Nanotechnologies in Food and Agriculture

The advent of nanotechnology has opened up a whole universe of new possible applications in food industry. Some of these applications include: improved taste, flavor, color, texture and consistency of foodstuffs, better absorption, bioavailability of nutraceuticals and health supplements, food antimicrobials development, innovative food packaging materials with enhanced mechanical barrier and antimicrobial properties, nanosensors for traceability and monitoring food condition during transport and storage, as well as encapsulation of food components or additives. Bio-separation of proteins, rapid sampling of biological and chemical contaminants and smart delivery of nutrients, and nanoencapsulation of nutraceuticals are few more budding areas of nanotechnology for food sectors. Nanotechnology promises to revolutionize food products within as well as around. Regulatory systems must be capable of managing any risks associated with nanofoods as well as the use of nanotechnology in food industry for gaining confidence. In this chapter, status of nanotechnology applications in food industry is discussed.

The field of nanotechnology has seen tremendous growth over the past decade and has had a measurable impact on all facets of our society, from electronics to medicine. Nevertheless, nanotechnology applications in the agricultural sector are still relatively underdeveloped. Nanotechnology has the potential to provide solutions for fundamental agricultural problems caused by conventional fertilizer management. Through this chapter, we aim to highlight opportunities for the intervention of nanotechnologies in the area of fertilizers and plant nutrition and to provide a snapshot of the current state of nanotechnology in this area. This chapter will explore three themes in nanotechnology implementation for fertilizers: nanofertilizer inputs, nanoscale additives that influence plant growth and health, and nanoscale coatings/host materials for fertilizers. This chapter will also explore the potential directions that nanotechnology in fertilizers may take in the next 5–10 years as well as the potential pitfalls that should be examined and avoided.

Fertilizers play a pivotal role in improving the productivity across the spectrum of crops. The nutrient use efficiencies of conventional fertilizers hardly exceed 30–35 %, 18–20 %, and 35–40 % for N, P, and K which remained constant for the past several decades. Nano-fertilizers intended to improve the nutrient use efficiencies by exploiting unique properties of nanoparticles. The nano-fertilizers are synthesized by fortifying nutrients singly or in combinations onto the adsorbents with nano-dimension. Both physical (top-down) and chemical (bottom-up) approaches are used to produce nanomaterials, and the targeted nutrients are loaded as it is for cationic nutrients (NH₄ ⁺, K⁺, Ca²⁺, Mg²⁺) and after surface modification for anionic nutrients (NO₃ ⁻, PO₄ ²⁻, SO₄ ²⁻). Nano-fertilizers are known to release nutrients slowly and steadily for more than 30 days which may assist in improving the nutrient use efficiency without any associated ill-effects. Since the nano-fertilizers are designed to deliver slowly over a long period of time, the loss of nutrients is substantially reduced vis-a-vis environmental safety. The work done on nano-fertilizers is very limited across the globe, but the reported literature clearly demonstrated that these customized fertilizers have a potential role to play in sustaining farm productivity. This chapter focuses on synthesis and characteristics of macro- and micronutrient carrying nano-fertilizers and their application in achieving balanced crop nutrition.

Outburst of world population in the past decade has forced the agricultural sector to increase crop productivity to satisfy the needs of billions of people especially in developing countries. Widespread existence of nutrient deficiency in soils has resulted in great economic loss for farmers and significant decreases in nutritional quality and overall quantity of grains for human beings and livestock. Use of large-scale application of chemical fertilizers to increase the crop productivity is not a suitable option for long run because the chemical fertilizers are considered as double-edged swords, which on the one hand increase the crop production but on the other hand disturb the soil mineral balance and decrease soil fertility. Large-scale application of chemical fertilizers results in an irreparable damage to the soil structure, mineral cycles, soil microbial flora, plants, and even more on the food chains across ecosystems leading to heritable mutations in future generations of consumers.

In recent years, nanotechnology has extended its relevance in plant science and agriculture. Advancement in nanotechnology has improved ways for large-scale production of nanoparticles of physiologically important metals, which are now used to improve fertilizer formulations for increased uptake in plant cells and by minimizing nutrient loss. Nanoparticles have high surface area, sorption capacity, and controlled-release kinetics to targeted sites making them “smart delivery system.” Nanostructured fertilizers can increase the nutrient use efficiency through mechanisms such as targeted delivery, slow or controlled release. They could precisely release their active ingredients in responding to environmental triggers and biological demands. In recent lab scale investigations, it has been reported that nano-fertilizers can improve crop productivity by enhancing the rate of seed germination, seedling growth, photosynthetic activity, nitrogen metabolism, and carbohydrate and protein synthesis. However, as being an infant technology, the ethical and safety issues surrounding the use of nanoparticles in plant productivity are limitless and must be very carefully evaluated before adapting the use of the so-called nano-fertilizers in agricultural fields.

In this chapter, we emphasize on the formulation and delivery of nano-fertilizers, their uptake, translocation, and fate in plants as well as their effect on plant physiology and metabolism. Ethical and safety issues regarding the use of nanotechnology in agriculture are also discussed.

In the last few years, the use of nanotechnology to control environmental pollution has considerably increased. Several nanostructured or nanometric dimensional materials have been used as carrier vehicles in the controlled release of agrochemicals due to their biodegradability, low toxicity, low cost, high reproducibility, easy and fast preparation and characterization, water uptake, and reversible properties. The major advantages of these systems are the gradual, sustained, and controlled release over a long period of time, with the aim to improve agricultural and crop protection. In the case of agrochemicals, the scientific community also aims to obtain biodegradable matrices (biodegradable carrier vehicles) able to reduce the number and frequency of applications of nutrients and pesticides in the soil that would contribute to a decrease in environmental pollution and contamination by pollutants. Thus, it is evident that nanotechnology can play a decisive role in the agriculture field. However, only a few references (including papers and reviews) were found in the literature. This gap is most likely related to the short time that these nanomaterials have been studied for this specific application. With this in mind, the aim of this chapter is to collect reports about different polymeric, inorganic, and hybrid nanomatrices (nanocomposites) with great potential for applications as carrier vehicles in the controlled release of agrochemicals.

The great advances in nanotechnology and materials science point to an important increase in the application of nanomaterials in agriculture and allied sciences in the next future. Microbial spoilage of crops and foods is associated with huge economical loses, and the utilization of nanoformulated antimicrobial substances arises as an interesting alternative to confront the damage caused by such microorganisms. Antimicrobial nanoparticles can find several applications in agriculture and food packaging, and the effectiveness of metallic nanoparticles including silver, nickel, iron, and zinc oxides has been demonstrated in many systems. Also, the entrapment of antimicrobial substances in different nanostructures may represent an alternative for delivery of these compounds. A diversity of nanovesicles has been developed for encapsulation of antimicrobial substances, including both natural and synthetic polymers as encapsulating material. Nanofibers may be interesting nanostructures for antimicrobial delivery, allowing different physical modes of antimicrobial loading, including direct adsorption on the nanofiber surface or the assembly of drug-loaded nanoparticles. Magnetic nanoparticles and nanotubes are also structures with potential application for entrapment of antimicrobials. This chapter presents the most important nanostructures as promising tools for antimicrobial delivery systems in agricultural and food applications.

Nanotechnology is defined as the study and use of structures between 1 and 100 nm in length (at least in one dimension). Due to the different properties of nanosized materials compared to the bulk material, research in nanotechnology has increased exponentially in recent years. The food sector is no exception, and nanotechnology is present in different stages of the food chain, from agriculture to food processing, supplements, or food packaging. Among them, the most active area of food nanoscience research and development is food packaging.

Nanomaterials are used in packaging to improve the packaging barrier properties, to create active or intelligent packaging materials, or to enhance the properties of edible and biodegradable packaging materials. In addition to the packages itself, nanotechnology can also be used in labeling applications, like a nano-barcode. In the present chapter, all these applications and the commercialized products already in the market will be discussed.

The current legislation related to nano-developments in food packaging is at different stages in different countries, and there are concerns about the safety of the use of such nanosized materials for food packaging applications. The different studies concerning the possible migration of the nanomaterials used in the packaging to the food will be reviewed.

Nanotechnology has recently become one of the most exciting forefront fields in biosensors fabrication. Nanotechnology has been changing the area of biosensor for many kinds of fields as food. Nanobiosensor, an integration of molecular engineering, physical sciences, chemistry, biology and biotechnology, holds the possibility of manipulating and detecting molecules and atoms using nano-devices/machines, which have the potential for a wide range of both domestic and industrial applications. The role of nanobiosensors in food analysis and detection of chemical and biological compounds in food is an interesting and important area. Biosensors permit the detection of a wide spectrum of analyte in complex sample matrices and have denoted great promise in areas like food analysis. There has been a steadily growing use of biosensor technology for the detection of food contaminants such as food dyes, processing contaminants, veterinary drugs, marine toxins and mycotoxins. On the other hand, there are both some benefits and bottlenecks of nanobiosensors in food fields.

The endogenously found free radical nitric oxide (NO) has important roles in several aspects related to plant defense and growth. NO is a signaling messenger in animals and plants due to its particular chemistry, as uncharged and small molecule, relatively lipophilic. In recent year, important papers have been describing the advantages of using NO donors in agriculture. Indeed, administration of NO donors to plants is reported to stimulate plant greening and germination, control iron homeostasis, and improve plant tolerance to metal toxicity, salinity, drought stress, and high temperatures. Low molecular weight NO donors are known to be thermally and photochemically unstable, impairing their applications in agriculture. In this context, the combination of NO donors with nanomaterials has been emerging as a promising approach to optimize the beneficial effects of NO in plants. In spite that nanomaterials have been employed to carry agrochemicals in plants, the combination of NO donors and nanomaterials is yet not deeper explored in agriculture. In this scenario, this chapter highlights the advantages of applications of NO donors in plants, the uses of nanotechnology in agriculture, and the necessity to develop new strategies based on the combination of NO and nanomaterials in agriculture.

In this chapter, we have discussed the novel nanotechnologies like nucleic acid-conjugated nanoparticles with their current status and future prospects in the development of gene transfer methods in plants. We have also highlighted the shortcomings of conventional techniques of gene transfer in plants and discussed the role of established nanotechnology and chemical-based strategy for surface modification of nanoparticles to improve efficacy, stability, and accuracy making it less time-consuming.

Agrochemical represented mainly by fertilizers and pesticides are vital inputs for agricultural production. However, their conventional application in field is poorly effective, with significant losses due mainly to volatilization and/or lixiviation of soluble agrochemicals. In some cases, the application exceeds two times the optimal quantity, meaning that other undesired consequences take part, such as environmental contamination or production of greenhouse gases. A considerable scientific effort has been made to develop viable systems for the controlled or slow delivery of agrochemicals, in order to adjust the nutrient availability in soil to minimal doses required for pest control or to levels needed by plants. Besides other technologies, the association of soluble materials containing fractions of minerals with very high surface area has shown to be an effective way for the optimization of agrochemical application, where the cation-exchange capacity (CEC) of minerals plays an important role. Then, the association of mineral structures (high CEC clays and layered double hydroxides, etc.) opens a new research field in the tailoring of nanocomposites, where the properties of minerals, polymers, and additives that are associated with agrochemicals (considered as the active moiety of the nanocomposites) can produce novel properties to the release control. Therefore, this chapter reviews the underlying principles in controlled or slow release of agrochemicals, the fundamentals of key technologies, and the current perspectives in the production of new materials, comparing their potential with conventional materials regularly produced.

Agricultural wastewater is one of the main types in agricultural nonpoint source pollution and mostly produced by the abusement of fertilizers, pesticides, and plastic film. Characterized by high BOD and ammonia, agricultural wastewater is generally degraded by microbial technique, including natural treatment and anaerobic or aerobic techniques. However, long reaction period and remnant of a persistent organic cannot be solved appropriately. Recently, nano-materials have drawn much attention in in situ remediation of groundwater because of their small particle size and high specific surface area. Especially, it was found that nano-iron corrosion in water produced molecular hydrogen, which can be used as an electron donor for autotrophic microbes. And nitrate, perchlorate, trichlorethylene, and other pollutants could be removed in this process. In addition, a photocatalytic technology using nano-TiO₂ as photocatalyst was an efficient and safe method for antibiotic degradation, which was hardly observed in conventional microbial treatment technology. Also, some researchers developed novel methods using nanofiltration membrane combined with microbial technology for wastewater treatment. The results showed that the quality of effluent including microbiological indicators, heavy metals, and POPs is in full compliance with the requirements of drip irrigation.

Manufactured nanomaterials are used in many commercially available consumer products, such as cosmetics, textiles, and paints. Due to the increasing production volumes, environmental exposure to these materials is evident. Here, we will discuss the toxicological impact of some nanomaterials, such as ZnO, TiO₂, and BaTiO₃ nanoparticles on aquatic microorganisms by giving some examples. It is clear that the physicochemical properties as well as the structure and morphology of nanomaterials have a high influence on toxicity. We will emphasize the importance of nanomaterial characterization before biological tests.

Rapidly expanding world population and dwindling arable land around the world demand innovative technologies to drastically enhance the global crop yield in the near future. The advancement in nanotechnology provides some possibility to achieve this goal. However, the application of nanomaterial-containing fertilizers and other agricultural products also carries environmental and health risks such as the accumulation of nanomaterial residues in edible tissues, which leads to potential phytotoxicity to agricultural crops and disturbance to the ecosystem. These environmental and health risks need to be well understood before the application of nanotechnology in agriculture can be fully embraced. This chapter presents a summary on the available information concerning the uptake, transport, and accumulation of engineered nanomaterials (ENMs) by agricultural crops and their potential toxicity to these crops. This chapter also discusses the modifications of the fate and transport of coexisting environmental chemicals by ENMs and potential correlations between the unique properties of ENMs with their fate and impact in agricultural systems to shed light on further beneficial applications of ENMs in agriculture.