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Natural Fibers: Applications

Fibers derived from bio-based sources such as vegetables and animal origin are termed as natural fibers. This definition includes all natural cellulosic fibers (cot-ton, jute, sisal, coir, flax, hemp, abaca, ramie, etc.) and protein-based fibers such as wool and silk. There are also man-made cellulose fibers (e.g., viscose rayon and cellulose acetate) that are produced with chemical procedures from pulped wood or other sources (cotton, bamboo). Natural fibers being cost effective and abundantly available yields high potential in various industrial and commercial applications such as in the interior applications of the passenger cars, panels for partition and false ceiling, partition boards, roof tiles, coir fibers in packaging, furniture applications, as insulating materials in low energy houses, geo-textiles for soil protection and erosion control, enhancing barrier properties, composites etc. Due to research and developmental work in modification and treatment methods of natural fibers, utilization of natural fibers has observed a significant growth in various applications. The chapter addresses the potential applications of natural fibers in various commercial sectors for the development of environment-friendly products with an aim to replace synthetic fibers or inorganic fillers with cost-effective and efficient products.

Introduction
The transition toward a bio-based economy and sustainable developments as a consequence of the Kyoto protocols on greenhouse gas reduction and CO 2 neutral production offers high perspectives for natural fiber markets. Changing to a biobased economy requires substitution of common raw materials that are currently largely produced from fossil (petrochemical) or mineral resources, by-products produced from renewable (plant and animal based) resources [1]. The development of a sustainable global economy, which permits improving purchasing power and living standards without exhaustion of resources for future generations, requires a fundamental change in attitude. On ecological grounds products should then be preferred that are based on photosynthetic CO2 fixation [1]. The benefit of those sustainable resources is that they can be regrown within the foreseeable future, without negative side effects on global biodiversity. Therefore, competitive products based on renewable resources need to be developed to have high quality, show excellent technical performance, and harm the environment less than current products based on petrochemical materials [2,3]. Table 1 below shows the major natural fiber producers in the world, their potential applications and associated by products.
In 2017, global fiber production exceeded 100 million mt resulting in the largest fiber production volume ever. Global fiber production saw a 10-fold increase from 1950 to 2017 from <10 million mt to over 100 million mt. Synthetic fibers have dominated the fiber market since the mid-1990s when they overtook cotton and became the dominant fiber. With around 65 million mt of synthetic fibers, this fiber category made up approximately 60% of the global fiber production in 2017. Polyester has a market share of around 51% of the total global fiber production. More than 53 million mt of polyester is produced annually. Cotton is the second most important fiber since synthetics took the lead in the mid-1990s [4]. With around 26 million mt, it has a market share of approximately 25% of global fiber production. An increasingly important fiber category is man-made cellulosics (MMCs) with a global production volume of around 6.5 million mt and a market share of around 6-7% in 2017. Wool has a market share of around 1% with a global production volume of a little over one million mt. Other plant-based fibers, including jute, linen, and hemp, together have a market share of about 5%. Silk and down have market shares of less than 1%. The need to decouple growth from resource consumption gets more urgent every year. The significant growth in fiber production results in a significant use of natural resources and a huge production of textile waste. There is a growing awareness of the urgent need for a more responsible use of resources, enabling growth without increased resource consumption. Table 1. Natural fiber type, producers and markets [4]. Natural Fibers: Applications DOI: http://dx.doi.org /10.5772/intechopen.86884 An innovation toward a circular economy and dematerialization can be seen in almost all fiber categories. Accelerating such initiatives will help to reduce the overall fiber footprint on the planet [4].
Natural fibers have three main components lignin, cellulose and hemi-cellulose, percent of each vary with each type of natural fiber. Hemicellulose is strongly tied to cellulose fibrils presumably by hydrogen bonds. Hemicellulose polymers are branched and fully amorphous and have a significantly lower molecular weight than cellulose. Because of its open structure containing many hydroxyl and acetyl groups, hemicellulose is partly soluble in water and hygroscopic. Lignin is amorphous, highly complex, and mainly aromatic polymer of phenyl propane units but had the least water absorption of the natural fiber components. Amorphous lignin matrix helps in the combination of helically arranged cellulose microfibrils, which results in the formation of composite fiber. Lignin plays a very important role in the plant fiber such as water holding capacity, provide protection against biological attacks, and strengthened the stem against wind and gravity forces. Hemicellulose found in the plant fibers is believed to be a compatibilizer between cellulose and lignin [5].
However, the quality of natural fibers is greatly influenced by various factors like the age of the plant, species, growing environment, harvesting, humidity, quality of soil, temperature, and processing steps, and there is a move to reduce the on-field processing to improve consistency and reduce costs [6].

Wind turbine blade
For centuries different sources like wood, oil, coal and currently materials like coke, natural gas, nuclear materials etc. are used for energy generation. With the significant increase in population, civilization, and industrialization, the consumption of energy has increased many folds. In today's scenario due to this imbalance of ecological system, more ecological awareness and stringent country law and policies have led to the increased interest on renewable and sustainable energy sources. There is a continuous search for sustainable development with minimum pollution and better efficiencies for reduction in energy consumption which have led to the development of wind energy. It is a prominent renewable energy source available to mankind which can be part of the solution of the global energy problem [7]. Currently the wind energy sector is growing, and highly efficient systems capable for converting the kinetic energy of the wind into mechanical or electrical energy are available. Generally the wind turbines consist of three rotor blades that rotate around a horizontal hub and convert the wind energy into mechanical energy and are the key component of the wind turbine. However the design aspect of these wind blades plays a major role in conversion process, the aerodynamic shape, the length of blades, and the material of construction used by the manufacturer.
Based upon the design of orientation of the shaft and rotational axis, wind turbines can be classified into two types (Figure 1). A turbine with a shaft mounted horizontally parallel to the ground is known as a horizontal-axis wind turbine (HAWT), and turbine with shaft normal to the ground is called vertical-axis wind turbine (VAWT). Today's leading large-scale turbine manufacturers favor HAWTtype turbines because of attributes like increased rotor control through pitch and yaw control [8][9][10].
Fiber-reinforced composite materials have been the choice for the commercial production of large-scale wind turbine rotor blades especially glass and carbon fibers. Carbon fibers are preferred over glass fibers because they provide superior mechanical strength due to their lower density and higher fatigue ratio which extends the life of the blades. The high cost of the carbon fibers which start with the expensive poly-acrylonitrile polymer (PAN) precursor and due to the environmental concerns and stringent laws, these are not considered as first choice since the commercial production of these types of fibers is highly dependent upon petroleum-based resources [11]. Because of these and similar reasons, researchers around the globe have shifted their focus on replacing these man-made fibers with natural fibers. Some of the main requirements for the wind turbine blade are (a) high strength, (b) high fatigue resistance and reliability, (c) low weight, and (d) high stiffness [12].
There is a huge potential to reduce the overall manufacturing cost of the wind turbine blades and replace the man-made fibers with natural fiber-reinforced composite materials. Balsa, flax, hemp, coir, abaca, alpaca, bamboo, and jute fibers have been marketed as potential and prospective substitutes to the traditional composite reinforcements. Lignin which is an aromatic biopolymer and abundantly available and can be sourced from plants and wood can be used as a precursor for production of carbon fibers. Low cost and easy availability can have a saving of 37-49% in the production cost of carbon fibers. However lignin has to be modified so as to be spun, stretched/aligned, and spooled into fibers, and these fibers can also be used in manufacturing of blades. Generally wind turbine blades are made up of array of sandwich panel strips and panels. Because of its light in weight and stiffness relative to density, balsa wood is being studied and used for making wind turbine interior panels and sandwich components [11,12].
The performance of NFC-based wind turbine blades depend upon the following factors [10]: 1. Matrix selection-Matrix plays an important role in fiber-reinforced composites. It acts as a barrier against environment and protects the surface exposed from mechanical abrasion. Most commonly used matrices are polymeric in nature as they hold certain advantages being light in weight and easy to fabricate, can be designed to withstand harsh temperatures, etc. Thermoplastic (e.g., polypropylene, polyethylene, nylon, polycarbonate, etc.) and thermoset (e.g., polyurethanes, polyester, epoxy etc.) polymers are being used with natural fibers [13].
2. Fiber selection-All the plant-based fibers hold cellulose as the major structural component. Choice of the fiber depends upon the country or region and size of the wind turbine blade. It is important to know the availability of the fiber since it varies from country to country. The size of the blade governs the nature of mechanical performance requirements; therefore one particular fiber might not provide adequate strength for a particular size blade. Generally  better performance can be achieved with fibers having higher cellulose content and cellulose microfibrils aligned more in fiber direction. Typical examples are flax, hemp, kenaf, jute, and ramie fibers. The properties of the natural fibers do vary depending upon the chemical structure and composition, growing conditions, treatment procedures, harvesting time, extraction method, and storage procedures [14].
3. Fiber orientation-Orientation of fibers in polymer matrix ultimately governs the performance of the composite material which is best achieved when the fibers are aligned in parallel to the direction of applied load, however it's difficult to achieve in reality. Some alignment can be achieved during injection molding process and manual placement of long fibers [15][16][17][18].
4. Interference strength-Though the natural fibers are obtained from renewable resources and the composite materials will be environment-friendly, there are certain disadvantages also associated with unmodified or raw natural fibers. Some of the major problems can be high moisture uptake, low thermal stability, poor adhesion, poor mechanicals, etc. However, the majority of these can be overcome by employing suitable treatment/modification procedures [19][20][21].

Hydrogel production
Hydrogels are polymers having a three-dimensional cross-linked hydrophilic structure produced by simple reaction of one or more monomers which renders them capability of absorbing, storing, and releasing water molecules. Hydrogels have been researched considerably over the past decades due to their promising application in various fields. Some of the application areas of hydrogels include the manufacture of personal hygiene products, medical devices, environmental, agricultural, drug delivery systems, pharmaceuticals, biomedical, tissue engineering and regenerative medicines, wound dressing, biosensor, separation of biomolecules or cells and barrier materials to regulate biological adhesions, etc. [22][23][24][25][26].
Hydrogels can be classified based upon the following [22]: 1. Source-Based upon the source, hydrogels can be categorized into two groups: natural and synthetic.
2. According to the polymeric composition-Preparation method leads to different class of hydrogels. (a) Homopolymeric hydrogels are formed using single monomer. Cross-linking will depend upon the nature of monomer and polymerization technique. (b) Copolymeric hydrogels are formed using two or more monomer species having at least one hydrophilic component. (c) Multipolymer interpenetrating polymeric network (IPN) is formed of two independent cross-linked natural or synthetic polymer components. In semi-IPN hydrogel, one is cross-linked, while the other component is non-cross-linked.
3. Type of cross linking-Based upon the chemical or nature of cross-linking junctions, hydrogels can be classified into two categories. Chemical crosslinked having permanent junctions and hydrogels with physical networks arising from physical entanglements or interactions [27].
4. Configuration-Based upon the chemical composition and physical structure, the hydrogels can be amorphous, semicrystalline, and crystalline.
5. Physical appearance-It is governed by the polymerization technique used for preparation. Hydrogels can be in form of matrix, films, microsphere, etc.
6. Network electrical charge-On the basis of the presence or absence of electrical charge located on the cross-linked chains, hydrogels are divided into four groups: nonionic, ionic, amphoteric, and zwitterionic (polybetaines) electrolytes.

Modification methods of natural fibers for hydrogel production
Lignin, hemicellulose, and cellulose are the major constituents of natural fibers. Lignin which coats or covers the cellulose part shows lower tendency to react with other molecules and poor adhesion with polymer matrix. Therefore the natural fibers most of the time have to undergo through treatment or modifications to improve the reactivity, interaction, and better adhesion with polymer matrix or other molecules [28].
For the hydrogel production, the natural fibers are modified in two stages: • Pretreatment step-It is a very common step even used when NF are used in composite material production also. The main objective of this step is the removal of lignin which is nonreactive toward other molecules and is achieved by alkaline treatment [29].
• Chemical modification-The step involves insertion of molecules into active sites of natural fibers of cellulose [30].
Collectively these steps increase the water absorption and retention capacity throughout with the help of modifying agents and active site generation.

Hydrogel synthesis from plant fibers
Hydrogel synthesis methods are mass polymerization, solution, and reverse suspension (use of initiator and a crosslinking agent). Generally hydrogel synthesis based upon the plant fibers uses solution polymerization method [28]. Figure 2 shows general hydrogel preparation process. Table 2 shows the different polymerization techniques, method employed, and type of characterization required during hydrogel synthesis. Solution polymerization is typically the preferred method for synthesis.
As reported by [29], during hydrogel synthesis, increase in the fiber content increased the swelling and elastic modulus, whereas Liang et al. showed change in pH, temperature, and salts leads to change in swelling behavior. In acidic environment, hydronium ions interacts with hydroxyl groups of cellulose to form hydrogen  linking forces resulting in increasing chain cross-linking and decreasing absorption capacity, whereas in basic media due to the neutralization of active sites, the swelling ability decreased. A temperature between 0 and 50°C is reported to have positive effect on the swelling ability. Zhong et al. [35] found the inclusion of the phosphoric rock in polymer matrix results into better swelling ability and water release rate. The effect of use of natural fibers at nanoscale level in the hydrogels also has been studied, and few of the advantages found are the following: • Better mechanical strength of hydrogels • Improvement in the swelling ability • Increase the density of cross-linking points • Promotes the formation of porous morphology Hydrogels can be tailored and designed as per the requirements and needs for different applications. Natural fibers as part of hydrogels synthesis can provide an eco-friendly alternative and fulfill the potential.

Automotive application
Today more than 50% of the vehicles' interior constitutes different polymeric materials. Automotive manufacturers and associations are under tremendous pressure to improve on fuel efficiency and lower emissions. One of the best ways is to reduce the overall weight of the vehicle which can be possible in replacing metal with lightweight composite materials [43]. Automakers have taken initiatives to design and utilize natural renewable resources as part of composite materials, though the use of natural biomaterials like natural fibers in automotive dates back to 1940s when Henry Ford produced the first composite component using hemp fiber. Similarly many other automotive manufacturers started following the same path down the line. Natural fiber-based composites hold great potential especially in automotive industry where studies have reported NFRC can contribute to cost and weight reduction by 20 and 30%, respectively [44]. Natural fiber-reinforced composite materials are generally utilized in interior parts like door panels, dashboard parts, parcel shelves, seat cushions, backrests, cable linings, etc. Applications to exterior are limited due to the high demand of mechanical strength [45][46][47][48]. Finished automotive door produced from hemp fiber is shown in Figure 3. The properties of the natural fiber-reinforced composite materials depend upon the interfacial compatibility of the polymer matrix. The inherent characteristics and properties of natural fibers, generally issues like poor adhesion, moisture absorption, poor wet ability, etc., cause lower bonding with the polymer matrix. Therefore, modification or pretreatment of natural fibers is done prior to composite preparation. Several techniques and processes have been studied and reported. Few of them are stretching, calendaring, and production of hybrid yarns which result into change in physical attributes of natural fibers. Corona treatment (electrical discharge) method is another method used which makes surface rough resulting in better adhesion with polymer. The use of oxidizing agents such as sodium/calcium hypochlorite and hydrogen peroxide for removal of dust and oil from natural fibers has been reported. Alkali treatment of natural fibers also have been extensively studied and found to improve wet ability and improve adhesion significantly. Further improvement can be made by the use of grafted polymers like polypropylene/polyethylene-grafted maleic anhydride as compatibilizers and the use of coupling agents. These specialty products facilitate in the introduction and formation of covalent bonds and cross-linking effect [49][50][51][52][53].
In a report published by SABIC Innovative Plastics, wood flour and curaua fiber-based composites have been developed. Results are shown in the table below. The company claims that the composites developed are more resistant to fungi growth and have good dimensional stability, lower moisture absorption, and intended mechanical properties as required for the application. Table 3 shows the comparison of unfilled PP and PA6 with filled natural fibers, glass fibers, and talc at similar loading level. Density advantage can be observed with NFRC as compared to other composite materials. Most of the mechanical properties of PP filled with NFs are almost similar to the talc-filled PP. Glass fiber-filled PP possess advantage in terms of tensile and flexural strength over NFRC and talc-filled PP materials. However, in automotive interior applications, composite materials with mild to high mechanical properties can serve the purpose. Mechanical properties of natural fiber-reinforced polymer composite are comparable to polypropylene talc and glass fiber composites (   Table 3.
Mechanical properties of filled and unfilled PP and PA6 composites [43]. Now different regions across globe opt for different natural fibers depending upon their availability and ease of use. European automotive industry prefers flax and hemp, whereas in Asian country India prefers jute and kenaf. Banana fibers are preferred in the Philippines, whereas sisal fibers are used majorly in the USA, Brazil, and South Africa. Table 4 shows the use of natural fibers in various automotive components.
The use and development of natural fiber-based composite materials in automotive are going on good pace, and in time better composite materials with mechanical performance similar to synthetic fibers will be developed. Continuous development in fiber modification techniques, compounding machines, additives, polymers, etc. will yield a promising future ahead.

Barrier properties and applications
Cellulose is the primary component of green plants and is the most abundant organic compound derived from biomass. Due to its characteristic chemical and physical properties, it has been investigated and applied to variety of products and materials for many decades [60,61]. Cellulose material exists in four different polymorphs [62,63]:  Table 4. [54][55][56][57][58][59]. • Type I-Native cellulose, the form in which cellulose occurs in nature.

Applications of natural fibers in automotive industry
• Type II-Regenerated cellulose, formed after recrystallization or mercerization with aqueous sodium hydroxide.
• Type III-This type of cellulose is produced by ammonia treatment of types I and II.
• Type IV-Heat treatment of type III yield type IV.
Type II is the most stable crystalline form of cellulose. The major difference between the type I and type II is the layout of their atoms. Chains in type I are layered in parallel fashion, whereas in type II they are in antiparallel.
About 36 individual cellulose molecules collectively form into a larger unit called elementary fibrils. Figure 4 depicts the details of cellulose fibers and microfibrils. Depending upon the dimensions, functions, and preparation methods, nanocellulose can be subdivided into three main types: (a) microfibrillated cellulose (MFC), (b) nanocrystalline cellulose (NCC), and (c) bacterial nanocellulose (BNC) [64], as shown in Figure 5.
Various petroleum-based materials are widely used for packaging application to prevent food, drinks, cosmetic goods, consumer goods, etc. against physical  and microbiological degradation and deterioration. These polymeric materials provide a layer of barrier against water vapor, oxygen, grease, and microorganisms. Packaging industry is one of the fastest-growing industries in the world. Now with the increased concerns due to the impact of these polymeric and other packaging materials like paper, glass, and metal on environment, materials derived from the renewable resources are strongly advocated. Recent research in more efficient and reliable preparation techniques for cellulose nanofibers and microfibrils synthesis, has attracted significant interest as potential barrier materials in packaging films. Cellulose nanomaterials have large surface area and diameter in range of 2-50 nm. Their ability to form hydrogen bonds results into strong network formation making it difficult for gas or water molecules to pass through it, thus providing excellent barrier properties [66][67][68][69].
Microfibrillated cellulose (MFC) films have better gas barrier property than cellulose nanocrystals (CNCs) because of the crystalline and amorphous regions in CNCs. Oxygen transmission rate (OTR) of 25 micron MFC film was found to be competitive with films of similar thickness made from ethylene vinyl alcohol (EVOH) and polyvinylidene fluoride (PVDF). OTR of MFC film was found to be lower than EVOH and PVDF films [71,72]. Figure 6 represents the kind of torturous path for permeating molecule because of nanocellulose. As reported, the barrier properties of MFC films can be tuned further. Rodionova et al. [73] in his work showed that oxygen permeability of MFC acetylated and carboxymethylated films can be further reduced. Carboxymethylated films had very low oxygen permeability of 0.009 and 0.0006 cm 3 m −2 /day kPa-1. Further the oxygen permeability can further be modified by using thermal treatment technique. Table 5 shows the OTR and WVTR values of commercial polymer films and MFC film.
MFC film have poor water vapor barrier property as compared to PVDF film due to hydrophilic nature of cellulose molecules however it can be improved thereby using different pre and post treatments during production process.
Cellulose nanocrystals have been studied as potential fillers for natural polymers to enhance their barrier properties. Results reported as in Saxena et al. [74] showed that nanocomposite film made by casting aqueous solution containing xylan, Figure 6. Schematic representation of increased diffusion path within nanocellulose film [70].  sorbitol, and cellulose nanocrystals had low oxygen permeability of 0.1799 cm 3 μm/ m 2 d kPa. As other reports [75,76] also indicate that cellulose nanocrystals when used in other polymer matrix like PLA and PVOH improved in OTR and WVTR values. Studies based upon the use of microfibrillated and nanocrystals of cellulose in polymeric materials have opened possibilities in films, composites, and coatings to substantially reduce especially the oxygen permeation rate. Microfibrillated cellulose and its nanocrystals have oxygen-barrier efficiency better some of the commercially available polymers.

Composites
There are considerable enhancement and suggestions for the natural fibers that can be implemented in order to enhance their mechanical properties resulting in high strength and structure so that it can be used as fillers and reinforcement agents instead of conventional materials like talc, calcium carbonate, mica, glass fibers, etc. After selecting the appropriate fiber and method of modification for the target application, the polymer matrix properties can be improved. Few of the parameters that effect the composite performance are the (a) orientation of fibers, (b) strength of fibers, (c) physical properties of fibers, (d) interfacial adhesion property of fibers, and many more [77][78][79][80]. Natural fiber-reinforced composite materials have shown better properties than pure polymer matrix in many cases. 75.8% of PLA's tensile strength was improved by the introduction of jute fibers. Properties of PP composites were improved by the incorporation of kenaf, cotton, and hemp fibers [77]. Ishagh et al. [81] investigated effects of azodicarbonamide (AZD) and nanoclay (NC) content on the physico-mechanical and foaming properties of HDPE/ wheat straw flour (WSF) composites. With the increase of AZD, the average cell size and density increased, whereas with addition of nanoclay up to 5phr, the cell size and density increased. Idicula et al. [82] investigated thermophysical properties of banana sisal hybrid-reinforced composites. Increase in the thermal conductivity by 43% was observed in fibers which were subjected to mercerization and polystyrene maleic anhydride treatments. Chensong dong et al. [83] reported flexural properties of wheat straw polyester composites. Natural fiber-reinforced composites due to their certain advantages such as high stiffness to weight ratio, lightweight, and biodegradability gave them suitability in different applications in building industries. Sisal fiber reinforced composite have shown good tensile and compression strength making it suitable for wide area of applications, for instance, structural building members, permanent formwork, tanks, facades, long span roofing elements, and pipes strengthening of existing structures [84]. On the other hand, bamboo fiber can be used in structural concrete elements as reinforcement, while sisal fiber and coir fiber composites have been used in roofing components in order to replace asbestos. Natural fiber-reinforced concrete products in construction applications like sheets (both plain and corrugated) and boards are light in weight and are ideal for use in roofing, ceiling, and walling for the construction of low-cost houses.

Silk fiber applications
Silk which is a natural fiber and produced in more than 20 countries finds application in various sectors. Silk proteins are used as special diet for cardiac and diabetic patients due to its low sugar content, easy digestibility, and low cholesterol [83,84]. The Japan Aerospace Exploration Agency (JAXA) has released a recipe as astronauts' food. Silk biopolymer is used in tissue regeneration for treating burn victims and as matrix for wound healing. Silk fibroin peptides are used in cosmetics due to their glossy, flexible, elastic powder coating; easy spreading; and good adhesion properties [89,90]. Silk is reported to be used to fight various health-related diseases like edema, cystitis, impotence, adenosine augmentation therapy, epididymitis, and cancer [91]. Derivatives of silk fibers are reported to be used as nonsteroidal antiinflammatory agents for treating rheumatoid arthritis [85,86]. Silk fibers are used as surgical sutures and as biodegradable microtubes for repair of blood vessels and as molded inserts for bone, cartilage, and teeth reconstruction [90,93]. Due to the phenomenal mechanical properties of silk as a biopolymer, it is suitable for biomedical applications.

Natural fiber-reinforced building material
Various natural fibers have been exploited to be used as reinforcements for building/construction industry. Bamboo due to its lightweight and strength is a very popular construction material. Bamboo-based material has been developed to make eco-friendly roofing product. Other such products such as bamboo mat board (BMB), bamboo mat veneer composites (BMVC), and bamboo mat corrugated sheets (BMCS) have been developed. Sisal fiber-based roofing sheets also have been under development as economical alternative. Rice husk and rice straw are nowadays used to manufacture medium density fiberboards, particle boards, straw bales, cement-bonded boards, etc. Ground nutshell is used for manufacturing building panels, building blocks, chip boards, roofing sheets, particle boards, etc. Cotton stalk fiber is used for making panel, door shutters, roofing sheets, autoclaved cement composite, paper, plastering of walls, etc. Coir fiber is a highly durable fiber used in all types of matrices like fly ash-lime, polymers, bitumen, cement, mud, gypsum, etc. Jute coir composites are seen as cheap and economical alternative to wood for construction industry. Jute coir boards are used for the production of boards which are more resistant than teakwood against rooting under wet and dry conditions with better tensile strength. Jute with rubber, wood, and coir is considered as good alternative to plywood [94].

Geotextiles for soil protection and erosion control
Soil protection using natural fibers and other bio-based materials includes leaves, straws, and plant residues for the mulching of unprotected soil. Nowadays woven and nonwoven textiles and blankets made from wheat straw, rice straw, long wood shavings, coir, and jute are used as soil protection products. These products are categorized under two subgroups of the rolled control product (RECP) category. These can be open-weave geotextiles made using coir and jute fibers termed as erosion control  meshes (ECM) or nonwoven from natural fibers or synthetic fibers glued or bonded by nets or meshes called as erosion control blankets (ECB) as shown in Figure 7.
Natural fibers are also commonly used in rolls stuffed with straw or coir fiber bundles held together by nets which further can be used as slope interruption devices or sediment retention fiber rolls [95].

Summary
Natural fibers and the products designed around these materials possess many distinctive advantages: cost-effective, low coefficient of friction, ease of availability, exhibit good thermal and dimensional stability, environmental friendly, etc. Because of these and many more reasons, the popularity of natural fibers is on increase, and a lot of scientific data and research is being done around the globe. However for effective utilization of natural fibers in various potential applications, all the aspects associated with them has to be studied and presented: (a) target application, advantages, and disadvantages of using natural fibers; (b) product design, studies to be carried out on the development of prototype and other engineering software; (c) preparation and fabrication technique, particular technique, or process to be identified which should reduce possibility of failure, etc.; (d) commercial production, should be cost effective and eco-friendly; (e) marketing and sales, product should be marketed to show case its potential benefits toward society and environment with good after-sale service.
Despite of current prevailing aforementioned issues, several commercial products has been launched by various manufacturers, automotive industry the most active and leading the development of natural fibers based products. Gradually other sectors related to sports, furniture, medical, etc. are catching up.

Author details
Jatinder Singh Dhaliwal Research and Development Center, Indian Oil Corporation Ltd., Faridabad, Haryana, India *Address all correspondence to: singhj4@indianoil.in © 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


provenance: AgriculturalAndFoodSciences,2019-2020-Agricultural And Food Sciences-2020.jsonl.gz.gz

text:
Food Supplements for Weight Loss: Risk Assessment of Selected Impurities.

Nowadays, food supplements are widely consumed, often without any medical supervision. In this study, 25 food supplements for weight loss, randomly purchased from five different suppliers in the European Union, were analysed by Wavelength Dispersive X ray Fluorescence spectrometry (WDXRF). The aim of this study was the risk assessment of trace elements and the mixture of elements present in food supplements for weight loss. The obtained Hazard Index (0.11) showed no potential risk of non-carcinogenic effects to human health. However, since humans are frequently exposed by different routes and/or sources to toxic metals, the additional consumption of these products may cause potential toxicological risks that cannot be ignored. In one analysed food supplement (FS), the simultaneous presence of Pb and Mn in high concentrations was detected. In two, FS chromium concentrations were above the reference daily dose. Unconformities were detected between the labelled and the detected values, which emphasises the misinformation of labels. This highlights the need for a deeper surveillance of food supplements.

Introduction
Vitamins, minerals, nutritional and herbal supplement sales have had a significant increase worldwide, due, in part, to the general misperception that natural indicates harmless [1][2][3]. Greater awareness about healthy ageing and the broader availability of products, as well as trends towards healthy lifestyles and disease prevention lead to an increase in vitamins and food supplements consumption. Besides the growth of self-diagnosis and self-medication by consumers, these products do not need medical prescription and are often consumed without any control or medical supervision, during extended periods of time, which constitutes a concern about the users' health [4][5][6][7][8].
In the United States (U.S.) it is estimated that approximately 150 million people (one half of the U.S. population) currently use food supplements, with 79% reporting daily consumption and 10% taking five or more different supplements per day [9], with women being the main consumers. In Europe, the use of food supplements is increasing in several countries, however, there is a lack of information with regard to the prevalence and types of food supplements used that can be compared across [10,11].
In Portugal, a study performed in 2006 with the purpose of characterizing the habits of consumption of food supplements, with a sample consisting of 1247 individuals, 60% of whom are habitual consumers and 40% of the individuals are classified as ex-consumers, occasional or non-consumers. The results showed that the use of food supplements mainly occurs among the female population, in younger age groups [12].
Legislation regarding the concentration of elemental impurities in food supplements (FS) is scarce and shows discrepancies between international authorities. Actual requirements for metal impurities in plant-based food supplements imposed by the European Commission (EC), World Health Organization (WHO) and United States Pharmacopeia (USP) only defines limits for As, Cd, Hg and Pb [13][14][15][16][17] ( Table 1). However, the presence of other elements other than the aforementioned may also have adverse effects and potentially put product quality and consumer safety in jeopardy. As USP and European Medicines Agency (EMA) establish limits for several metal impurities in drug products [18,19] (Table 2), it was decided in this study to extend to food supplements the monitoring of Cr, Cu, Ir, Mn, Mo, Ni, Os, Pt, Rh and Ru, all with a validated analytical procedure [20]. At present, the safety of FS and the authenticity of label information is exclusively ensured by the economic operators who place FS on the market. Since these products are usually taken without any medical supervision or counselling and attending to the potential adverse effects of elemental impurities in its composition, it is imperative that these products be placed under the same quality control of pharmaceuticals, regarding FS consumers health [21].
Despite the toxic effects triggered by each element per se, acute exposures to mixtures of elements may induce adverse effects at the same target organ [22,23]. Human health risk assessment related to elemental impurities exposure allows the evaluation of potential adverse effects associated with exposure to these impurities [24]. In practice, risk assessment corresponds to the hazard evaluated from the exposure to a chemical or chemical mixtures [25].
Quantification of risk to human health is performed in terms of non-carcinogenic and carcinogenic risk. In the characterization of non-carcinogenic risk, the United States Environmental Protection Agency (EPA) uses the reference dose factor (RfD) [26], and the values approved by this entity are listed in the Integrated Risk Information System-EPA (IRIS).
Nowadays, the challenge is to develop methodologies to assess the potential risk to health of concerning elemental mixtures, since this is the real scenario of exposure to humans [25]. Therefore, it is crucial to include the study of their adverse effects as an integral part of public health policies [27].
Several authors have reported the presence of elemental impurities in several products and the associated hazard risk [28][29][30][31].
Nevertheless, to the best of the authors' knowledge, an assessment of quantitative risk to human health concerning the consumption of food supplements for weight loss has not yet been performed, which demonstrates the innovative nature of the present study.
Besides, FS for weight loss is one of the best-selling dietetic products outside the pharmaceutical distribution network [32][33][34].
The aim of this study was the risk assessment of trace elements and the mixture of elements present in food supplements for weight loss.

Sampling
Twenty five food supplements for weight loss randomly purchased from five different suppliers in Portugal were monitored. All food supplements had a plant-based composition, which may include organic and inorganic compounds. For confidentiality reasons, the studied products were identified with FS nomenclature.

Sample Preparation and Analysis
All samples were solid oral formulations, which were reduced to loose powder and homogenised with glass mortar and pestle. To avoid cross contamination, all glassware and mortars were kept overnight in EDTA (0.1 M) and rinsed several times with Millipore-Q water (18.2 MΩ cm) prior to its use. Samples were preserved in a refrigerator at a temperature of 4 • C, until they were analysed.
Whenever needed, gelatinous coating of the pills was mechanically removed by opening the capsules, and the interior powder content was analysed.
For the preparation of calibration standards, cellulose loose powder was used and at least six concentration levels were considered (in µg/g) in the following ranges: 0-10 (Pb), 0-15 (Ir, Os, Pt, Rh and Ru), 0-30 (Cr, Mo and Ni) and 0-300 (Cu and Mn). The ranges of interest were defined following the recommendations for the studied elements and concentration limits used according to USP and EMA in drug products [18,19] and included the minimum ranges required by ICH guidelines [35].
Standards were prepared in triplicate, each of which weighed 5 g consisting of cellulose loose powder spiked with known amounts of each element in study and Millipore-Q water (18.2 MΩ cm). Stock solutions of Cr, Cu, Mn, Ni and Pb, in the concentration range of 0.5-1 mg/mL, were prepared with Millipore-Q water (18.2 MΩ cm), whereas stock solutions at 1 mg/mL of Ir, Mo, Os, Pt, Rh and Ru were purchased from Sigma-Aldrich. After homogenization with magnetic stirring, all standards were dried in an oven at 50 • C over 48 hr and homogenized in a glass mortar and pestle.
The WDXRF measurements were performed with a 4-kW commercial spectrometer (Bruker S4 Pioneer), using an X ray tube with a rhodium anode and a 75 µm Be end window. For all studied elements, a collimator aperture of 0.46 • was used with no filters and a 34 mm diameter collimator mask as well as automatic current reduction allowing for the achievement of the best sensitivity without detector overflow.
High-density polyethylene X ray fluorescence sample cups with a 40-mm diameter assembled with 4 µm prolene film to support the samples were used. The polyethylene cup was placed in steel sample cup holders with an opening diameter of 34 mm.

Risk Assessment
According to the EPA, if available data is scarce the Hazard Index (HI) to assess cumulative risk is recommended for use for element impurities present in the mixture, assuming the cumulative effect of dose [36]. The calculation of HI does not require the knowledge of action mode of the elements present in the sample and does not consider the interactions between them, it only requires that elements have the same target organ [37,38]. HI determination is based on various elemental constituents of the mixture, for each route of exposure of interest, taking into account a single specific toxic effect or toxicity to a target organ [36].
For non-carcinogenic risk the target hazard quocient (THQ) for each element was determined by the ratio between the estimated dose of the element, and the dose level below which there would be no appreciable risk to human health. THQ value is determined by Equation (1) [30].
where EF is the exposure frequency (days/year); ED is the exposure duration (years), IR is the ingestion rate (kg/day), C is the concentration of the contaminant (mg/kg), RfD is the reference dose (mg/kg/day), BW is body mass (kg), AT is the average time (days). The most direct approach to evaluating the potential risk is determination of HI with addition of THQ for each element to be known in the mixture: If HI > 1 there is an unacceptable risk of non-carcinogenic effects on health, while HI < 1 represents an acceptable level of risk [30].
The carcinogenic risk estimate is calculated using Equation (3) [39]: where CSF corresponds to the cancer slope factor listed in IRIS. EMA considers acceptable or tolerable risk for regulatory purposes the value of 1.0E-6 [40]. However, EPA considers a broader range between 1.0E-6 to 1.0E-4 [41]. The overall risk of effects as a result of exposure to multiple carcinogenic agents is the sum of individual carcinogenic risks of all impurities in the sample.
The values related to the RfD and CSF for the elements under study are shown in Table 3.

Results and Discussion
The majority of the analysed food supplements presented low levels of the elemental impurities studied as can be observed in Table 4. The presented values were calculated with concentrations equal or higher than the limit of quantification (LQ) obtained for each element.
In one analysed sample (FS i ), Mn was detected, although in the label of this supplement there was no mention of manganese in its composition.
The interactions between Mn and Fe play an important role in Mn toxicity. Chronic iron deficiency causes a build-up of higher levels of Mn in the basal ganglia in rats [43] and humans [44]. Since iron deficiency is common in obese and overweight individuals, and the products under analysis are for weight loss, the presence of Mn in these supplements should be considered judiciously [45].
In the same sample, Pb value doubled the limit established by USP (1 µg/g). Pb was also detected in another supplement but within the legal values.
Pb has a high risk of toxicity to humans, with potential effects in the neurological, reproductive, developmental, immune, cardiovascular and renal systems [46]. As reported in literature, fasting and low intake of Fe and Ca promotes greater absorption of Pb [47,48]. Since the analysed products are intended for weight loss, if the target consumers have dietary restrictions, it may increase Pb absorption and turn the consumers of these supplements more vulnerable to lead toxicity.
The simultaneous presence of high levels of Mn and Pb in the same supplement (FS i ) increases the concern of the potential toxic effects to human health, since both elements affect the central nervous system.
There is little information about potential adverse effects of co-exposure to Mn and Pb, but existing data suggests that they may have a synergistic neurotoxicity effect. According to Wright and Baccarelli (2007) coadministration of Pb and Mn in animals induces three-fold in Pb levels in the brain when compared with isolated Pb exposure. The joint exposure to lead and manganese resulted in a lower learning ability, relative to that obtained with only Pb exposure. Gestational co-exposure to Pb and Mn not only produces a reduction in fetal weights, but also a decrease in infant brain weight [49].
High levels of Cr were quantified in two samples (FS ii and FS iii ). However, in these supplements, chromium is labelled as an active ingredient. Therefore, the concentration of this element should be interpreted considering the value of the Cr daily reference dose and not its limit as an impurity.
According to European legislation (Directive 2008/100/EC), chromium may be present in food supplements up to a maximum daily intake of 40 µg/day [50]. On the other hand, the Office of Dietary Supplements from the USA National Institutes of Health [51] establishes different values for Cr intake, according to gender (35 µg/day for adult men and 25 µg/day for adult women), age and pregnancy/lactation. Currently, the European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain recently derived a Tolerable Daily Intake (TDI) of 300 µg Cr(III)/kg body weight per day from the lowest NOAEL (No Observed Adverse Effect Level) identified in a chronic oral toxicity study in rats [52].The differences between the regulatory authorities in order to a recommended daily dose of Cr are therefore evident.
However, the literature does not unequivocally point toxicity associated with excessive intake of chromium, and does not exclude potential adverse effects with high consumption of this element [53]. In Germany, all the special permissions for the use of chromium picolinate in food supplements were withdrawn in 2001, due to investigations that do not exclude adverse effects on human health [54]. Additionally, the EFSA [55] explicitly excludes chromium picolinate, based on in vitro studies that suggest it may cause DNA damage. However, more recently, EFSA concluded that the use of chromium picolinate was not a concern for the health of its consumers but also noted that recent reviews and evaluations related to Cr (III) show different results in genotoxicity tests. Therefore, EFSA reports that in the future Cr (III) limits should be re-evaluated [56].
In supplement FS ii , according to its label, each pill has 34 µg of chromium, which corresponds, according to the package dose instructions, to a daily intake of 136 µg of Cr. This dose was raised to more than three-fold the amount indicated in Directive 2008/100/EC (40 µg/day) and to more than five-fold that recommended by the National Institutes of Health (NIH) value for Cr intake by women (25µg/day), the major weight loss supplement consumers. This was confirmed by the obtained results (28.9 ± 2.0 µg Cr/pill, corresponding to 116.3 ± 3.8 µg Cr/day), as specified in Table 3.
In FS iii , chromium was present as chromium picolinate, in a 0.09% concentration, which corresponds to a Cr daily intake of 156 µg, taking into account the labelled instructions. This amount exceeds to almost four-fold the values of Directive 2008/100/EC and to more than six-fold the suggested NIH chromium intake for women. Furthermore, there is an evident discrepancy between labelled values and the obtained results (Table 5). Nevertheless, the detected value (59.9 µg/day) is still above the recommended value. The detected unconformities found between the measured concentrations of ingredients and the labelled ones were in accordance with several studies, which reported huge differences between the labelled and the measured values in herbal products [57,58]. In 2003, an investigation by the United States Department of Health and Human Services reported that most labels of supplements were misleading and inconsistent and that consumers revealed considerable difficulty understanding the labels correctly. About 85% of inspected labels contained no information about maximum recommended dose [59]. According to several studies, information related to product content in food supplements is frequently inaccurate and incomplete [60][61][62].
For the three aforementioned food supplements, the Hazard Index was determined according to Equation (1), based on 6 months intake, during a period of 2 years. Three distinct values were considered for body mass: 90 kg, 70 kg and 50 kg, where the lower one was based on a conservative approach similar to the calculation recommended by EMA and USP in the determination of elemental impurity limits in drug products.
As can be depicted in Table 6, all HI values were below 1, revealing that there was no potential risk of non-carcinogenic effects on health due to the consumption of the analysed food supplements. However, these results only reflect the intake of Cr, Mn and Pb through food supplements consumption and do not consider the cumulative risk associated with other exposure routes, such as inhalation and environment exposure, neither the eventual risk associated with food, water or other products consumption. None of the investigated elements were classified by EPA/IRIS as carcinogenic, so there was no CSF established and published, therefore it was not possible to estimate the Carcinogenic risk.
One supplement mentioned chromium as an ingredient in a concentration of 40 µg of Cr per pill. However, its analysis did not reveal the presence of this element, which emphasised the misinformation of the label.
Such as diet or water, these supplements are also potential sources of exposure to toxic elemental impurities. For example, As, Cd, Hg and Pb. may be found in foodstuffs.
Several studies have been published in the literature reporting the presence of elemental impurities in food supplements. Kauffman et al. (2007) analysed by Inductively coupled plasma mass spectrometry (ICP-MS) 45 samples of pharmaceutical products and FS in order to determine the concentration of Pb in these products. The obtained results revealed that Pb concentration was below the limit imposed by the international bodies for all analysed products [63]. Tumir et al. (2010) analysed by Atomic absorption spectroscopy (AAS) 30 FS, detecting the presence of Cr, Ni and Pb in high concentrations in five of them. In one sample, Cr and Ni were detected in high concentration [64]. In another study performed by Korfali et al. (2013), 33 FS samples of high consumption by the Lebanese population, were analysed using three different techniques (Energy Dispersive X-ray Fluorescence spectrometry (EDXRF), AAS and ICP-MS) in order to determine the presence of As, Cd, Cr, Cu, Fe, Hg, Mo, Mn, Pb, Se and Zn in these products. Approximately 30% of the analysed samples showed Cd concentrations above the established levels and in 62% of the analysed samples the concentration of As were above the established limit [4]. In further research developed by Filipiak-Szok et al. (2014) with 19 samples of food supplements (with asiatic and european plants) analysed by ICP-MS, high levels of Pb was detected in one product and As in another [65]. Dolan et al. (2003) analysed the As, Cd, Hg and Pb contents of 95 FS products using microwave digestion and high-resolution ICP-MS. In 11 of the products, levels of lead found result in exposures that exceed the tolerable intakes of some sensitive segments of the population such as children and women of child-bearing age, particularly pregnant women [66].
Through the research in RASFF it was possible to identify 16 alert notifications, between 2016 and 2020, linked to the high levels of elemental impurities in FS composition. Eight of these are related to the presence of Pb, two alerts report the presence of Zn, and three of them alert to the simultaneous presence of Pb + Al, Pb + Hg, and Pb + Hg + Al. High concentrations of Hg, Ni and As were also detected in three FS. However, it was not possible to know whether these FS correspond to FS for weight loss, since the information given in RASFF is "dietetic foods, food supplements and fortified foods" [67].

Conclusions
In one analysed food supplement (FS i ), the simultaneous presence of Pb and Mn in high concentrations was detected. In two FS, chromium concentrations were above the reference daily dose. This study also revealed discrepancies between label doses and the detected values, which discloses the deficiency in quality assessment and the unreliability of the labelling of these products. Therefore, it seems important to claim a more exigent regulation of food supplement labelling and to set the same quality standards for food supplements as for pharmaceuticals, extending concentration limits to other elements than those already imposed, due to the pernicious effects they may have on consumer's health.


extfieldsofstudy:
Environmental Science
Medicine

text:
Estimation of energy flow and environmental impacts of quinoa cultivation through life cycle assessment methodology.

Quinoa is an adaptable plant that is rich in terms of nutritional properties. Currently, the promotion and cultivation of quinoa are expanding in Iran. The present study aimed to investigate the energy consumption of quinoa grain production and its environmental impacts through life cycle assessment. In this regard, in order to evaluate the environmental and energy indices, required data were collected from quinoa farmers in Isfahan. The high energy ratio (ER > 1) and positive net energy show that quinoa cultivation is efficient. Based on the results, irrigation water and nitrate fertilizer were identified as the major contributors to energy consumption. Based on the normalization method, the highest and lowest environmental impacts during the production process were related to the indices of marine aquatic ecotoxicity and ozone layer depletion, respectively. Results showed that in the global warming potential impact, 354 kg CO2eq. were emitted per production of 1 tonne of quinoa grain. Diesel fuel and nitrogen fertilizer had a significant effect on most environmental impacts. Proper management of chemical fertilizers and agricultural machinery are key factors for sustainable cultivation of quinoa.

Introduction
Agricultural crops play an important role in human life. Population growth requires increased food production and consequently increased the quantity and quality of agricultural products. Most regions of Iran are located in arid and semiarid areas with high salinity soil. Quinoa (Chenopodium quinoa) has considerable resistance to a wide range of abiotic stresses such as cold, salinity, and water stress (Jacobsen et al. 2009). Quinoa is cultivated in most parts of the world due to the high quality of quinoa grain and its high production potential in tough cultivation conditions (Gomez-Pando and Eguiluz-de suitable alternative for rice. The protein content of quinoa is two times higher than it in wheat, and it is one of the few nonmeat proteins that is qualitatively and quantitatively better than other plant proteins (Ceccato et al. 2011).
According to the latest FAO statistics, in the worldwide, quinoa grain have been harvested as 146,735 tonnes from 173,242 ha farming area with an average crop yield of 847 kg ha −1 (FAO 2017). Dependence on energy resources in developed and developing countries has led to serious environmental, technical, commercial, and even social problems (Safa and Samarasinghe 2011). Efficient use of energy causes increased production, productivity, economy, profitability, and sustainable competition in agriculture. Energy saving is important for sustainable development in agricultural systems (Pishgar-Komleh et al. 2012). In order to use energy in an efficient way, it is necessary to know the pattern of energy consumption (Heidari et al. 2011). Given the high number of factors affecting agricultural production, it is difficult to calculate the energy input in agricultural production compared with the industrial sector. Therefore, the energy consumption pattern and its efficiency in the agricultural system were investigated and analyzed in this study. One of the prerequisites for achieving the sustainable agriculture is paying attention to environmental protection, identifying and reducing environmental pollutants. Life cycle assessment (LCA) is a tool to measure the environmental consequences of a product during its production cycle, or in other words, from the beginning to the end of the product formation process (cradle to grave approach). Also, the energy efficiency of a product can be estimated by LCA methodology. In this method, all the required steps and inputs used in the process are investigated. Despite the importance of the quinoa cultivation in Iran and considerable amount of research works that focused on the assessment of the energy use and environmental impacts of agricultural products, there is no serious attempt on these topics in the cultivation of quinoa. Only one study occurred on the environmental impacts of quinoa grain in Peru. Their results indicated that the environmental impacts of quinoa production were in the range of other agricultural products, but quinoa has less pollution than other protein products, especially animal protein (Cancino-Espinoza et al. 2018). In a comparative LCA study of winter wheat and summer maize in China, the results showed that the impacts of abiotic depletion and eutrophication in both of the systems contributed the most to the environmental pollutions (Wang et al. 2007). Pellizzi (1992) studied the energy balance of corn production. Based on their results, the specific energy value was obtained as 4.2-8.4 MJ kg −1 . The total energy consumption of the total production area was calculated to be 13 Mt of oil equivalent per year. Safa et al. (2009) reported that total input energy for irrigated and rainfed wheat production was 25,600 and 17,450 GJ/ha −1 , respectively, in New Zealand. In that research, chemical fertilizer and electricity played the most important role in irrigated farms output with 10,190 and 3430 GJ/ha −1 , respectively. Nemecek et al. (2011) compared the environmental burdens of organic farming vs. integrated production systems in Switzerland. They showed that the N 2 O and CO 2 emissions from chemical fertilizers made high contributions to GWP. In Chile, Iriarte et al. (2010) concluded that the N-based fertilizers had significant effects on the five impact categories of acidification potential, eutrophication, global warming potential, human toxicity potential, and marine aquatic ecotoxicity in sunflower and rapeseed productions.
The higher efficient use of energy and better environmental management in quinoa cultivation are important to provide a sustainable and cost-effective production, and was recognized as an important tool for both farmers and decision-makers in agriculture. To the best of authors' knowledge, there is no study up to date on the evaluation of energy consumption and environmental impacts in the quinoa production using the LCA approach in Iran.
For the first time in 2018, the quinoa was cultivated in Isfahan province of Iran to meet the food demands of those poorer populations. Accordingly, our objectives of this research were (1) to examine the quantity of energy used for quinoa production in the Isfahan province, Iran, and (2) to estimate the environmental impacts emitted from 1 tonne of quinoa production by LCA.

Sampling and data collection
The present study was conducted in Isfahan province which is located in the center of Iran (30°43′-34°27′ N / 4 9°3 6 ′ -5 5°3 1 ′ E ) w i t h t h e a r e a o f a b o u t 105,937 km 2 . This region has different climatic zones as well as different soil texture and salinity (Anonymous 2018). In order to assess the life cycle of the quinoa, required data relate to crop cultivation was collected from 30 quinoa growers in Isfahan province of Iran. Questionnaires and face-to-face interviews with growers were applied to analyze the energy consumption and environmental impacts. Therefore, due to limitation of population size, there is no need to the sampling and population size is equal to sample size. The completed inventory of inputs includes machinery used for agricultural operations, fuel consumption, chemical fertilizers, manure, insecticides, seed, human labor, water for irrigation, and electricity as well as outputs including quinoa grain and crop residues. The energy equivalent of inputs used in quinoa cultivation was selected from previous literature. Energy equivalent of quinoa grain and residues were measured in the laboratory using a calorimeter bomb (Table 1).

Energy analyses
Improving the productivity of energy cycle in agriculture is one of the main measures to improve energy consumption, save money, conserve natural resources, and reduce environmental pollution (Pahlavan et al. 2012). In order to compare and evaluate the energy input and output of the system, standard indices including energy ratio (ER), energy productivity (EP), specific energy (SE), and net energy gain (NEG) are calculated using Eqs. 1, 2, 3, and 4, respectively (Naderi et al. 2019). Energy demand in agriculture can be classified into direct and indirect energies or renewable and nonrenewable energies. In the present study, human labor, fuel, electricity, and irrigation water were considered as direct energy (DE) and all types of fertilizers, pesticides, seeds, and machinery were considered as indirect energy (IDE) resources. Renewable energy (RE) includes human labor, seeds, manure, and irrigation water, and non-renewable (NRE) resources include electricity, machinery, fuel, pesticides, and fertilizers (Erdal et al. 2007).

Energy use efficiency
Energy productivity Specific energy Net energy Gain Life cycle assessment Life cycle assessment (LCA) methodology consists of four stages: goal and scope definition, life cycle inventory (LCI), life cycle impact assessment (LCIA), and interpretation of results (ISO14040).

Goal and scope
The first stage of the LCA study is defining the goal and scope. The purpose of this study was to investigate the environmental impacts and energy consumption pattern for quinoa production. All operations involved in the life cycle, products, and processes must be specified. In the present study, system boundary was defined as farm gates, including all field operations such as tillage, planting to harvesting operations, all agricultural inputs (manure, chemical fertilizers, insecticides, and seeds), agricultural machinery, human resources, diesel fuel, water, and also output products including quinoa grain, crop residues, and emissions. It should be mentioned that the stages in this study are solely concerned with quinoa production and do not include the process of Saponin removal. Figure 1 indicates the system boundary. This study is a cradle to farm gate study in which the whole life cycle from inputs production to quinoa production were considered and investigated. The FU is the quantitative description of the production system that is used as a source in the LCA study (Sahle and Potting 2013). In this study, FUs were chosen: mass-based (1 tonne of quinoa grain) and land-based (1 ha of area under cultivation).

Life cycle inventory
Life cycle inventory (LCI) includes the measurement of various input materials, energy flows and environmental emissions. Data related to the foreground system (farm operations in quinoa production or inputs consumption) were directly collected using face-to-face questionnaire (third column of Table 1) and data from the background system (production of inputs) extracted from the Ecoinvent ®3.0 database available in Simapro V. 8.2.3 software, previous literatures, and IPCC guidelines that are shown in Table 2. Also, the equations of direct emissions are brought in the AppendixS1 (Nemecek et al. 2014;Nemecek and Kagi 2007;IPCC 2007;Pre-Consultants 2014;Wikström and Adolfsson 2004).
In this study in order to calculate the direct emissions, we used following assumptions. Based on the IPCC guideline (2007), 1.25 kg NO x is emitted to the air per 100 kg N-based fertilizer (Galloway et al. 1995). The amount of ammonia released from urea fertilizer is about 17% of the total nitrogen of urea fertilizer (Goebes et al. 2003;Brentrup et al. 2000). The recorded amount of CO 2 emitted from the urea fertilizer is 1570 g per 1 kg of urea in the Ecoinvent database. Also, 30% of the total N-based fertilizer emits to the groundwater in the form of nitrate (Erickson et al. 2001). The emissions from phosphate fertilizers were calculated based on Nemecek and Kagi (2007). The average amount of phosphorus emitted into groundwater is about 0.07 kg per 1 ha (Nemecek et al. 2014).
Different pesticides with different active ingredients are used in the study area. Thirty to 50% of all pesticides are emitted into the air. Spraying operations and evaporation are the most important factors in the emission of these substances (IPCC 2007). In the Ecoinvent database, 100% of pesticides are assumed to emit into agricultural soils (Nemecek and Kagi 2007). The only fuel used in the system is diesel fuel. Emission factors of diesel fuel were extracted from Ecoinvent database to calculate the total diesel fuel emissions. Based on that, direct emissions of diesel consumption were calculated by Nemecek and Kagi (2007) and emissions of 9 pollutants were quantified for diesel fuel.

Life cycle impact assessment and interpretation of results
In this stage, the environmental impacts of each input, output, and operation were determined in each of the environmental category. For this purpose, Simapro environmental software was used. Then the obtained results were analyzed and compared with those obtained from similar studies. Environmental impacts of quinoa production were identified and possible solutions were recommended to correct the environmental hotspots and enhance the positive impacts. In the software database, a lot of information about each particular product around the world was stored. The amount of all environmental inputs and emissions were calculated using the above coefficients and formulas and were entered into Simapro V.8.2.3 software, then they were analyzed using CML-IA baseline V3.01/EU25 modeling approach in the form of some environmental impact categories. According to ISO 14040 standard (2006), the stage of life cycle impact assessment consists of two steps: a mandatory step and an optional step. The mandatory step includes the selection of impact categories and categorization, and the second step includes normalization and weighting. In the normalization step, the values of each category of impact are divided into a reference value. Typically, this reference is the average annual environmental impact in a country or climate per person. However, since this amount has not been calculated for this purpose in Iran, the exact results cannot be obtained. On the other hand, the mandatory steps cover the objectives of this study. In such a way, the index can be calculated for each impact category, and, on the other hand, the inputs with a greater impact on each category are identified. Therefore, in this study, only the mandatory steps were performed. Accordingly, eleven impact categories including global warming potential (GWP), abiotic depletion (AD), fossil fuels abiotic depletion (FAD), eutrophication (EU), ozone layer depletion (OLD), human toxicity potential (HTP), terrestrial ecotoxicity (TE), freshwater aquatic ecotoxicity (FAE), marine aquatic ecotoxicity (MAE), photochemical oxidation (PhO), and acidification potential (ACP) were selected as the most important impact categories and were studied for the initial data analysis (Goedkoop et al. 2008).

Pattern of energy consumption
The results of energy analysis of quinoa production are presented in the fourth row of Table 2. As can be seen, total inputs The results also revealed that the insecticide and seed had the least demanding energy inputs for quinoa production. The use of appropriate irrigation strategies such as drip irrigation can reduce water and electricity consumption. In the life cycle study of wheat, electricity, chemical fertilizer, and irrigation were the most influential inputs on energy consumption (Khoshnevisan et al. 2013). In a study that was conducted on potato energy flow in Isfahan province, the highest energy consumption was related to chemical fertilizers (Pishgar-Komleh et al. 2012). The difference between chemical fertilizer and organic fertilizer consumption indicates that increasing yield using more chemical fertilizer consumption cannot be an appropriate alternative. Diesel fuel is used for tractors and agricultural machinery. The shortage of complex machinery has increased the number and traffic of tractors in farms which causes high fuel consumption. Inefficient irrigation causes excessive water consumption and increases water loss. Also, output energy of quinoa grain and crop residues were found to be 27,378 MJ ha −1 and 51,384 MJ ha −1 , respectively. The results related to energy indices in quinoa cultivation are reported in Table 3. The ER without considering crop residues was calculated as 1.07 and the NEG was 1864 MJ ha −1 , which indicates efficient quinoa grain production. As a result, the ER of quinoa is lower than the rapeseed oil. It can be attributed to lower energy consumption in quinoa compared with rapeseed (Mousavi-Avval et al. 2011;Choobin et al. 2016). Currently, the residue of cultivated quinoa is used as either livestock feed or fertilizer or can be burnt by farmers. The total ER for quinoa cultivation (quinoa grain and crop residues) was obtained as 3.08. This amount indicates the necessity of the residues retain managing in the quinoa cultivation. EP and SE indices were compared in two scenarios as considering just quinoa production as first scenario and quinoa grain production and its residues as second scenario and results showed that about two-thirds of the consumed energy in production is related to the crop residue.  Higher accuracy in timing, amount, and type of fertilizers can be effective in increasing the grain to residue ratio. The difference in the amount of RE and NRE can be attributed to chemical fertilizers and fossil fuels. Consumption of NRE resources has hazards for environment. Sustainable agriculture and a healthier environment can be achieved by proper fertilizer management, applying advanced machinery, and renewable fuels. The amount of IDE is higher than DE that can be attributed to chemical fertilizers. This gap can be reduced through proper management of chemical fertilizers. Table 3 shows the distribution of total energy input as DE vs. IDE and RE vs. NRE. The results revealed the contribution of 68% and 32% of total energy input for DE and IDE, respectively. The shares of RE and NRE are 32% and 68% of total energy input. Several researches have shown that the contribution of DE is higher than that of IDE, and the share of NRE is more than that of RE in production of different agricultural products (Rafiee et al. 2010;Mohammadi and Omid 2010;Kizilaslan 2009). the basis of the mass-based and land-based FUs in quinoa cultivation are presented in Table 4. The values of environmental impact categories related to 1 ha of quinoa cultivation were approximately 1.6 times the relevant impact categories for one tonne of produced quinoa. This can be attributed to the yield of quinoa grain which is 1.6 tons per ha. Also, to better understand the sources of environmental emissions, impact categories associated with direct (on-farm) and indirect (offfarm) emissions of quinoa cultivation are reported in Table 4. Potential for fossil resources depletion is determined based on available reserves and extraction rates. As can be seen in Table 4, FAD was obtained as 7292 MJ per 1 tonne of quinoa production. This is about half of this index for rapeseed (Choobin et al. 2016). Figure 2 shows the contribution of each input to total environmental impacts for each impact category. Diesel and nitrogen fertilizers are identified as hotspots for FAD impact. GWP is the creation of global warming over a 100-year period that is generated by materials released during the production of products. In the present study, this impact was calculated as 354 kg CO 2eq. for the production of one tonne of quinoa. The results of a study in Peru indicated that 880 kg CO 2eq. is emitted per production of 1 tonne of packaged organic quinoa (Cancino-Espinoza et al. 2018). In a study by Habibi et al. (2019), the effect of rice cultivation on GWP impact was analyzed in Amol and Rasht counties and obtained as 277 and 276 kg CO 2eq. per tonnes of rice, respectively. Figure 2 shows that the most effective factors on the GWP impact are nitrogen fertilizer and on-farm emissions (direct emissions) which is in agreement with results obtained from a study on canola cultivation in Isfahan province (Khanali et al. 2018). Elhami et al. (2016) found agricultural machinery and chemical fertilizers as the most important inputs affecting GWP in chickpea production in Isfahan province. Based on Nemecek et al. (2011), emissions of nitrogen dioxide and carbon dioxide from chemical fertilizers and diesel fuel were identified as major contributors to global warming potential.

Life cycle impact assessment
OLD increases the amount of harmful solar radiation by chlorine, bromine, and chlorofluorocarbons chemicals. This phenomenon causes some serious consequences on the environment and human such as skin cancer, molecular damage to materials, and damage to plants and animals due to increased UV radiation. The impact of greenhouse gases is quantified in OLD impact category (Bare 2011). In the present study, this impact was accounted as 19 mg CFC11 eq. per defined FU. Figure 3 shows that pesticides with the contribution of 94% to OLD were identified as environmental hotspots. The amount of OLD in canola production was obtained 13 times higher than value in this study, and pesticides are the most effective factor for this impact (Mousavi-Avval et al. 2017). Using physical and biological pest control methods, management of time and pesticide amount and proper operational adjustment of the sprayer will be effective in reducing these pollutants.
The HTP impact indicates the damage potential caused by chemicals emission to the environment. As can be seen in Table 4, HTP was obtained as 280 kg 1,4-DB eq. per one tonne of quinoa grain production. The highest contribution to this impact is related to diesel fuel input. The use of reduced tillage and no-tillage cultivation operations in quinoa farms can reduce diesel fuel consumption. Nikkhah et al. (2016) reported that high on-farm emission rates for agricultural productions in Iran could be attributed mainly to diesel fuel combustion and nitrogen fertilizer application. In the present study, phosphorus fertilizers had the highest contribution (65%) on TE impact. Based on Sahle and Potting (2013), the most effective input to the TE impact in Ethiopian roses production was fertilizer with the contribution of 75.5% to the total impact. In the present study, Potassium fertilizers were identified as the only input that had a positive effect on the environmental impacts per one tonne of quinoa production with the most positive effect on TE impact. The PhO impact is mainly caused by the formation of ozone in the lower layers of the atmosphere which is abnormal (Bare et al. 2003). As can be seen in Table 4, the Pho impact was estimated as 161 g C 2 H 4eq. per defined FU. Nitrogen fertilizer was identified as hotspot in this impact which was followed by diesel fuel. Emissions of NH 3 , NO 2 , SO 2 , and NO x into the air have a significant effect on ACP impact. Based on the results ACP was calculated as 3.2 kg S 2 O eq. per production of one tonne quinoa. In the current study, the major contributor to ACP was nitrogen fertilizer application with the share of about 80%. In the rapeseed study by Choobin et al. (2016), phosphate fertilizer accounted for 30% of the total contribution to ACP. The use of crop residue management and proper selection of the right method, the right timing, and the right rate for fertilizer application, precise and desired placement of nutrient materials, use of manure, and other types of bio-fertilizer can reduce the consumption of chemical fertilizer.
Increasing the nitrate and phosphate concentration in water causes unusual algae growth, which reduces the oxygen of water and degrades aquatic ecosystems. This phenomenon is quantified by EU impact. During the production of one tonne of quinoa, EU impact was obtained as 495 g PO 4 3− eq. . Phosphorus has been introduced as a major contributor to the EU in most European ecosystems (Charles et al. 2006).
Comparison of the environmental impacts of quinoa production with wheat, barley, maize, rice, and rapeseed is presented in Fig. 3. The results show that the environmental impacts of quinoa are similar to those of agricultural crops such as wheat, barley, or rice. Quinoa is usually compared with cereals because of its texture and plant origin. However, it has high protein content, as well as all the proteinogenic amino acids, which make it an attractive product to compete with animal protein (Ruiz et al. 2014;Vega-Galvez et al. 2010).
However, if the results of environmental impacts are compared with other protein-rich foods (meats, eggs, seafood, etc.), it is observed that quinoa's environmental impacts are significantly lower than other crops (Cancino-Espinoza et al. 2018). Finally, it must be mentioned that farmers in the Isfahan province have begun to cultivate quinoa, a healthy plant whose glutton-free seeds are rich in protein, dietary fiber, B vitamins, and dietary minerals in amounts greater than in many grains. Growing quinoa has been fully mechanized in the region since its harvest began recently using combine harvesters. Patients with celiac disease who are suffering from gastrointestinal problems can replace wheat with quinoa. By informing people about the benefits of using this plant, its market can be boosted, and it will provide a good incentive to grow this plant, especially in salt lands.

Conclusion
The present study investigated the energy flow and environmental impacts of quinoa grain production in Isfahan province using the life cycle assessment methodology. The energy pattern indicated the significant effect of chemical fertilizer and diesel fuel inputs on the amount of energy consumed which shows the priority of non-renewable energies. Investigation of energy indices indicated the efficient quinoa production; however, by comparing quinoa energy indices, it was found that the share of energy consumption for quinoa residue production was more than quinoa grain. Inefficient and imprecise use of fertilizers and pesticides has negative impacts on the environment. Some measurements can be recommended for mitigation of environmental impacts such as precise use of agrochemicals, soil and plant testing for determining fertilizer requirements of soil, and limiting nitrogen cycles by applying suitable crop rotation. Also, the use of modern methods of spraying can reduce the biocides application. The lack of proper machinery and consequently increasing farm traffic as well as faults in applied machinery increase diesel fuel consumption. Development of biofuels production, introduction, and production of multi-fuel engines will greatly help to reduce environmental pollutions. Also, production and introduction of complex and advanced agricultural machinery, software, and monitors and usage of reduced tillage and notillage cultivation operations can provide better control over tractor function and reduce operation hours in quinoa cultivation.
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