Nanotechreport

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UNIVERSITY OF AGRICULTURE SCIENCES, GKVK, BANGALORE65

DEPARTMENT OF FOOD SCIENCE AND NUTRITIONPG SEMINAR, FSN 651 (0+1)

II SEMINAR 2009-10

Submitted to Dr. H.B.ShivaleelaProfessor and HeadDept of Food Science and Nutrition

Submitted by Mamata. Mannuramath

PAK 8170

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INDEX

• Introduction

• Definition

• History

• Applications

• Risks

• Reviews

• Summary

• Conclusion

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INTRODUCTION

Nanotechnology is old science. It is responsible for determining not only that biological and non-biological structures measuring less than 100 nm exist but also that they have unique and novel functional applications. Nanotechnology – “Nano” Greek word, means “Dwarf”. In technical terms, the world “nano” means 10-9 or one billionth of something. The terms “Nanotechnology” evolved over the years via terminology drift to mean “anything smaller than micro technology”. Nanotechnology is the emerging scientific field of 21st century which involves working with materials and devices that are at nanoscale level. A nanometer is one billionth of meter that is about 1/80000 of diameter of human hair or ten times diameter of hydrogen atom. So this technology manipulates physical, chemical and biological properties at nanoscale, but at such scales, the ordinary rules of physics and chemistry no longer apply for instance materials characteristics such as their color, strength, conductivity and reactivity can differ substantially between nanoscale and micro scale carbon ‘nanotubes’ are 100 times stronger than steel but six times lighter.

Nanotechnology is hailed as having the potential to increase the efficiency of energy consumption, to help the clean environment and solve major health problems. It is said to be able to massively increase manufacturing production at significantly reduced costs, the products of nanotechnology will be cheaper, smaller, lighter yet more functional and require less energy and fewer raw materials to manufacture (Bhat, 2003). In fact, the National Nanotechnology Initiative (NNI) defines nanotechnology as “the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications.” Ideally, systems with structural features in the nanometer length range could affect aspects from food safety to molecular synthesis.

Food is nanofood when nanoparticles, nanotechnology techniques or tools are used during cultivation, production, processing, or packaging of the food. It does not mean atomically modified food or food produced by nanomachines

History

1959: Richard Feynman: Concept of Nanotechnology; lecture “There's plenty of room at the bottom.”

1974: Norio Tanigutchi: Coined the term “Nanotechnology”. It refers to precision manufacturing at the scale of nanometers (nm).

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1981 – IBM develops Scanning Tunneling Microscope

1985 – “Buckyball” - Scientists at Rice University and University of Sussex discover C60

1986 – “Engines of Creation” - First book on nanotechnology by K. Eric Drexler.Atomic Force Microscope invented by Binnig, Quate and Gerbe

1989 – IBM logo made with individual atoms

1991 – Carbon nanotube discovered by S. Iijima

1999 – “Nanomedicine” – 1st nanomedicine book by R. Freitas

2000 – “National Nanotechnology Initiative” launched

Nanotechnology, as a new enabling technique has the potential to revolutionize agriculture and food systems. Agricultural and food systems security, disease treatment drug delivery systems, new tools for molecular and cellular biology, new materials for pathogen detection and protection of the environment are examples of the important links of nanotechnology to the science and engineering of agriculture and food systems. Some overreaching examples of nanotechnology as an enabling technology are: production processing and shipment of food products can be more secured through the development and implementation of nanosensors for pathogen and contaminant detection.

The development of nano-devices can allow historical environmental records and location tracking of individual shipments. System that provides the integration of “Smart systems” sensing, localization, reporting and remote control can increase efficiency and security. Agriculture and food systems security is of critical importance to homeland security food supply must be carefully monitored and protected. Nanotechnology holds the potential of such system becoming a reality, agriculture has long dealt with improving the efficiency of crop production, food processing, food safety and environmental consequences.

Nanotechnology development:-

First generation-(~2004~2010)-Called as passive nanostructure generation phase. Focus on basic R & D in nanomaterials Include nanoparticles, nanopolymer etc.

Second generation: - (~2005 onwards) - called as Active nanostructure generation phase. It deals with Transistors, amplifiers, sensors, fuel cells, solar cells. This phase is going on in the laboratory.

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Third generation: - (~2012 onwards), this generation will be called as 3 dimensional nanosystem with heterogeneous nanocomponents, aim to develop robotic devices.

Fourth generation:- (~2018 onwards) In this generation develops heterogeneous molecular systems. Here we can do nanosurgery inside cell at molecular level

Nanoscale Fullerence Co60

1.27 × 107 m 0.22 m 0.7 × 10-9 m

10 millions times smaller 10 millions times smaller

Fig 3 – nanoscale

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Range of nano-size particles in foods

Structures Diameter or length (nm)

DNA 12

Glucose 21-75

Liposome 30-10000

LDH 40-300

Amylopectin 44-200

Casein micelle 60-100

PLA nanosphere 100-300

Zein 200

Cubosome 500

Nanosensors <1000

Source : Trends in Biotechnology, 2009

Stages of Nanofabrcation :

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Nanofabrication refers to manufacturing or construction of nanostructures at least with one dimension in nanometer serge, which involves two approaches.

1. Top down approach: This means reducing the size of the smallest structure to the nanoscale

Ex.: Photonics applications in nanoelectronics and nano-engineering.

2. Bottom up: This involves manipulating individual atoms and molecules into nano-structure and more closely resembles chemistry or biology (Pabi et al, 2001).

Nano materials:

Carbon Fullerenes:-

Carbon fullerenes are large, closed caged carbon structures in a spherical shape. Fullerenes, discovered in 1985, are stable in gas form and exhibit many interesting properties that have not been found in other compounds before. Figure 4 is a representation of a C60 Fullerene molecule. A fullerene is a spherical structure composed of both pentagonal and hexagonal carbon rings. Fullerenes are considered zero dimensional quantum structures which exhibit interesting quantum properties. Once fullerenes were proven to exist, research for other fullerene like structures led to the discovery of Carbon nanotubes in 1991.

Carbon nanotubes:-

Nanotubes are the one dimensional wire form of a diameter is typically 1 to 5 nanometers, while the length can be in the range of microns. The society stands to be significantly influenced by carbon nanotubes. The world already dream of space elevators, hydrogen powered vehicles, artificial muscles and so on that would be made possible by emerging carbon nanotube science. The first carbon concentric multiwall nanotubes were developed in 1991 as byproducts of the formation of fullerenes by the electric arc technique. But the real breakthrough occurred two year later when attempts were made to fill the nanotubes with various metals in situ led to the discovery of single walled carbon nanotubes. Ideally carbon nanotubes can be considered to be a perfect grapheme sheet to roll it into a cylinder so that the hexagonal rings if put in contact join coherently, then to close the tips by two caps, each cap being a hemi-fullerene with the appropriate diameter. The sidewalls of CNT consist of only hexagonal carbon rings, whereas the end caps are made of pentagons and hexagons in order for curvature to exist. Due to the symmetry of the cylindrical tube, CNT have a discreet number of directions that can form a closed cylinder.

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These are used in ideal force sensors in scanning probe microscope and USED in field emitters on flat panel display for TV or computer

Thermally stable in vacuum up to 2800 ºc Capacity to carry electric current 1000 better than copper wire. These have twice the thermal conductivity than diamond. Nanocomputers based on carbon nanotubes have already been demonstrated.

Fig 4–Nano wires and nano tubes.

Nanoelectromechanical System (NEMS) Sensors

NEMS technology enables creation of ultra small and highly sensitive sensors for various applications.

The NEMS force sensor shown in the figure is applicable in pathogenic bacteria detection. The nanosensors to be developed will work on different types of immunoassays depending on the application. Single modules will be developed for the detection and quantification of specific contaminants which can be combined according to users’ requirements. It is planned to develop on-line systems with suitable software and automated decision support systems for large industries as well as bench top and/or handheld devices for small companies with flexible production units.

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Fig 5 –Nanosensors for bacteria detection

Why We Use Nanotechnology….?

The texture of food can be changed as food spread ability and stability improve with nano-sized crystals and liquids for better low fat foods. The flavour of a food can be changed with bitter blockers or sweet and salty enhancers. Nano-enhanced bacteria keep oxygen sensitive foods fresher.

Nanotechnology enters the food chain.

The term ‘nanofood’ describes food which has been cultivated, produced, processed or packaged using nanotechnology techniques Tools manufactured nanomaterials have been added Eg.nano-ingredients nanoparticles of iron or zinc, and nanocapsules containing ingredients like co-enzyme Q10 or Omega 3.Nanotechnology is moving out of the laboratory and into every sector of food Production Manufactured nanomaterials are already used in some food products.

Application of nanotechnology:-

1. Agriculture:-

Nanotechnology in Agriculture

There are new challenges in this sector including a growing demand for healthy and safe food an increasing risk of disease; and threats to agricultural and fishery production from changing weather patterns. However, creating a bio economy is a challenging and complex process involving the convergence of different branches of science. Nanotechnology has the potential to revolutionize the agricultural and food industry with new tools for the molecular treatment of diseases, rapid disease detection,

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enhancing the ability of plants to absorb nutrients etc. Smart sensors and smart delivery systems will help the agricultural industry combat viruses and other crop pathogens. In the near future nanostructured catalysts will be available which will increase the efficiency of pesticides and herbicides, allowing lower doses to be used. Nanotechnology will also protect the environment indirectly through the use of alternative (renewable) energy supplies, and filters or catalysts to reduce pollution and clean-up existing pollutants. An agricultural methodology widely used in the USA, Europe and Japan, which efficiently utilizes modern technology for crop management, is called Controlled Environment Agriculture (CEA). CEA is an advanced and intensive form of hydroponically-based agriculture. Plants are grown within a controlled environment so that horticultural practices can be optimized. The computerized system monitors and regulates localized environments such as fields of crops. CEA technology, as it exists today, provides an excellent platform for the introduction of nanotechnology to agriculture. With many of the monitoring and control systems already in place, nanotechnological devices for CEA that provide “scouting” capabilities could tremendously improve the grower’s ability to determine the best time of harvest for the crop, the vitality of the crop, and food security issues, such as microbial or chemical contamination.1.1 Precision Farming:-

Precision farming has been a long-desired goal to maximize output (i.e. crop yields) while minimizing input (i.e. fertilizers, pesticides, herbicides, etc) through monitoring environmental variables and applying targeted action. Precision farming makes use of computers, global satellite positioning systems, and remote sensing devices to measure highly localized environmental conditions thus determining whether crops are growing at maximum efficiency or precisely identifying the nature and location of problems. By using centralized data to determine soil conditions and plant development, seeding, fertilizer, Chemical and water use can be fine-tuned to lower production costs and potentially increase production- all benefiting the farmer. Precision farming can also help to reduce agricultural waste and thus keep environmental pollution to a minimum. Although not fully implemented yet, tiny sensors and monitoring systems enabled by nanotechnology will have a large impact on future precision farming methodologies. One of the major roles for nanotechnology-enabled devices will be the increased use of autonomous sensors linked into a GPS system for real-time monitoring. These nanosensors could be distributed throughout the field where they can monitor soil conditions and crop growth. Wireless sensors are already being used in certain parts of the USA and Australia. For example, one of the Californian vineyards, Pickberry, in Sonoma County has installed wifi systems with the help of the IT Company, Accenture. The initial cost of setting up such a system is justified by the fact

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that it enables the best grapes to be grown which in turn produce finer wines, which command a premium price. The use of such wireless networks is of course not restricted to vineyards.

The union of biotechnology and nanotechnology in sensors will create equipment of increased sensitivity, allowing an earlier response to environmental changes. For example:• Nanosensors utilizing carbon nanotubes12 or nano-cantilevers13 are small enough to trap and measure individual proteins or even small molecules.• Nanoparticles or nanosurfaces can be engineered to trigger an electrical or chemical signal in the presence of a contaminant such as bacteria.• Other nanosensors work by triggering an enzymatic reaction or by using nanoengineered branching molecules called dendrimers as probes to bind to target chemicals and proteins. Ultimately, precision farming, with the help of smart sensors, will allow enhanced productivity in agriculture by providing accurate information, thus helping farmers to make better decisions.1.2 Smart Delivery Systems:-

The use of pesticides increased in the second half of the 20th century with DDT becoming one of the most effective and widespread throughout the world. However, many of these pesticides, including DDT were later found to be highly toxic, affecting human and animal health and as a result whole ecosystems. As a consequence they were banned. To maintain crop yields, Integrated Pest Management systems, which mix traditional methods of crop rotation with biological pest control methods, are becoming popular and implemented in many countries, such as Tunisia and India. In the future, nanoscale devices with novel properties could be used to make agricultural systems “smart”. For example, devices could be used to identify plant health issues before these become visible to the farmer.

Such devices may be capable of responding to different situations by taking appropriate remedial action. If not, they will alert the farmer to the problem. In this way, smart devices will act as both a preventive and an early warning system. Such devices could be used to deliver chemicals in a controlled and targeted manner in the same way as nano-medicine has implications for drug delivery in humans. Nano-medicine developments are now beginning to allow us to treat different diseases such as cancer in animals with high precision, and targeted delivery (to specific tissues and organs) has become highly successful. Technologies such as encapsulation and controlled release methods have revolutionized the use of pesticides and herbicides. Many companies make formulations which contain nanoparticles within the 100-250 nm size range that are able to dissolve in water more effectively than existing ones (thus increasing their activity). Other companies employ suspensions of nanoscale particles (nanoemulsions), which can be either water or oil-based and contain

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uniform suspensions of pesticidal or herbicidal nanoparticles in the range of 200-400 nm. These can be easily incorporated in various media such as gels, creams, liquids etc, and have multiple applications for preventative measures, treatment or preservation of the harvested product. One of the world’s largest agrochemical corporations, Syngenta, is using nanoemulsions in its pesticide products. One of its successful growth regulating products is the Primo MAXX® plant growth regulator, which if applied prior to the onset of stress such as heat, drought.

2 Food safety and quality

Pathogen detection:-

Nano-biosensors can minimize the time of lengthy microbial testing in laboratories. Applications include detection of contaminants in water supplies, raw food materials and food products, plant pathogens in the crops, its seed materials and animal products. Enzymes can be used as the sensing materials in nanobiosensors to increase the accuracy and specificity of the testing. Nanobiosensors, apart from its specificity and accuracy will be easy to hurdle in the field and remote areas owing to its size.

Today sensors provide an abundance of information about such parameters as temperature and weather data and data that provide information on air, land and sea transportation, chemical contaminants, deceleration for release of airbags in automobiles and countless other variables. Biological organisms also have the ability to sense the environment. Humans sense the environment through sight, touch, taste, smell and sound. For example, the human ear uses nanostructures to transduce the macro-motion of ear drum-induced fluid motion into a chemical/electrical signal2. In living organisms, sensors operate over a range of scales from the macro (ear drum vibrations) to the micro (nerve cells) to the nanoscale (molecules binding to receptors in our noses).

The exciting possibility of combining biology and nanoscale technology into sensors holds the potential of increased sensitivity and therefore a significantly reduced espouse-time to sense potential problems. Imagine, for example, a bioanalytical nanosensor that could detect a single virus particle long before the virus multiplies and long before symptoms were evident in the plants or animals. Some examples of the potential applications for bioanalytical nanosensors are detection of pathogens, contaminants, environmental characteristics (light/dark, hot/cold, wet/dry), heavy metals, and particulates or allergens. Many significant challenges remain. For example, while it is likely that we will be able to

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detect a single virus or other foreign particle, getting the foreign particle to the detection point at an opportune time will be a significant challenge. The panel identified desirable characteristics of biosensors as: small, portable, rapid response and processing (i.e., real-time), specific, quantitative, reliable, accurate, reproducible, robust and stable.

3 Food additives:-

Currently, some food additives with nanoingredients (according to claims by the producers) are being sold in the USA and Germany. These additives may imply that nanoparticles are present in the food. The additives are mainly aimed at the diet, sports and health food markets and contain minerals with a nano-formulation, such as silicon dioxide, magnesium, calcium, etc. The particle size of these minerals is claimed to be smaller than 100 nanometre so they can pass through the stomach wall and into body cells more quickly than ordinary minerals with larger particle size. Nano-additives can also be incorporated in micelles or capsules of protein or another natural food ingredient. Micelles are tiny spheres of oil or fat coated with a thin layer of bipolar molecules of which one end is soluble in fat and the other in water. The micelles are suspended in water, or conversely, water is encapsulated in micelles and suspended in oil. Such nanocapsules can for example contain healthy Omega3 fish oil which has a strong and unpleasant taste and only release it in the stomach such as in “Tip Top Up”® bread sold in Australia.

3.1 Nano in your sausage :-NovaSol the solution for meat curing and colour stability”

Industrial sausage and cured meat production requires the addition of numerous additives to speed up the production process, to stabilize colour and ‘improve’ taste. German company Aquanova has developed a nanotechnology-based carrier system using 30nm micelles to encapsulate active ingredients such as Vitamins C and E and fatty acids which can be used as preservatives and aids (Aquanova undated). Aquanova markets its micelles as “NovaSol” and claims that the nanoscale carrier system increases the potency and bioavailability of active ingredients. The German industry magazine “Fleischwirtschaft” claims that NovaSol offers considerable advantages for meat processors: faster processing, cheaper

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ingredients, higher colour stability, and ready to use liquid form. These nanoformulations of these additives have been available to German manufacturers since 2006. They may be used in an assortment of cured meats and sausages currently available to European consumers. The failure to identify nano-ingredients on product labels prevents their tracking. However it is conceivable that consumers worldwide have been exposed to these nano-materials through exports. Nanoparticles and particles up to 300nm in size are added to many foods as processing aids.

Nano-encapsulated active ingredients including vitamins and fatty acids are now sold commercially for use in processing and preservation of beverages, meats, cheese and other foods (Aquanova undated). Nanoparticles and particles a few hundred nanometres in size added intentionally to many foods to improve flow properties (e.g. how well it pours), colour and stability during processing, or to increase shelf life. For instance, aluminum-silicates are commonly used as anti-caking agents in granular or powdered processed foods, while anatase titanium dioxide is a common food whitener and brightener additive, used in confectionery, some cheeses and sauces. In bulk form (conventional, larger particle size), these food additives are usually biologically inert and are considered by regulators in the European Union and elsewhere to be safe for human consumption.

Dairy products, cereals, breads and beverages are now fortified with vitamins, minerals such as iron, magnesium or zinc, probiotics, bioactive peptides, antioxidants, plant sterols and soy. Some of these active ingredients are now being added to foods as nanoparticles or particles a few hundred nanometres in size. Colour and stability during processing, To increase shelf life Aluminum-silicates are commonly used as anti- caking agents in granular or powdered processed Foods Anatase titanium dioxide is a common food whitener and brightener additive, used in confectionery, some cheeses and sauces

4 Food processing:-

Knives and chopping boards can be coated with antibacterial silver nanoparticles. When products treated with nanosilver are washed, nanoparticles are released into waste water treatment facilities and can never destroy beneficial bacteria

4.1 Electronic tongue:-Electronic tongue detecting chemicals released during food spoilage. It detects chemicals, pathogens, & toxins in food. Can detect allergen proteins to prevent adverse reaction to foods. Colour change in the packaging to alert the consumer.

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Fig 6- Electronic tongue

5 Food packaging:-

Applications of nanotechnology within the food sector is in packaging Between 400 and 500 nanopackaging products are estimated to be in commercial use now, while nanotechnology is predicted to be used in the manufacture of 25% of all food packaging within the next decade. A key purpose of nano packaging is to deliver longer shelf life by improving the barrier functions of food packaging to reduce gas and moisture exchange and UV light exposure For example, DuPont has announced the release of a nano titanium dioxide plastic additive ‘DuPont Light Stabilizer 210’ which could reduce UV damage of foods in transparent packaging . In 2003, over 90% of nano packaging (by revenue) was based on nano-composites, in which nanomaterials are used to improve the barrier functions of plastic wrapping for foods, and plastic bottles for beer, soft drinks and juice (PIRA International cited in Louvier 2006; see Appendix A for products). Nano packaging can also be designed to release antimicrobials, antioxidants, enzymes, flavours and nutraceuticals to extend shelf-life

5.1 Edible nano coatings:-

Most of us are familiar with the waxy coatings often used on apples.Now nanotechnology is enabling the development of nanoscale edible coatings as thin as 5nm wide, which are invisible to the human eye. Edible nano coatings could be used on meats, cheese, fruit and vegetables, confectionery, bakery goods and fast food. They could provide a barrier to moisture and gas exchange, act as a vehicle to deliver colours, flavours, mantioxidants, enzymes and anti-browning agents, and could also increase the shelf life of manufactured foods, even after the packaging is opened. United States Company Sono-Tek Corp. announced in early 2007 that it has

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developed an edible antibacterial nano coating which can be applied directly to bakery goods; it is currently testing theprocess with its clients 5.2 Chemical release nano packaging:-

Chemical release nano packaging enables food packaging to interact with the food it contains. The exchange can proceed in both directions. Packaging can release nanoscale antimicrobials, antioxidants, flavours, fragrances or nutraceuticals into the food or beverage to extend its shelf life or to improve its taste or smell. In many instances chemical release packaging also incorporates surveillance elements, that is, the release of nano-chemicals will occur in response to a particular trigger event. Conversely, nano packaging using carbon nanotubes is being developed with the ability to ‘pump’ out oxygen or carbon dioxide that would otherwise result in food or beverage deterioration. Nano packaging that can absorb undesirable flavours is also in development.

Table 2 - Example of chemical release nano packaging under development

5.3 Nano-based antimicrobial packaging and food contact material:-Distinct from trigger-dependent chemical release packaging, designed

to release biocides in response to the growth of a microbial population, humidity or other changing conditions, other packaging and food contact materials incorporate antimicrobial nanomaterials, that are designed not to be released, so that the packaging itself acts as an antimicrobial. These products commonly use nanoparticles of silver although some use nano zinc oxide or nano chlorine dioxide. Nano magnesium oxide, nano copper oxide, nano titanium dioxide and carbon nanotubes are also predicted for future use in antimicrobial food packaging.

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Table 3: Nano-based antibacterial food packaging and food contact materials

5.4 Nano-sensor and track and trace packaging:-Packaging equipped with nano sensors is designed to track either the

internal or the external conditions of food products, pellets and containers throughout the supply chain. For example, such packaging can monitor temperature or humidity over time and then provide relevant information on these conditions, for example by changing colour. Companies as diverse as Nestlé, British Airways, MonoPrix Supermarkets, 3M and many others are already using packaging equipped with chemical sensors, and nanotechnology is offering new and more sophisticated tools to extend these capabilities and to reduce costs (Nanotechnology is also enabling sensor packaging to incorporate cheap radio frequency identification (RFID) tags Unlike earlier RFID tags, nano-enabled RFID tags are much smaller, can be flexible and are printed on thin labels. This increases the tags’ versatility (for example by enabling the use of labels which are effectively invisible) and thus enables much cheaper production. Other varieties of nano-based track and trace packaging technologies are also in development. For instance, United States company Oxonica Inc has developed nano barcodes to be used for individual items or pellets, which must be read with a modified microscope. These have been developed primarily for anti-counterfeiting purpose). An ingestible nano-based track and trace technology is promised by pSiNutria, a spin out of nanobiotechnology company pSivida. Potential

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pSiNutria products include: “products to detect pathogens in food, for food tracing, for food preservation, and temperature measurements in food storage.5.5 Nano biodegradable packaging:-

The use of nanomaterials to strengthen bioplastics (plant-based plastics) may enable bioplastics to be used instead of fossil-fuel based plastics for food packaging and carry bags Potential environmental benefits.

Table 4 -Development of nano-composite bioplastics

5.6 Non-stick nano lining for mayonnaise and tomato sauce bottles:-Promising an end to the need to tap or shake mayonnaise or ketchup

bottles to remove the last of their contents, several German research institutes, industry partners and the Munich University of Technology have joined forces to develop non-stick nanofood packaging. The researchers have applied thin films which measure less than 20nm to the inside surface of food packaging. They have already developed their first samples, and hope to release the new packaging commercially in the next 2 – 3 years. The researchers promote their product as an environmentally friendly solution to reduce leftover traces of condiments in bottles. However there are concerns that manufactured nanomaterials are released into the environment from waste streams or during recycling. This may present a new range of serious

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ecological risks. It is therefore possible that such packaging may introduce more pollution problems than it solves

6. Other applications:-6.1 Medicine: The biological and medical research exploited the properties of nano-materials for various applications. Ex.: Contrast agents for cell imaging and therapeutics for treating cancer. The field described as

♦ Biomedical nanotechnology

♦ Bio-nanotechnology

♦ Nano-medicine

♦ Molecularly engineered biodegradable chemicals for nourishing plant and

protecting against insect.

♦ Genetic improvement for animals and plants.

♦ Delivery of genes and drugs to animals.

♦ Nano-array based technologies for DNA testing

The integration of nano-material with biology has led to the development of diagnostic devices, contrast agents, analytical tools, and therapy and drug-delivery vehicles. 6.2 Cancer treatment:- Golden “nanobullets” are developed that can destroy inoperable human cancers. The nanobullet consist of Silica shells plated with gold and when these are heated with infrared light the cancer are destroyed for which carbon nanotubes have been transported in to cell nucleus and continuous infrared radiation is made available (Ferrari, 2005).6.3 Water purification:-

The physical filters with nanometer – scale pores can remove 100% of bacteria, viruses and even prions. Well structured filter materials and smaller actuators will allow even the smallest filter elements to be self monitoring and self cleaning. For the treatment of wastewater, PiO2, ZnO and SnO2 are used. Nanoparticles are used i.e., these decomposes waste and toxic pesticides which take a long time to degrade under normal condition.

6.3 Nanobarcodes:-The identification tags are ultra miniatures used multiplexed

bioassays and general encoding. It contains different fluorescent materials, that are identified by using UV light and optical microscope are used for application in DNA hybridization assays. These nanobarcodes are encodeable, machine readable and durable. 6.4 Toxic gas detection:-

Electronic Nose (E-Nose) is a device mimicking the operation of the human nose, which uses a pattern of response across on array of gas

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sensors to identify different types of odors, estimates the concentration and its properties. These gas sensors are composed to ZnO2, narowires.6.5 Solar energy:-

The nanoparticles help in storage, conversion etc. by reducing materials and process rates, which ultimately helps in energy saving. Ex. : Thermal insulation and by enhanced renewable energy source. 6.6 Animal husbandry:-

These nano sensors help in alternate uses and better residual management. It also helps in reduced discharges of pathogens, veterinary pharmaceuticals, ebtogen and androgens, stored hormones, reduced air emissions of ammonia methane, hydrogen sulfide and pathogen, water and soil monitoring. I) Animal tracking devices:

Tracking devices used in valuable farm animals or wild life conversation. The microchips are injected for improving animal welfare and safety to study the behaviors in the wild life. These microchips act as nanosensors which are fitted with animals to locate about their health and geographical location to a central computer. ii) Microfluidics for breeding animals: Nano-Eugenics are used to accelerate genetic uniform within livestock species. 6.7 Fisheries:-1) DNA nano-vaccines using nano-capsules and ultrasound:-

The mass vaccination of fishes is done by using ultrasound. These nano capsules containing a short stand of DNA which are added to on fish pond, where they are adsorbed into the cells of the fish, sound is used to rupture the capsule and release, the DNA and eliciting immature response from the fish.Ex. : Tested on rainbow trout by clear springs foods.

2) Clearing of fish pond:-Navada based Altair® - Nano-technologies make water clearing products for swimming pool and fish ponds called nano-checks. There are 40 nm particles. These absorb phosphates from water and prevent algal growth. 6.7 Food processing and storage:-

The improved plastic film coating for food packaging and storage that enable a wider and more efficient distribution of food products to remote areas in less industrialized countries, antimocribial emulsions made with nano-materials for the decontamination of food equipment, packaging of food and the nanotech based sensors to detect and identify contamination.

Pre-harvest :-♦ Addition of specific nano-particles to remove the infecting bacteria.

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♦ Nano-particles block the bacterial colonization.

Post-harvest:-Nano-technological antimicrobial and polymer films are used in food safety and quality. Need of agri food inventory:-

A large focus on food packaging and sensing for food borne pathogens and also focus on retail and consumer application. Generally, more focus on health, benefits than on environment.

6.7 Drug delivery systems:-Nanocapsules, dendrimers and bucky balls are made up of carbon atoms

at nanoscale for slow and sustained drug release within the system. This reduces transportation cost and dosage by improving shelf life, thermostability and resistance to change in climatic condition. • Drugs are packed into nanoparticles deliver drugs at targeted parts,

which avoids side affects e.g. fumagillin• Targeted drug delivery is facilitated by conjugating nanoparticles with

certain binding groups such as monoclonal antibodies or ligands• Small enough to pass through cell barriers & circulate inside body or

taken up by cells by endocytosis.

6.8 Chemistry and environment:

Chemical catalysts and filtration techniques are two prominent examples where nanotechnology already plays a vital role. The synthesis provides a more material with fixed/specific features and chemical properties. Ex: Nano-particles with a distinct chemical surrounding ligands or specific optical properties. 6.9 Energy : The most advanced nanotechnology projects related to energy as storage, conversion, manufacture, improvement by reducing materials and process rates and energy saving. Ex: Thermal insulation and by enhanced renewable energy sources.Main thrust of research in nanotechnology 1. Electronics2. Automation 3. Medicine4. Life science

Risks may pose by nanotechnology:

Nanoparticles are more chemically reactive than larger particles

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Nanoparticles have greater access to our bodies than larger particles

Greater bioavailability and greater bioactivity may introduce new toxicity risks

Nanoparticles may have longer term pathological effects

Our bodies’ defensive mechanisms are not as effective at removing nanoparticles from our lungs, gastro-intestinal tract and organ

Nanoparticles will be more toxic per unit of mass than larger particles of the same chemical composition.

Nano particles have larger surfaces this makes them susceptible to to get absorbed in the macromolecules in an animal body. They can hinder biological processes, thus intervening the functionality of nature.

Since these particles are very small, problem can actually arise from inhalation of these minute particles.

Fabrication of nanomaterials is very costly method and also very difficult.

Atomic weapons are made to be more powerful and more destructive these can become more accessible with nanotechnology.

Nanocomposite edible films from mango puree reinforced with cellulose nanofibers

Objective:

To evaluate the effect of different concentrations of cellulose nanofibres added as nanoreinforcing component on tensile properties, water vapor permeability and glass transition temperature of mango puree edible films

Materials and Methods:

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The mango puree (29% total solids, 27% total soluble solids) and cellulose nanofibers(CNF) were procured.

An aliquot of the CNF suspension was mixed with an equal volume of 2% urinyl acetate(UA)

A 10 μl drop of the UA fibril mixture was dispensed on to a 400 mess copper grid allowed to stand for 30 to 60s.

The grid was air dried.

Fiber lengths and widths were directly measured from transmission electron graph.

Different concentration of CNF were added to the mango puree and dispersions were homogenized.

A control film was elaborated only with mango puree.

The physical properties Tensile strength, water vapor permeability and glass transition temperature and elongation at break of the films were analysed.

Results:

Table 1: Physical properties of mango puree edible films with different concentration of CNF nano reinforcement

CNF (g/100g)

TS (MPa) EB (%) WVP (g.mm/kPA.H.m2)

Tg (ºC)

0 4.09 44.07 2.66 -10.60

1 4.24 42.42 2.40 -8.51

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2 4.42 43.40 2.17 -8.57

5 4.58 41.79 2.16 -7.72

10 4.91 43.19 2.03 -6.81

18 5.54 39.8 1.90 -5.88

36 8.76 31.54 1.67 -6.04

• Cellulose nanofibers were effective in increasing tensile strength

• Elongation at break was not significantly impaired at CNF

concentrations; it decreased when compared to the control.

• CNF was more effective to decrease water vapor permeability (WVP) of

mango puree films

• Although Transition temperature increases have been small with CNF

incorporation, it was significant.

Conclusion:

The cellulose reinforcement was well dispersed into the mango puree matrix.

The performance of mango puree edible films was noticeably improved by CNF reinforcement.

Mechanical properties except elongation, were improved by the by the addition of cellulose nanofibres.

Physical, chemical and microbiological changes in stored green asparagus spears as affected by coating of silver nanaoparticles-PVP

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Objective:

To evaluate the effect of a silver nanoparticles-PVP coating on the weight loss, ascorbic acid, total chlorophyll, crude fibre, color, firmness and microbial quality of green asparagus stored at 2 and 10º c

Materials and methods:

Preparation of silver nanoparticles

Plant material and handling:

Fresh green asparagus was harvested

Straight, undamaged spears, 8-20mm in diameter and 22cm in length

Submerged in 100mg/L NaOH solution for 15 min at room temperature

Immersed in the coating solution for 3 min at room temperature

Treated asparagus was dried in cold air dried for 10 min

All the asparagus samples were stored for up to 20 days at 2 ant 10º c with RH 90-95%.

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Both control and treated were analyzed for the following at a 5 day interval

Weight loss and ascorbic acid

Total chlorophyll and crude fibre

Firmness

Color

Microbial analysis

Statistical analysis

Results:

The silver nanoparticles were almost spherical with mean diameter around 15-25 nm

Transmission electron microscopy (TEM) of silver nanoparticles (×100,000).

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Changes of weight loss (A), ascorbic acid (B), total chlorophyll (C) and crude fiber (D) in green asparagus stored at 2 and 10 °C. Control, stored at 2 °C □. Coated, stored at 2 °C( ) Control stored at 10 °C( ) Coated, stored at 10 °C ( ) Different letters within the same storage day indicate that means are different at the 0.05 level of significance.

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Total aerobic psychrotrophic count (A), yeasts and moulds (B) on asparagus stored at 2 and 10 °C. Control, stored at 2 °C ( ) Coated, stored at 2 °C ( ). Control, stored at 10 °C ( ) Coated, stored at 10 °C ( … ….)

Results:• The diameter of the silver nanoparticles prepared in this research was

about 20 nm, spherical with diameter 15-25nm• The weight losses were reduced from 9.2%to 13.8%. the coating

significantly reduced weight loss over the storage period at both temperature.

• The largest weight loss reduction was obtained from coated application of nanosilver particles PVP at the end of the storage.

• Significant increase in the ascorbic acid loss after treatments took place at 2ºC during the storage time from 5 to 10 days but at 10ºC only for the storage of 20 and 25days

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• Significant differences are found between the coated asparagus and the control sample in total chlorophyll content of the green spears were observed after stored at 2ºC from 5 to 10 days but at 10ºC only for 25 days.

• The presence of silver nanoparticles-PVP coating had a positive effect on chlorophyll content at only 2ºC.

• Asparagus with silver nanopartcle - PVP coating had lower the crude fiber content compared to the control samples.

• A decrease in the hue angle was observed with storage time. The reduction of the hue angles of the samples correlated well with reduction of the total chlorophyll concentration over the storage.

• Changes in the total aerobic psychotropic count were found at both temperatures. The silver nanoparticles-PVP coating significantly hindered the increase in total aerobic psychotropic count compared to control.

• Similar effect of coating was observed in reducing the growth of yeasts and moulds during the storage.

Conclusion:

Applications of silver nanoparticles-PVP coating to green asparagus were shown to be beneficial in keeping the quality of the storage. Coating of silver nanoparticles-PVP slowed down the weight loss, ascorbic acid and total chlorophyll, reduced the color changes in the skin of asparagus, the growth of microorganism and increased the shelf-life of asparagus by about 10 days at 2 °C.

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Effect of nano-packing on preservation quality of Chinese jujube (Ziziphus jujuba Mill. var. inermis (Bunge) Rehd)

Objective: To prepare a novel nano-packing material and investigate its effect on preservation of Chinese jujube during room temperature storage.

Materials and methods:

500g matured green Chinese jujube were selected.

Packed in nano packing (15 bags) and polythene bag (15 bags)

Stored at 16-26ºc for 12 days

They were subjected to Physical property analysis and microstructure

observation Firmness and weight loss rate Fruit decay rate and browning rate Evaluation of total soluble sugars and reducing sugars Measurement of total soluble solids, titrable acid and

ascorbic acid

•Statistical analysis

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Results:

• Physical properties of normal packing and nano-packing materials

Relative humidity transmission rate (g/m2 24 h)

O2 Transmission rate (cm3/m2 24 h·0.1 MPa)

Longitudinal strength (Mpa)

Normal packing

2.85 12.83 32.35

Nano-packing

2.05 12.56 40.16

Fig. 1. SEM micrographs of nano-packing materials (a) and normal packing materials (b).

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Fig. 2. Effects of nano-packing and normal packing on sensorial qualities of jujube during room temperature storage. (a) firmness; (b) weight loss rate; (c) fruit decay rate and (d) browning rate.

Fig. 3. Effects of nano-packing and normal packing on physicochemical indices of jujube during room temperature storage. (a) total soluble sugars content; (b) reducing sugars content; (c) total soluble solids content; (d) titratable acid content and (e) ascorbic acid content.

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• The transmission rate of humidity (RH) and oxgen of nanopackaging materials were decreased when compared to control.

• The longitudinal strength of nanopackaging was 1.24 fold higher than that of the control.

• From the microstructure observation it appeared that the nanoparticles were uniformly distributed in the nano-packing film with irregular shape.

• The dimensions of nano particles 300-500nm• Fruit firmness rapidly decreased in control group compare to

nanopacking.• The nano packing delayed the decline of firmness and had a beneficial

effect on firmness retention.• Compared to the control, jujube stored with nano-packing exhibited a

significantly lower weight loss.• Fruit decay rate: The jujube stored with control packing started

decaying from on day 1 and reached 66% decay rate on day 12 during room temperature storage.

• During storage, the browning rate of all groups increased with time. Moreover the browning rate of nanopacked jujube was always lower than that of the control.

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• Total soluble sugars: nano packing could significantly inhibit the increase of total soluble sugar content compound with the control.

• The reducing sugars content of the nano-packing group was lower than that of the control.

• The results indicated that the application of nanopacking might be able to slow down the metabolism to give prolonged life to the fruit.

• The total soluble solids of jujube increased with the time during room temperature storage.

• The Titrable acid and ascorbic acid content was decreased continuously for all the packing which was consistent with the decline in edible quality.

• The nano-packing was better for maintaining the content of Titrable acidity and ascorbic acid compared to control.

Conclusion

The nano-packing material had quite beneficial effects on physicochemical and physiological quality compared with normal packing material. Further research will be needed to explore the exact nano-packing mechanism during storage to facilitate the application of nano-technology over a broader range in the future.

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SUMMARY

The performance of mango puree edible films was noticeably improved by CNF reinforcement.

Coating of silver nanoparticles-PVP slowed down the weight loss, ascorbic acid and total chlorophyll, reduced the color changes in the skin of asparagus, inhibited the increasing of the tissue firmness, the growth of microorganism and increased the shelf-life of asparagus by about 10 days at 2 °C.

The nano-packing material had quite beneficial effects on physicochemical and physiological quality compared with normal packing material.

Conclusion

Nanotechnology is becoming increasingly important for food sector.

As with any new technology there is a significant challenge to create awareness and gain acceptance of the use of nanotechnology in the food industry.

In its widest sense nanotechnology is a part of food processing and conventional foods because the characteristic properties of many foods rely on nanometre sized component.

Most aspects of incremental nanotechnology are likely to enhance the product quality and food safety.

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