Processed foods currently form a major part of the diet of industrialized societies. A number of processed foodstuffs have low levels of key nutrients, either due to the method of processing or due to the cultural trend towards foods high in sugar, salt, and fat.
It is becoming more and more important to find solutions that offer the necessary nutrients for a healthy lifestyle, and that enhance the sustainability of the food supply chain - all whilst maintaining the low cost of processed food that so many depend on.
Many researchers in the food industry are now looking for ways to use nanotechnology to design delivery mechanisms for nutrients and to improve the efficiency of nutrient delivery from food.
The design of efficient nanoparticle delivery systems for nutraceuticals, nutrients, and related active ingredients requires a deep understanding of the biological processes regulating bioavailability and uptake.
Nanoencapsulation could make the delivery of vitamins and other nutrients to the body much more efficient - effectively adding tiny vitamin tablets to our food.
There are many nutrients that are essential for good health, and that can help us to maintain a healthy immune system. Not all of these are well suited to nanoencapsulation, however. Nutrients that can be targeted for nanoencapsulation are typically those that are less soluble in water - these include vitamins and antioxidants such as carotenoids, omega-3 fatty acids, green tea polyphenols, curcumin, coenzyme Q10, and quercetin.
The features of a good delivery system are:
- Must contain a sufficient amount of bioactive substance and retain it during processing, storage, and transport
- Must prevent chemical degradation or oxidation of the active substance
- Must be incorporated easily into food and drink without a change in texture, flavor or appearance
- Must be made using materials that are proven safe as per safety standards and comply with good manufacturing practices
- Must show an optimal cost/benefit ratio
- Must show efficacious targeted delivery and controlled release of the nutrient
Types of Nano Encapsulation
Nanotechnology has been used in the development of several nutritional supplements - reducing the particle size of the active compounds is a well-proven way to improve their absorption.
The active nutrient molecules are isolated and then enclosed in a shell material which can be effectively and immediately absorbed in the body. There are several materials available for this purpose based on both synthetic and natural materials.
These platforms include the following:
Nanoemulsions made from food-grade ingredients are used extensively in the food industry to protect, encapsulate, and deliver lipophilic functional components such as oil-soluble vitamins, preservatives, and nutraceuticals, and biologically active lipids.
Solid Lipid Nanoparticles are either semi-crystalline or crystalline and stabilized by a surfactant coating. These are also made by emulsion technologies, are stable, and enable the delivery of hydrophobic materials.
Liposomes are capsules that consist of a lipid bilayer with a watery interior and normally include phospholipids, such as phosphatidylcholine. Liposomes enable the delivery of hydrophilic compounds.
Micelles are droplets of surfactants, which may be biopolymers or lipids in a liquid. Micelles normally enable the delivery of hydrophobic compounds.
Whey proteins include β-lactoglobulin and α-lactalbumin. They can form hydrogels, fibrils, and nanoparticles based on processing conditions. It is resistant to enzymes and stomach acid. These proteins can deliver hydrophilic compounds to the intestinal mucosa. It can be used to provide a nanoscale structure to food.
Chitosan carbohydrate is taken from crustaceans. It is bio-compatible, non-toxic, and mucoadhesive. It forms hydrogels and nanocapsules. It enables the delivery of different compounds to the oral or to the intestinal mucosa as part of a multi-component layered system.
Degradable and bio-compatible silica can be made highly nanoporous. It enables the delivery of various hydrophilic nutrients to the stomach.
Examples of Nanoencapsulation
A number of research groups and companies are striving to develop new on-demand foods that will remain dormant in the body and deliver nutrients to cells whenever required. A key element is developing nanocapsules that can be incorporated in food to develop nutrients. Certain examples of nanoencapsulation are given below:
Tip-Top, a leading bakery in West Australia, has incorporated nanocapsules containing tuna fish oil in their bread products. These nanocapsules break open only when they reach the stomach, avoiding the unpleasant taste of fish oil.
Nutralease uses nano-sized, self-assembled liquid structures (NSSL) technology to deliver nutrients to cells. The nanoparticles are expanded micelles, which have an aqueous interior able to contain “nutraceuticals”. The included nutraceuticals are beta-carotene, lycopene, lutein, phytosterols, CoQ10, and DHA/EPA. These particles allow these compounds to enter the bloodstream from the gut improving their bioavailability. The technology is presently been marketed by Shemen Industries to deliver Canola Activa oil, which is claimed to bring down cholesterol intake by 14%.
Biodelivery Sciences International has developed nanocochleates - 50 nm coiled nanoparticles which can be used for the delivery of nutrients such as lycopene, omega fatty acids, and vitamins.
Aquanova has combined two active substances for satiety and fat reduction into a single nano-carrier, the innovation being a novel approach to intelligent weight management. NovaSOL Sustain makes use of CoQ10 for fat reduction and alpha-lipoic acid for satiety.
Food giants like Kraft, Unilever and Nestle are actively developing nano-emulsions of oils and fats to carefully control food texture - this not only allows for a more consistent product but can also potentially decrease the amount of fat needed in a product to achieve the desired properties, potentially making processed foods much healthier.
livethesource® nutritional products use a patented and proprietary all-natural nanoencapsulation material. The company has made use of natural plant lipids as a basis of its nanoencapsulation material. Hence the food-grade material is not just absorbed and recognized as safe by the body, it also delivers the active ingredient in a quick and effective way, with no danger of any adverse response from the body.
There is still a lot of debate on nano ingredients in food including some on encapsulation. According to the Friends of the Earth (FoE), nanoencapsulation may reduce the number of additives needed - increasing profits for food manufacturers. Some commentators are concerned about possible health risks due to a greater potential for the uptake of nanomaterials at the cellular level - the effect of their chemical activity at this level is not well understood. FoE is also anxious that nano-additives may result in further increased consumption of unhealthy processed foods.
Nanoencapsulation offers the potential to provide a method to deliver difficult-to attain nutrients in fortified food products. Nutraceuticals provide nutrients that have clear disease prevention or therapeutic effect and promise to be better delivered and more bioavailable through nanoencapsulation. The legislation is probably the biggest barrier to the commercialization of this technology. There needs to be a clear regulatory landscape without which growth in this area and usage of research findings will be limited.