CHAPTER ONE
1.0    INTRODUCTION
Yam is another crop cultivated across Nigeria. It is a seasonal crop and very difficult to preserve as it tends to rot. Nearly all Nigerians consume yam on regular basis and in large quantities particularly the Yoruba tribe in Nigeria. Nature allows yam to form a bond when it pounded or beaten in a mortar, it is then consumed as a meal with a choice soup. Pounded yam is a staple food consumed by the indigenous process of pounding yam is very laborious. It requires physical pounding by one or more people.
Depending on the quantity in the mortar, in a bid to reduce the labour involved in yam pounding came the manufacturing of Herbert mixer, the Kenwood mixer and Hammer mill in early 1975. These intended yam pounders failed due to some limitations in their operational functions. The Herbert and Kenwood mixers had almost the same operational principle and they had been identified for poor pounding due to the flapping (moving up and down) of their stirrer or mixer which is keyed to the electric rotating shaft. In addition to the poor pounding of both pounders, the Herbert mixer was found to heat excessively and as a result, the machine has to be stopped intermittently for cooling purpose.
1.1    HISTORICAL BACKGROUND
Yam belongs to the class of carbohydrate type of food and had been one of the oldest recipes known to man. It has been a major food crop in many of the African/Caribbean’s countries  such as Ghana, Ethiopia, Benin Republic and Nigeria in particular. Also, in some other parts of the world like Brazil, India, Oceania and Latin American, yam is a major source of food.
The word “yam” was derived from the wolof word “nyam” which is a Portuguese name meaning “to taste”. Also, in other African language, it can mean “to eat” e.g. in Hausa “nyam”. This perennial herbaceous crop is of different species such as white yam (dioscorea-rotundata) yellow yam (dioscorea-Acayenensis), water yam (dioscorea alata) and trifoliate yam (dioscorea-dumentorum). The fruit of yam consists of a membranaceous, three-wing capsule. The yam family is mostly of the weak-stemmed vines with large, under ground food storage organs-tuber-rhizomes.
Yam has found its use in the preparation of steroid hormones by syntax synthesis of cortisone from yam extract. Also, its lower glycemic index than potatoes product accounts for its more sustainable energy and better protection against obesity and diabetes.
According to the food information network in 2008, it was estimated that the world production of yam in 1993 was at 28.1million tons in which 96% of this estimate was from the West Africa tropical regions and 71% from Nigeria. This figure was later reviewed in 1998 accounting for about 72.4% of the world total production of 29.6million tones. Also, according to the Federal Office of Statistics, Nigeria is the world largest producer of yams having the water yam (dioscorea alata) and the yellow yam (dioscorea rotumdata) as her most cultivated species of yam.
Yam, been one of the most sumptuous meals can be prepared in diverse ways. While the Yoruba tribe may prefer its dried, milled and then made into a slightly solid paste called “Amala”, the Igbos would prefer cutting the tuber into smaller blocks or bits, boiled and eaten in order to avoid the tedious nature of pounding the boiled yam which results to bond formation like the Nigeria locally prepared fufu. However, the process of meshing or beating something into pulp or powder with repeated heavy blows is known as pounding.
Yam has remained one of the most highly regarded food products in West Africa and particularly Nigeria as virtually all her ethnic groups feed on it; hence its close integration into socio-cultural, economy and religious aspect of life such as marriage where some tubers of yam are presented to the bride family in accordance to the customs of the people. Also, there is the new yam festival which marks the harvest and eating of the newly harvested yams and are also used as sacrificial and appreciation items.
However, the background of this study originated from the desire of a Nigerian family of four who spent majority of his career life in the United Kingdom (Bristol, England) in the medical field who came back home and needed to adopt to his home culture which he found pounded yam very sumptuous meal but the rigorous processes involved in the traditional method which he also observed to be unhygienic and the noisy effect of the process due to the number of strokes during pounding to be uncalled for.