PRODUCTION AND EVALUATION OF CASSAVA WHEAT BREAD FROM FIVE IMPROVED CASSAVA VARIETIES

In many developing countries such as Nigeria, bread consumption is expanding and there is an increasing dependence on imported wheat which depletes the country's foreign exchange (Dewettnick et al., 2008). Bread can be described as a fermented confectionary product made mainly from wheat flour, water, yeast and salt by series of process involving mixing, kneading, proofing, shaping and baking. It is an important staple food in both developing and developed countries and constitutes one of the major sources of nutrients such as carbohydrates, protein, fibre, vitamins and minerals in the diet of many people worldwide (Ogunjobi et al., 2010). The consumption of bread in Nigeria is on a steady increase because it is convenient and ready to eat food normally consumed as breakfast and sometimes lunch. It has become the second most widely consumed non - indigenous food after rice (Siddiq et al., 2009). 

Milligan  et  al.,  (2010)  defined  composite  flour as a mixture of flours, starches and other ingredients intended  to replace  wheat  flour  totally or  partially in  bakery  and  pastry  products.  Shittu  et  al.,  (2007) also  stated  that  as the  composite flours  used were either binary or ternary mixtures of flours from some  other  crops with  or  without  wheat flour. The use  of  composite  flours  had  a  few  advantages  for developing  countries  such  as  Nigeria  in  terms  of: i) the saving of hard currency; ii) promotion of high-yielding, native plant species; iii)  a  better  supply  of protein for human nutrition; and iv) better overall use of domestic agriculture production (Bugusu et al., 2001).  Composite  flour is considered advantageous  in  developing countries  as  it  reduces the  importation  of wheat  flour  and  encourages  the use  of  locally  grown  crops  as  flour  (Hasmadi  et  al.,  2014).  Local raw materials substitution for wheat flour is increasing due to the growing market for confectioneries (Noor and Komathi, 2009). Thus, several developing countries have encouraged the initiation of programmes to evaluate the feasibility of alternative locally available flours as a substitute for wheat flour (Abdelghafor et al., 2011). Moreover, the  concept of composite  technology initiated by the Food and Health Organization (FAO) in  1964  was  targeted at  reducing  the  cost  of  support for  temperate  countries  by  encouraging  the  use  of indigenous  crops  such  as cassava,  yam, maize  and others  in  partial  substitution  of wheat  flour (Satin, 1988).  The FAO reported  that  the  application  of composite flour  in various food  products  would be economically  advantageous  if  the imports  of  wheat could be reduced or even eliminated, and that demand for  bread  and pastry  products  could  be met  by  the use of domestically grown products instead of wheat (Jisha  et  al.,  2008).  The bakery  products  produced using  composite  flour  were  of  good  quality,  with some  characteristics  similar  to  wheat-flour  bread, though the texture and the properties of the composite flour bakery products were different from those made from wheat flour, with an increased nutritional value and the appearance. Apart from being a good source of  calories  and  other nutrients,  wheat  is  considered nutritionally poor, as cereal proteins are deficient in essential  amino  acids  such  as  lysine  and  threonine (Dhingra and Jood, 2001). Therefore, supplementation of wheat flour with inexpensive  staples,  such  as cereals  and  pulses,  helps  improve  the  nutritional quality of wheat products (Sharma et al., 1999). For example, the protein quality of both the cassava-soya and the cassava-groundnut breads is higher than that of common wheat bread (Nilufer et al., 2008).

Most of the studies conducted on the use of composite flour for bread making purposes (Dhingra et al., 2005;  Adeyemi et al., 2007;) were devoted to determining the effect of biological origin of flour and level of wheat flour substitution on their bread making quality while Shittu et al., (2006) were concerned with the effect of baking time and temperature on some physical properties of the cassava-wheat bread loaf but very few detailed studies concerning the nutritional evaluation of bread loaves produced from cassava wheat flour have been performed till now. Hence, the aim of this research was to assess the anti-nutrient, physical, chemical and nutritional properties of the cassava tubers, flour and bread respectively.

Cassava which has become one of the largest cultivated food products has been found to be a very good source of energy as it contains carbohydrate, dietary fibre, minerals, vitamins and ash. It is also a readily available food product and it is affordable. An inclusion of this essential raw material in bread production will aid in reducing the cost of production of bread and also provide a richer bread product containing essential nutrients.

The main objective of this work was to identify and produce cassava-wheat flour bread using five improved varieties of cassava (TME 4779, TME 419, TMS 30572, NR 8082 and TMS 93604) from Enugu state.

The specific objectives were to;

i. obtain some improved cassava varieties from Enugu state.

ii. produce cassava flour from the roots and evaluate functional composition of the flour.

iii. produce bread from the cassava-wheat flour.

iv. evaluate physical and sensory properties of the bread produced.

v. evaluate proximate, mineral and hydrogen cyanide contents of the root, flour and bread.