Mr. Vinit Maru, Dr. S. M. Wankhede
I/C Professor, Dept. Of Animal Nutrition, COVAS, Parbhani
Encapsulation is one of the processes where bioactive core compounds are coated with various carrier materials to protect them against external as well as internal adversities and to ensure the viability of the active ingredients for longer periods. Application of such kind of techniques has increased since bioactive materials can be protected from moisture, heat, or other extreme conditions, thus enhancing their stability as well as maintaining their quality. Encapsulation is used in many fields such as pharmacology, chemistry, cosmetics, medicine, biotechnology, textile, agriculture and food. Without encapsulation, many compounds lose their activity due to feed processing, storage or even in the rumen or stomach before being absorbed from the small intestine and are being utilized by the body.
Present Scenario of Encapsulation Industry
The food encapsulation market was valued at USD 11.5 billion in 2022; it is projected to grow at a compound annual growth rate (CAGR) of 8.2% to reach USD 17.0 billion by 2027. The encapsulation market is growing globally at a significant pace due to its numerous applications and multiple advantages over other technologies. Also factors such as rising demands for encapsulated feed additives, vitamins and minerals, and growing demand for dietary supplements that use encapsulated bioactive compounds and advancements in technology to increase animal production with the product quality play a role in its growth.
The results from the research and experimentation with encapsulated nutrients are astounding. The productivity of the animal is found to be increased greatly at the same time the cost of feeding has been reduced as new technologies are fabricating cheap but high-quality products.
Encapsulation was already used in the pharma and agricultural industries for the past five-six decades but it is gaining popularity in animal nutrition since these two decades. In the agriculture industry encapsulation is used in the manufacturing of biofungicides, biopesticides, biofertilizers etc. The human food industry uses encapsulation the most. Encapsulated ingredients are used in every food product category such as confectionary, beverages, dairy, ready-to-eat snacks and also in convenience foods.
Some of the objectives of encapsulation are to increase the stability of formulated systems, retain and protect active properties, reduce lipid oxidation and maintain the bioactive compounds even in extreme thermal, radiation and pH conditions. Encapsulation can also help in the site-specific release of ingredients at controlled time and rate, increase shelf life and masking undesirable flavour, colour and taste.
Microencapsulation and nanoencapsulation
These are the most commonly used techniques nowadays. Nanoencapsulation dispenses particle size of less than 1 micron, while microencapsulation dispenses a particle size between 1 to 1000 microns. Various techniques produce particles in the form of microspheres or microcapsules. Microspheres are dense matrix systems in which the bioactive compound is homogenously dispersed or suspended with the carrier material. Microcapsules are reservoir systems in which the bioactive compounds are heterogeneously separated, where the carrier material forms a membrane shell around the core bioactive compound.
Carrier materials used for encapsulation
Determining the appropriate carrier material is important as it has to be compatible with the core material, be stable and should protect the core material from external adversities.
Ideal coating materials should have the following properties-
Machinability- Should be able to handle physical feed processing methods.
Inert- Should not react with the core material both during processing and storage.
Protection- Should protect the core material against various physical and chemical adversities.
Economical- Should be cheap and easily available.
It is difficult for a single carrier material to have all the properties so different combinations of materials are used. Food biopolymers are generally used.
Biopolymers are of three types
- Synthetic polymers derived from petroleum. Eg. Polyethylene glycol, polyvinyl alcohol, etc.
- Synthetic polymers derived from renewable resources. Eg. poly(lactic acid) (PLA), poly(glycolic acid) (PGA), etc.
- Naturally produced renewable polymers. Eg. chitosan, maltodextrin, alginate, gelatin, etc.
Core material used in encapsulation
Core materials are sensitive bioactive compounds, with low stability and are highly susceptible to variations in temperature, light, pH, or other environmental conditions. To improve their stability and bioavailability there is a need to encapsulate these bioactive compounds. Many volatile and heat-sensitive compounds like polyphenols and essential oils can be saved from being degraded by various feed processing methods and in long storage periods. Some compounds like vitamins, minerals, probiotics and bioactive peptides are functional only if released at a specific site, at a particular time. Due to development in encapsulation technologies, the release of these bioactive compounds can be site-specific, stage-specific or even signalled by any physio-chemical changes in the animal body.
Some animal as well as plant-based feed additives like fish oil, terpenes and tannins have an unpalatable taste as well as undesirable odour. This decreases the animal’s feed intake and affects production, therefore encapsulating these compounds is important before adding them to an animal’s feed. Encapsulation allows active ingredients such as polyphenols, carotenoids, pigments, fatty acids, phytosterols, probiotics, vitamins, minerals, and bioactive peptides to be trapped within a core of different carriers. Generally, the stability of these bioactive compounds is low, and encapsulation generates a powder with higher stability against variations in temperature, light, pH, or oxygen, increasing the release rate of these active ingredients.
Novel technologies of Encapsulation
The human population is increasing and so is the demand for animal products. To meet these increasing demands animal feed industry is being upgraded and various new encapsulation techniques are being researched to enhance the quality of feed. Some of these techniques are given below.
Spray drying:- It is the most commonly used and most economical method in which the core bioactive material is homogenized with the carrier material to form an emulsion and passed through hot air using an atomization process to obtain a powdered encapsulated product.
Freeze drying:- It is a process based on dehydration by sublimation of the emulsion of the bioactive core material and carrier material. It is used for sensitive bioactive compounds as it does not expose the emulsion to high temperature as in spray drying.
Extrusion:- In this method two immiscible compounds (core material and carrier material) are dispersed and passed through a dye or nozzle, obtaining droplets into a drying agent in which the carrier materials surrounds the core material.
Coacervation:- It is a method where two or more polymeric and charged carrier materials form a membrane of tiny coacervates around the core material by altering their physiochemical properties and inducing phase separation.
However, the selection of the technique depends on several factors such as the type of bioactive compounds, encapsulating agent, the sensitivity of bioactive compounds and the cost of the technique. Each technique will give different results in terms of shape, structure, size, distribution and bioavailability
Encapsulation of nutrients is an amazing technology which if used appropriately could revolutionize the animal nutrition industry. The positives of this technology surpass the negatives and we could really use it to increase production in animals. The cost of manufacturing encapsulated products is low, and the ruminal or stomach degradation in animals is reduced moreover it results in site-specific release of nutrients are excellent and should be taken into account.