THE SOCIO/ECONOMIC IMPACT OF THE EBEDEBIRI CASSAVA AND STARCH PROCESSING FACTORY AND ITHE USES

Part 1.

Dave Ikiedei Asei

18/05/2019

Cassava Starch Processing has multiple uses, it includes food and non food uses. Today, we shall talk about non food uses of the above product, thus -

Starch makes a good natural adhesive. There are two types of adhesives made of starches, modified starches and dextrins: roll-dried adhesives and liquid adhesives.

The application of cassava in adhesives continues to be one of the most important end uses of the product. In the manufacture of glue the starch is simply gelatinized in hot water or with the help of chemicals. For conversion into dextrin it is subjected separately or simultaneously to the disintegrative action of chemicals, heat and enzymes.

In gelatinized starch adhesives, quality requirements are such that the medium-quality flours can be used. In dextrin manufacture, the demands are much more exacting: only the purest flours with a low acid factor are acceptable. Cassava dextrin is preferred in remoistening gums for stamps, envelope flaps and so on because of its adhesive properties and its agreeable taste and odour.

Dextrins were accidentally discovered in 1821 when during a fire in a Dublin (Ireland) textile mill one of the workmen noticed that some of the starch had turned brown with the heat and dissolved easily in water to form a thick adhesive paste.

Three primary groups of dextrins are now known: British gums, white dextrins and yellow dextrins.

British gums are formed by heating the starch alone or in the presence of small amounts of alkaline buffer salts to a temperature range of about 180°220°C. The final products range in colour from light to very dark brown. They give aqueous solutions with lower viscosities than starch.

White dextrins are prepared by mild heating of the starch with a relatively large amount of added catalyst, such as hydrochloric acid, at a low temperature of 80º-120°C for short periods of time. The final product is almost white, has very limited solubility in water and retains to varying degrees the set-back tendency of the original starch paste.

Yellow dextrins are formed when lower acid or catalyst levels are used with higher temperatures of conversion (150°-220°C) for longer conversion times. They are soluble in water, form solutions of low viscosity and are light yellow to brown in colour.

The following are some of the major uses of dextrins in nonfood industries.

1. Corrugated cardboard manufacture. One of the large users of dextrins is the corrugated cardboard industry for the manufacture of cartons. boxes and other packing materials. The layers of board are glued together with a suspension of raw starch in a solution of the gelatinized form. The board is pressed between hot rollers, which effects a gelatinization of the raw starch and results in a very strong bonding. Medium-quality flours are suitable for this purpose provided the pulp content is not too high.

2. Remoistening gums. These adhesives are coated and dried on surfaces, such as postage stamps and envelope flaps, for moistening by the user before application to another surface. Cassava dextrins in aqueous solution are well suited for this purpose as they give a high solids solution with clean machining properties.

3. Wallpaper and other home uses. Various types of starch-based products are used as adhesives for wallpaper and other domestic uses.

4. Foundry. Starch is used as an adhesive for coating the sand grains and binding them together in making cores which are placed in moulds in the manufacture of castings for metals.

5. Well drilling. Starches and modified starches mixed with clay are used to give the correct viscosity and water-holding capacity in bores for the exploratory drilling of oil wells or water wells. These starch products are replacing other commercial products for making the muddy materials which are indispensable for drilling wells. For this purpose a coldwater-soluble pregelatinized starch which can be made up to a paste of the required concentration on the spot is desired.

6. Paper industry. In the paper and board industries, starch is used in large quantities at three points during the process:

(i) at the end of the wet treatment, when the basic cellulose fibre is beaten to the desired pulp in order to increase the strength of the finished paper and to impart body and resistance to scuffing and folding;

(ii) at the size press, when the paper sheet or board has been formed and partially dried, starch (generally oxidized or modified) is usually added to one or both sides of the paper sheet or board to improve the finish, appearance, strength and printing properties;

(iii) in the coating operation, when a pigment coating is required for the paper, starch acts as a coating agent and as an adhesive.

Cassava starch has been widely used as a tub size and beater size in the manufacture of paper, in the past mainly on account of its low price. A high colour (whiteness), low dirt and fibre content, and, above all, uniformity of lots are needed in this instance.

An important new application of starch is in the machine-coating of magazine paper, formerly done exclusively with caseins. There are indications that cassava is particularly well suited to the purpose; however, definite specifications for the starch still have to be worked out.

7. Textile industry. In the textile industry, starches occupy an important place in such operations as warp sizing, cloth finishing and printing. Warp sizing is the application of a protective coating to prevent the single yarns from disintegrating during weaving. The size consists of an adhesive and a lubricant and is generally removed after weaving. Cloth finishing alters the "feel" of the fabric by making it firmer, stiffer and heavier. Cassava starch is also used for cloth printing or producing certain designs in various colours on the smooth surface of a finished fabric. While cassava accounted for about 20 percent of all starch for these purposes in 1937, it has been largely replaced by other starches after the Second World War.

An exception is the manufacture of felt, where cassava continues to be used exclusively in the finishing process.

8. Wood furniture. Before the Second World War the manufacture of plywood and veneer relied mainly on cassava as a glue. The basic material in this case is gelatinized at room temperature with about double the amount of a solution of sodium hydroxide. After prolonged kneading of the very stiff paste in order to give it the required stringy consistency, the glue is applied to the wood with rollers. As the presence of a certain amount of the pulp is useful, medium- to low-quality flours are acceptable or even preferable, although the presence of sand is objectionable.

Since 1945, however, the use of cassava as a glue has declined to second place owing to the increasing success of water-resistant plastics.

9. Electricity generation. The Ebedebiri Cassava and Starch factory could be bused for electricity generation. 

When operational, this plant could generate power to serve many communities in the area.

Thank God for having a visionary leader who appointed Honourable Doodei Agbabou Week. The Honourable Commissioner for Agriculture and Natural Resources who is at working tirelessly day and night to make sure that this project is completed.

Already, work on the project has reached  80% completion. Governor Henry Seriake Dickson is a visionary leader for appointing an expert in Agriculture as the Honourable Commissioner for Agriculture and Natural Resources, Honourable Doodei Agbabou Week. When you use the right person for the right position, this is the result you get.