By Nneka Nwogwugwu, Abuja
A food scientist, Dr. Rachael Omodamiro, has explained the different techniques farmers should adopt to achieve best results in yam processing.
Omodamiro, explained these techniques while giving a lecture on Yam Processing Technique at a recent workshop organized by the Federal Ministry of Agriculture and Rural Development at the National Root Crop Research Institute (NRCRI), Umudike, Abia State.
She said that Yams (Dioscorea spp) are among the oldest food crops andWest Africa is leading in global production of Yam among the three continents (West and Central Africa, Asia and South American) that cultivates the crop.
Omodamiro who is also a Root and Tuber processor, said that the world yam production is about 30million tons of fresh tubers per year of which over 90% are produced in West Africa (FAO, 2007) and West Africa depends on yam as a major source of their calorie intake up to one-third supply.
She said Nigeria produces 45.00 million metric tonnes annual production of yams.
The expert explained that the different forms of yams consumed in West Africa include; boiled (peeled or unpeel) and eaten with some kind of sauce; peeled, boiled and pounded into a thick paste and eaten with desire soup.
‘’Yam is also processed into flour that is used in the preparation of another type of paste. It may also be baked, fried, roasted or mashed to suit regional tastes and customs. Other specific ways of preparing yam (puree, dry chips as basic ingredients for snack,’’ she added.
While explaining the different techniques of yam processing, she said, ‘’Food processing can be defined as the application of scientific principles to the preservation or modification of foods to make safe, appealing products with a uniformly high quality.
‘’All food processes are made up of a series of steps called unit operations which have to be followed in a particular sequence in order to make the food.
‘’Processing starts with harvesting (e.g. of crops such as roots and tubers) or slaughter (e.g. of animals) and finishes when the processed foods are eaten.
‘’The only traditional method for processing yam for storage has been processing into yam flour. This process involves washing, peeling, washing, slicing, parboiling, drying, milling and bagging, but the process has not been scientifically investigated to establish the processing parameters.
‘’In Nigeria, though yams can be consumed by boiling, roasting and processed to yield Amala (especially in the South western part of the country), it can also be processed into the production of Instant Pounded Yam Flour (IPYF).’’
She said that the process of producing pounded yam is very labourious because it requires physical pounding.
However, she said, the production of Instant Pounded Yam Flour (IPYF) brings succour to pounded yam lovers as the drudgery of pounding is eliminated.
Omodamiro explained that the production process of Instant Pounded Yam Flour Technology (IPYF) include,
• Washing: The selected tubers are washed thoroughly to remove sands.
• Peeling and Slicing: The washed tubers are carefully peeled manually, with stainless steel knives. The peeled tubers are mechanically sliced to desirable thickness in a slicing machine made of stainless steel blades
• Parboiling: The yam slices are put in boiling water (parboiled) for 30 minutes, depending on the thickness of the slices.
• Drying: The parboiled yam slices are dried in a dryer at 60°C for 48 hours. The dried yam chips are stored in air tight containers before milling.
• Milling: The dried yam chips are milled directly into flour
• Packaging: The yam flour is packed into airtight moisture proof containers
• They can be quickly reconstituted into pounded yam and prepared for eating.
She also advised processors to ensure they observe quality control measures such as: Following the specification set by regulatory bodies, the Moisture content (max 12%), it should free from fecal matters and free from mould/insect.
