Food Biophysics and Nanotechnology Research Program

Food Science is an applied science whose ultimate aim is to improve the production, manufacturing, distribution and utilization of foods. The aim of the research program in food biophysics and nanotechnology is to contribute to the science and technology development for food products and processing in a number of different ways:

• Aid food manufacturers in developing high quality, safe food formulationsmy maximizing activity of preservative (aka food antimicrobials)

• Continue the development of new encapsulation systems that allow for incorporation of bioactives (antimicrobials, antioxidants, nutraceuticals, flavors) in food products in which they previously could not been incorporated

• Maintain or mprove the biological activity or bioavailability of functional compounds in complex food systems to ensure health and wellness, food safety and quality.

• Nanofabricate colloidal and nanostructures from food biopolymers to increase use of byproducts or underutilized materials that could be converted into valuable food ingredients

• Investigate wider use of high-intensity ultrasonication to assist traditional food processes, reducing costs and processing time for food manufacturers and generate new stuctures and functional molecules.

 

Nanofabrication of Food Structures

Nanotechnology has emerged as one of the most revolutionary scientific fields in decades. Nanotechnology focuses on organic or inorganic systems that are in the size range of 100 nm and exhibit unexpected new functionalities because their behavior is not dominated by bulk physicochemical properties but instead is driven by surface or interfacial properties that are based on intermolecular interactions at phase boundaries. Of key interest to our research efforts are to develop "bottom-up" aseembly processes that create this new and exiting structures.

Figure 1 . Top-to bottom versus bottom up approach to the assembly of food structures.

Traditionally, food products have been manufactored from top to bottom, that is the raw materials were bulk processed to create the bulk food product. Nanotechnology in contrast requires a fundamental understanding of the interactions that can lead to self-assembly of structures. Manipulations of the conditions required to achieve self-assembly can then be used to "direct" the assembly process and create a wide range of nanostructures with novel properties. These nanostructures can then be included in the food as ingredients, or assembled into larger microstructures than will form novel foods.

Novel Micro- and Nanoencapsulation Systems

Functional ingredients (such as drugs, vitamins, antimicrobials, antioxidants, flavorings, colorsants and preservatives) are essential components of a wide range of industrial products, including pharmaceuticals, health care products, cosmetics, agrochemicals and foods.  These functional ingredients come in a variety of different molecular and physical forms, e.g., polarities (polar, non-polar, amphiphilic), molecular weights (low to high), and physical states (solid, liquid, gas).  Functional ingredients are rarely utilized directly in their pure form. Instead, they are often incorporated into some form of delivery system.

Figure 2. Basic nanostructured encapsulation systems including microemulsions, liposomes, nanoemulsions, biopolymeric or solid lipid particles and fibers.

Association colloids. Association colloids, such as surfactant micelles, vesicles, bilayers, reverse micelles and liquid crystals have been used for many years to encapsulate and deliver polar, non-polar and/or amphiphilic functional ingredients.  For example, a non-polar functional ingredient may be solubilized within the hydrophobic core of a surfactant micelle or as part of the micellar “membrane” structure, and thus it can be delivered in an aqueous solution depending on the requirements of the specific application. 

Nano-emulsions.  Using high pressure valve homogenizers or microfluidizers it is often possible to make emulsions with droplet diameters below 100-500 nm.  These emulsions are often referred to as “nano-emulsions” in the modern literature.  Again it should be pointed out that this kind of emulsion has been produced and studied for many years, and that there is a great body of literature dealing with their preparation, characterization and utilization.  Functional food components can be incorporated within the droplets, the interfacial region or the continuous phase.

Nano-structured multiple emulsions.  Delivery systems with novel encapsulation and delivery properties can be created using multiple emulsions.  The most common examples of this type of emulsion are oil-in-water-in-oil (OWO) and water-in-oil-in-water (WOW) emulsions.  For example a nano-structured W1OW2 emulsion would consist of nanometer-sized water droplets or reverse micelles (W1) contained within larger oil droplets (O), which were dispersed within an aqueous continuous phase (W2).  Functional food components could be encapsulated within the inner water phase, the oil phase or the outer water phase, thus making it possible to develop a single delivery system that contained multiple functional components. 

Nano-structured multilayer emulsions.  Recent studies have shown that novel delivery systems can be created by using multilayer emulsions.  These systems typically consist of oil droplets (the “core”) surrounded by nanometer thick layers (the “shell”) comprised of different polyelectrolytes.  These layers are formed using a layer-by-layer (LbL) electrostatic deposition method that involves sequential adsorption of polyelectrolytes onto the surfaces of oppositely charged colloidal particles. 

Biopolymeric Nanoparticles.  Particles in the nanometer size range can often be produced using food grade biopolymers, such as proteins or polysaccharides.  These particles may be formed by promoting self-association or aggregation of single biopolymers or by inducing phase separation in mixed biopolymer systems, e.g., using aggregative (net attraction) or segregative (net repulsion) interactions.

Next Generation Nano- and Microstructures

An important area where food nanotechnology is increasingly used is in the design of functional food ingredients such as for example food flavors (Imafidon and Spanier, 1994) and antioxidants. Ultimately, the goal is to improve the functionality of these ingredients in food systems, which may minimize the concentrations needed. To this purpose, next generation encapsulation systems that build on the first generation of encapsulation systems shown above (Figure 2) are now designed These next gen nanostructures have improved stabilities, allow in some cases for better targeting and allow for a more controlled release of encapsulated compounds. The manufacturing of these structures is more involved but the added value of the generated structures often compensates for the increased production costs.

Figure 3. Next generation nano and colloids encapsulation systems with improced functional performance.