2.5.1 Controlled-release encapsulation system for food additives, ingredients and flavours
Multicomponent delivery system delivers multiple active ingredients that do not normally mix well, such as water-soluble and fat-soluble ingredients, and releases them consecutively.It enhances the stability and bioavailability of a wide range of nutrients and other ingredients, controls their release characteristics and prolongs their residence time in the oral cavity. The system consists of solid hydrophobic nanospheres composed of a blend of food-approved hydrophobic materials encapsulated in moisture-sensitive or pH-sensitive bioadhesive microspheres. A proprietary suspension technology generates nanospheres with a diameter of about 0.01-0.5 microns. The nanospheres are then encapsulated in microspheres of about 2050 microns in diameter. The nanospheres are not individually coated by the moisture-sensitive microsphere matrix, but are homogeneously dispersed in it. When the microsphere encounters water, such as saliva, it dissolves, releasing the nanospheres and other ingredients, c.f. Fig. 3. Nanospheres (blue) containing an active ingredient (purple) are encapsulated with other ingredients such as flavours, cooling or heating agents, or sweeteners, within a microsphere (yellow). Over an extended period of time the nanospheres release the encapsulated active ingredient via molecular diffusion and enzymatic degradation by lipase. The surface properties of the nanospheres (shown as squiggly lines) can be altered to be bioadhesive or negatively or positively charged depending on the intended target site.
The active ingredients and sensory markers encapsulated in the nanospheres can be the same as, or different from, those encapsulated in the microspheres. The nanosphere surface can include a moisture-sensitive bioadhesive material, such as starch derivatives, natural polymers, natural gums, etc., making them capable of being bound to a biological membrane such as the oral cavity mucosa and retained on that membrane for an extended period of time. The nanospheres can be localised and the target ingredient encapsulated within their structure to a particular region, or a specific site, thereby improving the bioavailability of ingredients with poor bioavailability. Enhancing the hydrophobicity of these ingredients enhances their bioavailability.
Figure 3 - How the controlled-release encapsulation system works
Major potential product applications for the nanosphere/microsphere system are:
- baked goods,
- refrigerated/frozen dough and batters,
- tortillas and flat breads,
- processed meats,
- acidified dried meat products,
- microwavable entrees,
- seasoning blends,
- specialty products,
- chewing gum,
- dessert mixes,
- nutritional foods,
- products for well-being,
- health bars,
- dry beverage mixes.
Some products based on this application are already on the market (see point 3.1.4 for examples).
Following functional attributes of multi-component delivery system can be considered as the main benefits of nanotechnologies:
- Ease of handling - The system can be utilised to transform volatile liquids such as flavours into a powder, which are in many cases easier to handle.
- Enhanced stability - The system can be utilised to isolate active ingredients as well as flavours that may interact with the other food ingredients. This provides long-term product shelf life.
- Protection against oxidation - The microspheres have very low surface oil (less than 0.5%) at very high payloads (3040%) compared to conventional spray-dried particles utilising materials such as gum arabic or starch.
- Retention of volatile ingredients - The moisture-sensitive matrix provides excellent retention of highly volatile ingredients, such as flavours, over an extended period of time to reduce the flavour loss during the product shelf life.
- Taste masking - Unwanted taste can be masked by preventing interaction between the active molecule and the oral mucosal surface. The nanospheres are hydrophobic and can prevent bitter ingredients encapsulated within their structure from going into solution and interacting directly with taste receptors.
- Moisture-triggered controlled release - As discussed above, the microspheres dissolve in the presence of water or saliva to release the active ingredients or flavours, thereby providing a high impact flavour "burst."
- pH-triggered controlled release - Ingredients can be encapsulated in the microspheres to enhance their stability during the product shelf life and to release them when needed or upon food consumption. This pH triggered release was initially designed to deliver drugs to different regions of the gastrointestinal tract.
- Heat-triggered release - The hydrophobic nanospheres are temperature sensitive and can be utilised to release active ingredients and flavours at a certain temperature, e.g., upon heating in an oven or microwave oven or the addition of hot water for hot drinks and soups.
- Consecutive delivery of multiple active ingredients - Two or more ingredients that would react with each other if put together can be separated and provided consecutively by placing one in the nanosphere and the other in the microsphere. An example is encapsulation of folic acid and iron that work synergistically.
- Change in flavour character - Encapsulation of a flavour in the nanospheres that is different from the flavour encapsulated in the microsphere can provide a perceivable change in the organoleptic perception in response to moisture during the use of the product.
- Long-lasting organoleptic perception - As a result of the bioadhesive properties of the nanospheres and their residence in the oral cavity, flavour perception and mouth-feel can be extended over a longer period of time.
- Enhanced bioavailability and efficacy - As a result of their hydrophobic/lipophilic nature, the nanospheres can enhance the bioavailability of various active ingredients, such as vitamins, nutrients and other biologically active agents encapsulated within their structure.
The further development in this area is strongly dependent on the perception of nanotechnologies in food and food contact materials by the public. Food companies are still hesitant to incorporate nanomaterials for uncertainty of future regulations and standards and for fear of negative consumer reactions. Experts also alert to the absence of reliable data relevant to consumer health and lack or regulations for use of nanomaterials, especially for food contact materials.
MultiSalTM Flavor/Cooling is a product of Salvona Technologies, which utilizes multi component nanotechnology to provide multi-sensorial and dynamic release of active ingredients. It consists of solid hydrophobic nanospheres encapsulated in a water or pH sensitive microsphere which can hold multiple ingredients in the same carrier system and release them, one after another; even target specific sites. A submicrontechnology with a brand name of MultiSalTM Collagen Tripeptide is used to enhance the bioavailability of Tripeptides used for antiaging by enhancing collagen production. This technology permits the use of water based actives in dry and anhydrous formulations such as lip care, serum, etc.
There is no economic information about the present products available; however, the global food additives market is expected to reach a value of 25.3 billion US$ in 2007. The recent growth has been most impressive in those additives most relevant to the prevailing trend towards lower-fat foods. In US the food and beverage additive demand is projected to exceed $8 billion in 2012. Growth will be prompted by greater use of additives to improve finished product quality and to control costs, as well as by fast growth of newer food and beverage products, such as enhanced and flavoured waters.
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