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Assignment #2

Research Topic: The use of nanotechnology in food. (Focusing primarily on nano-encapsulation)

http://dx.doi.org/10.1007/s11947-010-0328-2
 * [Full Marks JCB]**

Nanotechnology for the Food and Bioprocessing Industries by Suresh Neethirajan & Digvir S. Jayas

Introduction
 * A definition of nanotechnology as devices that enable people to work at a scale 10-9 of a meter.
 * Nanotechnology, a multidisciplinary field, allows research and experimentation at molecular and atomic levels. At these levels an increase in the surface to volume ratio increases the reactivity and alters the physical properties of the material.
 * As new problems arise for the food and biotechnology industry so does the need for new methods of maintaining and improving the safety of food products. Nanotechnology is a popular and viable option.
 * The US invested $7 billion in nanotechnologies in 2004. Around 400 food industry related companies had R&D departments working with nanotechnology. By 2015 the number of companies is estimated to increase to 1000 and the annual value of products created using this technology is ~ $ 1 trillion.
 * Nanofood is defined as food manufactured or grown using nanotechnology or food that has nanomaterials added to it.
 * This technology has applications at all stages of food production from growing to consumption.

Food Quality Monitoring
 * Nanotechnology can be used to create more efficient sensors to help maintain quality control ensuring safer food.
 * Nanosensors can be used to track contaminants in the food through all stages of production.
 * Certain grain quality monitoring sensors use conducting polymers that detect changes in the environment and use this data to pinpoint the source of the problem.
 * Ruengruglikit et al. (2004), have created a strip covered with nanosensors that detects gases released by the food as it spoils causing it to change color.
 * Reflective interferometry, created using nanotechnology, allows detection of biomolecules in complex mixtures, such as E Coli. It is used in sensors that detect the light scattered when E. Coli binds with specific protein sample introduced into the food attached to silicon chips that make it possible to collect data. The diminutive size of these sensors allows a large number of them to be placed inside the product. They can also reach small spaces macroscopic sensors cannot.
 * Another type of sensor employing nanotechnology works by attaching fluorescent dyes to a silicon/gold nanorod array covered in anti-salmonella antibodies. When the bacteria react with the array the dye can be seen. This method is a lot faster than normal lab testing.
 * Campylobacter jejuni are bacteria that come from contaminated poultry meat and cause diarrhea when consumed. Bioactive nanoparticles are added to the chicken feed that bind to the surface of the campylobacters and remove them through the chicken’s feces.
 * A company in Hong Kong has developed a spray that glows when it reacts with a pathogen strain on food. The glow is more intense when more bacteria react with the nanoparticles. Experiments have been conducted using nanoparticles attached to luminescent ATP to detect E. Coli. Similar experiments were conducted to detect pathogens in ground beef.

Food Packaging
 * Safer food packaging is important to increase the shelf life of the food. Packaging created using nanopolymers is expected to be able to heal itself and warn when its contents are spoiling. Nanotechnology can also help improve the properties of the materials used to create the packaging, e.g. heat-resistance of the foil.
 * Antimicrobial packaging reduces the growth rate of microorganisms. If antimicrobial nanoparticles are added to the packaging the can prevent microbial growth on non-sterilized food. These nanoparticles are introduced into the packaging through sachets.
 * Packaging comprising of antimicrobial nanoparticles can be used to protect the surfaces of foods that are liable to spoil. It can even be made so that it is edible using oils such and oregano and cinnamon and apple puree.
 * Silver oxide, zinc oxide, magnesium oxide nanoparticles and nisin particles are examples of antimicrobial nanoparticles that have already been synthesized and used in experimentation.
 * Self-cleaning surfaces can be created using a dirt-repellent coating that works at a nanoscale. It works on the principals of nanohydrophobisation and the sol-gel process making the surface absorbency effectively zero. This type of packaging is also biodegradable.
 * Oxygen inside food packaging causes a variety of problems. Nanotechnology produces compounds to neutralize the oxygen. It can also be used in packaging to neutralize ethylene and in moisture absorbing sheets.
 * Nanotechnology has been used to create packaging that can control the dispersion of oxygen and aroma effecting enzymes. Nanoparticles that can absorb oxygen via reactions catalyzed by food grade enzymes are commercially available in sachets.
 * Silicate nanoparticles can be added to packaging film to reduce the flow of gases and the release of moisture. Clay nanoparticles added to bottles make the material rigid thereby reducing its permeability and the loss of CO2, and increasing shelf life.
 * Biodegradable packaging has been manufactured from cornstarch using nanotechnology. Packaging created from starch and protein bio-nanocomposites can be used to carry functionally active substances.
 * Chitin a natural polymer from lobster shells can be used to create biodegradable packaging using an electron spinning technique. Chitin is dissolved in a solvent and forced through a tiny hole by applying electricity to produce fibers at nanoscale. These nanofibers are antimicrobial and very strong. Packaging has also been created using polymer nanocomposites from a corn plant.
 * Nanotechnology can also be used to improve shipping and tracking by making use of nanobarcodes.
 * A particular nanobarcode technology works by covering nanoparticles in strips of gold, silver and platinum of varying sizes that each reflect light differently.
 * Another technology involves encrypting food, pills and packaging directly using chemically engineered ink. Yet another deposits nanoscale markers in the packaging to aid in tracking. Another nanobarcode technology works by using fluorescence under UV light.

Encapsulation and Delivery
 * Nanoecapsulation has many advantages relating to the flavor, safety, shelf life and efficacy of the food. Enzymes can be encapsulated in nanosilicas produced from plants. These nanomaterials can come from processed waste materials or engineered plants.
 * Nanotechnology can improve the delivery of bioactive compounds such as lycopene and beta-carotene. This can be achieved by preserving them better through the production process. Nanotechnology accomplish this by increasing their solubility and stability.
 * Time-release nanocapsules have already been used to disguise the flavor of fish oil introduced to bread. By encapsulating probiotic organism with calciumalginate their effectiveness can be improved. Coating Bifidobacteria with starch has generally been successful.
 * Nanotechnology has been used to deliver vitamin D2 through nanosized micelles made using casein. It was also used to create nanofibers from maize proteins to coat beta-carotene.
 * Nanoencapsulators have been created from hydrolyzed alpha-lactalbumin (a milk protein) and from soya beans.
 * Nanoencapsulation can be used to make food that can be altered by consumers according to their needs. Certain elements will remain inactive unless activated by the user.
 * Nestle and Kraft have are working with universities to develop food that changes taste, nutritional value or color depending on the consumer.
 * This technology can be used to alter the nutritional components of food. It can also enhance flavor thereby reducing production and ingredient costs. An ice cream is being developed using nanoemulsion that has lower fat content.
 * Nanotechnology can be used to improve the texture of foods by controlling size. It can also be used to remove allergens and certain additives without damaging the food itself.
 * Decreasing the size of food particles improves its stability and spreadability. Nanotechnology has been used to develop bitter blockers that reduce the bitterness of some natural products.
 * The longevity of sorghum spirits can been enhanced using a photocatalytic process using nanogold particles. Nanozinc can be used to provide information concerning allergens, microbials and bioactive compounds by enhancing infrared absorption.

Safety and Societal Implication
 * Existing safety laws and conditions are inadequate to measure the risk posed by food altered using nanotechnology. There is a need for studies to determine the potential downside to using nanotechnology in food and bioprocessing industries.
 * Data concerning nanotechnology is not readily available as it is a relatively new discovery. There is a need for risk assessment analyses so that new regulations can be put in place. Studies have already been undertaken to measure the toxicity levels of nanoparticles. More research needs to be conducted into the effects of nanomaterials on humans.
 * Research bodies have been created in America and Europe to further investigate the health and safety issues related with nanotechnology. The potential of nanomaterials to generate free radicals and their reactivity are just some of the issues being looked into. Some research is also being conducted into the risk associated with working with nanotechnology.
 * In order to accurately categorize nanomaterials more information needs to be gathered about their toxicokinetics.
 * The British Standards Institution, International and European Committee for Standardization, and OECD are responsible concerns regarding the naming and categorization of nanotechnology and related safety issues.

Conclusion
 * Nanotechnology has helped invent sensors with greater sensitivity for detecting spoilage and tracking packages and also improved packaging material. It allows opportunity for research into safer methods of processing, growing and packaging food.

Assignment # 1

Chemical: Methyl Iodide (CH3I)

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