Studies on Reduction in Viscosity of Thick Rice Gruels with small Quantities of an Amylase-Rich Cereal Malt

In developing countries of Asia, including India, rice is widely used in gruel or cooked form as a first or early introductory food for infants and toddlers [1,2]. The starch granules in rice flour or rice grains not only swell on cooking but show a great propensity for taking up water (water-holding and binding). This contributes to the typical dietary bulk of a rice gruel with low caloric density per unit volume of food consumed. Older infants (over 6 months of age) and young toddlers (13 to 36 months of age) just cannot ingest sufficient amounts of such preparations to fulfil their daily energy requirements [3-6] . The formulation of high-energy (nutrient density) and low-bulk foods for young children utilizing simple and traditional processing methods, such as germination and malting, was recently proposed [7-11]. A series of studies conducted in our laboratory on malted and roasted mixes clearly indicated that the viscosity of a 10 per cent hot-paste slurry made of a mixture of individually malted and powdered wheat, bengal gram (Cicer arietinum), and groundnut (Arachis hypogaea), in the proportion 4:1:1, was significantly lower than that of the mixture in which each food ingredient was roasted [8,11, 12]. In a mixture consisting of cereals and legumes, the malted cereal constituent contributes substantially to the reduction in viscosity of a hot paste [9,13]. Although fully malted ready-to-mix (RTM) or ready-to-eat (RTE) mixes had decidedly higher nutrient density per unit volume of food than the roasted variety, the major and overriding constraints were the time, labour, and space required for their production. These, we felt, would make it too inappropriate and unfeasible a procedure to be readily adopted by rural, tribal, or slumd-welling mothers. Because of its high amylase content, 5 per cent malted barley (Hordeum vulgare) flour substantially reduces the viscosity of 15 per cent hot-paste slurries of weaning foods on the Indian market, such as Nestum, Farex, Cerelac, and Balamul [9] . We therefore hypothesized that a catalytic or small amount of any amylase-rich food (ARF) should be able to decrease the viscosity of a traditional weaning rice gruel, If this could be substantiated, it would be a useful and simple way to reduce the dietary bulk of starchy gruels. In the Gujarat region, barley is unknown. Among cereal grains, malted ragi (Eleusine coracana), bajra (Pennisetum typhoideum), sorghum (Sorghum vulgare), and maize (Zeas mays) flours have high amylase activity [9]. Since ragi (finger millet) was also unknown in this region and since bajra is a commonly consumed staple in the low-income groups, it was decided to develop an ARF from bajra and study its bulk-reducing properties on traditional weaning foods such as gruels prepared from rice flour, or flaked or puffed rice. The specific objectives of this study were: (i) to develop and standardize the method of preparation of ARF and to establish its organoleptic acceptability; (ii) to study the shelf life of the ARF; (iii) to compare the amylase activity and the viscosity-reducing properties of the ARF against those of a pure enzyme, namely, takadiastase; and (iv) to evaluate the acceptability of the rice gruels with and without ARF among mothers, and the intake of the same by infants.