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This certain antioxidants like carotenoids have the

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This
research proposal mainly revolves around the need of considering food as
medicine. The concept is not new, as it was first introduced in 1989 by Stephen L. DeFelice,
who also introduced the term ‘Nutraceuticals’, combining nutrition with
pharmaceuticals. Nutraceuticals are a class of compounds that are generally
used to improve health, delay the aging process, prevent chronic diseases,
increase life expectancy, or support the structure or function of the body.
These include nutrients like vitamins, minerals, structural lipids, amino
acids, polyphenols and Isoprenoids etc., which are mostly extracted from plant
and dietary sources. It has been widely reported that flavonoids which are
mainly plant extracts have an active role in preventing and curing cardio vascular
diseases. These flavonoids block the angiotensin-converting enzyme, which
further helps in blocking the cyclooxygenase enzymes that break down
prostaglandins, and prevent platelet aggregation. They also protect the
vascular system that carries oxygen and nutrients to cells. Recent interest in
Nutraceuticals has grown due to the fact that certain antioxidants like carotenoids
have the ability to inhibit cancer growth. Lycopene is one of the major
carotenoids and is found exclusively in tomatoes, guava, pink grapefruit, water
melon and papaya. Because of the unsaturated nature of lycopene it is
considered to be a potent antioxidant and a singlet oxygen quencher. Lycopene
concentrates in the prostate, testes, skin and adrenal where it protects
against cancer.

However,
even today after nearly 30 years of introduction of such a novel concept we are
yet to completely implement the use of these nutritional elements as medicine.
They are merely used as extra supplements without genuinely studying their fate
once consumed or how much is the actual bioavailability of these nutrients after
ingestion. Bioactive compounds like vitamins, minerals, polyphenols,
isoprenoids etc. are highly lipophilic in nature. Direct intake of these
bioactive compounds poses problems like poor solubility in aqueous phase,
crystallization, chemical instability and low bioavailability etc. In order to
encapsulate these bioactive compounds, a more technical matrix is required that
can provide controlled release during chewing and digestion, protection against
acidic conditions in our body, and long term stability with a targeted and
efficient delivery to the desired site. 

Conventionally
emulsions have proven to be useful in this particular interest, where the
lipophilic component can be encapsulated within the core of hydrophobic part of
emulsifier (surfactant) and remain solubilized in aqueous phase for easy
consumption/ handling. These emulsions are generally macro emulsions where the
particle size lies between a distributions of 1-100 µm in size. Due to larger
size ratios these emulsions are often prone to droplet aggregation, and
sedimentation leading to phase separation. A significant improvement in terms
of stability, release and bioavailability of nutraceuticals from the emulsion droplets can be achieved with the
help of nanotechnology, viz. making
nano-emulsions.

Nano-emulsions (1-100 nm) based delivery systems have
already captured much of the interest in drug delivery applications due their
controlled, selective and efficient delivery of drugs to desired parts of the
body, but their application in food industry is relatively new. These
nano-emulsions are found to be nearly monodisperse, highly stable against
aggregation, and hence do not undergo phase
separation owing to relatively small droplet size that have Brownian motion
effects dominating over gravitational forces. Due to high surface area to
volume ratios chemical reactions like lipid digestion occurring at the
oil-water interface are accelerated which offers promising ways for improving
bioavailability of lipophilic compounds like phytosterols, carotenoids and vitamins
etc. For this reason, the bioavailability of lipophilic substances encapsulated
within nano-emulsions is often considerably higher than that in conventional macro-emulsions.
Different classes of nanocarriers such as liposomes, polymeric nanoparticles,
nanocrystals, nano-emulsions, micro-emulsions, solid lipid nanoparticles (SLN’s)
etc. have been used to improve drug and gene delivery, targeted therapy, and diagnostics.
Although most of these systems have proven to be ideal systems for drug
delivery applications but their use in food industry is highly limited as they
require high surfactant concentrations for production, low payload, lack
chemical stability during storage and can undergo Ostwald ripening /
flocculation and, become structurally unstable in acidic conditions.

One
of the solutions to this problem can be encapsulating these bioactive compounds
in Nanostructured Lipid Crystals (NLC’s). These are basically modified SLN in
which the lipidic phase contains both solid (fat) and liquid (oil) lipids at
room temperature. The NLC contains lipid droplets that are partially
crystallized and amorphous solid structure. The purpose of NLC formulation is
to produce particles in which the oil is incorporated into the core of a solid lipid.
This helps in dissolving the bioactive lipophilic content in the solid &
liquid based lipid inside the NLC’s, which increases the payload efficiency and
provides controlled release. ­In combination to the  oil
based core in the NLC, the spherical shape of the particle may
account for improvement of the overall properties. It therefore seems that NLC overcome
the drawbacks, and at the same time possess the advantages of other lipid
nano-carriers.

 With the help of these NLC’s one can expect to
dispel the limitations of poor
water-solubility, chemical instability, and low bioavailability encountered
during fortification of aqueous-based foods with nutraceutical ingredients. A
combination of high payload and controlled release with targeted delivery of
these nutraceutical compounds can help large sect of masses in promoting
general well-being of individuals, control and prevent virulent conditions,
deal with deficiency and malnutrition and in post disease related conditions. After
ingestion these carrier systems have to travel through varying environments in
terms of temperature and pH changes (ranging from 7 to 1) accompanied by the
action of different enzymes like amylase, lipase, protease etc. at different
locations. To be a carrier system that can provide a better targeted delivery
with high bioavailability these NLC’s can be surface modified with biopolymers
that can provide physical and chemical barriers to resist the action of
digestive enzymes that defy the active compound from reaching Gastrointestinal (GI)tract.
The bioavailability is largely dependent on three factors viz. (1) Bio-accessibility
coefficients that define the amount of active compound released into the
digestive juices, (2) Transport
coefficient that is mainly the active compound that reaches the intestinal
epithelium, and (3) Metabolism coefficient which is the content that finally reaches
systematic circulation without getting metabolized where it finally gets
distributed between different tissues. 

Currently the industrial scale
production of these NLC’s is restricted to medicines due to unavailability of
food grade (Generally recognized as safe, GRAS) ingredients. Studies are
required for appropriate grade materials that can be
used in large quantities. This would further ask for carrying out stability
studies of NLC starting from processing, storing, heat treatment, freezing,
drying, changes in pH and ionic strength etc. Working closely on these aspects can help us in finding a way
to make supplements act like medicines in the form of functional food at
reasonable and more affordable prices so that they can be made available to
people who can be genuinely benefitted.