Introduction
Flavor encapsulation is the process of coating the flavoring substance with a protective layer. It is done to protect the flavor from degradation over time and increase the shelf life of the product by retaining its flavor. The modern encapsulation employs three major technologies viz. macro (> 5,000 μm), micro (1–1,000 μm), and nano (1–100 nm) technology. In the food processing industry, encapsulated flavor substances are used in a variety of foods such as snacks, beverages, and dairy products. In beverages, flavor substances are primarily used in the form of micro or Nano-emulsions. The flavor substances in the colloidal dispersions are often encapsulated in micro or Nano emulsions before they are used in the formulation of beverages.
Flavor Encapsulation: Decoding the Pros and Cons
During the process of encapsulation, flavor substances are often trapped in a carrier or wall materials. These trapped flavor substances are then referred to as core or active ingredients. This wall material acts as a physical barrier between the sensitive core ingredient and the outer environment. It preserves the stability of the flavor substances during food processing and storage. As compared to other encapsulation technologies, nano-encapsulation technology is more effective at encapsulating flavor substances. It offers improved stability, encapsulation efficiency, and controlled release.
Materials Used For Encapsulation
Traditional Materials
The process of encapsulation uses various types of materials. These materials are based on biodegradable, food-grade, lipids, proteins, or polysaccharides. These encapsulation techniques help to protect flavor substances. However, these substances had limited ability to control the release of these ingredients.
Nanoencapsulation and Micro-Encapsulation: Novel Encapsulation Techniques
The food processing industry has also evolved with the development of science. It helped to develop novel encapsulation techniques to stabilize flavor substances. There are two main types of encapsulation technologies. They help in the protection and delivery of flavors and aroma compounds. These are Nano- encapsulation and micro-encapsulation. When coupled together, these technologies give rise to various encapsulation systems. These include Nano/microcapsules, molecular inclusion complexes, micro/nanoparticles, solid–lipid micro-particles, crystalline particles, fibrous films, nanotubes, nanoparticles, conventional or micro/Nano-emulsions, and multiple emulsions.
Physical–Mechanical Encapsulation Methods
Extrusion
Extrusion is a physical mechanical and gelation technique for the encapsulation of flavor substances. It includes preparation of an aqueous solution of the wall material (sodium alginate). Then a nozzle, a spinning disk, or a double capillary is used to force the mixture into a gelling environment. This technique is useful for the encapsulation of heat-degradable flavor substances.
Subcategorization of extrusion technique includes electrospinning/electrostatic, jet cutting, co-extrusion/centrifugal, coaxial airflow, dripping/prilling, particle from gas-saturated solution, hot–melt extrusion, and melt injection.
Spray Drying
It is a rapid, simple, and relatively cost-effective encapsulation technique. Food Processors employ this encapsulation technique to produce powdered flavor by the solidification of a homogenized colloidal solution of the flavor compound and delivery agent.
Spray Chilling
This encapsulation technology is also known as prilling, spray congealing, and spray cooling. It is a microencapsulation technique that employs a similar operation process as spray drying. But instead of a hot air chamber, it employs a cooling chamber.
Significance of the Flavor Encapsulation
The process of flavor encapsulation is important in the food system. It decreases the volatility, oxidation, evaporation, thermal, and photo and chemical degradation of flavor substances. It also helps to improve gustatory and olfactory perception. Olfactory perception is the process by which the brain interprets smells while gustatory perception is the ability to sense the taste of food or other substances.
Flavor Protection
Encapsulation checks oxidation, evaporation, and migration of flavors extending the acceptability of the food products.
Flavor Release Control
Encapsulation ensures the release of flavors at the desired time and in the desired amount. It helps to enhance the taste of the food products.
Handling
It makes flavors easier to incorporate into food mixtures in the right proportion giving an option to explore different tastes.
Shelf Life Extension
The process prolongs the time flavors are effective in a particular food product. Hence, it helps in the extension of the shelf life of the food products.
Challenges Faced by the Encapsulation Process
The characteristics of Nano-encapsulation such as the smaller particle size and increased surface area help in achieving the aforesaid goal. However, the encapsulation process faces several challenges.
Smaller Size of Flavoring Substances
The decreasing size of the flavoring substances in the food has made the process of encapsulation challenging. The use of spray drying, spray chilling, emulsification, and coacervation for the development of micro or nanoparticles of flavor substances has made coating challenging.
Conclusion
In the food processing sector, the development of functional foods and functional ingredients in foods (including flavor substances) has brought new challenges. These substances are volatile and become unstable during processing and storage. Further, flavor substances also play important roles in improving the consumer acceptability of functional foods which in turn promotes their consumption. Hence, their protection becomes a necessary part for food scientists. The industry must focus on some more technologies in flavor encapsulation to meet the rapidly changing food processing landscape.