Development of Soya-based high-protein-vitamin A rich flour to be used as a supplement in porridge of young children
Oiye, S O
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This study aimed at developing and testing the stability and acceptability of a proteinvitamin A rich flour supplement. The flour mixture, as a nutrient supplement, can be added to complementary foods rich in energy but deficient in protein and vitamin A. Vitamin A deficiency is a public health problem, lacking in most common diets. ~-carotene (the pro-vitamin A) from common sources can be added to such foods and stabilised using locally available natural stabilizers. A flour-based product containing 64% soya bean flour, 7% dried meat powder and 29% carrot flour was formulated. Soya bean flour is a protein rich legume and compared to animal-source foods, is a cheap source of proteins. However, animal source foods are implicated for rapid cognitive and physical development, and was included in small amount in form of meat (beef powder). Carrot powder was added as a locally available ~- carotene source. The formulated flour was analysed for proximate and ~-carotene content. The product was also tested for acceptability in a consumer study involving caregivers. To preserve (stabilise) the product, rosemary spice was added to the formulation at rates of 0, 0.1, 0.2, 0.3 and 0.4% based on weight of the flour. The product was stored at 35° C and analysed for ~-carotene and microbial stability. For rancidity development, the flour mixture was stored at 550C- accelerated shelf life study. ~- carotene was analysed every two weeks for a maximum period of 7 weeks, microbial analysis was on weeks 2, 5 and 7, while the rancidity tests were carried out at intervals of 2 days until rancidity was detected. Acceptability tests on consumers were done using a cross-sectional consumer survey with 297 caregivers (mothers) in Kangemi slums. Sixty caregivers were also used for sensory evaluation of porridge made of 7% maize flour containing 3 grams of the supplement per 100g of the porridge. Sensory procedures developed by Mounts and Warner (1980) were modified for testing the odour and taste flavour changes due to autoxidation of the lipids in the soya flours. The developed flour had 37.70 ± 0.61g protein, 16.60 ± O.OOg lipids, 29.00 ± 0.64g carbohydrates, 2.50 ± 0.03g ash, 3.80 ± 0.08g moisture, 10.S0 ± 0.02g fibre and 22.S0 ± O.l9mg ~-carotene per 100g of the flour. When 3g per of the flour was added to maizebased 100g porridge daily, the flour could provide about 20% of the Recommended Daily Allowance for vitamin A. When rosemary spice was added and ~-carotene content monitored, the control with no rosemary spice recorded a significantly lower ~-carotene content than the samples with the spice (7.22± 0.10 mg/lOOg; p<O.OOS)after 7 weeks of storage at 3SoC. The sample with increasing levels of the spice namely; 0.1%, 0.3%, 0.2% and 0.4% of spice had 1O.64mg ± 0.07, 10.74 ± 0.07mg, 10.87 ± O.OOmgand 11.05 ± 0.10mg of ~-carotene respectively after 7 weeks of storage at 3SoC. It was evident that rosemary spice exhibited antioxidant effect and was able to conserve some meaningful retinol equivalents in the product. Rancidity was first detected in the control sample without rosemary spice - rancid odour on day 6 (equivalent to month 6) and flavour on day 8 (equivalent to 8 months). There after, the intensity of the rancid flavour and odour increased with the days. For samples with rosemary spice, the rancid odour was first detected in month lOin samples with 0.1 and 0.3% spice levels. Rancid flavour was detected after 10 days (equivalent to 10 months of months storage- accelerated shelf-life study) in samples with 0.3% and 0.4 % spice levels. The control sample with no spice had highest microbial load throughout the storage period. Further, the load at any given time in the same samples was above the maximum recommended of 1.0 xl06 CFU/g in foods. Samples with 0.1%, 0.2%, 0.3% and 0.4% spice had counts of 5.8 x lO''CFU/g, 8.5 x105 CFU/g, 1.1 xl06 CFU/g and 7.9 x105 CFU/g respectively. These were lower than the microbial load of the sample with no spice (1.0 xl06 CFU/g) after 7 weeks of storage. In a population sample having 59.6% and 77.8% (n=297) awareness of sources of vitamin A and proteins respectively, most (58.2%) identified porridge as a potential and suitable children food item to which the developed flour could be added as a supplement. About 38.7% suggested solid foods while only 2.4% suggested the flour was not suitable for children. Comparatively, the sample with highest rosemary spice, 0.4%, was most accepted with 34.3% of the caregivers preferring it. Sample with 0.1% rosemary spice was least preferred (7.4%). About 20.2, 8.4, and 20.5% of the caregivers preferred samples with 0.0%, 0.2% and 0.3 % of rosemary spice respectively. It seemed that people either liked samples with no spice (common and familiar) or the outright different samples (with high level of spice), and not the intermediaries. About 9.1% of the respondents rejected all the samples provided. Porridge with added supplement (containing 0.4% rosemary spice) had the highest average score of 4.22 in a 5 point hedonic scale, but score was not significantly different from other samples. It was however learned that higher levels of spice could probably score higher. The disadvantage is that the products with higher amounts of rosemary spice were the most expensive. The sample having 0.4% rosemary spice was the most expensive (Ksh 237 per Kg of the supplement) while the sample having no spice which was least costly (Kshs 147 per Kg of the flour supplement) From the results, it was concluded that an acceptable and shelf-stable flour-based product can be produced with soya bean, meat and carrots as sources of protein and ~-carotene respectively. Rosemary spice can preserve and conserve a high-protein-vitamin A rich flour supplement against ~-carotene degradation, rancidity development and microbial damage.