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The recipes of 50 multi-ingredient dishes consumed by the population in an urban district were noted down. The nutritional value was determined as well as the cook value of the dishes in order to evaluate the severity of the thermal treatment. The recipes were simple and involved steps such as boiling, mixing, and cutting. Fibre contents were rather low except when the leaf stems were included. All the dishes had very high beta-carotene content (15.8-25.0 mg/100 g dry matter) and retinol activity equivalent (RAE) (1.3-2.3 mg RAE/100 g dry matter) because of the high proportion of fresh leafy vegetables (from 41.2% to 58.8% of the total dry matter of the ingredients). When meat was added to the preparation, the micronutrient content (iron, zinc, and retinol) was not increased significantly. In three dishes, a positive correlation was found between the thermal treatment severity and the 13-cis-beta-carotene amount.

Ben-kida and ben-saalga are popular pearl-millet-based fermented gruels in Burkina Faso. A survey of 318 households in Ouagadougou (Burkina Faso) showed that they are often used as complementary food for young children. Pearl millet and gruels, sampled in 48 production units, were analysed for proximate composition, factors reducing nutrient bioavailability (phytate, insoluble fibres and iron-binding phenolic compounds), alpha-galactosides, sugars, total lactic acid and d-lactic acid, zinc and iron contents. The effects of processing of pearl millet into fermented gruel are discussed. Both positive effects (e.g. a decrease in factors reducing nutrient bioavailability or alpha-galactosides) and undesirable effects (e.g. considerable lipid, protein, iron and zinc losses) were observed. Lactic acid was produced during processing and d(-)-lactate was detected in all samples. The gruels had very low energy density, even after addition of sugar, and low lipid, protein and mineral contents, well below recommendations for complementary foods.

The process of red sorghum malt production was monitored three times in five production units (PU) selected upon their ability to produce malt flours having a high capacity to fluidify high-energy-density gruels. Raw, germinated and degermed seeds were analysed for macronutrient, soluble sugars, phytate and cyanide contents and alpha-amylase activity. Know-how differences between producers lay mainly in the duration and type of equipment used for steeping and germination. Moreover, three PUs applied a maturation step before sun-drying and one PU added ashes to steeped seeds before germination. No significant difference was detected in the proximate composition of malts from the five PUs. For all PUs, traditional malting increased the protein content and decreased the lipid and ash contents, while the fibre content was not affected. Significant increases in sugar contents and in alpha-amylase activity were observed but in variable proportions from one PU to another. The phytate content decreased significantly in all PUs. The cyanide content increased in all PUs but more drastically or less drastically according to the PU. Finally, degerming lowered the cyanide content to an acceptable level for human consumption. The between-PU variability may be due either to the nature and origin of the raw seeds or to technological know-how differences between producers. Further investigations are needed to optimize and standardize the malting process with a view to maximizing alpha-amylase and phytase activities and minimizing the variability of their biochemical characteristics.

Numerous studies have been carried out to investigate energy density and consistency of gruels for infants in developing countries. However, starch-rich gruels have a complex rheological behavior and their consistency is difficult to characterize. Many published gruel viscosity data are available, but the lack of standardized viscosity measurement procedures makes comparisons and interpretations difficult. The influences of viscometer type and viscosity measurement conditions on gruels prepared with simple or multicomponent flours were assessed in this study. The results showed a drastic decrease in apparent viscosity when the shear rate increased. Other factors like shear time and gruel temperature also had a marked influence on apparent viscosity. For two types of gruel (maize or multicomponent flour) prepared at different concentrations, correspondences between a short qualitative description of the consistency and apparent viscosity values obtained with several viscometers in different measurement conditions are given. Finally, recommendations are put forward on techniques to obtain valid data on gruel consistency, adapted to each type of study (laboratory, field or large-scale surveys).

In free living conditions, 24 breastfed infants, aged 6 to 10 months, were given successively five experimental gruels to study the effect of energy density (ED) and sweetness (sweet taste) on energy intakes (EI). Four gruels (G0, G1, G9 and G20) were prepared with experimental flours which were composed of the same local ingredients and which contained different levels of sucrose. The fifth gruel (GC) was prepared with an industrial flour. G0 had an average ED of 45 kcal/100 g (189 kJ/100 g) and the other gruels an average ED of 110 kcal/100 g (461 kJ/100 g). Although the sugar contents of the flours were 1% for G1, 9% for G0 and G9 and 20% for G20, because of flour composition and gruel dry matter content, the gruel G1 had the same sweetness as G0, G20 the same sweetness as GC and G9 a sweetness between that of G1 and G20. The results show that the amounts of G0 consumed were significantly higher than those of high ED gruels (7.84 for G0 vs 6.12, 5.63, 4.46, 4.72 g/kg body weight/meal, respectively for G20, G9, G1 and GC, P < 0.05). However, EI from high ED gruels were significantly (P < 0.001) higher than those from G0 (6.65, 6.10, 4.86, 4.83 kcal/kg/meal, respectively for G20, G9, G1 and GC vs 3.46 for G0). Energy intakes from G9 and G20 gruels were not significantly different but were significantly higher than those from GC and G1 (P < 0.001). So, consumption of sweet gruels with high ED and composed of local ingredients increased, at least by 76%, the EI from gruels in comparison with those from low ED gruels, but the amounts consumed by the infants remained too low to cover more than 15% of their daily total energy needs.

Forty market samples of locally produced (33) and imported (7) cereal-based flours used for complementary feeding in some African countries and Vietnam were studied in order to characterise their macronutrient content and, when prepared as gruels, their viscosity, energy density, and osmolality. The results show that less than half were fairly balanced with respect to their protein and lipid content. When prepared as gruels following the manufacturers' instructions, out of the 21 locally produced flours with complete instructions, ten had energy densities too low to provide sufficient energy to complement breastmilk for 9-11-month-old infants even at three meals a day (< 77 kcal or 322 kJ/100 g), nine were satisfactory if fed more than twice a day, and two if fed twice a day (> 116 kcal or 485 kJ/100 g). Two of the 11 with acceptable energy density had osmolality values higher than those reported in literature for complementary feeding (< 660 mOsm/kg H2O). In addition, when prepared as gruels with viscosities within the range of viscosity (1 to 3 Pa.s) usually observed in African countries, 14 of the 32 (44%) locally produced flours had insufficient energy densities to meet the energy requirements of infants even at three meals a day. These results call for greater concern and effort towards improving the nutritive value and energy density of cereal-based complementary foods produced in developing countries.

The biochemical changes occurring during growth and storage of two yam cultivars (Dioscorea rotundata cv. Oshei and Dioscorea dumetorum cv. Jakri) were studied. Tubers were harvested at monthly intervals from the fourth to the tenth month after 50% emergence of the planted yam sets. For storage studies, Oshei and Jakri tubers were harvested 9.5 and 9 months post-emergence, respectively. These were stored under prevailing tropical ambient conditions (18-31 degrees C, 62-100% RH) for 1,2,3 and 4 months. All samples were analysed for dry matter, crude protein, carbohydrate, essential amino acids and mineral contents. The maximum dry matter was reached in both cultivars 9 months post-emergence, being 40.4 and 26.4%, respectively for Oshei and Jakri tubers. This was judged to be the optimum time for harvesting. Starch reached maximum values of 86.7 and 78.3 g/100g, respectively after 6 months. Ethanol-soluble sugars declined from 9.4 to 2.3 g/100g in Oshei but remained constant at over 6.0 g/100g in Jakri tubers during growth. Crude protein values increased slightly to a maximum of 5.4 and 8.0 g/100g, respectively for Oshei and Jakri tubers. During storage, weight losses reached 31% in Oshei tubers and 35% in Jakri after 110 days due to sprouting and dehydration. Starch decreased by approximately 3.5-4.5 g/100g while sugars and fibre values increased slightly in both cultivars.