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3
CASSAVA STARCH

Global Perspectives

Cassava producing countries also import starch-based products that in many cases could be produced from cassava starch. The following table indicates the value of these imports[4] (Table 20), which is of an order of magnitude lower than the value of wheat flour or maize imports. Nevertheless these imports represent fledgling industries that could grow and offer cassava-based products a long future. It should be noted that 1995 imports of glucose and dextrose were approximately two and a half times greater than in 1990. The greatest opportunities appear to exist in Asia, especially in the area of glucose and dextrose production. These products are already being made in Thailand.

Table 20
Value of imports of starch-based products in 1995

(US$1 000)

Region

Glucose and Dextrose

Dextrin and other
Modified Starches

Maize Starch

Africa

4 365

375

-

Asia

37 263

3 859

6 351

Latin America

19 221

3 589

5 765

FAO concurs that there may be active growth in the demand for starch (FAO, 2 000). The FAO study suggests that global demand for cassava starch could increase at an annual rate of 3.1 percent, while regional growth rates are expected to be for Asia 4.2 percent, Latin America 3.4 percent and Africa 2.3 percent. It should be noted that data available indicate that a number of countries do not import starch products. This may be the result of a number of countries recording starch imports as non-specific imports. In value terms the major importers of starch products are the Philippines and Indonesia (Table 21). The major importers of glucose, dextrin and maize starch listed below could also be considered to be the major candidates for developing domestic based cassava starch industries.

In some countries almost all starches could be replaced with cassava starch, while in other countries very little imported starch can be replaced. This is because starches, such as glucose and dextrose, etc., represent a broad range of products with a multitude of properties. Without information about the specifications and use of imported starches it is difficult to provide estimates of the potential market for import substitution for cassava starch as was done for the other domestic market opportunities.

Table 21
Major importers of glucose, dextrin and maize starch in 1995

(US$1 000)

Region/country

Glucose

Dextrin

Maize starch

Africa




Kenya

2 312

0

0

Cameroon

960

0

0

Malawi

265

0

0

Madagascar

260

0

0

Senegal

190

0

0

Zimbabwe

173

0

0

Rwanda

73

0

0

Burundi

68

0

0

Gabon

41

208

0

Zambia

11

0

0

Togo

9

0

0

Cent. Afr. Rep.

3

0

0

Angola

0

140

0

Nigeria

0

26

0

Asia




Philippines

19 808

1 543

2 070

Indonesia

8 820

1 038

1 432

China

3 246

5

3

Malaysia

1 959

1 088

2 191

Thailand

1 766

112

115

Sri Lanka

1 491

0

466

India

173

27

72

Latin America




Ecuador

2 459

525

739

Jamaica

2 375

77

328

Colombia

2 162

146

967

Brazil

2 050

347

575

Guatemala

1 726

43

478

Argentina

1 540

1 008

451

El Salvador

1 482

40

19

Costa Rica

1 421

39

1 034

Panama

950

118

795

Venezuela

903

523

48

Peru

841

69

54

Bolivia

607

3

0

Paraguay

449

0

0

Nicaragua

256

0

2

Haiti

0

60

9

Guyana

0

0

22

Dominican Rep.

0

585

234

A perspective on cassava starch production in Benin, Ghana and Malawi

Overview

Starch is an important raw material for a number of industries including textiles, paper, adhesives, pharmaceuticals and food. As a country becomes more industrialised, demand for both native and modified starches increases, but this demand is typically met through imports rather than locally made starch. This case study looks at the potential production of native cassava starch in Benin, Ghana and Malawi as a substitute for imported products. The first section provides specific details from these three countries. The remainder of the case study deals with general physical and economic factors that are applicable to any nation planning to establish a cassava starch industry.

The information on Benin is derived from a feasibility study carried out by CIRAD on behalf of FAO (Faure 1993). Information on Ghana comes from DFID funded studies carried out by NRI (Day et al. 1996) and (Graffham et al. 1997), and information on Malawi comes from a Canadian International Development Research Centre (IDRC) funded project carried out by the University of Malawi (Fabiano 1998).

3.1. Benin

In 1993 Benin imported 120 tonnes of starch for use mainly in textiles, adhesives and food. Most of this came in the form of native starch derived from cassava (30 tonnes from Cote d' Ivoire), sweet potato (30 tonnes from China) and cornstarch (60 tonnes from European Union). Although small amounts of starch were produced locally as by-products of tapioca and gari production, none of this starch was used by industry because potential users perceived it as being of poor quality. Imported starch costs between US$818 - US$940/tonne. Given that fresh cassava roots could be purchased for US$14- US$21/tonne, it was estimated that native cassava starch could be produced locally for between US$264 - US$343/tonne if suitable processing equipments were available. From these figures it would appear that an attractive margin exists for local cassava production. However, the market size is very small with little opportunity for significant growth and the capital investment required to exploit this opportunity would be very high. A small starch factory producing 10 tonnes dry starch per day would produce a years supply of starch in just 10 days and consume only 480 tonnes of fresh roots (national production of 1 million tonnes per annum).

In 1993 a proposal was made by a joint Beninian and Canadian company (Bencan Ltd) to establish a cassava starch factory in Ketou to produce 9,500 tonnes of dry starch per annum from 50 000 tonnes of fresh roots per annum. The projected cost of the venture was US$6.8 million (inclusive of capital investment, running costs and civil works). Bencan proposed to supply all national needs and then sell surplus to Japan and Europe to generate foreign exchange (Faure 1993). It is evident from this information that the national market for starch in Benin was too small to support a cassava starch industry. Exports might solve this problem but it should be kept in mind that the world market for starch is highly competitive.

3.2. Ghana

In 1996 the starch market in Ghana was about 4,200 tonnes (Table 22), most of this starch was imported and 60% of the market went to modified starches with high product specifications. A previous survey (Glucoset 1994) predicted that the market had potential to grow to 5,600 tonnes by the year 2 000. However, in view of the recent power supply crisis in Ghana this now seems uncertain.

Price of imported starch ranged from US$470 to US$510 per tonne for cassava and maize starch respectively. Imported maize starch based adhesives ranged in price from US$900 to US$1 260 depending on country of origin. Within Ghana only one maize starch company is operational. This company produces maize starch to order at US$700 per tonne and currently produces around 400 tonnes per annum. The owner of this company formerly produced cassava starch but switched to maize on the basis of increased durability and lower moisture content. Although the local maize starch appears expensive, it finds a ready market because the local product is not susceptible to the vagaries of the import system.

Table 22
Estimate of the starch (maize, cassava and potato) market in Ghana, 1996

Sector

Market share
(Percentage)

Metric tonnes
Per annum (estimated)

Textiles

40

1 680

Pharmaceuticals

20

840

Paper

10

420

Food

3

126

Plywood (glue extenders) and others

27

1 134

Total

100

4 200

Source: Graffham et al. 1997

Two companies produce flour-like products from cassava, which are sold as pure starch. One of these companies has a very poor track record and has difficulty marketing its product at US$350 per tonne. The other company sells an inferior grade of paperboard adhesive for US$430, which is popular with a number of users on the grounds of low price and reasonable product characteristics. In addition small amounts of cassava starch are produced as a by-product of agbelima processing (a fermented food) and are sold for the equivalent of US$320-US$470 per tonne. This product is used by several glue and textile manufactures, but is of very poor quality and only available in relatively small amounts.

In 1988 a company called Glucoset put forward a proposal for a large cassava starch factory in Volta Region to produce a minimum of 7 000 tonnes of dry starch (native and modified) per year. The proposed investment for this project was US$10 million. In 1996 this proposal was still under discussion and funds were being sought.

Currently the starch market in Ghana is quite small and dominated by modified starches with high quality specifications and thus offers limited scope for local production of cassava starch. However, there is scope to produce high quality cassava flours from dry cassava chips for use in starch-based paperboard adhesive and plywood glue extenders. This area is discussed in more detail in the section dealing with opportunities for cassava flour.

3.3. Malawi

In 1997 the market size for starch (excluding food uses) in Malawi was around 780 tonnes (Table 23). This requirement was met by importing maize starch from South Africa and Zimbabwe for US$650 per tonne. All of the manufacturers listed have relatively low specifications and could use locally produced native cassava starch or products derived from cassava starch.

Table 23
Estimate of the starch (maize) market in Malawi, 1997

Sector

Market share
(Percentage)

Metric tonnes
Per annum (estimated)

Packaging industries

33

260

Carton manufacturers

17

130

Nzeru Radio (dry cells)

17

130

Plywood

20

156

Textiles

13

104

Total

100

780

Source: Fabiano 1998

As part of an IDRC funded project, the University of Malawi has been collaborating with two local manufacturers of paperboard and Forintek Canada (supplier of wood glues) to assess the technical potential for local manufacture of cassava starch and cassava starch based adhesives for the paperboard industry. Laboratory and factory trials have shown that locally produced cassava starch can be used to replace 50 to 100% of maize starch in starch-based adhesives. Cassava starch has the added advantage of reducing the amount of sodium hydroxide (gelatinisation modifier) and borax (viscosity enhancer) required to prepare a suitable adhesive for paperboard manufacture, thus further reducing costs. While this project has been essentially a technical and laboratory based, it is hoped that the project will suggest options for commercialising cassava starch production.

Processing

There are two main methods for industrial processing of native cassava starch. There is the traditional approach favoured in India and some Latin American countries and the modern approach "Alfa Laval type" used for large-scale industrial processes in many parts of the world. A brief description of these two processes is given below with comparative advantages, costs and inputs.

In the traditional process, fresh roots are washed and de-barked before crushing in a rotary rasper (Balagopalan et al. 1988). Starch is separated from the crushed pulp before passing through a series of reciprocating nylon screens of decreasing mesh size (50250 mesh). The resultant starch milk is settled over a period of 4-8 hours using a shallow settling table or a series of inclined channels laid out in a zigzag pattern. Settled starch is sun dried on large cement drying floors for approximately 8 hours. During this period the moisture content reduces from 45-50% down to 10-12%. To achieve efficient drying, sunny conditions are required with ambient temperatures of >30°C and relative humidity of 20-30%. Dried starch is ground to a fine powder and packaged for sale.

In the modern "Alfa Laval type" process, roots are washed and de-barked, sliced and then crushed in a rotary rasper. Starch pulp is passed through two conical rotary extractors to separate starch granules from fibrous materials, and then fed via a protective safety screen and hydro cyclone unit to a continuous centrifuge for washing, and concentration. The concentrated starch milk is passed through a rotary vacuum filter to reduce water content to 40-45% and then flash dried. The flash drying reduces moisture content to 10-12% in a few seconds, so starch granules do not heat up and suffer thermal degradation.

A comparison of the traditional and modern processes for cassava starch processing is given in Table 24. The modern process has the advantage of a very short processing time and excellent product quality. However, modern factories require a high level of capital investment, are costly to operate and require highly skilled labour to maintain the equipments. In addition a reliable electricity supply must be available throughout the process.

In contrast, the traditional factory offers greatly reduced capital and operating costs at the expense of a longer processing time and some loss of quality. In practice the quality is sufficient to meet the specifications of food, pharmaceutical and textile industries in India and Latin America and thus unlikely to limit access to either national or export markets. In the traditional factory electricity is only required for rasping and filtration, while settling relies on gravity and drying using solar energy. This can be useful in areas where electricity is in short supply, and also helps to greatly reduce operating costs.

The downside of the traditional factory is the large area of land required. Another inconvenience is the need for more regular maintenance to replace mild steel, plastic and nylon parts, which are much less durable than stainless steel.

Overall it can be seen that the choice of method will depend on local conditions, availability of capital, scale of production and quality of starch required. Only Ghana would currently appear to have a sufficient market to suggest considering establishing a "modern" starch factory.

The precise specification for cassava starch will vary according to its intended application. However, starch should always be white in colour, free from contaminates and off odours. Moisture should be between 10-12%; pH 4.5 - 5.5; ash content 0.2% (max) and the granule size should be such that 99% of starch granules pass through a 100-mesh screen. Viscosity is a key parameter for determining starch quality, and its specifications vary according to use. In general a high viscosity indicates good quality whereas low paste viscosity will indicate that the starch underwent some degradation during processing.

Table 24
Comparison of traditional and modern methods of native cassava starch production

Factor

Traditional factory processing
4 000 tonnes roots/annum

Modern factory processing
42 000 tonnes roots/annum

Quantity of roots processed in tonnes

4 000 tonnes per annum

42 000 tonnes per annum

Quantity of dry starch produced in tonnes

1 000 tonnes per annum

10 500 tonnes per annum

Processing capacity (tonnes of roots per hour)

4.5 tonnes roots/hour

6.0 tonnes roots/hour

Total processing time (from fresh roots to dry starch)

2 days

1 hour

Capital cost for basic equipment (1)

US$25 000

US$2.5 million

Pay off period (2)

1-2 years

2-5 years

Minimum operating season for economic return (3)

4-6 months/year

10 months/year

Materials used for construction (4)

Mild steel to reduce costs at expense of slight discoloration of product.

Stainless steel to avoid colour problems.

Water consumption without water conservation

7.5 cubic meters per tonne of roots

5.5 cubic meters per tonne of roots

Water consumption with water conservation

3.0 cubic meters per tonne of roots

1.5 cubic meters per tonne of roots

Power consumption

20 kW per tonne of roots

75 kW per tonne of roots

Fuel oil for flash dryer

Not applicable

18 kg per tonne of roots

Sulphur for sulphur dioxide generator

Not applicable

1.1 kg per tonne of roots

Land requirement

Large space is required for settling tanks and drying yards

Small factory is compact and can be contained in one bldg.

Labour requirement

Semi-skilled labour to operate and maintain factory

Skilled labour to operate and maintain factory

Quality of starch

High quality but not as good as product from modern factory. Starch loses some quality Because of long process time.

Highest quality possible but depends on quality of roots used.

1). These figures are for basic equipment costs and exclude transportation and customs duties, civil works, purchase of land, labour and ancillary structures.

2). The pay off period will be determined by the profitability of the factory, which is associated principally to costs of raw materials, utilities and electrical power.

3). This is the minimum operating season required for the factory to provide an economic return.

4). When cassava is crushed hydrocyanic acid is released which can react with iron components in the factory to form ferricyanide complexes that give the starch a bluish shade when wet. This can be avoided by using stainless steel fittings or peelings roots, and can be reduced by using flexible plastic Pipes where possible and operating a regular maintenance schedule.

Source: Trim and Curran 1993; Alfa Laval Limited 1992 and Nivoba Engineering 1995

Growth Opportunities

The market opportunity for native cassava starch will exist to some extent in any country that is becoming more industrialised and therefore consuming more starch in various industrial processes. It is assumed that starch processing will be carried out in a factory environment because of the sophisticated equipment requirement. Dry starch can be sold by the factory direct to the end user or further processed at the starch factory. Processing may include conversion into dextrins or formulation into starch based adhesives for the paperboard industry.

The main physical factors that are likely to determine success in exploiting this market opportunity are as follows:

Road infrastructure: A good road infrastructure is required to ensure that cassava roots can reach the factory for processing within 12 hours of harvest.

Cassava supply: To produce high quality cassava starch, a reliable supply of roots with optimal maturity of 10-12 months is critical. Immature roots will have high water content and soluble sugars and less starch. Over mature roots will contain reduced amounts of starch of lower quality and high fibre.

Water supply: Starch factories require large amounts of good quality water for processing. Water used in processing should be free of solid particles, low in iron (<0.3m12 ferrous ions/litre) and as soft as possible.

Power supply: Starch is a mechanized process, so a reliable source of power needs to be provided.

This may have to be self-contained as starch factories are likely to be situated in rural, close to the cassava farms.

Access to land: This is most important for traditional factories that require a large area for settling tanks and drying yards.

Availability of skilled labour: Modern and traditional starch factories have a relatively low labour requirement, and both require efficient management. But the modern factories need highly skilled personnel both to operate and to maintain the facility.

Choice of drying method: Sun drying will reduce costs but increases processing time. Moreover sun drying can only be used if the factory is situated in an area of low rainfall, high air temperatures and low humidity. Artificial drying may seem the obvious solution, but flash drying represents the major cost burden of any modern factory both in terms of capital investment and running costs. To be economic a flash dryer must have a high loading for most of the year.

Constraints in cassava starch production

A cassava starch factory, once established could face a number of physical bottlenecks that interfere with production. These include:

Cassava supply and seasonality of supply: Starch factories require at least 20-40 tonnes of high quality fresh roots a day for a period of at least 100 days in a year to be effective. To meet these demands cassava has to be treated as a high value cash crop and grown on a large-scale. Reliability of supply could be a serious issue in an area where cassava had always been perceived as a low value, food security or marginal crop. To be effective starch factories need a long processing season with continuous supplies of roots of consistent quality. In many cases climatic problems reduce the season to between four to six months. Factories relying on sun drying face the additional difficulty of finding that, the peak season for root availability often coincides with periods of wet and cloudy weather, which are unsuitable for sun drying.

Root maturity: Starch factories have highly critical requirements in terms of root maturity. However, farmers will be tempted to harvest roots early to maximize use of available land, and may occasionally leave roots in the ground for too long in the hope of getting a better price.

Water and power supplies: These two factors are most likely to cause problem during the dry season, and limited supplies of either could disrupt processing.

Cassava: Although popular as a source of starch, cassava roots can be seen as a liability owing to their high degree of perishability and high water content (70% of fresh weight). As a result there is no margin for error in handling cassava. Also the high water content of roots introduces the added expense of transporting a large amount of water from field to factory for no useful purpose. This problem might be overcome by producing dry chips, but starch recovery and quality from dry chips is poor.

Local processing of native cassava starch is often seen as an attractive option, because it offers a means of converting a relatively low cost raw material into a high value product, which can readily substitute for imported starch. In Ghana a local producer of maize starch found that he could price his product at similar levels to the imported products. This was possible because users valued the guaranteed nature of the local supply and freedom from importation problems such as holding of safety stocks and fluctuations in international markets. Starch is also seen as a potential high value foreign exchange earner.

However, to access this market opportunity a high level of investment is required. A traditional factory would require a minimum of US$150 000 to establish. A proposal for a modern starch factory would typically budget US$8 million-US$l0 million for initial capital investment and significant amounts of additional funding to cover running costs in the first few years of production.

The potential economic bottlenecks for native cassava starch production are as follows:

Capital and running costs: Production of native starch from cassava on an industrial scale requires a high level of capital investment, followed by high running costs. Modern factories may require five years to pay off the initial investment (Table 3.5), and start providing an economic return. The risk involved in investing in starch production is high because of the number of variables involved.

Market size, access and price competitiveness: In Ghana, Malawi and Benin the national markets for starch remain small and may not grow significantly in the short to medium term. The reason could be found in a combination of macro-economic factors that limit the rate of industrialisation. Given this situation it would be difficult to imagine a modern starch factory providing an economic return by basing its supply only to the domestic market. The alternative may be to aim primarily at the export markets. It is known that cassava starch is a versatile material that competes well with maize, wheat and sweet potato starches. However, it should be realised that many markets are not completely open in nature (e.g. European Community) and also that price competition is fierce. Much of the market will be for modifie and speciality starches prepared from the cheapest raw material available. To enter any of the markets, be they national or international, the product price and quality must be competitive. Potential users will always aim for the lowest price from reliable sources.

Users perceptions of quality and reliability: In the three countries dealt with in this case study (Benin, Malawi and Ghana) industrial users of starch had attempted to reduce costs by purchasing locally prepared products. These products sold as "cassava starch" generally turned out to be either very poor quality cassava starch, produced as a by product of traditional food processes such as gari and agbelima; or low grade cassava flours that varied widely in quality from batch to batch. These products did not meet the users' specifications and led users to consider locally produced starches to be of poor quality. Hence new entrants to the market may find it difficult to persuade users that they can deliver a high quality product of consistent quality on a regular basis.

As with other market opportunities, native starch production involves a number of stakeholders who all have key roles to play in ensuring successful exploitation of the opportunity. The role of the farmer in this case is to provide a consistent supply of high quality roots harvested at optimum maturity for starch extraction. This may prove to be a novel concept for many farmers who would normally consider cassava as a food security crop that can be harvested at almost any time from 8-24 months.

The processor takes responsibility for getting the cassava to the factory within 12 hours and then extracting starch as quickly as possible. To ensure root quality the processor would be advised to provide support to farmers in terms of credit and educate farmers as to the requirements of the factory. To be successful, the processor will need a financial backer who is willing to accept the risks associated with this type of venture. The processor would also be advised to involve local research and development institutes, to collaborate with local users of starch in the development of products that make use of locally produced cassava starch. Their collaboration is necessary to maximize opportunities within the national markets.

The international market for starch seems likely to continue to grow, particularly in the area of speciality starches for novel applications in a wide range of manufacturing industries (Jeffcoat 1998). Within this context cassava is likely to continue to have a role as a source of raw material for starch production. However, a would-be entrant to the native starch market in Africa would be well advised not to rely on prediction for the international market but to give serious consideration to the potential for growth of the national market. The size and growth potential of the national market for starch will depend on the level of industrialisation and the macroeconomic climate of the nation. For example Ghana has a relatively high level of industrialisation and a good market for starch, which should expand on a long-term basis. However, in the short-term problems such as power supply crisis and general economic conditions may limit investors' willingness to invest in the expansion of the manufacturing sector. Thus limiting the potential for growth of the starch market.

There are many advantages of utilizing cassava for starch production. Cassava offers a relatively cheap source of raw material containing a high concentration of starch (dry matter basis) that can match or better the properties offered by other starches (maize. wheat, sweet potato and rice). Cassava starch is easy to extract using a simple process (when compared to other starches) that can be carried out on a small-scale with limited capital. In addition cassava starch has a high level of purity due to the low levels of proteins and lipids found in cassava roots.

Cassava starch production could have potential with sufficient supplies of raw material and a degree of industrialisation to support a national market for cassava starch. However, potential entrants to this market will only succeed if they have sufficient capital to back the venture, and can deliver reliable supplies of starch that meet the users' specifications at a competitive price. If the market is mainly for paperboard and plywood adhesives, which have low specifications, it should be possible to establish a market for products based on high quality cassava flour in place of starch. This option would have the advantage of low capital investment, simpler technology and less critical processing, whilst still creating a competitive product that can replace imported starch and starch based adhesives.


[4] It should be noted that available data indicate that a number of countries do not import starch products. This may be the result of a number of countries recording starch as non-specified imports.

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