Fabrication Of Yam Pounding Machine

2.1.3 UTILIZATION AND PROCESSING OF YAM
Yam flour is traditionally processed by peeling, sometimes slicing parboiling in hot water (65oC) for varied time followed by steeping for 13-24houirs by sun drying to give a dry yam which is milled into flour “Elubo’. The flour is used in making a thick paste by stirring it in boiling water to produce a product known as ‘Amala’ which is eaten with stew by the consumers. Industrial process and utilization of yam includes starchy, poultry and livestock feed, production of yam using pestle and mortar is highly valued but is gradually being replaced in the market with instant pounded yam flour. Instant pounded yam flour requires short processing time and less energy.
Processed yam can be easily stored for a long period (12-18 months) if absence of moisture, hence yam is commonly processed into varying forms such as yam flour, poundo yam flour, flakes, starch chips etc. using different methods of processing. In recent years, much attention has been drawn to the quality of dehydrated food products obtained through yam processing. The lack of quality consciousness by the producers and sellers is astonishing, considering the fact that processed yam of various forms is a major staple food in the country. There are many export opportunities for Nigerian products to other countries in the West African sub region. Yam flour is one of the Nigerian food products which could be exported if produced and displayed in a more hygienic condition. Thus the result from this study will help, provide information to yam processors and marketers, to give insight information on yam processing into various forms.
2.1.4 YAM SELECTION AND WEIGHING
The whole some suitable yam tubers are selected for production, the wholesome tubers are then sorted out. During sorting, yam tubers that are disfigured during harvest are rejected and it is very important to select carefully or intern deterioration due to aging may have started. If the yam tubers have been stored for a long period of time, the enzymes that are present may have brought about deterioration due to temperature of the storage area (barn, store house, under ground etc). If the yam tubers have been exposed to some sunlight, this type of condition can lead to spoilage which may not be visible at mere looking at the yam tuber. A simple way of detecting spoilage is by scalping off the back of the yam tuber and carefully observing it, if there is internal spoilage, it will show brown or black discolouration depending on the level of spoilage.
The enzymes that can cause discolouration of yam and spoilage are polyphenoxidase (ppo), perioxide (opo), fenitic acid, flavanol dimanic acid, hexoainas phosphorylase, alcohol dehydrogenasion.
The second unit operation after the sorting of the yam tubers is weighing and it involves using a measuring balance to know the weight of the tubers.