-contact. Other examples include low-sodium foods, lactose-free milk made with lactase, foods for weight control and total diet replacements, and foods for sportspeople. Rules for these categories differ by country: the European Union reorganised them under Regulation (EU) No 609/2013, covering infant formula, processed cereal-based and baby foods, foods for special medical purposes and total diet replacements, while gluten-free and lactose-free claims moved to general food law.
Foods for special medical purposes (FSMP), defined in the Codex standard CXS 180-1991 and in national laws, are specially processed or formulated foods intended for the dietary management of patients who have a limited or impaired capacity to take, digest, absorb, metabolise or excrete ordinary food or certain nutrients, or who have other medically determined nutrient requirements, and they must be used under medical supervision. Examples include enteral feeds, given by mouth or tube, for patients who cannot eat enough ordinary food; protein-free or amino-acid-based formulas for inborn errors of metabolism such as phenylketonuria, in which the formula supplies all amino acids except phenylalanine; ketogenic formulas for epilepsy; renal and hepatic formulas; and thickened products for dysphagia. Their composition must be justified by generally accepted scientific data, and their labels carry statements about medical supervision and suitability. They sit between food and medicine, and in some countries they are reimbursed by health systems. Manufacturing standards approach those of pharmaceuticals, especially for products given to vulnerable patients.
Products for special dietary and medical needs demand careful formulation and control. A gluten-free bakery line must exclude gluten-containing cereals at every step, verify ingredients and the production environment by testing, and still produce bread that people want to eat, which means combining rice, maize or other flours with starches, hydrocolloids such as psyllium or hydroxypropyl methylcellulose, proteins and sometimes enzymes. A product for phenylketonuria must deliver a precise amino acid profile with flavour masking, because free amino acids taste unpleasant. Enteral feeds must be nutritionally complete, stable to heat sterilisation and shelf storage, free-flowing through feeding tubes, and consistent from batch to batch. Texture-modified foods for dysphagia must hold their IDDSI level through serving and temperature changes. In all these products, labelling and instructions for use are part of safety, and clinicians and dietitians are part of the development team. Small production volumes, strict specifications and the need for clinical feedback make these products costly to develop, so many are made by specialist manufacturers.
Breastfeeding is recommended by WHO as the best nutrition for infants, and the marketing of breast-milk substitutes is restricted in many countries under the International Code of Marketing of Breast-milk Substitutes. Infant formula, when needed, must on its own satisfy the nutritional requirements of infants during the first months of life; its composition is set by the Codex standard for infant formula and by national regulations, with minimum and maximum levels for energy, protein, fat, carbohydrates, vitamins and minerals. Modern formulas adjust cow milk protein toward the whey-dominant profile of human milk, use vegetable oil blends for fat, and may include DHA and arachidonic acid, structured lipids with palmitic acid at sn-2, and human milk oligosaccharides such as 2'-fucosyllactose produced by fermentation. Follow-up formula and young-child formulas, processed cereal-based foods and baby foods have their own standards, including strict contaminant limits. Powdered formula is not sterile, and Cronobacter sakazakii and Salmonella are the critical hazards; manufacturing uses stringent zoning and testing, as described in dairy-for-food-technologists.
Older adults have particular nutritional needs. Sarcopenia, the progressive loss of muscle mass and strength with age, is linked to frailty and falls; older people often need more protein per kilogram of body weight than younger adults to maintain muscle, and the amino acid leucine and adequate vitamin D and physical activity are part of the response. Appetite, taste and smell decline, so energy- and protein-dense foods in small portions, oral nutritional supplements and fortified everyday foods are used. Many older people, and patients after stroke or with neurological disease, have dysphagia, difficulty swallowing, which risks aspiration and malnutrition. Texture-modified foods and thickened drinks are prepared to defined levels; the International Dysphagia Diet Standardisation Initiative (IDDSI) framework describes eight levels, from thin liquids (level 0) to regular foods (level 7), with simple tests such as the flow test and the fork pressure test so that kitchens and manufacturers can produce consistent textures. Other concerns include vitamin B12 absorption, calcium and vitamin D for bone health, and hydration. Products must remain appealing, because a nutritious food that is not eaten has no effect.
A bioactive helps only if it survives processing and storage, is released from the food in the gut (bioaccessibility), is absorbed, and reaches its target in an active form (bioavailability). Many promising compounds fail at one of these steps. Curcumin is poorly soluble in water, poorly absorbed and rapidly metabolised; carotenoids need fat and a disrupted food matrix to be released; polyphenols are extensively conjugated and metabolised; probiotics must survive stomach acid. Bioaccessibility is studied with standardised in vitro digestion models, such as the international INFOGEST protocol, which simulate the oral, gastric and intestinal phases with defined enzymes, pH and times; absorption is studied with cell models and, finally, with human pharmacokinetic studies. Absorption can be improved by co-ingesting fat for fat-soluble compounds, by emulsions and nanoemulsions that increase surface area and solubility, by complexation, and by inhibiting metabolism (piperine, from black pepper, increases curcumin absorption in this way), although safety of such enhancers must be considered.
Many bioactives are unstable to heat, light, oxygen, moisture, pH or interactions with other ingredients, and some taste bitter or fishy. Encapsulation surrounds the active with a protective material. Spray drying of emulsions with protein and carbohydrate wall materials is the most widely used method, for oils and flavours; other methods include spray chilling in fats, extrusion and coacervation, liposomes, solid lipid particles and inclusion complexes with cyclodextrins. Encapsulation efficiency is the proportion of the active that ends up inside the capsule: if 12 g of oil is used and 9 g is encapsulated, the efficiency is 75%. Release can be designed to occur in the intestine rather than the stomach, for example with acid-resistant coatings for probiotics.
Stability during storage often follows first-order kinetics, so retention = exp(−kt). An ingredient with a degradation rate constant of 0.02 per day retains exp(−1.2) = 30% after 60 days, and its half-life is ln 2 ÷ 0.02 = 35 days. Since the label must be true at the end of shelf life, manufacturers add an overage, more than the declared amount, and test retention under real and accelerated storage. Excessive overages can create safety problems for nutrients with upper intake limits. Spray drying is covered in evaporation-dehydration and shelf-life testing in shelf-life-stability.
Health claims are judged on the totality of the evidence, and different kinds of study carry different weight. In vitro and animal studies show mechanisms and generate hypotheses but cannot show an effect in people. Observational studies (cross-sectional, case-control and cohort studies) show associations between diet and health but are open to confounding: people who eat more of a food often differ in many other ways. Randomised controlled trials (RCTs), in which participants are randomly assigned to the food or a suitable control and outcomes are measured, ideally double-blind, provide the strongest evidence for cause and effect from a single study. Systematic reviews and meta-analyses of well-conducted RCTs sit at the top of the hierarchy, provided the trials are of good quality and publication bias is considered.
Trials of foods are harder than trials of drugs: a suitable placebo is hard to make, background diet varies, effects are small and need large, long studies, and the people who take part may already eat well. Outcomes may be clinical events (heart attacks), which need huge trials, or validated biomarkers that are accepted as reflecting disease risk, such as LDL cholesterol for cardiovascular disease or blood pressure; markers such as in vitro antioxidant capacity are not accepted as surrogates.
Regulators such as the European Food Safety Authority ask several questions when assessing a claim. Is the food or constituent sufficiently characterised, so that it is clear what was tested? Is the claimed effect beneficial to human health, and is it defined and measurable? Is a cause-and-effect relationship established between consumption and the effect, in the target population and at a realistic intake? What quantity and pattern of consumption is needed, and can it be achieved as part of a balanced diet? The answers determine whether the claim is authorised and on what conditions of use. The US FDA applies a standard of significant scientific agreement for authorised health claims and allows qualified health claims with wording that reflects weaker evidence. In all systems, the evidence must relate to the specific ingredient, dose and population; studies of a different strain, extract or dose do not transfer.
Many applications fail: in the European Union, the majority of function claims submitted in the general claims review were rejected, mainly because the substance was poorly characterised, the effect was not beneficial or measurable, or cause and effect was not shown in humans. This record is a useful guide to designing studies before a product is launched.
Reviews of rejected health claim applications show recurring weaknesses that a development team can avoid. Studies used an ingredient that differed from the marketed one, such as another strain, extract or dose. Effects were measured with biomarkers that are not accepted as predictors of health, such as in vitro antioxidant capacity or poorly validated questionnaires. Trials were too small, too short, poorly blinded, or conducted in patients rather than the healthy target population of a food claim. The claimed effect was vague, such as 'supports immunity' or 'promotes wellbeing', and could not be measured. Results were inconsistent across studies, or only some outcomes reached significance, raising the risk of selective reporting. Planning a dossier from the start, with the regulator's requirements, a well-characterised ingredient, a pre-registered trial with a meaningful outcome, and a realistic dose, saves time and money compared with assembling evidence after launch. Independent scientific advice and early dialogue with the regulator, where the system allows it, help further.
Most systems distinguish several kinds of claim. Nutrition claims describe content ('high in fibre', 'low fat', 'source of vitamin D') and must meet defined compositional criteria. Health claims link a food or constituent to health. Within health claims, function claims describe a role in normal growth, development or body function ('calcium is needed for the maintenance of normal bones'); enhanced function claims describe a specific beneficial effect beyond normal function; and disease risk reduction claims state that a food or constituent reduces a risk factor for a disease ('plant sterols have been shown to lower blood cholesterol; high cholesterol is a risk factor in the development of coronary heart disease'). Claims to prevent, treat or cure a disease are reserved for medicines in nearly all jurisdictions. The Codex Guidelines for Use of Nutrition and Health Claims (CAC/GL 23-1997) set out these categories and the principle that claims must be substantiated and not misleading, and many national systems are built on them.
In the European Union, Regulation (EC) No 1924/2006 allows only claims on a positive list after EFSA assessment: general function claims (Article 13.1), claims based on newly developed evidence (Article 13.5), and disease risk reduction and children's development claims (Article 14); unauthorised claims are prohibited and nutrient profiles were foreseen to restrict claims on less healthy foods. In the United States, the FDA authorises health claims under the Nutrition Labeling and Education Act on significant scientific agreement, permits qualified health claims, and allows structure/function claims on dietary supplements without pre-approval, provided they carry a disclaimer that the FDA has not evaluated the statement and the product is not intended to diagnose, treat, cure or prevent disease. Japan regulates FOSHU (individually approved), Foods with Nutrient Function Claims and, since 2015, Foods with Function Claims notified by the business on its own evidence. China approves 'health foods' through registration or filing. Canada regulates natural health products under a licensing system. Australia and New Zealand allow general level and high level health claims under Food Standard 1.2.7. Several other countries have created dedicated categories within their food laws for health supplements, nutraceuticals, foods for special dietary and medical purposes, botanical products and probiotic foods. Because the rules change, a product team must check the current rules of each market before writing a label.
A student uses this subject to answer questions on what makes a food functional, the definitions of probiotics, prebiotics and postbiotics, how fibre is fermented in the colon, why DHA matters, what a structured lipid is, and how health claims are regulated. In the laboratory the same student measures probiotic counts over shelf life, runs an in vitro digestion, follows degree of hydrolysis by pH-stat, and calculates retention of a bioactive and the overage needed to meet a label claim.
Five years into a food, supplement or ingredient company, a technologist formulates products that deliver a stated amount of a bioactive at the end of shelf life, chooses encapsulation and packaging to protect it, manages taste problems such as fishy oils and bitter peptides, and works with regulatory colleagues so that every claim on the label is one that is authorised in the target market and supported by the specific ingredient, strain and dose used. The same person keeps the evidence file for each claim up to date as studies and rules change.
After twenty-five years a senior manager decides which health platforms a company invests in, whether a clinical trial is worth commissioning to support a new claim, how to respond when a regulator rejects a claim or a competitor makes an unsupported one, and how to keep products safe when consumers combine several fortified foods and supplements. The manager also judges trends critically, separating durable science from fashion. The manager also sets the ethical line on marketing to vulnerable groups such as infants, the elderly and the sick.
A researcher with long industry experience designs human studies that can actually substantiate claims, develops validated biomarkers, studies the bioavailability and metabolism of bioactives and their interaction with the microbiota, engineers delivery systems, and contributes to scientific opinions and standards. Such work moves the field from promising laboratory results to evidence that regulators and clinicians accept. It also includes publishing negative results, which are essential for an honest evidence base and are often missing from the literature. Training the next generation of food scientists in critical appraisal of evidence is part of the same responsibility.
This manual does not list the full register of authorised health claims, permitted ingredients or maximum levels for any country; these change and must be read from the current regulations. It gives intakes only where they form part of well-known authorised claims (plant sterols, oat β-glucan) and does not give therapeutic doses of any supplement. Evidence for many bioactives is evolving, and statements about the microbiome, polyphenols and peptides reflect the cautious consensus rather than the most optimistic studies. Probiotic dairy products in depth are in the Dairy Technology track (probiotics-functional-dairy); plant proteins in pulses-oilseeds-plant-proteins; additives and sweeteners in food-additives-ingredients; fat modification in fats-oils-technology; and clinical nutrition practice is beyond the scope of a food technology course.
Original practice questions written to the syllabus and pattern of the exams named in each question's examTags. They are not past papers and do not reproduce any board's questions. Every numerical answer was computed by script. Health claims are regulated and differ by country; statements about effects follow authorised claims and cautious scientific consensus, and no question gives therapeutic doses.
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