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INGREDIENTS AND FLAVOURS

Indian wheat quality on the basis of end-use

Monday, 16 November, 2015, 08 : 00 AM [IST]

Rajbir Yadav, Naresh Kumar and Kiran Gaekwad

Wheat is among the most primitive plant species, domesticated as food crops, nearly 8,000 years ago. Since then it has been the major staple food for most parts of the world including Europe, West Asia, South-East Asia, America and North Africa.

At present, wheat occupies largest acreage with its production leading all other food crops including rice, maize and potato and is important grain source for humans. It is most widely distributed crops with cultivation being reported from sea level to about 4,570 metre above sea level in Tibet, but it grows best between the latitudes of 30° and 60°N and 27° and 40°S. Wheat grows best in the area with temperature around 25°C, with minimum and maximum temperature of 3° to 4°C and 30° to 32°C, respectively. Wheat is the most important source of carbohydrate in a majority of countries. Beside food, low grade wheat, unsuitable for human consumption, is used for animal feed and for making adhesives, paper additives and alcoholic beverages.

Area along with increased productivity led to dramatic increase in world wheat production during the period 1951-1990. World production achieved new heights by producing about 592 m tonne during 1990 and since then world wheat production was hovering above 550 m tonne. In 2007-08, a new record of harvesting about 684.6 m tonne was achieved. This indicates a gain of about 12.1 per cent over the production of 2006-07 (610.3 m tonne). A world wheat food crisis triggered by continued lower production during the period 2002-2006 has been averted and a healthy world stock to use ration of around 29.8 m tonne is maintained.

According to International Grain Council, world wheat production was likely to be around 721 m tonne during 20014-15 of which 154 m tonne would be traded across the world, China with 126 m tonne estimated wheat production in 2014-15 was the largest producer, followed by India (90.78 m tonne). Other major wheat producers are European Union with 156.2 m tonne, Russia with 59.7 m tonne and USA producing around 55.1 m tonne. Argentina, Australia, Canada, the EU, Kazakhstan, Russia, Ukraine and the United States are traditional major exporters of wheat. India became almost self-sufficient with green revolution technologies adopted by farmers in 70s. The next three years i.e. 1981-1983 were not so good and India again became a net importer with significant wheat import (2.0, 2.486 and 3.270 m tonne, respectively), however since then Indian dependence on external wheat has remained bare minimum with occasional import during 1988 (2.1 m tonne and 1992 (2.50 m tonne).

Due to extended drought like situation in the end of 20th century, India had to again import wheat from 1996 to 1999. However, the country achieved a unique feet of not importing wheat continuously for six years from 2000 to 2005. During the same period, India became a player in the international export market with continuous export from 1999 to 2005. Due to severe drought, India imported around 5.379 m tonne of wheat during 2006-07 and 1.84 m tonne in 2007-08. India in last two years has also exported wheat to the tune of 6.0 and 3.4 m tonne of wheat, respectively in 2013-14 and 2014-15. Major export destinations of wheat are Bangladesh, the United Arab Emirates, Indonesia, Turkey and Sudan.

Table 1: Two major phases of Indian Wheat Export (source: USDA)

Phase I		Phase II
Year	Wheat export (m tonne)	Year	Wheat exported (m tonne)
2000	1.569	2010	0.072
2001	3.087	2011	0.891
2002	4.850	2012	6.824
2003	5.650	2013	6.053
2004	2.120	2014	3.500

Wheat Varieties Released in India
Wheat breeding in India was scientifically taken up during 1905 by Howard and Howard, since then it has metamorphosed into a well oiled programme due to changing needs, mechanisation and better and faster tool and techniques available to the breeder. The systematic selection and evaluation practiced by the earlier workers resulted in the development of number of varieties of NP, Pb and K series with few of them like NP4 were recognised internationally due to better grain quality. However, higher incidence of disease in the released varieties, forced the breeders to develop rust-resistant varieties and as a consequence number of varieties of NP 700 and 800 series were released. Some of them like NP 809 became popular largely due to their resistance against all the three rusts. As most of the varieties were tall and therefore, lodging under high fertility and irrigated conditions hampers the bumper harvest and this was largely the reason that India was producing only 12.3 million tonne of wheat till 1964-65 crop season.

The introduction and testing of Norin-10 based strains like Sonora 63, Sonora 64, Mayo 64 and Lerma Rojo 64 along with number of segregating material from CIMMYT, Mexico, changed the Indian production scenario dramatically. The selection of Mexican material led to the release of PV 18, Kalyan Sona, Sonalika, Chhoti Lerma and Safed Lerma and laid the foundation for Green Revolution. Indian wheat production since then has continuously increased with the continuous flow of improved material like Sonalika, HD 2009, WL 711, WH 147, UP 262, Lok 1, HUW 234, HD 2285, HD 2329 and PBW 343, HD 2687, HD 2733 and HD 2932. Near about 399 varieties have been released (335 bread, 54 durum, 5 dicoccum & 5 triticale) since the beginning of All Indian Coordinated Programme on Wheat Improvement. Varieties are released centrally by Central Varietal Release Committee as well as at state level by State Level Variety Release Committee.

Table 2: Important Wheat Varieties grown in India under Various Production Conditions

Zone	Production condition
	Timely sown irrigated	Late sown irrigated	Rain fed and Restricted irrigation condition
North western plain zone Bread wheat Durum wheat	WH 542, PBW 343, PBW 502, UP 2338, HD 2687, UP 2338, Raj 3077, KRL-19 DBW 17, PBW 550, HD 2967, DBW 88, HD 3086, WH 1105	DBW 16, PBW 373 UP 2425, ,RAJ 3765, WH 1021, PBW 590, DBW 71, WH 1124 and DBW 90	PBW 299, PBW 396 WH 533, HD 3043, WH 1142, PBW 644
	PDW 291, PBW 34, PDW 215, PDW 233, WH 896, PDW 314
North eastern plain zone Bread wheat	K 8804, K 9107, HUW 468, PBW 443, DL 784-3, K 0307, HP 1731, HP 1761, HD 2733, NW 1012, HD 2824, Raj 3077, KRL-19, HD 2967, DBW 39, Raj 4120	DL 784-3, HD 2643, HP 1633, HP 1744, NW 1014, HW 2045, DBW 14, NW 2036, HD 2985, HI 1563	K 8962, K 9465, K 8027, HD 2888
Central zone Bread wheat Durum wheat Dicoccum wheat	GW 190, GW 273, GW 322, GW 366, HI 1544 Raj 3077, KRL-19, MP 3288	GW 173, DL 788-2 MP 4010, HD 2864, HD 2932, MP 1203,	HW 2004, JWS 17, HI 1500, HI 1531
	HI 8381, HI 8498, HI 8663 , MPO 1215, UAS428, HI 8713, HD 5216, MP 3336	-	HD 4672, HI 8627
	DDK 1001, DDK 1025, DDK 1009	-	-
Peninsular zone Bread wheat Durum wheat Dicoccum wheat	HD 2189, DWR 162, GW 322, MACS 2496, RAJ 4037, NIAW 917, UAS 304(I), MACS 6222 (I), MACS 6273(I)	DWR 195, HD 2501, NIAW 34, HD 2833, HUW 510, PBW 533 HD 2932, AKAW 4627, HD 3090	K 9644, HD 2781, HD 2987
	MACS 2846	-	AKDW 2997-16
	DDK1001, DDK 1009, DDK 1025	-	-
			DT 46
Southern Hill Zone	HW 318, HW 1085, HW 2044 , HW 5207
Salinity/Alkalinity	KRL 19, KRL 210, KRL 213

Different Classes of Wheat and their Suitability for Various End-use Products
Wheat provides nutrients and the raw materials for industrialised food production and its commercial value is determined by its end-use quality which in turn depends upon the genetic makeup and environment of crop production. Faster economic growth in industrial and service sectors in both developed and developing countries has increased urban population resulting in increased demand for fast/ ready-to-eat/ frozen foods, and so on and wheat flour being highly amenable to these products due to elasticity and strength, demand for wheat- based products has been increasing over the years.

Wheat has unique characteristic of possessing a viscoelastic storage protein complex called gluten - the main factor making wheat the most important food crop in the world. A cultivar suitable for one food type may not be suitable for different one. Quality differences among wheat cultivars have gained even more importance in grain trading due to important global economic and social trends. Many developing countries are experiencing a shift towards processed wheat-based foods due to urbanisation and better standards of living. Among the various species of wheat grown, two most important species from end-use quality purposes are Triticum aestivum L., and Triticum turgidum L. var. durum, known commercially as common wheat and durum wheat, respectively. The two species differ not only in genomic structure but also in their suitability for end-products because of differences in grain composition.

Table 3: Common Food Preparations from Wheat Flour in India

Types of Wheat	Products
Bread Wheat	Chapati/ Roti/ Phulka, Tandoori roti, Naan, Kulcha, Bhatura, Rumali Roti, Puri, Pizza, Samosa, Kachori, Matthi, Papad, Paratha, Paysam, Jalebi, Ghewar, Sawaian, Chikki, Vattayappam, Palappam, Sattu, Noodles etc.
Durum Wheat	Porridge, Rawa Idli, Rawa Puttu, Khichdi, Chapati etc.
Dicoccum	Godi Huggi, Payasam, Sweet Pan Cake etc.

Hard Wheat Product: Bread
Bread is most common preparation of wheat. It is an only food product which provides nutrients (carbohydrates, proteins and vitamins B and E) to the world population than any other single food source. Three general types of bread viz., leavened, flat and steamed are prepared from refined flour-water dough. These breads differ from each other on specific end-product properties, processing conditions and grain quality needs. Grain quality characteristics for various bread types and other wheat-based baking products are shown in Table 4. Hard to medium-hard grain is preferred for the manufacture of leavened breads. This is because when hard wheat is milled, there is greater starch damage and more granular flour is obtained. Damaged starch absorbs more water and consequently produces rising of loaf during baking. Mechanised bread-making process requires hard to medium-hard wheats for the mechanised production of leavened breads, such as pan-type bread and hamburger and hot-dog buns. Manual or semi-mechanised way of bread making requires medium-strong doughs which are suitable for making French-type and flat-type breads, such as Arab baladi bread, Indian chapati, and Mexican flour tortilla. Soft wheats, which produce weak doughs, may be suitable for Asian steamed breads. In India, common food preparations made from wheat flour are mentioned in Table 3.

Table 4 : Wheat Quality Characteristics for Various Food Types

Type	Grain hardness	Grain protein (%)	Gluten (dough) strength type
Leavened breads
Pan-type, buns	Hard	>13	Strong-extensible
Hearth, French	Hard/Medium	11-14	Medium-extensible
Steamed	Hard/Soft	11-13	Medium/Weak
Unleavened (flat) breads
Arabic	Hard/Medium	12-14	Medium-extensible
Chapati, tortilla	Medium	11-13	Medium-extensible
Crackers	Medium/Soft	11-13	Medium
Noodles
Yellow alkaline	Medium	11-13	Medium/Strong
White	Medium/Soft	10-12	Medium
Cookies, cakes, pastries	Soft/Very soft	8-10	Weak/Weak-extensible

(Adopted from Pena RJ 2002)

Soft Wheat Products
In soft wheats, the starch molecules are less damaged during flour recovery and hence are inert to water, thus, rising does not take place. In preparing soft wheat-type products, the development of dough viscoelasticity is prevented by the addition of high proportions of sugar and fat in the baking formula. Even small amount of damaged starch molecules during flour recovery is highly undesirable in cookies and cake / pastries making flour as it may reduce considerably the expansion capacity of cookie doughs. This is the reason why the cookie and cake industries use soft wheat flour, which has a minimum mechanically damaged starch and, consequently, low flour water absorption.

Flour Noodles
Flour noodles are widely consumed in East Asia and are a staple food in northern China. The consumption of instant, dried and steam pre-cooked noodles is increasing in the Western countries. Noodles can be categorised in to two basic types: white salted noodles (WSN) made with flour, salt and water and yellow alkaline noodles (YAN) are made with ingredients of WSN and include alkali (roughly 1 g of alkaline salts/100 g of flour) to develop their characteristic yellow colour. Flour used for preparing WSN has more protein content and gluten strength than flours used for producing YAN.

Biscuits
Most biscuits can be prepared from flour, which has low quantity of protein and has a gluten content that is weak and extensible. Thus flour with protein level of less than nine per cent is best and levels of more than 9.5 per cent often create processing problems. High protein in the flour leads to hardness of texture and coarseness of internal grain and surface appearance. Biscuits may be classified in various ways viz., based on the texture and hardness; based on the method of forming dough and dough pieces e.g. fermented, develop laminated, cut, moulded extruded, deposited, wire cut, co-extruded etc. and the enrichment of recipe based on fat and sugar.

Physical and Genetic Characteristics of Grain affecting End-product Quality
Grain Hardness: Is a measure of force required to break a mature grain. Hard wheat required more force for milling than soft wheat. When hard wheat is milled, starch molecules get greater damage than soft wheat. In soft wheat due to less damage of starch molecules, water absorption is fairly minimum, thus, rising does not takes place.

Cultivated hexaploid or ‘bread’ wheat (Triticum aestivum L., genome AABBDD, 2n=6x= 42) can be classified as soft or hard wheat depending on the force required to crush its grains. Soft wheat has soft endosperm texture and requires less energy for milling. Kernel texture has long been associated with a group of ~13 kDa proteins termed ‘friabilin’ due to their abundant association with water-washed starch from soft friable grains, scarce in hard wheat and complete absence in durum. Kernel texture in wheat is a highly heritable trait, with the two major texture classes controlled by the Hardness (Ha) locus on the short arm of chromosome 5D. This locus contains the genes Puroindoline a and Puroindoline b (Pina-D1 and Pinb-D1) that encode the main components of friabilin, PINA and PINB and the gene Grain Softness Protein-1 (Gsp-1), encoding GSP-1. In hexaploid wheat, the tight linkage among these three genes (Pina-D1, Pinb-D1 and Gsp- D1) is associated with soft kernel texture phenotype. Both Pin genes have been deleted from chromosomes 5A and 5B during the evolution of tetraploid wheat that resulted in the loss of the softness-conferring PIN proteins in durum wheat; consequently durum has very hard kernel texture. In hexaploid wheat, both the Pina and Pinb genes are required to be in their wild state for grain softness.

Storage Protein Sub-units
Wheat end-use quality is influenced by the quality and quantity of wheat gluten proteins. Gluten contributes about 80-85% of the total flour protein and it is comprised of two prolamine groups, gliadins and glutenin. The glutenins, in turn, are long chains of polypeptides linked by disulfide bonds, and comprising further of low molecular weight glutenin subunits (LMW-GS) which is about 40% and high molecular weight subunits (HMW-GS) which is about 10% but still have a major influence on the bread making properties of flour. The HMW-GSs designated as Glu-A1, Glu-B1 and Glu-D1 are encoded by multi-allelic genes located on the long arms of chromosomes 1A, 1B, and 1D respectively. Allelic variation in HMW-GS composition was found strongly correlated with differences in bread making quality.

Wheat storage proteins have long been used as genetic markers for identifying wheat varieties, characterising genetic diversity, and predicting bread-making quality. Allelic variations of wheat storage proteins, which directly form a part of wheat gluten, provide a basis for studying relationships between the particular gluten proteins and wheat’s bread-making properties. Studies have suggested that ‘soluble’ or non-prolamin proteins, i.e. mainly albumins and globulins, which influence bread making quality, are linked with chromosome 3A. DNA chips containing the major wheat storage protein alleles, is the future of making breeding for quality improvement easier. Thus, in breeding for improved bread-making quality, it might be better to breed for improved protein composition than to breed for higher protein concentration.

Glutenin Sub-units and Chapati-making Quality in India
Cultivars with a protein content of about 130g kg-1, a gluten content of about 120g kg-1 and an SDS sedimentation value around 75 ml were found to be excellent for chapati making. In contrast to this, wheat varieties with protein subunits 2+12, a protein content of about 115g kg-1and SDS sedimentation value around 55 ml has poor chapati making quality. The varieties with IB/IR segment released in late 90s are thought to be poor in chapati making, however, systematic studies found that the presence of the 1BL/1RS chromosome had no adverse effect, and rye unadjusted Glu-1 score showed a good correlation with chapati quality. In general, cultivars having 5+10 subunits with 1BL/1RS chromosome were found to be quite suitable for chapati making.

Breeding Implications for Complex Inheritance
Despite the different growing and harvesting conditions, the dough parameters of the wheat were highly significantly correlated between the different environments resulting in high heritability values, suggesting that the genetic component represented the largest amount of total variation. The quality parameters having high heritability values make it possible to select effectively for these traits in a breeding programme. Pronounced segregation and continuous variations suggest that several genes with major or minor effects are involved in the phenotypic expression of these traits. Indeed, the number of QTL detected was between eight for thousand kernel weight and 10 for kernel hardness. However, reports suggesting single or fewer major genes detected or estimated might include the genetic background, the population size, the number of environments and/or the marker coverage.

It is thus clear that most of the important traits influencing end-use quality traits have complex inheritance and realisation of genetic gain for these traits is difficult. However India still made a tremendous contribution in developing wheat varieties which are suitable for different end-products.

Table 5. Product-specific Indian Wheat Varieties

Product	Wheat Varieties
Chapati	C 306, Sujata, Lok 1 , RAJ 1482, HD 2189, HW 2004, Raj 3077, DW 162, HD 2967, HD 2285, HD 2987, PBW175, RAJ 3765, GW 273, GW 322,
Bread	PBW 343, Raj 3077, HD 2786, Gw 276, HD 2967, DBW 17, HI 977, HD 2733, DWR162, HD 2932, PBW 533, HD 2864, HD 2781
Biscuit	Sonalika, PBW 373, UP 2425, PBW 496, HS 277, NW 2036
Pasta Products	HI 8498, WH 896, Raj 1555,

Role of Nutrients on end-use Product Quality
Varietal differences were observed for hardness score, sedimentation value and protein per cent. These differences have genetic basis as discussed earlier. However, what is more important that environment is equally important for these traits. Fertiliser applied in the form of vermicompost and NPK showed significant difference for sedimentation value and protein per cent. Vermicompost application significantly enhanced the concentration of micronutrients (Fe, Zn, Cu and Mn). Application of urea at the time of heading though does not impact yield significantly, it improves the protein content in the seed.

(Yadav is principal scientist and corresponding author, Kumar and Gaekwad are scientist, division of genetics, Indian Agricultural Research Institute, New Delhi. They can be reached at rajbiryadav@yahoo.com)