Organisation:The Central Research Institute for Field Crops, P.O.Box. 226, Ulus, Ankara,Turkey
Author: Taner Akar, Muzaffer Avci and Fazil Dusunceli
Edited by AGST/FAO: Danilo Mejía, PhD, FAO (Technical), Emanuela Parrucci (HTML transfer)

CHAPTER XXXI - Barley: Post-Harvest Operations

Preface

1 Introduction

1.1 Socio economic impact of the crop

1.2 World Trade

1.3 Primary Product

1.4 Secondary and Derived Product

1.5 Quality Assurance

Preface

Barley is grown in about 70 million hectares in the world. Global production is 160 million tons. Developing countries accounts for about 18 % (26 million tons) of total barley production and 25 % (18.5 million hectares) of the total harvested area in the world. Barley grain is mostly used as feed for animals, malt, and food for human consumption. Malt is the second largest use of barley. Farmers also use barley straw as animal feed in West Asia, North Africa, Ethiopia, Eritrea, Yemen, the Andes region and East Asia.

Crop quality and post harvest operations are very important for human nutrition in dry areas, on the other hand economic development and farmer revenue for more humid areas. In the developing countries, farmers are mostly too poor to afford any loss of production.

In general, barley is more productive and its yield is more stable against seasonal variation than wheat and most of other small grains. Therefore, resource poor farmers tend to prefer barley production. Successive poor production seasons leads farmers particularly those of poor to replace wheat with barley for the aforementioned reasons. In dry years, barley flour is mainly used for bread making or it is added to wheat flour to make bread (Oluç, 1946). The barley crop is considered as a kind of guarantee against very low yield or crop failure risks.

Due to the fact that barley crop is utilized for animal feed as well as human nutrition, poor production and any kind of loss after harvest adversely affect farmers' livestock production and consequently socio-economic conditions.

Growing crops and protecting them until consumption have been the major preoccupation of mankind since the inception of agriculture. Storage is an essential interim operation in the food pipeline that moves crops from producer to processor and foodstuffs from processor to consumer. It equilibrates the quantitative fluctuations derived from the imbalance of supply and demand. Hunger today may be threatening the lives of about 800 million people in the developing world, with approximately 60% of them living in Asia. People may suffer from food shortage or malnutrition heavily, especially in the poorest countries where agricultural production is never in surplus, where facilities for storage are lacking, and in regions subject to extreme climatic fluctuations from one year to the next (Navvaro, 1997).

While post harvest production systems and post harvest losses are largely controlled by market imposed political and economical conditions in developed countries, ecological factors play more decisive role in those systems and losses in the developing world. In developed countries qualitative aspects of food loss are of greater importance than the quantitative ones. In these countries cereal grains are stored in large centralized storage facilities or on-farm in bulk. Under these conditions quantitative losses are generally at low levels and therefore further loss reductions are not cost effective. Losses of biological origin such as grain or insect respiration, or limited drying due to aeration of grain in storage are common. These losses on an annual basis are usually less than 1%. Developing countries are characterized by small scale farming where deficiencies in handling and storage methods, and very often warm and humid climatic conditions promote rapid deterioration of the stored foodstuffs. In developing countries the major portion of grain and pulses (sometimes up to 80% of the national production) is kept on the farms for home consumption. Post harvest losses in food grains in developing countries have been estimated conservatively during the 1980s as 10-15% by the FAO's Special Action Program for the Prevention of Food Losses. However, actual losses may be higher in certain areas depending on storage types and conditions. For example, losses of corn due only to insects in farmers' stores in Nigeria, Swaziland and Kenya, were estimated to be in the order of 6-10% (Navarro, 1997).

1. Introduction

Barley (Hordeum vulgare L.) is one of the most important cereal crops in the world. It is widely grown fourth cereal and among top ten crop plants in the world. Barley was mainly cultivated and used for human food supply in the last century but nowadays it is significantly grown as animal feed, malt products and human food respectively. In addition, barley is very well known as a model crop for plant breeding methodology, genetics, cytogenetics, pathology, virology and biotechnology studies (Hockett and Nilan 1985; Hogberg, 1987).

Barley is mainly produced in unfavorable climate and soil conditions of the world. Wide adaptation to these conditions mentioned above, versatile utility mainly for animal feed and food and superiority for malt and beer industry as a raw material are the main reasons that enable barley to be commonly cultivated crop plant over centuries. Barley is cultivated in highly diverse regions of the world from 330 m below sea level near the Dead Sea in the Middle East up to 4200 m on Atipano and the Andes in Bolivia.

Fertile Crescent of the Middle East consisting of Turkey, Iran, Iraq and Lebanon has been reported as original area of cultivation and most likely origin of barley, the most ancient crop of cereals (Harlan, 1979). According to the excavations, barley was domesticated in the Nile River Valley of Egypt at least 17.000 year ago (Wendorf et al., 1979).

1.1 Socio economic impact of the crop

Barley is very important cereal in terms of 132 million tons production, 55 million ha acreage and 2.4 t/ha yield in the world (Table 1.1.1). Barley production is generally and drastically affected by environmental and seasonal conditions. Considering the reasons, production, acreage and yield data are reported below as a-three year average. It is clearly seen from Table 1.1.1. that nearly 74% of world barley production is met by ten leading countries during the last three year period (1998-00).

The largest producer country was Canada with 4.2 million hectare acreage and 13.1 million ton production in the world. 10 % of world barley production is met by only Canada. France together with Germany has the highest yield level (6.4 t/ha and 5.9 t/ha) while Russian Federation together with Ukraine has the lowest one (1.4 t/ha and 1.8 t/ha).

Seven out of ten leading barley countries are in Europe and Eurasia (Russian, Federation, Germany, France, UK, Spain, Turkey and Ukraine), two of them (USA and Canada) are in Northern America and the last one is in Oceania (Australia). World barley production trend from 1961 to 2000 with an average of a-ten-year period is summarized in Table 1.1.2. If it is compared in terms of area harvested, production and yield level criteria, in spite of the fact that there are some decline in terms of area harvested (18%), both production and yield level have increased by 33% and 61%, respectively.

1.2 World Trade

World barley grain export is totally 20 million tons and its value is 25 billion $ as average of three years between 1998 and 2000 (Table 1.2.1). Europe is the main exporter with 12.3 million tons barley grain export and 1.5 billion $ value. It is followed by Oceania, North and Central America and Asia. Leading barley grain exporting countries are France, Australia and Germany and Canada with 4.8, 3.6, 1.8 and 1.7 million tons, respectively in the world. These leading countries mainly export malting barley and naturally get more money due to 20-30 % of price superiority of malting barley grain over feeding barley.

World barley import is almost equal to the export in terms of amount and value with 19.5 million tons and 2.6 billion $, respectively (Table 1.2.2). On the contrary to export, Asia continent is the main importer with 10.7 million tons and 14 billion $ value and it is followed by Europe and Africa (Table 1.2.2). Saudi Arabia, China, Japan and Bel-Lux are the four leading importer with 4.3, 2.1, 1.5 and 1.4 million tons, respectively in the world. Generally Asian and African countries import feeding barley both for animal and human consumptions.

1.3 Primary Product

Barley is mainly used as feed for animals. Barley grain is also very important source for malt and food for human. According to Bhatty (1993), barley is predominantly consumed for feeding animals even in some European countries such as Germany, France, UK, Denmark and Italy (Table 1.3.1). Ratio of the feed consumption changes from 70% (in UK) to 89 % (in Canada). The trend shows some variations, but globally 70% of barley production used directly or indirectly for feeding animals. Highly diverse regions of the world where maize can not be cultivated due to short growing period, cool temperature in spring and rainfall deficiency and higher evaporation, barley is predominantly grown as principal feed grain (Poehlman, 1985). Turkish highlands characterized with 1500 m altitude and severe cold and long winter period are a good example for this issue. A survey conducted on two provinces (Sivas and Kayseri) located in Turkish highlands indicated that barley is mainly grown (87 %) for animal feeding and according to the economical analysis result it is the most profitable crop for this purpose (Bayaner et al., 1993). 

Barley with maize, oat and wheat is one of the most common feed grain of the world. If used as feed, its grain should be ground or cracked to improve efficiency in a given ration. It is overwhelmingly considered as carbohydrates and protein sources in livestock feed. Protein content, which is strongly affected by environmental conditions where barley is grown, changes from 10 % to 15%.

In addition to this, annually 5% of world production is generally retained for seed. Barley straw is used for animal bedding in developed countries but also for animal feeding especially in rural areas of developing countries. Mix cropping with vetches is another practice for quality forage production for grazing or cutting for making of hay or silage.

1.4 Secondary and Derived Products

The second largest use of barley grain is for malt. Globally, 30 % of the world barley production is used for malting purpose and 70 % for feed use. In addition to barley, wheat and rye are also malted but barley grain has been preferred to other grains. The reasons why barley is commonly used for malt are its husk protecting the coleoptiles during germination process and filtering, firm texture of barley grains and tradition. 90 % of malted barley is utilized for malting beer and the remainder for food substitutes. Table 1.4.1 clearly shows that barley malt can be substituted in to a lot of food stuffs such as biscuits, bread, cakes, desserts, etc.

Traditionally, barley is very important food crop plant in the semi-arid regions of Africa (Morocco, Algeria, Libya and Tunisia), Middle East (Saudi Arabia, Iran, Iraq and Syria), highlands of Nepal, Ethiopia and Tibet, Andean countries of South America (Peru and Chile) and in some Asian counties (China, North Korea and Himalaya).

Morocco is leading country in terms of food consumption in the world with 88.3 kg per capita (Table 1.3.1). Barley has also some by-products that can be used for various purposes. The most valuable by product is the straw which is used mainly for bedding in developed countries but also for animal feeding in developing and under-developed countries. Brewer's and distiller grains and sprouts from malting barley also have desirable protein level for animal diets.

Table 1.3.1: Feed and Food use of Barley in Some Countries (1)
Countries	Feed use (% of Total)	Countries	Food use (kg-person /year) (1986-88)
Canada	89	Morocco	88.3
Turkey	88	Ethiopia	19.0
Denmark	87	Algeria	18.1
Spain	87	Afghanistan	15.4
Finland	86	Iraq	11.5
Italy	86	Tunisia	10.6
France	85	Libya	8.9
Sweden	85	Korea Rep.	7.5
Norway	81	Iran	7.1
Austria	79	Poland	6.1
Switzerland	79	Peru	4.8
Ireland	78	Japan	1.1
Germany, FDR	72	Netherlands	0.9
UK	70	New Zealand	0.9
(1) Bhatty, R.S.  (1986). Non-malting uses of barley. In ‘Barley: Chemistry and Technology’. Chapter: 8, P:355-418.

 

Table 1.4.1: Food Uses of Malt as By-product (1)
Food Stuff	Colour	Enzyme	Flavour	Sweetness	Nutrition
Biscuits and crackers	X	X	X	X	X
Bread	X	X	X	X	X
Breakfast cereal			X	X	X
Cakes	X		X	X	X
Dessert	X		X
Ice cream	X		X
Malted food drinks		X	X	X	X
Meat products	X
Sauces	X		X	X
Soft drinks	X		X	X	X
Type of malt products used	Soluble Extract (SE)	SE or flour	SE or flour, flake	SE	SE flour, flake
(1) From : Bamforth, CW, and Barclay, A.H.P., (1993). Malting Technology: the uses of Malt. Page: 298. Barley: Chemistry and Technology. A.A.C.C .Inc. St. Paul, Minnesota, USA.

 

Due to the fact that barley grains have higher soluble dietary fiber and lower low density lipoprotein (LDL) content than that of wheat, some food manufacturers now favor barley as an excellent food stuff (Oakenfull, 1996). Soluble fiber has a cholesterol lowering property and LDL cholesterol is the fraction associated with increased risk of heart diseases. Considering these two important factors, a lot of hull-less barley have been registered specially for human consumption and its acreage has been increased even in the western countries such as Canada (Bhatty,1986).

In fact, although barley is used mostly as mixtures in flours for bread making either due to lower price of barley compared to wheat or due to its nutrition value. Similarly, barley malt and its extract are used in various types of commercial breads in Turkey and many developing countries. Such breads can include various ingredients. For example ‘Diva' light form bread contains wheat flour, Wheat bran, Malt extract, Roasted whole malt flour, Warm water, Ascorbic acid (Vitamin C), Regular yeast, Salt (Diva unlu mamuller sanayii, Demirlibahçe, Ankara, Turkey). Various recipes containing barley products for human consumption in developing countries are described by Saari & Hawtin (1977). Some of these are given in the Annex. Intensive efforts are also made for promotion of barley as major human food in developed countries because of its valuable nutrition properties. Various Canadian recipes for use of barley as human food in the form of whole bread making and main dishes are described at www.albertabarley.com/recipes. Barley is also used for production of soft drinks in the form of barley juice in some developing countries such as in India (Kochar, 1981).

1.5 Quality Assurance

Grain quality is the most complicated trait and affected by many factors. Some of the criteria that are required by feed and malt industry are as follows:

1.5.1 Cultivar:

Uniform germination is a key point during malting process. Therefore, all grains used should originate from a single variety. This also applies to grains used for feed purposes, but in this case cultivars with same color can be stored and then easily used for feed making in the industry.

1.5.2 Moisture:

Low moisture content below %12 is the optimum moisture level and facilitates long term storage of barley grains in many developing countries, including Turkey. However, in the northern part of the world known as humid weather conditions, 16% of moisture is permitted.

1.5.3 Grain size:

Thousand kernels weight is a good indicator of mean kernel size. In addition to this, there is another specification for two and six rowed malting barley cultivars. For this 85% of grains should be retained on a 2.5 mm sieve and be free from extraneous matters. Test weight is also used for an indicator of grain and samples having 70% and higher test weight should be preferred especially for effective storage.

1.5.4 Protein content:

Low protein content is preferred from 9% to 12% for brewing and distilling purposes. Farmers can get more premiums if they apply suitable rate of nitrogen. So, contracted farming system between private malting companies and farmers is a common procedure in many countries to guarantee desirable protein level and grain size. In contrast, higher protein ratio with lysine amino acid is required by feed industry.

1.5.5 Modification capacity:

The grain lots finally should have ready and even modification potential with sufficient enzymes to mobilize the endosperm. This means that the grain has 95% and higher germination capacity and a starchy endosperm.

1.5.6 Microbial infections

Mould, yeast and bacterial infections are main sources of microbial infection. However, the most important one is fungi that their infections generally occur under field conditions. The main fungal species that infect grains in the field are Alternaria spp., Helminthosporium spp., Fusarium spp. and Cladosporium spp. During storage, these tend to decline and are replaced by species of Aspergillus and Penicillium that are able to grow under lower temperature. These fungi cause toxic effects when consumed both human beings and animals. Thus, malt and feed factories prefer to purchase barley grains free from microbial infections. Pest issues are discussed in section 4.

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