Nanotechnology has been applied in various industries, including electronics, medicine, pharmaceuticals, and food and agriculture. This article focuses on the influence of nanoparticles in the food industry.
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Nanomaterials are small materials whose size ranges between 1 and 100 nm and are synthesized using chemical and biological methods. Nanoparticles are used in the food industry owing to many unique physical, chemical, and biological properties.
Nanomaterials can promote crop production and protect them from harmful pests and pathogens. In addition, several nanoparticles protect plants from various biotic and abiotic stresses. In the food industry, different types of nanomaterials are used for pre-harvest processing and food packaging.
Could Nanoparticles Solve the Food Crisis?
The continual increase in the global population has increased the demand for food production. However, climate changes and global warming have affected agricultural production.
The food industry incurs massive losses due to food wastage. According to the Food and Agriculture Organization of the United Nations, around 1.3 billion metric tons of consumable food are wasted every year due to inferior post-harvest techniques and issues in the supply chain.
Predominantly, foods are spoiled due to microbial contamination, which reduces the shelf life of food products and affects their quality. Hence, to meet the global food demand and maintain food security, it is important to enhance crop production as well as minimize food wastage.
The development of nanotechnology-based food packaging has proved superior to the conventional packaging that uses plastic barriers.
The major contribution of the nano-food packaging system is that it enhances the shelf life of the food products due to the antimicrobial properties of nanoparticles. The nano-based delivery system has improved the nutraceutical values of the food components.
Nanotechnology and Agriculture
Scientists have applied nanotechnology to increase food production as well as restore soil health. This is important because excessive use of chemical pesticides and fertilizers has detrimental effects on the soil and humans.
As stated above, nanomaterials, such as titanium oxide nanoparticles, enhance plant growth and seed germination in the model organism Arabidopsis.
Researchers have also reported that the application of nanocrystals significantly improves water uptake potential in plants. The antimicrobial properties of nanoparticles protect plants from pathogen attacks while applying nanofertilizers and nanopesticides decreases environmental pollution.
Nanotechnology and Food Industry
The food products developed by using nanotechnology methods are referred to as nano-food.
Scientists have applied nanotechnology extensively in post-harvest processing, which has enhanced food bioavailability, texture, taste, and consistency.
Additionally, inorganic and organic nanomaterials are also used for food product preservation.
For instance, silver nanoparticles immobilized in cellulose and collagen sausage casings can effectively remove E. coli and Staphylococcus aureus owing to their strong bactericidal activity. This nanoparticle is not harmful to humans and the environment.
Some of the nanoparticles, such as copper, magnesium oxide, silver, and iron are used in the food industry for their antimicrobial effects. These nanoparticles are used in nanoemulsions or nanoencapsulations.
Scientists have designed various nano-based products, such as nanocoatings, nanofilters and nanoadditives which have immensely benefitted the food industry. Some of the applications are discussed below:
Researchers have developed edible nanocoatings whose main functions are to serve as a barrier from oxygen, carbon dioxide, moisture, UV radiation, and volatiles. Additionally, these are used to prolong shelf life and add flavor, color, enzyme, antioxidant and anti-browning properties to the food product.
Food packaging materials coated with nanoparticles reduce food wastage. Nanocoatings can also be directly used on various food products, including meat, cheese, and confectionery products.
The nanoencapsulation technique is widely used in the food industry. The shelf life of tomato and many other fruits and vegetables have been substantially enhanced by bionano-encapsulated quercetin. This technique has been used in the production of many commercially available products such as nanocapsules containing dietary supplements such as vitamins (A, C, D, E, and K), beta-carotene, and nanogreen tea.
Scientists reported that the application of zinc oxide-encapsulated halloysite–polylactic acid nanocomposites improves the shelf life of the chicken breast fillets and reduces bacterial growth and lipid oxidation.
Nanoadditives are used in the production of food containing low fats, sugars, and salts. These inhibit food contamination and, therefore, prevent food-borne diseases. Two of the commonly used nanomaterials that are used as nanoadditives are silicon dioxide and titanium oxide. Some of the metallic nanoparticles such as iron, silver, carbon, zinc oxide, titanium oxides are used as antimicrobial agents in food products. These nanoparticles either produce reactive oxygen species (ROS) or enhance the heat resistance of the food components.
Nanoemulsions are colloidal particulate systems whose size varies from 10 to 1000 nm. These contain solid spheres with amorphous and lipophilic surfaces. These nanoproducts are used for the decontamination of food packaging equipment.
Glycerine-based nanomicelle products are used to remove traces of pesticide residues from fruits and vegetables. Nanoemulsifies bioactive compounds are used to control microbial contamination without altering the texture or flavors of beverages, while nanoliposomes are used as cargos for nutrients, enzymes, and food antimicrobials.
Nanoparticles, such as clay, silicate, carbon nanotubes, starch nanocrystals, and cellulose-based nanofibers are incorporated in the polymeric matrix to develop nanocomposite plastics with improved properties.
These packaging materials are heat resistant, provide antimicrobial properties, and have low permeability to gases. Interestingly, carbon nanotubes can eliminate unpleasant flavors generated in food products.
The organically modified nanoclays inserted in the polymer matrix or ethylene-vinyl alcohol copolymer and polylactic acid (PLA) biopolymer improve the packaging material's mechanical strength and gas barrier properties.
Nanofilters or nanoscale filters are used to remove microbes, such as bacteria, from milk or water without boiling. These nano-sieves are also used in the filtration of beer.
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Are Nanoparticles Toxic to Humans?
The toxicity of the nanoparticles can be attributed to their dynamic, kinetic, and catalytic properties. Additionally, toxicity could be due to net particle reactivity, agglomeration, and its reaction with the functional environment.
Food packaging nanomaterials are extensively tested and are not toxic to humans. Studies have shown that nanoparticles enter the human body via skin penetration, ingestion, inhalation, or intravenous injections.
Toxicokinetic issues associated with nanoparticles are primarily because they are highly reactive, persistent, non-dissolvable, and non-degradable nature—toxicity increases as the size of metal-based nanoparticles decreases.
Some nanoparticles bind to enzymes and trigger ROS production and oxidative stress, which causes degeneration of mitochondria and induces apoptosis. Previous animal-based studies have shown that nanoparticles-induced toxicity affects organs, such as the liver, kidney, and immune system. Additionally, nanomaterials could cause genetic damages in the cells and result in genotoxicity.
Several regulatory bodies have been formed, such as Food Standards Australia and New Zealand (FSANZ), which determine the safety of nano-based food products, agricultural products, and food packaging materials.
In Europe, the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) evaluates the safety of nanotechnology-based food ingredients before being authorized for human use.
A widely accepted international regulatory system is required to provide proper guidelines to the food industry to ensure the safer development of nano-based food products.
Continue reading: Why Nanotoxicology Should be the First Step Towards a Nanotechnology Future.
References and Further Reading
Mittal, D. et al. (2020) Nanoparticle-Based Sustainable Agriculture and Food Science: Recent Advances and Future Outlook. Frontiers in Nanotechnology. Available at https://www.frontiersin.org/articles/10.3389/fnano.2020.579954/full
Nile, S.H. et al. (2020) Nanotechnologies in Food Science: Applications, Recent Trends, and Future Perspectives. Nano-Micro Letters. 12. 45. Available at: https://doi.org/10.1007/s40820-020-0383-9
He, X. et al. (2019) The current application of nanotechnology in food and agriculture. Journal of Food and Drug Analysis. 27 (I). pp. 1-21. Available at: https://doi.org/10.1016/j.jfda.2018.12.002
Bajpai, K. V. et al. (2018) Prospects of using nanotechnology for food preservation, safety, and security. Journal of Food and Drug Analysis. 26(4). pp. 1201-1214. Available at: https://doi.org/10.1016/j.jfda.2018.06.011