Physicochemical, Pasting and Sensory Properties of Yam-plantain Flour Enriched With Soybean Flour
Chapter One
Aim and Objective of the Study
Aim of the study
The aim of this study is to determine the physicochemical, pasting and sensory properties yam/plantain flour enriched with soybean flour.
Objective of the study
The objectives include the followings
- To produce the flour from yam, plantain and soybean
- To blends the flour produced in together in different ratios
- To determine the physicochemical, pasting and sensory properties of the 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 (Alexander and Coursey, 2009; 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, Coursey, 1976), 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, 2002).
- 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, 2007). 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 (Owusu and Ofori, 2009).
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).
Uses of yam
The importance of yams in the West Africa yam zone is due to the fact that for several decades, before the introduction of maize and cassava, yam was probably the main sustenance for the people (Onwueme, 2008; Coursey, 1976). The greatest competitor to yams has been cassava, which was introduced into the yam growing zone in the 16th century from South America (Carter et al., 2002); Mankind has therefore been using the yam for food since time immemorial and is still used extensively. It is an important staple food. It is also considered as a man’s crop as it has ritual and socio-cultural significance. It is the food of choice at many ceremonies and festivals, and an indispensable part of bride price (Hahn et al., 2007). The uses of yams can be categorised into alimentary; non-alimentary and industrial uses.
CHAPTER THREE
MATERIALS AND METHODS
Collection of Materials
Yam, plantain and soya bean used for this research were sourced from Emure-ile market in Owo Local Government Area of Ondo State, Nigeria. While the other equipment used for this research were from the Department of Food Science and Technology, Rufus Giwa Polytechnic Owo, Ondo State.
Methods
Production of yam flour
The yam was peeled and washed. The peeled tubers are cut to pieces with the aid of knives. The yam cubes are immediately put in water containing sodium metabisulphate (1 gm to 1 litre of H2O) sulphiting for 20minutes helps to prevent browning reaction. The sulphated yam are blanch for 7 to 10 minutes and the yam was dried in cabinet dried in cabinet drier set at between 50oc and 60oc to a moisture content of about 5.7% and it was milled.
CHAPTER FOUR
RESULTS AND DISCUSSION
Results
Table 1: Proximate Composition of Yam, Plantain and Soybean flour blends
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
Conclusion
The findings of this study indicate that the addition of yam flour, plantain flour and soybean flour blends in this study successfully produced a high protein energy food. The substitution of yam with plantain flour and soybean flour showed a remarkable improvement in the protein (6.47%- 10-15%) the formulated diet. Also the substitution at 15% of soybean increase the protein content. The increased in energy value is an indication that the food will give more energy and the increase level of protein would be able to alleviate the problems of protein malnutrition. Sensory panelist score showed that there is a significant difference in the sensory properties of 100% flour and other blends.
Recommendations
These samples, most especially at 15% level substitution is recommended for human consumption. The combination is capable of meeting the nutritional requirements of man and solving the issue of malnutrition by reducing it to the barest minimum level. Furthermore, research especially on the microbiology, mineral and antinational composition of those blends could be carried out.
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