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Technology options for formulating weaning foods for the economically weaker segments of populations in developing countries

H.S.R. Desikachar
Central Food Technological Research Institute, Mysore, India

The need for weaning foods to feed babies from six months to two years old is now being met through commercially produced weaning foods prepared by extrusion or roller-drying processes. Weaning foods thus prepared are excellent products and meet the nutritional requirements of the infant in both developed and developing countries. However, the products as marketed are too expensive for the target groups who need such a product in developing countries. It is therefore desirable to study ways and means of developing less costly but equally nutritious weaning foods that may be within the reach of the wider population. The basic bulk raw materials for developing such foods should be locally available staple grains such as millets or other cereals and legumes, or edible-grade oilseed meals in some areas. The process or technology for production should not be sophisticated and should be highly adaptable. If possible, there should also be the possibility for choices in technologies for making such foods.

From the point of view of children's nutritional requirements, the weaning-food mix should be nutritionally well balanced in proteins and essential vitamins and minerals. It should be precooked if possible so that it can be fed to babies as a soft product by simply stirring in hot or boiling water. The fibre content in the material should be low and within permitted limits.

With the above requirements in mind, an adaptation of the process of germination or malting for developing a malted weaning food using ragi (Eleucine coracana) and green gram (Phaseolus mung) as raw materials was attempted earlier (1-4). This product was widely tested in hospitals and children's institutions and found to be well tolerated. The product is now being produced and marketed. As ragi may not be universally available, the possibility of replacing it with other cereals and millets has since been explored, and it has been found that wheat, sorghum, pearl millet, or maize could be used in its stead. The germination period would have to be longer for sorghum, maize, and wheat. Where enzyme production during malting is low, this could be made up by addition of a small amount of barley malt powder to the final mix so that the bulk or viscosity of the porridge or gruel could be brought down to the desired level.

While the malting technique is simple and useful, germination requires space and time and demands sun-drying or mechanical drying facilities for thorough drying of the germinated product. It was therefore felt that other simple technologies less exacting in these requirements should also be explored for the production of weaning foods.

The following techniques, commonly practiced in the household, were considered:

- rolling dough into a thin sheet and making chapaties or rotis by baking on a hot pan,
- extrusion of a cooked dough into a vermicelli or sheet or thin, ribbonlike product and then drying it.
- roasting dry or slightly moist conditioned grains at high temperatures for a short period to cause puffing or expansion of the grains and cooking and gelatinization of the starch.

The roasted grains could also be flaked by pounding or mechanical flaking. Chapaties made by the first method could be dried in the sun, in a solar drier, or partially on the pan and partially by aeration to a moisture level of less than 12 per cent, enabling them to be powdered. The vermicelli or ribbonlike product can be sun-dried and later ground to powder. The first two processes above are both, in a sense, age-old household versions of the modern roller- drying or extrusion process for making weaning foods.

The third technique is adopted for making puffed cereal grains, particularly from sorghum, maize, ragi, Bengal gram, green gram, etc., and also as a first step for making flaked products (poha, aval) from rice. The high-temperature roasting helps in pre-drying the materials to a large extent and therefore is ideal for places where drying facilities are not available or the weather is rainy or damp.

To explore the usefulness of these techniques for producing weaning foods, trials were carried out with weaning foods formulated from different raw materials. Chapaties or rotis were made using mixtures of legume flours {Bengal gram and green gram) and specially prepared nutritious cereal flour from wheat, maize, or sorghum with the major portion of bran removed (5). Chapaties prepared by rolling the dough and baking on a hot pan were dried in an air current for the large-scale studies. It was also found that chapaties could be baked for a longer period on the hot pan to reduce the moisture to about the 18 per cent level, after which they could be broken into pieces, dried to about 12 per cent moisture content by toasting over low heat, and then ground. The vermicelli-type product was formulated from a mixture of sorghum flour and toasted legume flours made into a dough with water, extruded through a hand-screw press, steam-cooked, dried in a current of air, and powdered. The slurry of the flour mix could also be cooked to a thick porridge or dumpling before extrusion. Using the principle of flaking, formulations were based on rice flakes (poha, aval) and puffed green gram, Bengal gram, and soybeans. Similarly, a mixture consisting of puffed pearl millet and puffed chickpea {Bengal gram) was also made.

Consumer acceptance of all the formulated weaning foods was quite good. Sweetening with about 5 per cent sugar or jaggery (crude brown sugar) powder further increased the palatability of these foods. Some of the products were found to be highly acceptable even to adult tastes and would therefore be highly adaptable for producing low-cost, balanced foods for geriatric and convalescent patients and other adults.

Some of the relative merits and limitations of the different technologies for preparing weaning foods are as follows:

Malting:

- The process allows partial predigestion of starch and protein.
- The viscosity can be reduced to any desired level depending on the extent of germination, making the process especially suitable for foods for very young babies.
- The proper aroma is developed during the kilning process.
- Phytase hydrolyses the phytin to available phosphate.
- Elaboration of vitamin C and Iysine is reported in many cereals.
- A long processing time and adequate sun-drying or other mechanical drying facilities are required.
- Debranning of the cereal or legume can be assured after the germination process.
Chapati process:
- This process can be applied to any composite mix based on cereals, legumes, millets, etc.
- Highly acceptable products are obtained with sorghum- based and wheat-based formulations.

The normal process of chapati-making practiced at home can be extended. Moisture reduction can be effected by sun-drying, by toasting at low heat, or by air currents. The process is easily applicable in households, particularly in non-rice areas where chapati-making is common. The product has high viscosity

Vermicelli process:

- The process allows full cooking and gelatinization of the constituents.
- A high moisture content is required for extrusion with a hand press.
- A long drying time is required.
- The process causes the least damage to nutritive value.
- The product has high viscosity.

Puffing by high-temperature, short-time roasting:

- This is basically a dry-condition process.
- It can be practiced even in areas where humid and rainy weather prevails much of the Year.
- Puffing is achieved by roasting in a hot medium (salt or sand) for less than one minute.
- It does not permit removal of bran, particularly from the cereal component.
- The formulation has very low moisture and can be preserved for a long period.
- The viscosity of the product is high.
- The process is particularly suitable for formulations based on sorghum, bajra, ragi, Bengal gram, and green gram.
- It is more suitable for foods for older children.
- A fine aroma is developed during puffing.

High-temperature, short-time roasting with flaking:

- This process is best suited to rice-based weaning food, as rice flaking is practiced both commercially and in households.
- It allows the mother to buy flakes and roasted legumes from the market and formulate her own mixture for baby feeding by simple mixing of ingredients.
- The roasting develops the proper aroma and can bring moisture to a low level.
- No drying facilities are required.
- There is a possibility of damage to Iysine during the roasting.
- The product has high viscosity.

As can be seen, each method has some specific merits that may make it suitable for particular localities or situations. The protein content and PER of formulations typical for each method are given in table 1. Supplementation with 5 per cent skim milk solids and necessary vitamins and minerals could increase the nutritive value of weaning foods and make them nutritionally complete. When the formulation is made at home where skim milk solids may not be available, small amounts of fresh liquid milk available in the household can supplement a weaning food made only from grains. Seventy-five grams of these foods would supply about 300 calories to an infant. These weaning foods may be made for one-quarter of the cost of conventionally prepared weaning foods.

TABLE 1. Viscosity and Protein Value of Weaning

* cP = centipoise, cgs unit of viscosity.
**. Malted cereal and green gram in a ratio of 70:30.
*** Cereal, green gram, and puffed Bengal gram in a proportion of 70:20:10.

The viscosities of the formulated weaning foods when stirred with water and boiled was, however, variable, depending on the raw materials used and the processing methods employed {table 11. Lowest viscosities were found with malted weaning foods. Even in these, those cereals with high amylase levels (ragi and bajra) gave products with very low viscosities. Weaning foods made by the other processes exhibited high viscosity, which may be a disadvantage in assuring adequate caloric intake by infants. As already indicated, supplementation of such foods with about 20 per cent malted ragi powder, or even 5 per cent barley malt powder, can reduce the viscosity to the desired level.

It is clear from the above that there is a wide choice not only of raw materials for formulation but also of technologies for manufacturing weaning foods that might be especially suitable for use in the developing world. Depending on requirements, operating capacity, and the corresponding degree of mechanization, the processes can also be varied to suit local conditions. Decentralized production and regional marketing may reduce overhead to a minimum. It would be useful to set up pilot production of weaning foods using each of the different processes so that the experience gained would be useful to all countries in the developing world.

REFERENCES

1. H.S.R. Desikochar, Weaning Food Formulations with Low Hot Paste Viscosity Suitable for Home/Village Level Application," Proceedings of the Symposium on Food Needs of Infants and Preschool Children, Madras,, India,, 1979, pp.54-61.

2. H.S.R. Desikachar, Development of Weaning Foods with High Caloric Density and Low Hot-Paste Viscosity Using Traditional Technologies," Food and Nutrition Bull. 2 (no.4): 21 (1980).

3. B. Brandtzaeg, N.G. Malleshi, U. Svanberg, H.S.R. Desikachar, and O. Mellander, "Dietary sulk as a Limiting Factor for Nutrient Intake- with Special Reference to the Feeding of Preschool Children. Ill. Studies of Malted Flour from Ragi, Sorghum and Green Gram," J. Trop. Pediat, 27: 184 (1981).

4. N.G. Malleshi and H.S,R. Desikachar, "Formulation of a Weaning Food with Low Hot-Paste viscosity Based on Malted Ragi (Eleusine coracana) and Green Gram (Phaseolus radiatus)," J. Food Sci. Technol., in press.

5. N.G. Malleshi and H.S.R. Desikochar, "Studies on the Suitability of Roller Flour Mill, Hammer Mill and Plate Grinder for Obtaining a Refined Flour from Malted Ragi (Eleusine coracana)," J. Food Sci, Technol., 18:1 (1981).

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