Corn- A Vital Crop for Our Economy

 

Archana Jain¹*, Deepali Rastogi², Bhawana Chanana³

¹Research Scholar, Lady Irwin College, University of Delhi

²Associate Professor, Lady Irwin College, University of Delhi

³Professor and Head, Amity School of Fashion Design and Technology, Mumbai

 

ABSTRACT:

Corn, which is one of the staple food crops of our country could be exploited as a potential source of textile fibres as well. Agro waste like sugarcane bagasse, rice husk and cornhusk etc. have traditionally been used as fuels but their burning adds to air pollution. They need to be utilized more efficiently to add to our existing renewable resources. One such agro waste that can be employed to broaden our textile resource basket is; cornhusk, the outer covering of the corn cobs. This could prove a major breakthrough for our economy as same crop will yield both food and textile fibre.

 

 

INTRODUCTION:

Corn is the 3^rd most important food crop after rice and wheat in India. In India, maize is cultivated in all the states except Kerala. It is cultivated throughout the year in different parts of the country for various purposes. Corn production in India has grown at a compounded annual growth rate of 5.5 per cent over the last ten years from 14 million metric tons in 2004-05 to 23 million metric tons in 2013-14 (India Maize Summit, 2014).

Most of the corn produced is processed for its grains to be used for various purposes like flour, snacks and animal feed. During processing cornhusk is removed from the cob and burnt in case of most of the varieties for corn. Only husk of baby corn is used as animal feed as it is believed to enhance the yield of milk in cattle. Agro waste like sugarcane bagasse, rice husk and cornhusk etc. have traditionally been used as fuels but their burning adds to air pollution. They need to be utilized more efficiently to add to our existing renewable resources. One such agro waste that can be employed to broaden our textile resource basket is; cornhusk, the outer covering of the corn cobs.

 

Corn Production

Corn is believed to have highest genetic yield potential amongst all the food grain crops. Globally, it is cultivated on nearly 150 million hectares in about 160 countries which are diverse in soil, climate and management practices.

 

 

 

Corn contributes about 36% (782 m t) in the global grain production. The United States of America (USA) has the highest harvest of corn in the world, and it is the driver of the US economy. The other major countries having significant contribution to the global corn production are China, Brazil, Mexico, India and Indonesia. Figure 1 shows the world corn production for the year 2011-12.

 

 

 

Figure 1: World corn production 2011-2012

(Source: USDA FAS, Grain: World Markets and Trade, 1/12/12)

 

 

 

 

In India, corn holds the distinction of being 3^rd most important food crop after rice and wheat. In India, corn has a contribution of nearly 8 % in the national food basket and more than Rs. 100 billion to the agricultural GDP. Moreover, it provides employment to over 100 million men at the farm and downstream agricultural and industrial sectors. In addition to providing staple food for human beings and quality feed for animals, maize acts as a basic raw material as an ingredient to thousands of industrial products that includes starch, oil, protein, food sweeteners, alcoholic beverages, pharmaceuticals, cosmetics, textiles, package and paper industries etc. In India, maize is used as human food (25%), poultry feed (49%), animal feed (12%), industrial (starch) products (12%), beverages and seed (1% each).

 

Generally Indian corn production has been showing an increasing trend in last few years and in 2010-11, it crossed 20 million tons. In India, maize is cultivated in all the states except Kerala (Figure 2). The major maize growing states which contribute more than 80% to the total maize production are Andhra Pradesh (20.9%), Karnataka (16.5%), Rajasthan (9.9%), Maharashtra (9.1%), Bihar (8.9%), Uttar Pradesh (6.1%), Madhya Pradesh (5.7%), Himachal Pradesh (4.4%). Hence, corn has emerged as an important crop in the non-traditional regions i.e. peninsular India (www.agridaksh.iasri.res.in).

 

 

 

Figure 2: State-wise production of corn in India

(Source: www.farmer.gov.in)

 

Major corn producers, exporters and importers: United States is the world's top exporter of corn. On an average, about 20 percent of U.S. corn is exported. During the year 2008-09, United States exported 47.5 million metric tons (1.9 billion bushels) - accounting for 59 percent of total world corn exports of 84 million tons. Though China is a big grower of the crop, it sometimes has to import corn to overcome its demand-supply gap. There has been continuous increase in the demand of corn due to increase in the consumption from meat and starch sector. There is also growing requirement of corn from poultry sector, which uses corn as feed. Japan is the largest buyer of corn in world market roughly importing 20% of the world trade.

 

Corn production and consumption has been rising consistently in India. The feed uses of corn are projected to increase by 10% annually. Increased production of corn has helped India to become one of the top suppliers to South East Asian region as the country enjoys the freight advantage also for this region over its American competitors. In West Asian market, Ukraine is the major competitor for India (www.agricommodityprices.com).

 

Corn Agriculture

Corn (Zea mays, Poaceae family) is a cereal crop that can be grown in va­rious agro-ecological zones, either as a single crop or as mixed crop. Although corn can be cultivated in many different regions, the savannah is the most favourable climatic zone having an average annual rainfall between 800 and 1200 mm with strong sunlight, which helps in reducing parasitism. It requires tempera­ture between 10-19 °C, and should not be cultivated at an altitude above 1800 m [1]. Corn can be successfully grown in a wide range of soils ranging from loamy sand to clay loam. But soils having good organic matter content and high water holding capacity with neutral pH are considered good for better productivity.

 

Corn can be grown in all seasons viz; Kharif (monsoon), post monsoon, Rabi  (winter) and spring. The optimum time of sowing in different seasons are given in Table 1.

 

Table 1: Optimum sowing time for corn in different seasons

Season	Optimum time of sowing
Kharif	Last week of June to first fortnight of July
Rabi	Last week of October for inter cropping and up to 15th of November for sole crop
Spring	First week of February

(www.agridaksh.iasri.res.in)

 

 

Figure 3: Parts of a corn plant

(Source: www.plantandsoil.unl.edu)

                      

Figure 4: Arrangement of layers of  corn husk

(Source: www.bioportal.bioontology.org)

 

Corn Plant

The corn plants generally have a single stem, which is called as stalk, growing vertically upwards from the ground. The height of the stalk varies depending upon the variety of the corn and also the climate in which the corn plant is grown. As the stalk grows, leaves emerge and the lower part of the stalk is wrapped by leaves. The leaves are attached to the stalk at a point called as node. Certain varieties of corn produce secondary stalks, which are known as tillers and they grow outward from the base of the main stalk. Each corn plant comprises of both male and female parts. The male part, known as tassel, grows from the top of the plant, after all the leaves have emerged. The tassel generally contains several branches, along which many small male flowers are present (Figure 3).                                                    

 

Occasionally, a plant produces an ear at several consecutive nodes, but the ear located uppermost on the stalk forms the largest ear. The immature ear comprises of a cob, eggs that develop into kernels after pollination, and silks. The kernels are arranged on the cob in pairs of rows. A hair-like structure called silk grows from each egg which finally emerges from the tip of the husk (a group of leaves attached to the shank that encloses the entire ear) [2].

 

Cornhusk Anatomy

The husk is the name given to modified leaves arising from short lateral branch (shank) bearing the ear. These leaves surround the developing ear. The outer husk is arranged in a distichous pattern while inner husk is polystichous in arrangement (Figure 4). Husk is considered to be somewhat similar to the adult and juvenile leaves (foliar leaves). Husk is relatively thin and flat, as compared to the adult and juvenile foliar leaves. The sheath of the husk is much broader and thinner than the sheath of the foliar (ordinary) leaves. There is no distinct mid vein and lateral veins predominate throughout the husk. Each husk is attached to a specific lateral branch node on the shank of the ear. Botanically, the term husk is being used for the entire structure, comprising of husk sheath, husk ligules and husk leaf (www.bioportal.bioontology.org).

 

Classification of Corn

Most of the corn is grown for its grains, which is called as normal corn. Other than grain, corn is also cultivated for various purposes like quality protein maize and other special purposes which is known as speciality corn. The various speciality corn types are quality protein maize (QPM), baby corn, sweet corn, pop corn, waxy corn, high oil corn etc. In India, QPM, baby corn and sweet corn are being promoted and cultivated by a large number of farmers. The different types of specialty corn are as follows, 

 

Quality Protein Maize (QPM): 

As more than 85 % of corn is used directly for food and feed, the quality of grains has a great role in food and nutritional security in our country. QPM is nutritionally superior over the normal maize and is important for quality feed in poultry, piggery and animal sectors as well. It has specific features of having balanced amount of amino acids with high content of lysine and tryptophan and low content of leucine and isoleucine.

 

Baby corn: 

Baby corn is a young finger like cob which is unfertilized and has one to three centimetres long emerged silk. Baby corn is quite nutritive and its nutritional quality is equivalent or even superior to some of the seasonal vegetables. Apart from proteins, vitamins and iron, it is one of the richest sources of phosphorus. It is almost free from residual effects of pesticides. Baby corn can be cultivated throughout the year and hence, three to four crops of baby corn can be produced in a year. 

 

Sweet corn: 

Sweet corn is one of the most popular vegetables in countries such as; USA, Europe and many other developed countries of the world. It is very delicious in taste and a rich source of energy, vitamin C and A. It can be eaten raw, boiled or steamed. Recently, sweet corn has become very popular in urban areas of India; therefore, its cultivation is quite fruitful for peri-urban farmers. Due to cultivation of sweet corn green fodder is also available to the farmers for their cattle along with the green cobs.

 

Pop corn: 

Popcorn is popular as a common snack item in many parts of the world which is liked because of its light, porous and crunchy texture. The popcorn flour is also used for preparing many traditional dishes.

 

Waxy corn: 

It originated in China but is largely used in USA.  This grain has wax-like appearance due to presence of 100 % amylo pectin starch as compared to normal corn in which, the starch is nearly 30 % amylose and 70 % amylopectin. Waxy corn is mainly used for industrial purposes.

 

High oil corn: 

Most of the normal corn crops have 3- 4 % oil content. Corn with more than 6 % oil is considered as high oil corn. 95 % of the total oil is in the germ. When the oil percent increases the starch decreases. In India more than 60000 tons of corn oil is produced for various uses.

 

Fodder corn: 

Corn fodder can be used at any stage of crop growth. The tall, leafy and longer duration varieties are most preferred for corn fodder cultivation. The cultivation of corn for fodder can be done round the year. Generally the farmers practice growing composite varieties or advance generation of hybrid seeds as it is economical to them (www.agridaksh.iasri.res.in).

 

Various Applications of Corn in Textiles

Corn fibre:

Corn fibres are the fibres made from PLA (poly lactic acid) obtained from corn. Corn fibre products are quite similar in look and feel to regular fibre, but they are 100% biodegradable and compostable. PLA fibre is however biologically degradable only when subjected to the right conditions. It very well suits for waste treatment through composting. As corn is a renewable resource, it makes corn fibre much more sustainable than regular fibre (www.2wtextile.com). In the 1980’s, PLA was synthesized from corn starch for the first time. Production of fibres from corn PLA started at a large scale around the year 2000 while it was introduced globally in 2003 on a commercial scale with the trade name, Ingeo. Ingeo is the first melt-processable natural fibre manufactured with the PLA resin using polyester type fibre manufacturing processes (www.vasantkothari.com). 

 

PLA is aliphatic polyester, having relatively small pendant methyl groups to hinder rotation and easy access to the oxygen atoms in the ester linkage. The PLA molecule tends to assume a helical structure.  Polymer characteristics may be unique due to the fact that the lactide dimer occurs in three forms which are; the L form, which rotates polarized light in a clockwise direction; the D form, which rotates polarized light in a counter-clockwise direction and the meso form, which is optically inactive.  The relative proportions of these forms can be controlled during polymerization which results in relatively broad control over important polymer properties. Ingeo fibre is a novel fibre that combines the best of both the worlds i.e. the performance of a synthetic fibre and the advantages of a natural material.  This fibre has good strength and the fabric thus formed has many properties such as gentle bright lustre, good air permeability, good crease recovery, moisture absorption, shrink resistance and high resistance to ultra violet rays (www.vasantkothari.com).

 

Sisodia and Parmar (2014) evaluated the dyeing behaviour of corn (PLA) fibre using disperse dyes and reported that colour strength of the fibres increased with increase in temperature but the strength decreased due to the degradation of fibre structure [3].

 

Cornhusk fibres:

Very limited work has been done on cornhusk fibres across the world. Some of the studies reporting varied applications of cornhusk fibres are as follows,

·  Textiles: Reddy and Yang (2005) examined the properties and potential applications of natural cellulose fibres from cornhusk. They extracted natural cellulose fibres from cornhusk and claimed that the extracted fibres have properties between cotton and linen. They blended the fibres with cotton in various proportions and processed on the ring and rotor spinning machines and concluded that fibres extracted from cornhusk were suitable for high value textile applications and had better processability than natural fibres from other agricultural by products [4].

 

In another study by Salam, Reddy and Yang (2007) kenaf and cornhusk fibres were bleached to CIE whiteness indices of 66. Bleaching was used to partially remove the lignin from the fibres without affecting other fibre properties and variables such as the concentration of hydrogen peroxide, time, temperature, and pH were optimized for both the kenaf and cornhusk fibres. The effects of various bleaching parameters on the whiteness index and the breaking tenacity of the fibres were reported [5].

 

According to a study conducted by Reddy, Thillainayagam and Yang, (2011) natural cellulose fibres extracted from cornhusk had better dyeing properties for direct and sulphur dyes and similar dyeing properties for reactive and vat dyes when compared to cotton fibres dyed under similar dyeing conditions. They quoted short single cells, higher amounts of lignin and hemi cellulose, lower percent crystallinity and relatively coarse fibres of cornhusk as the reasons which make common cellulose fibre dyeing conditions unsuitable to dye cornhusk fibres. They also concluded that higher dye sorption on cornhusk fibres too was due to the above mentioned reasons [6].

 

Yılmaz (2013) studied the effect of chemical parameters like alkali concentration and treatment time on the properties of extracted cornhusk fibres.  The study proved that highest strength properties were achieved with 5-10 g/l sodium hydroxide treatment for 60-90 minutes and also reported that average length, linear density and moisture content of extracted fibres decreased with increase in alkali concentration and duration. It was also deduced from FTIR spectrum analysis that harsher treatments led to increase in cellulose content while lignin and hemicelluloses content were lowered [7].

 

Yılmaz, N.D., Çalışkan, and Yılmaz, K. (2014) investigated the effect of xylanase enzyme on the mechanical properties of fibres extracted from fresh and dried cornhusk. They extracted the fibres using alkali followed by xylanase treatment at different concentrations. Their results showed that drying did not have any negative impact on the fibre properties but the colour of fibres obtained was dull as compared to those extracted from fresh ones. They reported that increase in concentration of enzyme and drying decreased the linear density of fibres. Increasing enzyme concentration also led to increase in the breaking tenacity and initial modulus up to a point after which it decreased [8].

 

Zhuanzhuan, Pan, Xu, Huang, and Yang, (2015) obtained cellulosic fibres with high aspect ratio from cornhusk by controlled swelling in organic solvent and simultaneous tetra methyl ammonium hydroxide post treatment. They concluded that cornhusk fibres obtained had qualities comparable to cotton and linen and thus could be successfully used in industrial applications [9].

 

·  Twines: Bridgehouse and Hawthorne (1982) carried out a study to form twine of cornhusk and leaves. The extraction of fibres was done from cornhusk and leaves or cornhusk such that it became free for any binding vegetable material. The fibrous material extracted was combed and formed in to a tow of required thickness. This bundle was then twisted and drafted to form the twine. He claimed that the cornhusk twine was comparable to jute/ sisal twines of similar thickness with respect to strength and durability [10].

 

·  Reinforcement in composites: Another research was conducted to extract cornhusk fibres with chemical treatment and use the fibres as reinforcement in light-weight polypropylene (PP) composites. The composites from cornhusk fibre (CHF) and PP were evaluated for flexural and impact resistance, tensile and sound absorption properties. The authors compared jute/PP composites and CHF/PP composites and found that CHF/PP composites were similar in impact resistance, 33% higher in flexural strength, 71% lower in flexural modulus, 43% higher in tensile strength, 54% lower in tensile modulus, and had slightly higher noise reduction coefficient. They also reported an increase in mechanical and sound absorption properties after enzyme treatment of cornhusk fibres [11].

 

Youssef, El-Gendy and Kamel (2014) evaluated cornhusk fibres reinforced recycled low density polyethylene composites and suggested their applicability in packaging [12].

 

·  Pulping fraction: Byrd, Jameel, and Johnson (2006) explored the feasibility of pulping the three fractions of corn stalk i.e. stalk, leaves and husks. Each (unmilled) fraction was pulped, using a mild soda-AQ process. A portion of each fraction was milled and tested for ash content, hot water solubles, NaOH solubles, solvent extractives, and klason lignin content. They concluded that pulping of corn residue should be explored further as it showed the prospects for being used as a source of pulp [13].

Ekhuemelo, Oluwalana and Adetogun (2013) also found cornhusk to be suitable for application in paper and pulp industry [14].

 

·  Cellulosic nano fibres: Cardoso, Teixeira, Paes, Marconcini and Mattoso, (2008) extracted and characterized cellulose nano fibres from cornhusk. The extraction of nano fibres was done by acid hydrolysis (as given in Orts et al., 2005 and Moran et al., 2008). Nanostructures of cellulose were characterized by thermo gravimetric analysis (TGA), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FTIR), and X Ray Diffraction (XRD). Their results showed a possibility to extract cellulose nano fibres from cornhusk, with potential application in polymer nano composites [15].

 

·  Composite biodegradable film: Norashikin and Ibrahim (2009) carried out a study to prepare a biodegradable film from corn husks which was characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA) and atomic force microscope (AFM) observation. The fabricated film showed a high degradability rate as it readily degraded within 7-9 months under controlled soil conditions. The film was used in making biodegradable pot for seedlings plantation. The authors concluded that the pot produced from corn husk composite biodegradable film was appropriate for planting a seedling as it would give plant more comfortable growing conditions without harming the environment [16].

 

CONCLUSION:

Looking at the multifarious usages of cornhusk, as reported by various researchers, there is no doubt that this bio-waste from corn can aid in reducing the bio-burden on our ecological system and also add to the bundle of natural resources for textile usages. Efforts need to be made at a wider spectrum and faster pace as cornhusk is available in huge quantities across the country, almost throughout the year. All of this is getting wasted and adding to the bio-burden. A milestone could be established if cornhusk fibre is projected as a natural resource catering to the needs of future generations to come.

 

REFERENCES:

1.     Hoopen, M., E., and Maïga, A. (2012). Maize Production and Processing. Retrieved from  http://publications.cta.int/media/publications/downloads/1724_PDF.pdf

2.     Russell, K., and Sandall, L. Corn Breeding: Lessons From the Past - Overview and Objectives. Retrieved from http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1075412493andtopicorder=3andmaxto=12

3.     Sisodia, N., and Parmar, M. S. (2014). Dyeing behavior and fastness properties of corn (pla) fiber. Journal of Polymer and Textile Engineering. Volume 1(2), 01-07.

4.     Reddy, N., and Yang, Y. (2005). Properties and potential applications of natural cellulose fibers from cornhusks. Green Chemistry, 7(4), 190-195

5.     Salam, A., Reddy, N., and Yang, Y. (2007). Bleaching of kenaf and cornhusk fibers. Industrial and Engineering Chemistry Research, 46(5), 1452-1458.

6.     Reddy, N., Thillainayagam, V. A., and Yang, Y. (2011). Dyeing natural cellulose fibers from cornhusks: A comparative study with cotton fibers. Industrial and Engineering Chemistry Research, 50(9), 5642-5650.

7.     Yılmaz, N. D. (2013). Effect of chemical extraction parameters on corn husk fibres characteristics. Indian Journal of Fibre and Textile Research, 38 (1), 29-34.

8.     Yılmaz, N. D., Çalışkan, E. , and Yılmaz, K. (2014). Effect of xylanase enzyme on mechanical properties of fibres extracted from undried and dried corn husks. Indian Journal of Fibre and Textile Research, 39 (1), 60-64.

9.     Zhuanzhuan, Ma, Pan, G., Xu, H., Huang, Y., and Yang, Y. (2015). Cellulosic fibers with high aspect ratio from cornhusks via controlled swelling and alkaline penetration. Carbohydrate polymers, 124, 50-56.

10.   Bridgehouse, E. S., and Hawthorne, W. M. (1982). U.S. Patent No. 4,359,859. Washington, DC: U.S. Patent and Trademark Office.

11.   Huda, S., and Yang, Y. (2008). Chemically extracted cornhusk fibers as reinforcement in light‐weight poly (propylene) composites. Macromolecular Materials and Engineering, 293(3), 235-243.

12.   Youssef, A. M., El-Gendy, A., and Kamel, S. (2015). Evaluation of corn husk fibers reinforced recycled low density polyethylene composites. Materials Chemistry and Physics, 152, 26-33.

13.   Byrd, M., Jameel, H., and Johnson, W. (2006). Chemical and pulping characteristics of corn stalk fractions. Paper presented at Proceedings of New Technologies in Non-wood Fiber Pulping and Papermaking, Guangzhou: Press of South China University of Technology, 8.

14.   Ekhuemelo, D. O., Oluwalana, S. A., and Adetogun, A. C. (2013). Potentials of agricultural waste and grasses in pulp and papermaking. Journal of Research in Forestry, Wildlife and Environment, 4(2), 79-91.

15.   Cardoso, R. F. O., Teixeira, E. M., Paes, M. C. D., Marconcini, J. M., and Mattoso, L. H. C. (2008). Cellulose Nanofibers from Corn Husks: extraction and characterization. Retrieved from http://ainfo.cnptia.embrapa.br/digital/bitstream/item/87431/1/Proci-08.00079.PDF

16.   Norashikin, M. Z., and Ibrahim, M. Z. (2009). The potential of natural waste (corn husk) for production of environmental friendly biodegradable film for seedling. World Academy of Science, Engineering and Technology, 58, 176-180.

Websites visited

·      www.agridaksh.iasri.res.in (Last accessed on 12.09.2015)

·      www.farmer.gov.in (Last accessed on 06.09.2015)

·      www.agricommodityprices.com (Last accessed on 11.03.2014)

·      www.plantandsoil.unl.edu ( Last accessed on 17.08.2014)

·      www.bioportal.bioontology.org ( Last accessed on 18.08.2015)

·      www.2wtextile.com (Last accessed on06.09.2015)

·      www.vasantkothari.com (Last accessed on 11.02.2014)