Any native (unmodified) starch can be used - it doesn't have to be cassava starch. The purer the starch is, the better the product will be. Maltose can even be made from whole flour or roots, but the quality will be poor. In Vietnam, about 80 kg of wet starch or about 50 kg of dry starch is used per batch, to make about 50 kg of product. In Benin, about 50 kg of wet starch was used per batch, to make about 30 kg of product. Batches should not be too small because of the inter-relationship between heat losses and temperature changes during the process - a batch which is too small will get too cold too quickly.
Amylases are naturally occurring enzymes that plants use to convert their starch reserves to the sugars which are needed for early growth. In Vietnam, rice seedlings are the preferred source of the enzymes that are needed for making maltose, but maize seedlings have also been used in commercial operations both in Vietnam and Benin. Millet seedlings have also been used successfully in laboratory trials. Caution should be exercised with sorghum seedlings, because the seedlings are so poisonous.
There are many varieties of both rice and maize which can be used as the source of enzymes. Whichever cereal is selected for its enzymes, an entrepreneur should identify a suitable local variety before committing himself (herself) to setting up a factory. Suitable tests are described later.
16 kg of seedlings should be enough for each 50 kg batch. This amount can normally be obtained from about 5 kg of grain. If the best available grain has insufficient amylase, a larger quantity might be needed. For a smaller batch, proportionally less would be needed.
Various chemicals are used for lightening the colour of sweeteners. 40 g of any of the following may be used in each batch:
| Sodium metabisulphite, | Na2S2O5 |
| Potassium metabisulphite, | K2S2O5 |
| Sodium hydrosulphite, | NaHSO3 |
| Potassium hydrosulphite, | KHSO3 |
Different chemicals may also be needed for pH adjustment. If the starch is badly fermented, a little Ca(OH)21 should be used in each batch to raise the pH. pH indicator paper strips are useful, but pH control of the final product is not always necessary. If industrial customers require a particular acidity in the maltose syrup, they should be able to advise on suitable treatment.
1 Calcium hydroxide, also known as slaked lime, milk of lime.
Fuel is needed to boil liquids and to evaporate water. The quantity of fuel that is needed depends on a number of factors:
Very little water is needed for the process, but its quality will affect the quality of the end product. The water that is used should be clean, and any particles in it should be removed by sedimentation or filtration. Enough water should also be available to keep the equipment and surfaces clean.
In Vietnam, two people working full time and one person working part time can make up to 400 kg of product per day, but to do this, considerable experience is needed. Also, in Vietnam, the factory workers do not normally grow or crush the seedlings they use - the chopped seedlings are bought ready to use. In addition, if less expensive but more labour intensive equipment is installed, as is likely to be the case in a factory built before a market for the product is fully established, more labour still will be needed to make 100 kg of product. For all these reasons, in the input estimates below, 1.5 man-days have been allowed for making 100 kg of product, rather than the 0.7 man-days that are normally required in Vietnam.
| Input | Number | Units |
|---|---|---|
| Wet starch | 145 | kg or 95 kg of dry starch. |
| Labour | 1.5 | md |
| Wood | 200 | kg |
| Chopped seedlings | 40 | kg |
| Chemicals | 0.15 | kg |
| Electricity | 1 | kwh |
Depreciation and interest costs have not been included in the above estimates, because these costs depend so much on local factors. These costs prorated to 100 kg of product depend on:
the cost of equipment, which will vary depending on the type of equipment selected, the quality of its construction and the cost of materials in the country where the factory is being built. In Vietnam, for a factory in which 400 kg of maltose can be made every day, the estimated cost of the buildings in 1994 was about US$ 250 and that of the equipment also about US$ 250. Equipment is normally amortised over 5 years, and buildings over 10 years. In most countries, things generally cost much more than they do in Vietnam and the buildings and equipment may well cost ten times what they cost in Vietnam.
current interest rates, which depend on many social factors
the output of the factory, which will depend on the demand for the product. The low installation costs in Vietnam can be prorated over an annual production of 60 tonnes or more per year, far more than can be expected in the early production of a new factory in a new market.
This is an area of calculation that an entrepreneur must do for himself, using an interest rate he might expect to pay, realistic cost figures for the location where the factory is to be built and a realistic forecast for demand for the product.
Providing installation costs are kept reasonably low and regular sales can be achieved, it is unlikely that depreciation and interest costs will be very high relative to the other costs of manufacturing glucose syrup.
