Comparative Assessment of the Chemical Composition of Wheat, Plantain, and Yam Flour
Chapter One
The Objective of the Study
The objective of this project study is to determine the chemical composition of antinutrients of yam, plantain, and wheat flour blends.
CHAPTER TWO
LITERATURE REVIEW
Origin of Yam (Dioscorea spp)
Yams are members of the genus Dioscorea, which produce edible tubers. They are monocots, despite occasional evidence of a second cotyledon (Lawton and Lawton, 2009). Various species of food yams are cultivated in the tropics and sub-tropics (IITA, 2002). The six most economically important species grown as staple foods in Africa are D. rotundata Poir (white guinea yam), D. cayenensis Lam (yellow yam), D. alata L (water yam), D. dumentorum (Kunth) Pax (bitter yam) D. bulbifera L (aerial yam) and D. esculenta (Chinese yam) (Onwueme, 2008). These six species constitute over 90% of the food yams produced in the tropics (Hahn et al., 2007).
In West Africa, man began to gather yams for domestic use as early as 5000 BC, i.e. during the Paleolithic era (Davies, 2007). Agricultural archaeologists estimate that true yam-based agriculture started in West Africa approximately 3000 BC, the same time it started in South East Asia (Coursey, 2007; Davies, 2007). The earliest domesticated yams in West and Central Africa included D. rotundata, D. cayenensis, and D. dumentorum whilst in South East Asia, D. alata was the first species cultivated (Coursey, 2007; Onwueme, 2008). The occurrence of large number of cultivars of D. rotundata arising from thousands of years of domestication and culture of this species in eastern Nigeria (Uzozie, 2001), lends support to the belief that D. rotundata is native to Nigeria, with its most probable place of origin at the eastern banks of the River Niger where it is the most preferred food crop (Hahn et al., 2007, Orkwor et al., 2008).
- esculenta (Chinese yam) has its origin in Indo-china. Chinese farmers have the longest production culture, dating back eighteen centuries. It is an important food in South East Asia, Indonesia, the Philippines and in the South Pacific Islands down to New Guinea. The aerial yam D. bulbifera originated both in Africa and Asia and spread to the other parts of the world. Nigeria alone accounts for 69% of world yam acreage and 78% of world production (Onwueme, 2008). The spread of yam, particularly D. alata from South-East Asia to Africa (Hahn et al., 2007) is believed to have occurred by the intervention of early agriculturalists and more recently by Portuguese and Spanish seafarers (east-west movement).
Although there is an extensive cultivation and use of D. alata in the West Indies, these cultivars appear to have arrived in the West Indies from Africa. The African species, D. rotundata and D. cayenensis were taken westward to America and have now become important food crops in South and Central America and the Caribbean (Hahn et al., 2007). The Niger and Benue river belts in Nigeria have the largest genetic base in cultivated D. rotundata. The D. rotundata is however cultivated in the West Africa zone/belt which stretches from west of the Cameroon mountains to the Bandama river in central Cote d’Ivoire (Coursey, 2007; Hahn et al., 2007). This yam zone comprising Nigeria, the Republic of Benin, Togo, Ghana, Cameroon and Cote d’Ivoire produces about 95% of the total world yam production estimated at 30.2 million metric tonnes in 1997 (FAO, 2008).
Currently the Asiatic yams, especially D. alata and D. esculenta are distributed widely in Africa. D. alata is now a major staple food in Cote d’Ivoire where it constitutes 65% of the yams grown in the country (IITA, 2005). In Nigeria D. alata comes second to D. rotundata in production and consumption. In West Indies, Papua New Guinea and New Caledonia, D. alata is the major food yam grown and consumed by the people. Similarly African food yams D. rotundata and D. cayenensis are widely grown in the Caribbean (Hahn et al., 2007).
West Africa is believed to be the home of yams due to the fact that more yams are produced and consumed in this sub-region especially Nigeria. Clearly yams are produced and eaten in three continents: Africa, Asia and South America especially North Eastern parts of Brazil and the Caribbean Islands and South Pacific. In Ghana, the yam-growing belt is very narrowly delimited within the derived savannah area. The most important areas where yams are grown commercially are Berekum-Wenchi districts, covering Banda, Techiman, Kintampo, Nkoranza and Atebubu districts in Brong Ahafo region; Northern Ashanti (Mampong and Ejura districts); Gonja and Dagomba districts; Bimbila in the Northern region; Mankessim and Bawjiase in the Central region; Asesewa in the Eastern region and Karachi, Kpando in the Volta region.
Importance of yams
The heart of yams importance is in the excellent eating quality of the tubers. Food prepared from yam is always preferred at social gatherings. Yams are excellent sources of carbohydrate energy. They provide 200 dietary calories per day to over 60 million people. They are also relatively nutritious, providing some vitamins (including vitamin C), minerals and dietary protein (Bradbury and Holloway, 2008). Virtually, all of the world’s yam production is used as food in contrast to other root crops e.g. cassava and sweet potato, which are also used for livestock feed. A consequence of the popularity of yam as food is that farmers always have considerable confidence that cash income can be obtained from yams, in addition to direct use by the family.
Additionally, yams play a significant role in African socio-cultural traditions. This role is not unique to West Africa. In various parts of Oceania, similar ceremonies and customs involving yams are an integral part of yam production. Notable in West Africa is that, the commercial importance of the crop has not eroded its traditional status. This coexistence of traditional food security and food business with respect to yam production illustrates that the strength of the long-standing tradition does not impede the realization of changes that relate to the crop’s commercial value. An example is the widespread marketing of ware yam tubers which are easy to handle, transport, and sell because price per tuber suites a wider range of potential buyers. Alongside this; the production of very large tubers for ceremonial purposes continues (Quin, 2008).
CHAPTER THREE
MATERIALS AND METHODS
Source of Materials
Yam tubers, unripe mature plantain and whole wheat grains were purchased from Ikoko market in Owo, Ondo State.
Preparation of samples
Preparation of Yam Flour
The yam tubers were washed, peeled and sliced into small pieces. After slicing, it was then blanched for 2 ½ hours, drained and sundried for 7 days. This was milled to powders in Attrition mill, sieved and packaged inside a plastic container for analysis (Figure 3.1).
CHAPTER FOUR
RESULTS AND DISCUSSION
Results
Table 4.1: Chemical Composition of Wheat, Plantain and Yam Flours
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
Conclusion
The results of the analyses revealed that the wheat four had the highest protein, fat and phytic acid values of 15.30%, 1.85% and 5.30mg/100g respectively. The fat content will make the wheat flour liable to become rancid during storage while the phytic acid (antinutrient) will prevent the absorption or bioavailability of divalent minerals such as calcium, magnesium, zinc and iron of the flour is not well processed into other food forms. The yam flour has the least protein, crude fibre and near zero value fat content. Though the protein content in plantain flour is low (3.20%), the plantain flour had the highest dietary fibre (4.60%) and ash content of 5.05% with no detected phytic acid, therefore making it a perfect flour alternative among the time flours analysed.
Recommendations
It is therefore recommended that further studies should be carried out on the antinutrient properties of the flour sample i.e. wheat, plantain and yam flour.
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