Introduction

In recent years the development of new products has proliferated thanks to technological advances produced in disciplines such as chemistry, pharmacology, food technology, chemical engineering, etc. These advances have allowed us to respond to the growing demands of consumers of innovative products, more comfortable to use, safer, and more pleasant from the organoleptic point of view. For example, the growing interest in the development of functional ingredients shown by consumers and food producing companies can be highlighted. These ingredients are characterized by being present in conventional natural foods and providing health benefits when their proportion is increased or incorporated into products in which they did not exist naturally. In this way, at BIOEXTRACTO new products are gradually being developed, for example: milk with omega-3, yogurts with vegetable sterols, juices enriched in vitamins, cookies with minerals and amino acids, etc. One of the difficulties of developing new food products such as these lies in the mode of incorporation and dosage of new ingredients, in addition to the alteration of flavors. In some cases, these are substances that can be altered by environmental conditions, which can cause them to lose functionality (for example, oxidation of omega-3, degradation by pH or temperature of amino acids and vitamins).
The encapsulation of these components beneficial to health, provides protection to its active ingredients sensitive to external factors. Therefore, in this context, encapsulation has aroused a growing interest in recent years given its ability to confer high benefits to various substances to be used in multiple sectors, as evidenced by the work that gradually appears on the subject. The application of microencapsulation extends to fields as diverse as food, agriculture, cosmetics and pharmacy. In food industries, ingredients with complex properties are increasingly in demand, which can sometimes only be achieved by applying microencapsulation processes. The fact of advancing in technology towards an even smaller scale, such as nanoencapsulation, allows us at BIOEXTRACTO to bring new advantages to these encapsulated products, improving the absorption of the active ingredient, protection against external factors, such as light, oxygen, pH, or presence of free radicals; improving controlled release at the desired time and place; incorporating modifications in the state of apparent aggregation of volatile substances, stability during storage or improving the organoleptic and functional qualities of food products.
Some examples of the potential of this technology could be for instance, products that change flavor, systems that change color or the development of foods with more stable flavors and aromas over time. On the other hand, nanoencapsulation technologies can be a very useful tool in the development of new functional products and in the improvement of their absorption pathways. From a global point of view, the general trends detected in the market point to the encapsulated ingredients among products with a growing demand. This demand derives from the advantageous properties that encapsulation provides to substances, among which, as stated before, the ease of handling and dosing, protection against external agents, masking of unwanted characteristics in the final product, the controlled release at the desired time and place, or the decrease in the amount necessary for a given effect.

Identification of food substances or molecules of interest in nano-scale encapsulation processes

At BIOEXTRACTO the selection of the most appropriate method depends largely on aspects such as: the average particle size to be achieved, the physicochemical properties of the encapsulating agent, the substance to be encapsulated, the applications of the encapsulated material, the desired release mechanism and the costs associated with the level of production required.
At a general level, depending on their function in the organism, encapsulated products can be divided into the following main categories: essential substances for the organism; oils and fats whose contribution to the diet provides health benefits; herbal extracts and compounds with bioactive properties; and finally, ingredients that provide specific flavors and other food ingredients with diverse properties such as enzymes.

Coating substance identification

Coating substances must first function as a stabilizer of the core material, not react with it or deteriorate its active content, and release its content at the time when the specific desired conditions occur, depending on the application of the product.
The encapsulating materials generally form protective films, must be flexible, tasteless, nonhygroscopic, soluble in water and have an easily attainable phase transition. There is a wide variety of encapsulating materials, which allows selecting those that provide the desired properties, as intended to work under conditions of solubility in aqueous medium or in lipid medium; dissolve melt or break the encapsulating material at the time of release, or give the desired texture to the additive. They are usually natural substances or derived from natural products such as: carbohydrates, gums, lipids and fatty acids, waxes, proteins, peptides, cellulose or inorganic materials.

Technological alternatives of encapsulation of food additives and molecules on a nanometric scale

Depending on the nature of the substances and the needs of the product, at BIOEXTRACTO one or another miro or nano encapsulation process can be applied. Each process is based on a series of different mechanisms for encapsulation, requires the intervention of different process variables and makes use of different facilities and equipment for the process to be carried out in optimal conditions. Since microencapsulation methods can be classified according to the different needs according to the type of application required, at BIOEXTRACTO, different technologies for the encapsulation of active molecules have been developed from the micrometric to the nanometric scale in order to fulfill these requirements. Sometimes the techniques we us directly generate encapsulated nanoparticles such as liposomes and micelles, on other occasions it is necessary to first generate nanoparticles that will later be encapsulated. In certain occasions, it might be better to develop regular micelles or inverted ones, or make use of a series of proteins with specific physicochemical characteristics defined by BIOEXTRACTO, able to form nanoparicles.
Depending on the type of process, in our hands encapsulation methods have been classified into physical, chemical and mixed methods:
- Physical methods are those processes governed primarily by physical laws such as spray coating, extrusion and spray drying.
- Chemical methods such as interfacial polymerization and molecular inclusion are governed primarily by chemical laws.
- In physicochemical or mixed processes such as multiple coacervation, complex coacervation or liposome entrapment, both chemical and physical phenomena are important.

Forecast

During the last fifteen years, there has been a large increase in nanotechnology-focused research activity as a result of having acquired the ability to measure, manipulate and organize matter on a nanometric scale. According to a study carried out by Helmut Kaiser Consultancy a few years back, the nano-food market could grow from 2.6 billion dollars to 20.4 billion dollars in just ten years. The same source would indicate that sales of products derived from the nanotechnology to the food and beverage sectors went from around 150 million dollars to 860 million dollars in just ten years.
Taking into account this type of forecast, and although the application of nanotechnology is relatively new to the food sector compared to other sectors such as the pharmaceutical, cosmetics or new materials sector, the applications of nanotechnology in this sector are aimed at providing a wide variety of benefits to the consumer, contributing at the same time to the development of cutting edge science within the food industry.