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 * Applications of Nanotechnology in the Food Industry **


 * Abstract **

Nanotechnology is one of the most promising new technologies in the food and bioprocessing industries. It offers opportunities to improve the quality, safety and cost effectiveness of food at every stage, from production to processing to consumption. More effective delivery of nutrients via nanoencapsulation, prompt identification of contaminants using sensors, smart food packaging and flavor, texture enhancement are just a few applications of nanotechnology. This paper explores the current and possible future applications of nanotechnology in the food industry as well as their societal impact and the risks they pose.


 * Introduction **

Nanotechnology is the understanding and engineering of materials at a 10-9 meter scale. At this level matter exhibits unique characteristics not seen at a micro or macroscopic level. The physical and chemical reactivity of particles changes dramatically at a nanoscale; this is because reducing the particle size to this scale increases the surface to volume ratio. [1] Bioactive compounds benefit from this down scaling as it improves their solubility, absorption and resistance to degradation inside the gastrointestinal tract. [2]

As the use of this technology in the food industry is a fairly recent development a lot of its applications are still in the R&D stage. Certain fields where it is currently being employed are in food packaging materials, delivery of bioactive compounds to the body, delivery of pesticides to crops and soil-wetting agents, improving the texture and flavor of food and silver lined, antimicrobial storage containers. [3] The introduction of organic and inorganic additives to food and animal feed, nano-filtration systems using porous silica, nanoencapsulation to improve delivery and prevent microbial activity, nanosensors to detect spoilage and track food, water purification, and the production of nanosized agrochemicals are future applications that are presently being researched. [4]

Despite a slow start by the food and bioprocessing industries in the direction of nanotechnology there has been significant economic input and output in the field. In 2008, $15 billion were invested globally in research and development and over 400,000 researchers were employed worldwide. [5] This was more than double than the amount invested in 2004, US $ 7 billion. [1] By 2020 it is expected that annual value of nanotechnology related food would be close to $3 trillion. [5] The most significant economic impact was in the food and beverage packaging market. Worldwide sales have increased from US $ 150 million in 2002 to US $4.13 billion in 2008. These sales projected to grow at a rate of 11.65% annually to yield sales of $7.3 billion by 2014. [1,5]

Public acceptance is a major factor in the commercial application of food industry related nanotechnology. Studies have found that while people still prefer natural food products there is a greater willingness to accept the use of nanotechnology is the processing and packaging stages than in the production stage. Which is to say that the public is less likely to allow food to which nanomaterials have been added. [5]

Another obstacle faced by the industry is a lack of defined regulations whilst dealing with nano-food. The toxicology, toxiokentics, absorption and adsorption capabilities within the body, and other interactions of nanoparticles with living cells need to be researched further so that appropriate safety measures and laws can be put in place. [1] As mentioned due to the increased surface to volume ratio of nanoparticles they behave differently from macroparticles; it is believed that a substance deemed safe by the FDA maybe harmful but only at this smaller scale. However, no regulations are as yet in place that deal primarily with nanotechnology and its health impacts. [2]


 * Applications **

Beginning with the production process, here is a detailed overview of how nanotechnology can be applied in the food industry.

// Production //

In the agriculture industry nanotechnology has been used to create more effective pesticide delivery systems, track nonpoint source pollution, the control of time-release agrochemicals and gathering raw materials for cellulose nanocrystal composites (to be used for creating biodegradable packaging materials). [6]
 * Agriculture **

Poultry and livestock are susceptible to many diseases that can impact the animals’ health, and through food borne pathogens, the consumers. Nanotechnology can be implemented to prevent this via rapid detection using nanosensors.
 * Animal Production **

Nanosensors can be used on farms to detect and remove pathogens from animals. nanoDETECT is a hand held device created by a company called Illuminaria that uses nanomaterials to detect pathogens in real-time by using polymerase chain reactions. This technology has been used in association with immunomagnetic beads that bind to Salmonella Typhimirium on chickens to remove the virus via magnetic recovery at a nanoscale. [3]

A second function of nanosensors on farms is using another hand held detector for foot-and-mouth disease. This device works by attaching a foot-and-mouth disease specific antibody as a functional group to a nanostructured gold film. The gold film is designed so that the small foot-and-mouth virus can fit into an indentation on it and thereby be detected. The sensor also picks up on the orientation of liquid crystals depending on its proximity to the virus. [3]

Another key use of nanotechnology in this stage of production is animal waste treatment. Campylobacter jejuni are bacteria that can cause stomach cramps and diarrhea in humans and their most common source is poultry [1]. Therefore it is of importance that steps are taken to safeguard against contamination. Studies have been conducted to research the use of nanopolymers in the removal of Campylobacter bacteria from poultry waste. [3] This is expected to be achieved by feeding the nanoparticles directly to turkeys theorizing that the pathogens should bind to the nanoparticles inside the stomach to prevent further growth.

Another advantage of adding nanoparticles to animal feed is their ability to diminish microbial growth. Continued usage of antibiotics in the treatment of livestock and poultry has resulted in more resistant strains of food borne illnesses. Nanoarticles are a potential alternative to these treatments.

Nanotechnology can also be applied towards veterinary medicine, to overcome obstacles faced by genetic engineering, and tracking animal feed and food products. The latter is discussed in the Processing and Packaging section of the paper.

// Food Enrichment / Food Applications //

Food enrichment is the process of adding micronutrients, or in this case nano-nutrients, to food to enhance certain aspects of it. Nanotechnology has been employed to improve upon not only the nutritional value of foodstuffs but also flavor and texture.


 * Nutritional Value **

Nanotechnologies are generally designed based on biological models. [2] Casein Micelles being an example of nanoecapsulation in nature. Semo et al. conducted a study to encapsulate Vitamin D2 in casein micelles in order to create a more effective delivery system. The vitamin was found to be 5.5 times more concentrated within the micelles than in the serum. The nanocapsule was also shown to have a positive impact on the stability of Vitamin D2 against UV-light induced degradation. [7]

RDA for Vitamin D is 15mcg for people between the ages of 1 and 70. [8] It is essential for the human body as it helps transport calcium and phosphates to the bones, aids absorption of calcium in the intestine and the re-absorption of calcium and phosphates in kidneys. Current trends in health have made it so low or non-fat dairy products are significant sources for calcium and phosphates. However, Vitamin D is fat-soluble and so is not found in these dairy products. [6] By loading Vitamin D2 onto casein micelles this problem can be averted.

A potential use of casein micelles is to help produce nanostructured ice cream which is low-fat but as ‘creamy’ as regular ice cream. [4]

Research has also been conducted by Sauvant et al. in encapsulating Vitamin A. Vitamin A is a hydrophobic molecule and rather unstable during processing and storage. [9] Studies have shown that tablets containing Vitamin A in a self nanoemulsified system had an increase in the extent of drug absorption and the bioavailability of the vitamin. [9]

Probiotic organisms, in yogurt, encapsulated in calciumalginate were found to have improved bioactivity. [1] Zein, a prolamin from corn, has been used to encapsulate beta-carotene. [2, 1] Auweter et al. have shown that the fortification of lycopene in tomato products using nantechnology can increase its bioavailability.

In one study essential oils were nanoencapsulated to monitor their antimicrobial activity when added to fruit juices. While fortification of foodstuffs has been carried out using microcapsules for sometime now, effects are not as significant as with nanocapsules. With microcapsules the physical stability of essential oils was maintained but there was no effect on antimicrobial activity. [10]


 * Flavor **

Like with nutraceuticals, flavor-enhancing compounds can also be encapsulated using nanotechnology.

// Processing and Packaging //


 * Packaging Materials **

Proper packaging is extremely important in the food industry in order to maintain the freshness, safety, taste, texture and color. Nanotechnology is currently being used to improve upon all these features, as mentioned this is the most economically viable field in nanotechnology within the food and bioprocessing industry.

The varied nature of food products, from fresh fruit to carbonated beverages, which require packaging is making its demands on the packaging industry and traditional materials such as metal, cardboard and glass are not cutting it anymore. [5]

Permeability is probably the most important factor to consider in any type of food packaging. While no material is completely impervious to environmental elements or natural substances contained within the food being packaged or even the packaging material itself, nanotechnology can be used to ‘enhance’ preexisting materials.

Polymer nanocomposites, created by dispersing an inert, nanoscale filler throughout a polymeric matrix, have better thermal properties and degrade faster than regular polymers. [5] The nanofiller causes increased permeability firstly by creating a winding path for the gas to diffuse through and secondly by altering the polymer matrix itself. Polymer strands close to the nanoparticle are partially immobilized.

The biodegradability of packaging material is of significance, especially in today’s environmentally aware world. Introducing clay to the polymer matrix greatly aids this process but conversely effects the permeability [2, 5] Dissolving zein in ethanol or acetone can produce a biodegradable material with good water barrier properties and tensile strength. [2]

Silver is a prominent antimicrobial agent. Historical research shows that silver vessels were often used to store milk or water in order to prevent spoilage. It is also known to be able to penetrate biofilms and can be easily incorporated into the other materials like textiles. All this makes silver nanoparticles excellent additions to any packaging material.

Photoexcitation of silver nanoparticles coated with a thin layer of porous silica at visible light frequencies has been shown to enhance anti- microbial activity against E. coli significantly. Another study showed that when silver nanowires were subjected to external electric fields, they had 18.5–63% better antimicrobial potency due to enhanced silver ion production at the wire termini. [5]


 * Nano Sensors **

Nanosensors, sensors built at a nanoscale, can be used for a variety of different purposes.
 * 1) To detect spoilage at any stage of production, or delivery, in real-time. [1]
 * 2) Track food components. [1,3]
 * 3) Biosensors, for use as electric tongues and noses. [11]


 * Risk Assessment **

Although nanotechnology has existed in its current sense for some time its advent into the food and biprocessing industry is recent. For this reason a lot of research still has to be conducted into the potential harm of introducing nanomaterials to foodstuffs.

Exposure to nanomaterials as a result of nanotechnologies being used in the food industry can take three main routes, dermal contact, inhalation and ingestion, primarily ingestion. [12] As such further investigations need to be made regarding the toxiokinetics of nanoparticles. The availability of nanoparticles to traverse barriers within the body, such placenta, blood-brain barrier, also need to be investigated. [13]

Regulatory bodies exist but as yet, due to the limited amount of knowledge regarding risks available, there are no proper risk assessment methodologies existing.


 * References **

[1] S. Neethirajan and D. Jayas. Nanotechnology for the food and bioprocessing industries. //Food and Bioprocess Technology 4(1),// pp. 39-47. 2011. [|DOI] [2] N. Sozer and J. L. Kokini, "Nanotechnology and its applications in the food sector," //Trends Biotechnol.,// vol. 27, pp. 82-89, 2, 2009. [|DOI] [3] K. Jennifer, "Nanotechnology in animal production—Upstream assessment of applications," //Livestock Science,// vol. 130, pp. 14-24, 5, 2010. [|DOI] [4] Q. Chaudhry and L. Castle, "Food applications of nanotechnologies: An overview of opportunities and challenges for developing countries," //Trends Food Sci. Technol.,// vol. 22, pp. 595-603, 11, 2011. [|DOI] [5] D. Timothy V., "Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors," //J. Colloid Interface Sci.,// vol. 363, pp. 1-24, 11/1, 2011. [|DOI] [6] J. Kuzma, J. Romanchek and A. Kokotovich, "Upstream Oversight Assessment for Agrifood Nanotechnology: A Case Studies Approach," //Risk Analysis,// vol. 28, pp. 1081-1098, 2008. [|DOI] [7] E. Semo, E. Kesselman, D. Danino and Y. D. Livney, "Casein micelle as a natural nano-capsular vehicle for nutraceuticals," //Food Hydrocoll.,// vol. 21, pp. 936-942, 8, 2007. [|DOI] [8] National Institutes of Health [|Fact Sheet] [9] P. Sauvant, M. Cansell, A. Hadj Sassi and C. Atgié, "Vitamin A enrichment: Caution with encapsulation strategies used for food applications," //Food Res. Int.,//. [|DOI] [10] F. Donsì, M. Annunziata, M. Sessa and G. Ferrari, "Nanoencapsulation of essential oils to enhance their antimicrobial activity in foods," //LWT - Food Science and Technology,// vol. 44, pp. 1908-1914, 11, 2011. [|DOI] [11] M. Ghasemi-Varnamkhasti, S. S. Mohtasebi and M. Siadat, "Biomimetic-based odor and taste sensing systems to food quality and safety characterization: An overview on basic principles and recent achievements," //J. Food Eng.,// vol. 100, pp. 377-387, 10, 2010. [|DOI] [12] M. Cushen, J. Kerry, M. Morris, M. Cruz-Romero and E. Cummins, "Nanotechnologies in the food industry – Recent developments, risks and regulation," //Trends Food Sci. Technol.,//. [|DOI] [13] H. Bouwmeester, S. Dekkers, M. Y. Noordam, W. I. Hagens, A. S. Bulder, C. de Heer, S. E. C. G. ten Voorde, S. W. P. Wijnhoven, H. J. P. Marvin and A. J. A. M. Sips, "Review of health safety aspects of nanotechnologies in food production," //Regulatory Toxicology and Pharmacology,// vol. 53, pp. 52-62, 2, 2009. [|DOI]