Effect of Taro Variety and Soybean Blending Ratio on Physicochemical Composition, Functional Properties and Sensory Acceptability of Taro-soybean-carrot Based Complementary Food

Abstract

In Ethiopia about 45% of the children are undersized and about 42% are underweight, in association with protein-energy malnutrition and vitamin A, vitamin C, iron, iodine, and zinc deficiencies. To reduce the incidence of malnutrition, formulation and development of nutritious complementary food from locally and readily available crops such as legumes in supplementation with cereals or starch roots and tubers are important. This study focuses on processing of nutritious complimentary food from locally available crops such as taro, soybean and carrot, and on the suitability of locally available taro variety for processing infant complementary food. The effect of two factors, soybean blending ratio (35g, 40 g and 45 g) and taro varieties (boloso-1 and local) were analyzed using factorial design by SAS software and control and reference samples were analyzed in triplicates. In this work proximate analysis, some of anti-nutritional factors, beta carotene, some of functional properties, mineral content and sensory acceptability of samples were determined. The proximate analysis of taro based complimentary food showed energy, crude protein, crude fiber and crude fat contents were significantly (P<0.05) higher (385.90 to394.94 kcal100g-1, 21.87 to 25.30%, 4.79 to 3.59%, and 9.13 to 10.14 %, respectively) than control samples of two varieties of taro flours (349.98 kcal100g-1, 6.98%, 2.53% and 1.86%, respectively for local taro and 352 kcal100g,-16.62%, 2.29% and 1.63%, respectively for boloso-1taro). However, carbohydrate contents of the two varieties of taro (77. 23% for local taro and 77.75% for boloso-1 taro), ash content of local taro variety (5.28%) and moisture content of boloso-1 taro variety (7.68%) were higher in the control samples than soybean blended samples. There was no significant difference between energy density of commercial complementary food and soybean complimentary flour.  However, commercial infant food contains the lowest crude fiber content. Crude protein contents of all blended foods fall within the range of RDA of infant food and the energy contents were above the minimum suggested energy density 370 kcal/100 g (db). All blended foods had greater beta carotene contents than the control samples. This could be due to carrot content in the complimentary flour.  The beta carotene content of all complimentary flour met the estimated intake of beta carotene, 63–92 μg RE for breast-fed infants of aged 6–11 Months and 125 μg RE for breast-fed children aged 12–23 Months. Iron, calcium, phytic acid, total penolic, water activity and water solubility index were higher in the complimentary flour than in the control samples of taro varieties. Phytate level in taro used in this study was 33.13 mg/100g for boloso-1 and 34.79 mg/100g for local. The phytate level for soaked, blanched and roosted soybean flour was 80.6mg/100g. The availability of calcium and zinc of all products was below the critical limit in all samples analyzed. Phytate: calcium molar ratio <0.24 and [phytate][calcium]:[Zn] millmol < 0.5. Therefore this shows that phytate level in all samples was favorable for calcium and zinc absorption. Phytate: iron molar ratios > 0.15 is regarded as indicative of poor iron availability. The color acceptance of all gruel was above nether like nor dislik and below extremely like. As degree of soybean blending ratio increased, the color acceptance of the gruels from both varieties had decreased but flavor, taste, and overall acceptability increased. Overall acceptability of all complimentary flour was found to be above “neither like nor dislike” and below “extremely like”. Among complimentary flour gruel from boloso-1 taro variety blended with 45 g soybean was found to have better nutritional content, reduced anti-nutritional level and better sensory acceptability.

Keywords: Blending ratio, Carrot, Complementary w food, Functional properties, Micronutrient, Proximate composition, Soybean, Taro.