| Nanotechnology: Giving a new dimension to Food | | | | food surface (McClements et al., 2005). While there |
| Industry | | | | are various methods that can cause adsorption, it is |
| INTRODUCTION: | | | | commonly a result of an electrostatic attraction |
| A derivative of chemistry, engineering, and physics, and | | | | between substances that have opposite charges. The |
| micro fabrication techniques, nanotechnology involves | | | | degree of a substance’s adsorption depends |
| manipulating matter at the nanoscale level. It is | | | | on the nature of the food’s surface as well as |
| responsible for determining not only that biological and | | | | the nature of the adsorbing substance. Different |
| nonbiological structures measuring less than 100 nm | | | | adsorbing substances can constitute different layers of |
| exist but also that they have unique and novel | | | | a nanolaminate; examples are polyelectrolytes |
| functional applications. In fact, the National | | | | (proteins and polysaccharides), charged lipids, and |
| Nanotechnology Initiative (NNI, 2006) defines | | | | colloidal particles. Consequently, different nanolaminates |
| nanotechnology as “the understanding and | | | | could include various functional agents such as |
| control of matter at dimensions of roughly 1 to 100 | | | | antimicrobials, anti-browning agents, antioxidants, |
| nanometers, where unique phenomena enable novel | | | | enzymes, flavors, and colors. |
| applications.” Because applications with | | | | Nanofibers and Nanotubes: |
| structural features on the nanoscale level have | | | | Two applications of nanotechnology that are in the |
| physical, chemical, and biological properties that are | | | | early stages of having an impact on the food industry |
| substantially different from their macroscopic | | | | are nanofibers and nanotubes. Because nanofibers are |
| counterparts, nanotechnology can be beneficial on | | | | usually not composed of food-grade substances, |
| various levels. Research in biology, chemistry, | | | | nanofibers have only a few potential applications in the |
| engineering, and physics drives the development and | | | | food industry. Produced by a manufacturing technique |
| exploration of the nanotechnology field. Consequently, | | | | using electrostatic force, nanofibers have small |
| certain industries such as microelectronics, aerospace, | | | | diameters ranging in size from 10 nm to 1,000 nm, |
| and pharmaceuticals have already begun | | | | which makes them ideal for serving as a platform for |
| manufacturing commercial products of nanoscale size. | | | | bacterial cultures. In addition, nanofibers could also |
| Even though the food industry is just beginning to | | | | serve as the structural matrix for artificial foods and |
| explore its applications, nanotechnology exhibits great | | | | environmentally friendly food-packaging material. As |
| potential. Food undergoes a variety of postharvest and | | | | advances continue in the area of producing nanofibers |
| processing-induced modifications that affect its | | | | from food-grade materials, their use will likely increase. |
| biological and biochemical makeup, so nanotechnology | | | | As with nanofibers, the use of nanotubes has |
| developments in the fields of biology and biochemistry | | | | predominantly been for non-food applications. Carbon |
| could eventually also influence the food industry. Ideally, | | | | nanotubes are popularly used as low resistance |
| systems with structural features in the nanometer | | | | conductors and catalytic reaction vessels. Under |
| length range could affect aspects from food safety to | | | | appropriate environmental conditions, however, certain |
| molecular synthesis. | | | | globular milk proteins can self-assemble into similarly |
| Potential Food Applications: | | | | structured nanotubes (Graveland- Bikker and de Kruif, |
| All organisms represent a consolidation of various | | | | 2005, 2006; Graveland-Bikker et al., 2006a, b). |
| nanoscale-size objects. Atoms and molecules combine | | | | Regulations: |
| to form dynamic structures and systems that are the | | | | In India, the nanotechnology is at nascent stage and |
| building blocks of every organism’s existence. | | | | there does not exist any regulation for its application in |
| For humans, cell membranes, hormones, and DNA are | | | | food industry. Similarly in the United States, no special |
| examples of vital structures that measure in the | | | | regulations exist for the use of nanotechnology in the |
| nanometer range. In fact, every living organism on | | | | food industry. In contrast, the European Union has |
| earth exists because of the presence and interaction | | | | recommended special regulations that have yet to be |
| of various nanostructures. Even food molecules such | | | | accepted and enforced. The Food and Drug |
| as carbohydrates, proteins, and fats are the results of | | | | Administration says that it regulates “products, |
| nanoscale- level mergers betweensugars, amino acids, | | | | not technologies.”Nevertheless, FDA expects |
| and fatty acids. As it applies to the food industry, | | | | that many products of nanotechnology will come under |
| nanotechnology involves using biological molecules | | | | the jurisdiction of many of its centers; thus, the Office |
| such as sugars or proteins as target-recognition | | | | of Combination Products will likely absorb any relevant |
| groups for nanostructures that could be used, for | | | | responsibilities. Because FDA regulates on a product- |
| example, as biosensors on foods. Such biosensors | | | | by-product basis, it emphasizes that many products |
| could serve as detectors of food pathogens and other | | | | that are already under regulation contain particles in the |
| contaminants and as devices to track food products. | | | | nanoscale range. Accordingly, “particle size is not |
| Nanotechnology may also be useful in encapsulation | | | | the issue,” and any new materials will be |
| systems for protection against environmental factors. | | | | subjected to the customary battery of safety tests. |
| In addition, it can be used in the design of food | | | | The Institute of Food Science and Technology, a |
| ingredients such as flavors and antioxidants. The goal | | | | United Kingdom–based independent professional |
| is to improve the functionality of such ingredients while | | | | body for food scientists and technologists, has a |
| minimizing their concentration. As the infusion of novel | | | | different view of nanotechnology. In its report (IFST, |
| ingredients into foods gains popularity, greater | | | | 2006), the organization says that size matters and |
| exploration of delivery and controlled-release systems | | | | recommends that nanoparticles be treated as |
| for nutraceuticals will occur. Although nanotechnology | | | | potentially harmful until testing proves otherwise. Still it is |
| can potentially be useful in all areas of food production | | | | the European Commission’s intention to apply |
| and processing, many of the methods are either too | | | | existing food laws to food products using |
| expensive or too impractical to implement on a | | | | nanotechnology. Consequently, the European |
| commercial scale. For this reason, nanoscale | | | | Commission says that the technology will likely require |
| techniques are most cost-effective in the following | | | | some modification for it to adhere to existing laws. |
| areas of the food industry: development of new | | | | Commissioned by the UK to assess the potential |
| functional materials, food formulations, food processing | | | | effects of nanotechnology, the Royal Society and the |
| at microscale and nanoscale levels, product | | | | Royal Academy of Engineering recommend indicating |
| development, and storage. | | | | nanoparticles in the lists of ingredients. The UK |
| Nanodispersions and Nanocapsules: | | | | government agrees that the inclusion of nanoparticles |
| As the fundamental components of foods, functional | | | | on ingredient labels is necessary for consumers to |
| ingredients such as vitamins, antimicrobials, antioxidants, | | | | make informed decisions; thus, updated ingredient |
| flavorings, and preservatives come in various | | | | labeling requirements will be necessary. The UK |
| molecular and physical forms. Because they are rarely | | | | government plans to consult with its EU partners to |
| used in their purest form, functional ingredients are | | | | determine whether IFST’s recommendation to |
| usually part of a delivery system. A delivery system | | | | scrutinize nanoparticle ingredients for safety is valid. |
| has numerous functions, only one of which is to | | | | Conclusion: |
| transport a functional ingredient to its desired site. | | | | As developments in nanotechnology continue to |
| Besides being compatible with food product attributes | | | | emerge, its applicability to the food industry is sure to |
| such as taste, texture, and shelf life, other functions of | | | | increase. The success of these advancements will be |
| a delivery system include protecting an ingredient from | | | | dependent on consumer acceptance and the |
| chemical or biological degradation, such as oxidation, | | | | exploration of regulatory issues. Food producers and |
| and controlling the functional ingredient’s rate of | | | | manufacturers could make great strides in food safety |
| release under specific environmental conditions. | | | | by using nanotechnology, and consumers would reap |
| Because they can effectively perform all these tasks, | | | | benefits as well. More than 200 companies are |
| nanodispersions and nanocapsules are ideal | | | | conducting research in nanotechnology and its |
| mechanisms for delivery of functional ingredients. | | | | application to food products (IFST, 2006), and as more |
| These types of nanostructures include association | | | | of its functionalities become evident, the level of |
| colloids, nanoemulsions, and biopolymeric nanoparticles. | | | | interest is certain to increase. |
| § Association Colloids: | | | | R E F E R E NC E S: |
| Surfactant micelles, vesicles, bilayers, reverse micelles, | | | | Cagri, A., Ustunol, Z., and Ryser, E.T. 2004. Antimicrobial |
| and liquid crystals are all examples of association | | | | edible films and coatings.J. Food Protect. 67: 833-848. |
| colloids. A colloid is a stable system of a substance | | | | Cha, D.S. and Chinnan, M.S. 2004. Biopolymer-based |
| containing small particles dispersed throughout. An | | | | antimicrobial packaging: Review. Crit. Rev. Food Sci. |
| association colloid is a colloid whose particles are | | | | Nutr. 44:223-237. |
| made up of even smaller molecules. Used for many | | | | Chang, Y.C. and Chen, D.G.H. 2005 Adsorption kinetics |
| years to deliver polar, nonpolar, and amphiphilic | | | | and thermodynamics of acid dyes on a |
| functional ingredients (Golding and Sein, 2004; Garti et | | | | carboxymethylated chitosan- conjugated magnetic |
| al., 2004, 2005; Flanagan and Singh, 2006), association | | | | nano-adsorbent. Macromol. Biosci. 5: 254-261. |
| colloids range in size from 5 nm to 100 nm and are | | | | Charych, D., Cheng, Q., Reichert, A., Kuziemko, G., Stroh, |
| usually transparent solutions. The major disadvantages | | | | N., Nagy, J., Spevak, W., and Stevens, R. 1996. A |
| to association colloids are that they may compromise | | | | ‘litmus test’ for molecular recognition using |
| the flavor of the ingredients and can spontaneously | | | | artificial membranes. Chem. Biol. 3: 113. |
| dissociate if diluted. | | | | Chen, H., Weiss, J., and Shahidi, F. 2006. |
| § Nanoemulsions: | | | | Nanotechnology in nutraceuticals and functional foods. |
| An emulsion is a mixture of two or more liquids (such | | | | Food Technol. 60(3): 30-36. |
| as oil and water) that do not easily combine. | | | | Flanagan, J. and Singh, H. 2006. Microemulsions: A |
| Therefore, a nanoemulsion is an emulsion in which the | | | | potential delivery system for bioactives in food. Crit. |
| diameters of the dispersed droplets measure 500 nm | | | | Rev. Food Sci. Nutr. 46: 221-237. |
| or less. Nanoemulsions can encapsulate functional | | | | Garti, N., Shevachman, M., and Shani, A. 2004. |
| ingredients within their droplets, which can facilitate a | | | | Solubilization of lycopene in jojoba oil microemulsion. J. |
| reduction in chemical degradation (McClements and | | | | Am. Oil Chem. Soc. 81: 873-877. |
| Decker, 2000). In fact, different types of nanoemulsions | | | | Garti, N., Spernath, A., Aserin, A., and Lutz, R. 2005. |
| with more-complex properties— such as | | | | Nano-sized self-assemblies of nonionic surfactants as |
| nanostructured multiple emulsions or nanostructured | | | | solubilization reservoirs and microreactors for food |
| multilayer emulsions—offer multiple encapsulating | | | | systems. Soft Matter 1: 206-218. |
| abilities from a single delivery system that can carry | | | | Golding, M. and Sein, A. 2004. Surface rheology of |
| several functional components. In structures such as | | | | aqueous casein-monoglyceride dispersions. Food |
| these, a functional component encased within one | | | | Hydrocoll. 18: 451-461. |
| component of a multiple emulsion system could be | | | | Graveland-Bikker, J. and de Kruif, C. 2005. |
| released in response to a specific environmental | | | | Self-assembly of hydrolysed |
| trigger. | | | | ?-lactalbumin into nanotubes. FEBS J.272 (Suppl 1): 550. |
| § Biopolymeric Nanoparticles: | | | | Graveland-Bikker, J.F. and de Kruif, C.G. 2006. Unique |
| Food-grade biopolymers such as proteins or | | | | milk protein-based nanotubes: Food and |
| polysaccharides can be used to produce | | | | nanotechnology meet. Trends Food Sci. Technol. 17: |
| nanometer-sized particles (Chang and Chen, 2005; | | | | 196-203. |
| Gupta and Gupta, 2005; Ritzoulis et al., 2005). Using | | | | Graveland-Bikker, J.F., Fritz, G., and Glatter, O. 2006a. |
| aggregative (net attraction) or segregative (net | | | | Growth and structure of ?-lactalbumin nanotubes. J. |
| repulsion) interactions, a single biopolymer separates | | | | Appl. Crystallogr. 39: 180-184. |
| into smaller nanoparticles. The nanoparticles can then | | | | Graveland-Bikker, J.F., Schaap, I.A.T., Schmidt, C.F., and |
| be used to encapsulate functional ingredients and | | | | de Kruif, C.G. 2006b. Structural and mechanical study |
| release them in response to distinct environmental | | | | of a self assembling protein nanotube. Nano Lett. 6: |
| triggers. One of the most common components of | | | | 616-621. |
| many biodegradable biopolymeric nanoparticles is | | | | Gupta, A.K. and Gupta, M. 2005. Synthesis and surface |
| polylactic acid (PLA). Widely available from a number | | | | engineering of iron oxide nanoparticles for biomedical |
| of manufacturers, PLA is often used to encapsulate | | | | applications. Biomaterials 26: 3995 -4021. |
| and deliver drugs, vaccines, and proteins, but it has | | | | Haruyama, T. 2003. Micro- and nanobiotechnology for |
| limitations: it is quickly removed from the bloodstream, | | | | biosensing cellularresponses. Adv. Drug Delivery Rev. |
| remaining isolated in the liver and kidneys. Because its | | | | 55: 393-401. |
| purpose as a nanoparticle is to deliver active | | | | IFST. 2006. Nanotechnology information statement. |
| components to other areas of the body, PLA needs | | | | Institute of Food Science and Technology (IFST) Trust |
| an associative compound such as polyethylene glycol | | | | Fund, London, UK. |
| to be successful in this regard (Riley et al., 1999). | | | | Imafidon, G.I. and Spanier, A.M. 1994. |
| Nanolaminates: | | | | Unraveling the secret of meat flavor. Trends Food Sci. |
| Besides nanodispersions and nanocapsules, another | | | | Technol. 5: 315-321. |
| nanoscale technique is commercially viable for the | | | | Lawrence, M.J. and Rees, G.D. |
| food industry: nanolaminates. Consisting of two or | | | | 2000.Microemulsion-based media as novel drug |
| more layers of material with nanometer dimensions, a | | | | delivery systems. Adv. Drug Delivery Rev. 45: 89-121. |
| nanolaminate is an extremely thin food-grade film | | | | McClements, D.J. and Decker, E.A. 2000. Lipid oxidation |
| (1–100 nm/ layer) that has physically bonded or | | | | in oil-in-water emulsions: Impact of molecular |
| chemically bonded dimensions. Because of its | | | | environment on chemical reactions in heterogeneous |
| advantages in the preparation of edible films, a | | | | food systems. J. Food Sci. 65: 1270-1282. |
| nanolaminate has a number of important food-industry | | | | McClements, D.J., Decker, E.A., and Weiss, J., inventors; |
| applications. Edible films are present on a wide variety | | | | University of Massachusetts, assignee. 2005. UMA |
| of foods: fruits, vegetables, meats, chocolate, candies, | | | | 05-27: Novel procedure for creating nanolaminated |
| baked goods, and French fries (Morillon, 2002; Cagri et | | | | edible films and coatings, U.S. patent application. Morillon, |
| al., 2004; Cha and Chinnan, 2004; Rhim, 2004). Such | | | | V., Debeaufort, F., Blond, G., Capelle, M., and Voilley, A. |
| films protect foods from moisture, lipids, and gases, or | | | | 2002. Factors affecting the moisture permeability of |
| they can improve the textural properties of foods and | | | | lipid-based edible films: A review. Crit. Rev. Food Sci. |
| serve as carriers of colors, flavors, antioxidants, | | | | Nutr. 42: 67-89. |
| nutrients, and antimicrobials. Currently, edible | | | | Park, H.J. 1999. Development of advanced edible |
| nanolaminates are constructed from polysaccharides, | | | | coatings for fruits. Trends Food Sci.Technol. 10: |
| proteins, and lipids. Although polysaccharide- and | | | | 254-260. |
| protein-based films are good barriers against oxygen | | | | Rhim, J.W. 2004. Increase in water vapor barrier |
| and carbon dioxide, they are poor at protecting against | | | | property of biopolymer-based edible films and coatings |
| moisture. On the other hand, lipid-based nanolaminates | | | | by compositing with lipid materials. Food Sci. Biotech. |
| are good at protecting food from moisture, but they | | | | 13:528-535. |
| offer limited resistance to gases and have poor | | | | Riley, T., Govender, T., Stolnik, S., Xiong, C.D., Garnett, |
| mechanical strength (Park, 1999). Because neither | | | | M.C., Illum, L., and Davis, S.S. 1999. Colloidal stability and |
| polysaccharides, proteins, nor lipids provide all of the | | | | drug incorporation aspects of micellar-like PLA-PEG |
| desired properties in an edible coating, researchers are | | | | nanoparticles. Colloids Surf., B 16: 147-159. |
| trying to identify additives that can improve them, such | | | | Ritzoulis, C., Scoutaris, N., Papademetriou, K., Stavroulias, |
| as polyols. For now, coating foods with nanolaminates | | | | S. and, Panayiotou, C. 2005. Milk protein-based emulsion |
| involves either dipping them into a series of solutions | | | | gels for bone tissue engineering. Food Hydrocolloids 19: |
| containing substances that would adsorb to a | | | | 575-581. |
| food’s surface or spraying substances onto the | | | | |