INTRODUCTION TO FUNCTIONAL FOODS AND NUTRACEUTICALS Classification of Functional Foods and Nutraceuticals

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INTRODUCTION TO FUNCTIONAL FOODS AND NUTRACEUTICALS

Classification of Functional Foods and Nutraceuticals

Objectives: After studying this module, the student shall be able to:

• classify functional foods

• identify different groups of functional foods

• illustrate functional foods from different classifications

Introduction:

The number of purported nutraceutical substances is in the hundreds, and some of the

most common known substances include carotenoids, polyphenols, fibers, curcumin,

and allyl sulfur compounds. In light of a long and ever growing list of nutraceutical

substances, organization systems are needed to allow for easier understanding and

application. This is particularly true for academic instruction, as well as product

formulation by food companies. Depending upon one’s interest and/or background, the

appropriate organizational scheme for nutraceuticals can vary. Whether it is for

 

UGC PG MOOC on Functional Foods and Nutraceuticals

Module 2: Classification of Functional Foods and Nutraceuticals

academic instruction, clinical trial design, functional food development, or dietary

recommendations, nutraceutical factors can be organized in several ways. In the

present module, we shall study different types of classifications of functional foods and

nutraceuticals.

Classification of Functional Foods and Nutraceuticals

Functional foods may be classified in various ways and can be identified/selected

on the basis of their properties, clinical significance or composition. Some of the

important criteria used for classifying functional foods are:

1. Food Source

2. Nutrient and Non Nutrient Source

3. Organ/Organ System

4. Modifications in foods

5. Specific Foods

6. Mechanism of actions

7. Chemical Nature

A. Classification based on Food Source

According to origin or food source, the Functional foods may be classified into

plant, animal and microbial groups and has been depicted in Figure1.

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Classification of Functional Foods according to Food Sources

Food Non Food

sources Sources

Plant Animal Microbial
Derived Derived Foods

 

Probiotics Prebiotics Synbiotics Postbiotics

Figure 1: Classification of functional foods according to food source

a. Plant-derived functional foods

Plant-derived functional foods are separated into primary and secondary

metabolites; primary metabolites are plant compounds necessary for growth and

include plant proteins, beta-glucans, and omega-3 fatty acids.The secondary

metabolites are not essential for growth, but are used for plant survival mechanisms

and include phytoestrogens, antioxidants, vitamins, tocopherols, steroids and gamma-

linolenic acid (GLA).

 

b. Animal-derived functional foods

Zoochemicals, which are animal-derived functional foods, include omega-3 and

omega-6 fatty acids, conjugated linolenic acid (CLA), small peptides, whey and

casein, and glucosamine.Omega-3 fatty acids include alpha-linolenic,

docosahexaenoic (DHA), and eicosapentaenoic (EPA) fatty acids whereas Omega-6

fatty acids include linoleic, gamma-linoleic, and arachidonic fatty acids.

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c. Microbial functional foods

Microbial-derived functional foods include four groups of foods viz., Probiotics,

Prebiotics, Symbiotic, and Synbiotics. Recently, a new food has been included and

that is Postbitics.

i. Probiotics: Probiotics are the mono or mixed culture of living

microorganisms, which when ingested in certain amounts, has a positive

impact on host health, beyond conventional nutritional effects.These

stimulate the growth of certain other bacteria in the colon, thus improve

health.Bacteria most often used as probiotics are Lactobacilli and

Bifidobacteria which can be given along with the fermented foods e.g.

youghrt, fermented vegetables/ meat.

ii. Prebiotics: Prebiotics are ingredients/ compounds that have a beneficial

effect on microflora in the large intestine of the host e.g. fibre, fructo

oligosaccherides, lactulose, sugar alcohols. Generally they are

carbohydrate that may be fermented in the large bowel and stimulate

growth of potentiality beneficial Bifidobacteria. The most prevalent forms

of prebiotics are nutritionally classed as soluble fiber.

iii. Sybiotics and Synbiotics: Symbiotics contain probiotics and prebiotics

combined randomly while synbiotics contain specific probiotics and

prebiotics mixed together to benefit one another.Because the word alludes

to synergism, this term should be reserved for products in which the

prebiotic compound selectively favors the probiotic compound. For e.g., a

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product containing oligofructose and probiotic bifidobacteria would fulfill

the definition.

iv. Postbiotics: Postbiotics are the non-viable bacterial products or

metabolic byproducts from probiotic microorganisms that have biologic

activity in the host. General, postbiotics include bacterial metabolic

byproducts, such as bacteriocins, organic acids, ethanol, diacetyl,

acetaldehydes and hydrogen peroxide, but it is also found that certain heat-

killed probiotics can also retain important bacterial structures that may

exert biological activity in the host.

Non Food Sources: Apart from plant,animal and microbial sources there are non

food sources of nutraceuticals. Using modern fermentation methods, few

nutraceuticals can also be produced. For example, amino acids and their

derivatives have been produced by bacteria . Eicosapentaenioc acid produced by

some algae and bacteria. But now using recombinant – genetic techniques , this

EPA can also be produced by non –EPA producing bacteria.

B. Classification based on Nutrient and Non Nutrient Components

From the nutritional viewpoint, they can be categorized as nutrients and non

nutrients and has been presented in Table 1.

Table 1: Classification of Functional foods based on nutrients and non nutrients

components

Nutrient Non nutrients

Lipids Fibre: insoluble and soluble fibre

N3 fatty acids Phenolic Compounds: Phenolic

Conjugated fatty acids acids, Flavonoids, catechins and

Vitamins Tannins

Folates Non digestible oligosaccherides:

Vitamin E Fructans, Galacto oligosaccharides,

Carotenoids: b-carotene and isomaltos oligosaccharides, Xylo

alpha carotene oligosaccharides

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Vitamin c Phytosterols

Minerals Glucosinolates

Selenium Carotenoids: Lutein, cryptoxanthine

Lycopene
Organosulphur Compounds

 

C. Classification based on Organ/Organ System

Another classification is by the target organ/system benefitted. This is of clinical

significance especially with respect to treatment and management of various

diseases. Examples of functional foods, on the basis of their beneficial impact on

different organ system, have been presented in Table 2.

Table 2: Classification of functional foods according to organ/organ system

 

SN Organ/organ system Food Component

1. Gastrointestinal tract Prebiotics, soluble and insoluble fibres, Probiotics,

Polyphenols, Phytate

2. Cardiovascular system N-3 fatty acids, Polyphenols, Micronutrients,

Soluble fibre

3. Kidney Fructans

4. Immune System Prebiotics, Probiotics, Nutrients, n-3 fatty acids,

polyphenols

5. Skeletal system Fructans

D. Classification According to Modifications in Foods

Some foods are naturally functional and do not require much modification whereas

others do. Foods may be made functional by:

1. Elimination of components e.g. toxins or allergenic proteins

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2. Increasing the concentration of natural component e.g. fortification

3. Addition of components with beneficial effects e.g. non vitamin antioxidants.

4. Addition of beneficial microbes e.g. some yeasts, bacteria.

5. Replacement of a component, usually a macronutrient e.g. fat replaced with

modified or emulsified carbohydrates. And

6. Enhancement of bioavailability of components.

According to modifications done the foods are classified as:

1. Fortified foods

2. Enriched foods

3. Enhanced foods

4. Altered foods

 

Fortified foods are foods fortified with additional nutrients e.g. vitamin fortified milk

and Calcium-fortified orange juice. These nutrients which are fortified are present in

foods but are not in appreciable amounts.

Enriched foods are foods with added new nutrients or components not normally

found in a particular food e.g. folic acid enriched breads, butter with phytochemicals,

probiotics etc.

Altered products are foods from which harmful components has been removed,

reduced or replaced with another substance with beneficial effects.E.g. fibers as fat

replacers in high fat products.

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Enhanced commodities are foods in which one of the components has been

naturally enhanced through special growing conditions, new feed composition,

genetic manipulation or otherwise. Examples are eggs with increased omega 3 fatty

acids content achieved by altered chicken feed, Conjugated linoleic acid enriched

milk achieved by feed manipulation etc.

E. Classification based on Nutraceutical Factors in Specific Foods

This classifiction is more appropriate when there is interest in a particular

nutraceutical compound or related compounds. There are several nutraceutical

substances that are found in higher amounts in specific foods or food families such

as capsaicinoids are found primarily in pepper fruit, and allyl sulfur (organosulfur)

compounds are chiefly concentrated in onions and garlic. The nutraceuticals that

are considered exceptional to certain foods or food families have been presented in

Table 3.

Table 3: Foods with Higher Content of Specific Nutraceutical Substances

 

SN Nutraceutical

Foods of Remarkably High Content
Substance/Family

1. Allyl sulfur compounds Onions, garlic

2. Isoflavones (e.g., genestein,
Soybeans and other legumes,

daidzein)

3. Onion, red grapes, citrus fruit, broccoli,
Quercetin

Italian yellow squash

4. Capsaicinoids Pepper fruit

5. EPA and DHA Fish oils

6. Lycopene Tomatoes and tomato products

7. Cruciferous vegetables

Isothiocyanates cauliflower, cabbage, garden cress, bok

choy, broccoli, Brussels sprouts and

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similar green leaf vegetables

8. Β-Glucan Oat bran

9. CLA Beef and dairy

10. Resveratrol Grapes (skin), red wine

11. Β-Carotene Citrus fruit, carrots, squash, pumpkin

12. Carnosol Rosemary

13. Catechins Teas, berries

14. Adenosine Garlic, onion

15. Cabbage, broccoli, cauliflower, kale,
Indoles

brussels sprouts

16. Curcumin Turmeric

17. Ellagic acid Grapes, strawberries, raspberries, walnuts

18. Anthocyanates Red wine

19. 3-n-Butyl phthalide Celery

20. Cellulose Most plants (component of cell walls)

21. Lutein, zeaxanthin Kale, collards, spinach, corn, eggs, citrus

22. Psyllium Psyllium husk

23. Monounsaturated fatty acids Tree nuts, olive oil

24. Inulin, Fructooligosaccharides
Whole grains, onions, garlic

(FOS)

25. Lactobacilli, Bifidobacteria Yogurt and other dairy

26. Catechins Tea, cocoa, apples, grapes

27. Lignans Flax, rye

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F. Classification based on Mechanism of Action

This system groups nutraceutical factors together, irrespective of food source,

based upon their proven or assumed physiological properties. Among the

classes are anticarcinogenic, antioxidant, anti-inflammatory, antibacterial,

osteoprotective, and so on. This classification would be helpful to an individual

who is genetically predisposed to a particular medical condition , researchers are

trying to develop potent functional foods for such persons or planning diet and

product developer to develop a new functional food. The different groups of

nutraceuticals according to proven properties are as follows:

• Nutraceuticals having anticancer properties include components such as

capsaicin, genestein,daidzein, α- Tocotrienol and γ –Tocotrienol, Conjugated

Linoleic acid , Lactobacillus acidophilus, Sphingolipids, Limonene, diallyl sulfide,

Ajoene, α-Tocopherol, Enterolactone, glycyrrhizin, Equol, Curcumin, ellagic acid,

Luetin, Carnosol and L. bulgaricus.

• Positive Influence on Blood Lipid profile: β- Glucan, γ-Tocotrienol, δ-

Tocotrienol, MUFA,Quercetin, ω -3 PUFAs, Resveratrol, tannins, β-Sitosterol,

saponins, guar and pectin.

• Antioxidant activity: Conjugated Linoleic acid, Ascorbic acid, β- Carotene,

Polyphenolics, Tocopherols, Tocotrienols, Indole -3- carbonol, α-Tocopherol,

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Ellagic acid, Lycopene, Lutein, Glutathione, Hydroxytyrosol, Lutolin, Oleuropein,

Catechins, Gingerol, Chlorogenic acid, Tannins

• Antiinflammatory: linolenic acid, EPA, DHA, GLA(Gamma-linolenicacid),

capsaicin, Quercetin and Curcumin.

• Osteogenetic or Bone protective nutraceuticals: CLA, Soy protein,

Genesetin, daidzein, Calcium, Casein phospopeptides,

FOS(fructooligosaccharides), Inulin.

 

G. Classification of nutraceuticals based on chemical nature

This classification permits nutraceuticals to be categorized under

molecular/elemental groups. This preliminary model includes several large groups,

which then provide a bases for subclassification or subgroups, and so on. One way

to group nutraceuticals grossly is as follows:

• Isoprenoid derivatives

• Phenolic substances

• Fatty acids and structural lipids

• Carbohydrates and derivatives

• Amino acid-based substances

• Microbes

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• Minerals

a. Isoprenoid Derivatives (Terpenoids)

Isoprenoids and terpenoids are terms used to refer to the same class of molecules.

These substances are one of the largest groups of plant secondary metabolites. Many

popular nutraceutical families comes under this group such as carotenoids, tocopherols,

tocotrienols, simple terpenes and saponins. This group is also referred to as isoprenoid

derivatives because isoprene is the principal building block molecule which is

synthesized from acetyl coenzyme A (CoA).

b. Phenolic Compounds

Phenolic compounds are also considered secondary metabolites. The base for family of

molecules is a phenol structure, which is a hydroxyl group on an aromatic ring. From

this structure, larger molecules are formed viz., anthocyanins, coumarins, isoflavones,

flavonones, flavonols, tannins, and lignin.

c. Carbohydrates and Derivatives

Ascorbic acid (Vitamin C) is the glucose derivative and functions as an antioxidant.

Many plants produce some oligosaccharides which functions as prebiotic substances.

Several plant polysaccharide families are not readily available energy sources for

humans as they are resistant to secreted digestive enzymes. These polysaccharides

are grouped together along with lignin to form one of the most recognizable

nutraceutical families — dietary fibers. The nonstarch polysaccharides are further

divided into homogeneous and heterogeneous polysaccharides, as well as into soluble

and insoluble substances.

d. Fatty Acids and Structural Lipids

Fatty acids and/or their derivatives include the ω-3 PUFA found in higher amounts in

plants, fish, and other marine animals, and conjugated linoleic acid (CLA) produced by

bacteria in the ruminants.

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e. Amino Acid-Based

This group includes intact protein (i.e., soy protein), polypeptides, amino acids, and

nitrogenous and sulfur amino acid derivatives. A few amino acids are also being

investigated for their nutraceutical potential now a days. Among these amino acids is

arginine, ornithine, taurine, and aspartic acid. Arginine has been considered to be

cardioprotective since it is a precursor molecule for the vasodilating substance nitric

oxide (NO). Also, arginine may reduce atherogenesis. The nonprotein amino acid

taurine may also have blood pressure-lowering as well as antioxidant properties. Other

examples are isothiocyanates, indole-3-carbinol, allyl sulfur compounds, and

capsaicinoids. Another nutraceutical amino acid-derived molecule is folic acid, which is

believed to be cardioprotective by minimizing homocysteine levels. Other members of

this group would include the tripeptide glutathione and choline.

f. Microbes (Probiotics)

Other groups of nutraceuticals include molecules or elements, whereas probiotics

includes live bacteria. A good probiotic must be resistant to acid conditions of the

stomach, bile, and digestive enzymes normally found in the human gastrointestinal

tract; able to colonize the human intestine; be safe for human consumption; and have

scientifically proven efficacy. Among the bacterial species recognized as having

functional food potential are Lactobacillus acidophilus, L. plantarum, L. casei,

Bifidobacterium bifidum, B. infantis, and Streptococcus salvarius subspecies

thermophilus. Some yeasts have been noted as well, including Saccharomyces

boulardii.

g. Minerals

Several minerals have been recognized for their nutraceutical potential and thus have

been included under functional foods. Among the most evident is calcium with relation

to bone health, colon cancer, and perhaps hypertension and cardiovascular disease.

Potassium has also been found to reduce hypertension and thus improve

cardiovascular health. A couple of trace minerals have also been found to have

nutraceutical potential such as copper, selenium, manganese, and zinc. All these trace

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minerals have antioxidant property. Copper, zinc, and manganese are components of

superoxide dismutase (SOD) enzymes, whereas selenium is a component of

glutathione peroxidase. Certainly more research is required in the area of trace

elements in view of their metabolic relationships to other nutrients and the potential for

toxicity.

Let us summerize

Thus we have seen the classification of functional foods and nutraceuticals according to

source/origin, nutrient/non nutrient, organ/organ system, modifications in foods, specific

functional components, mechanism of action and chemical nature of food. According to

source or origin, functional foods are classified as plant foods, animal foods and

microbial foods. According to nutrient and nutrient, functional foods are classified as

nutrient viz., lipids, Vitamins and minerals. According to organs, functional foods have

been classified according to beneficial effects on Gastrointestinal tract, Cardiovascular

system, Kidney: Immune System and Skeletal system. According to modifications, the

foods are classified as: Fortified foods, Enriched foods, Enhanced foods and Altered

foods. According to mechanism of action, they are classified as antioxidant,

antibacterial, antihypertensive, antihypercholesterolemic, antiaggregate, anti-

inflammatory, anticarcinogenic and osteoprotective. According to chemical nature of

foods nutraceuticls have been classified as Isoprenoid derivatives, Phenolic

substances, Fatty acids and structural lipids, Carbohydrates and derivatives, Amino acid-

based substances, Microbes and Minerals.

References

1. Arai, S., Vattem, D., & Kumagai, H. (2016). Functional Foods-History and

Concepts. In D. A. Vattam, & M. Vatsala, Functional Foods, Nutraceuticals and

Nautral Products, Concepts and Applications, Lancaster,Pennsylvania,U.S.A.:

DEStech Publications Inc., 1-18.

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Module 2: Classification of Functional Foods and Nutraceuticals

2. Kerry, R. G., Patra, J. K., Gouda, S., Park, Y., Shin, H., & Das, G. (2018).

Benefaction of Probiotics for Human Health: A Review. Journal of Food and Drug

Analysis, 927-939.

3. Wildman, R., & Kelley, M. (2007). Nutraceuticals and Functional Foods. In R.E.C.

Wildman, Handbook on Nutraceuticals and Functional Foods (pp. 1-22). Taylor

and Francis Group: CRC Press.

4. http://egyankosh.ac.in/bitstream/123456789/33348/1/Unit-11.pdf accessed on 12

June 2018

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cheese-450w-243530956.jpg accessed on 5th June 2019.

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450w-722718097.jpg accessed on 5th June 2019.

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wicker-basket-450w-88218493.jpg accessed on 5th June 2019.

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66376402.jpg accessed on 5th June 2019.

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