Extending The Application of Root And Tuber Crops into Ready-To-Eat Breakfast Foods

Abstract

The demand for convenience, instant breakfast foods has resulted in importations and some local production of expensive products. Since these are generally high carbohydrate foods, exploring and diversifying the use of underutilized local food resources could provide inexpensive and interesting alternatives. This study investigated the use of locally abundant roots and tuber crops to partially substitute maize as the sole carbohydrate in the production of ready-to-eat breakfast foods. Extreme vertices mixture designs were employed to formulate blends of Cassava, Orange-fleshed sweet potato (OFSP) and Bambara groundnut flours to substitute 55% of maize in a ready to eat breakfast food. The flour blends were slurried in water in a ratio of 1:2 and drum dried at a temperature of 175 °C and a drum speed of 35rpm. The products were analysed for proximate composition, functional and physical characteristics. The in vitro protein and starch digestibility for raw and drum dried samples were also determined. Storage stability and conditions were evaluated by modelling the sorption behaviour of the precooked (drum dried) samples. Microbial load, and sensory characteristics were also determined. Generally, protein, fat and ash contents increased with an increase in bambara groundnut whereas carbohydrate and fibre content increased with an increase in both cassava and orange flesh sweet potato flour. With regards to - carotene content, an increase in OFSP substitution resulted in a significantly higher concentration ranging from 7.1mg/100g for high OFSP content to 1.5mg/100g for samples with the lowest OFSP. Product colors ranged from yellowish products with high orange sweet potato flour to creamy-white colour for samples with high cassava flour. The protein digestibility was significantly influenced by drum drying and an increase in bambara groundnut. Furthermore, the starch digestibility of the formulations was improved as OFSP increased. All formulated product fell under low glycemic foods with values ranging from 40.49±1.82 to 47.39±1.92 were observed amongst all formulations. The formulations were mostly smooth as more than 70% of the milled product passed through a sieve size of 140μm. Water solubility index, bulk density and soluble solids increased with an increase in OFSP flour substitution whilst water absorption index, oil absorption capacity, swelling power and viscosity decreased with increase in OFSP substitution. Increase in bambara groundnut increased the oil absorption capacity, emulsion capacity and emulsion stability of the formulations. Similarly, an increase in cassava flour increased the water absorption index and swelling power of flour blends. Sensory evaluation indicated significant differences (p < 0.05) within formulations in terms of colour, sweetness, and overall acceptability of the breakfast product. Generally, flours with high sweet potatoes were rated higher and flours with high bambara rated lower by sensory panellists. From this study, it can be implied that, orange-fleshed sweet potato, cassava and bambara groundnut flour are promising ingredients that can be used by processors to substitute some amount of cereal in breakfast food production in order to add value, improve nutritional composition (where OFSP will reduce vitamin A deficiency and bambara groundnut contribute protein), as well as contribute to food and nutritional security in Ghana and Sub-Sahara Africa.