Production Of Yam Flour
Yam flour, derived from the processing of yams, undergoes several stages to transform the raw tubers into a versatile and convenient culinary ingredient. Beginning with the selection of high-quality yams, typically of the Dioscorea species, the tubers are thoroughly cleaned to remove dirt and debris. Subsequently, they are peeled, sliced, and thoroughly washed to eliminate any residual impurities. The sliced yams are then subjected to either boiling or parboiling to soften them, facilitating the subsequent drying process. Following this, the softened yam slices are dried either through sun drying or mechanical drying methods, such as using industrial dryers, until they achieve the desired moisture content. Once sufficiently dried, the yam slices are milled into a fine powder, resulting in yam flour. This flour can be further processed into various forms, including instant yam flour or instant pounded yam flour, catering to diverse culinary preferences and enhancing the accessibility of yam-based products. With its nutritional richness and culinary versatility, yam flour serves as a staple ingredient in many traditional and contemporary dishes, contributing to food security and economic sustainability in regions where yams are cultivated extensively.
The project dealt on the production of yam flour from yam chips. The yams were
peeled and washed, 100grams samples coded sample A to G were subjected to
two different drying conditions. Some were dried using the sun drying method
while the others were dried through oven drying method kept at constant
temperature of 500C, sodium bi-carbonate was added to some of the samples, all
these were done to obtain a flour with the best colour and texture quality. From
the results obtained, it was observed that sample B (yam boiled with sodium bi-
carbonate and dried with oven) gave the best result and quality when tested with
hot water, this was as a result of the drying condition used, the constant
temperature maintained and the presence of the sodium bi-carbonate used which
helped in achieving the result. Generally, the samples dried through the oven
drying method at 500C gave better colour and result of the yam flour when tested
with hot water more than other samples dried by sun drying and this was due to
the stability in temperature in the oven drying method used.
Title page
Certification
Dedication
Acknowledgement
Abstract
Table of content
CHAPTER ONE
1.0 Introduction 1
1.1 Background of study 1
1.2 Statement of problems 2
1.3 Objective of the study 4
1.4 scope of the work 5
CHAPTER TWO
2.0 Literature Review 6
2.1 Yam 6
2.1.1 Origin and Cultivation of yam 6
2.1.2 Water yam 7
2.2 Agronomic characteristics of yam 9
2.3 Component of yam 9
2.4 Utilization and processing of yam 11
2.4.1 Processing of yam flour 11
2.5 Flour 12
2.5.1 Etymology 13
2.5.2 History 13
2.5.3 Composition 13
2.5.4 Bleached and unbleached flour 14
2.6 Types of flour 14
2.6.1 Yam flour 15
2.6.2 How to buy flour 16
2.6.3 How to store flour 16
2.7 Drying 18
2.7.1 Drying behavior 19
2.7.2 General principle 20
2.7.2.1 External conditions 22
2.7.2.2 Internal conditions 23
2.7.2.3 Drying Mechanism 24
2.7.3 Drying techniques and dryers 25
2.7.4 Modeling of drying curve 29
2.7.4.1 Mathematical modeling of drying curves 31
2.8 Weighing Machine 33
CHAPTER THREE
3.0 Methodology 34
3.1 Materials and Reagents 34
3.2 Equipments Used 34
3.3 Procedure 35
3.4 Determination of Moisture Content 37
CHAPTER FOUR
4.0 Result and discussion 38
4.1 Effect of total time on drying yam samples 38
4.2 Effect of batch size on the drying temperatures 40
4.2.1 Rehydration characteristics 41
4.3 Colour 41
CHAPTER FIVE
5.0 Conclusion and recommendation 44
5.1 Conclusion 44
5.2 Recommendations 45
Reference 47
Appendix A: Nomenclature and definition 48
Appendix B: Calculation of moisture content 50
INTRODUCTION
1.1 Background Of The Study
Yam (dioscorea spp.) is a multi-species crop that originated principally from Africa
and Asia before spreading to other parts of the world (Hahn et al.,1987). It
belongs to the family of dioscoreae within the genus dioscorea and serves as a
staple crop in west Africa.(Asiedu et al., 1992). There are many cultivars of yam,
though only six are important as staple foods in the tropics. the economically
important species grown are Dioscorea rotundata(white yam),D.alata (yellow
yam),D.bulbifera (aerial yam), D.esculenta (Chinese yam) and D.dumenterum
(trifoliate yam). Yam tubers which is the most important part of the plants can be
stored longer than other root and tuber crops. This ensures food security even in
times of general scarcity. Yam is the third most important tropical root and tuber
crop after cassava and sweet potato (fu et al., 2005). West Africa is the leading
producer of yam and grows over 90% of the worldwide production (40 tonnes
fresh tuber/year) followed by the west Indians where Jamaica is the leading
producer (FAOSTAT,2004). Nigeria is the world’s largest producer of yams
followed by Ghana, ivorycoast and togo (FAO,2003). Both fresh tubers and yam
flour are now exported from Ghana and Nigeria to developed countries such as
united kingdom and united states of America. These are mostly patronized by
emigrants from growing regions according to the Nigerian export promotion
council (NEPC) Nigeria realized N56 billion in 2007. Sustainable production and
utilization of yam are important steps in enhancing food security and alleviatind
poverty particularly in west Africa where it is estimated to provide more than 200
dietary calories each day for over 60 million people (Nweke et al.,1991., FAO
2002).
Yam is consumed in different forms,mainly boiled,fried or baked.tubers are often
dried and milled into flour for various product,boiled yams,poundes yams and
amala are the forms of yam mostly consumed in west Africa especially Nigeria and
benin (Akissoe et al.,2001). Yam production faces many constraints among which
are production cost (mainly planting material and labour cost),post-harvset
losses(low yields). Water yam (Dioscorea alata) posses a higher multiplication
ratio and tuber yields as well as better storability than the preferred indigenous
species such as D.rotundata, D.alata is popular and prevalent abakaliki agro
ecological zone of ebonyi state Nigeria where it is called ‘Mbala or Noula’ (igbo
names) (Udensi et al.,2008) even though D.alata is also eaten boiled,it is less
preferred to D.rotundata varieties. D.alata can also be processed into flour and
reconstituted into fufu though generally D.alata contains less sugar and has an
extended shelf-life (Raemackers,2001) which ensures availability in times of
scarcity.it is also known for its high nutritional content,with crude protein content
of 7.4%,starch content of 75-84% and vitamin C content of ranging from 13.0-
24.7mg/100g (Osagie.1992).breeders are therefore kein to improve the food
quality of the species as it has good agronomic characteristics.
1.2 STATEMENT OF THE PROBLEMS
The principal problem in yam production that has been identified is the high
cost of seed yam, high labour requirement, diseases, pest as well as high post
harvest losses(Orkwor 1998).another constraint to yam production is the limited
processing technology. About 30% of harvested yam tubers are lost to waste. The
bulkiness of fresh transport and low margins for both farmers and traders are
thus a matter of serious concern in the urban market (Cooke et al.,1988).
During the processing of yam through sun-drying method,the problem
encountered is the loss due to potential contamination of the product variability
in drying time, rain damage and so on. Ohweever, D.alata fresh texture is usually
not firm as the D.rotundata (white yam) and less suitable than other species for
the preparation of the most popular food product from yam in the west Africa
region(Wireko-manu et al.,2011).
Finally, during the production of flour from yam, in the western part of
Nigeria (the yorubas), the yam flour produced which is called “AMALA” is
normally brownish in colour and dark in nature, hence does not have a good
quality and colour. Technologies therefore have been discovered to bring about
the production of yam flour that has a high quality and a good colour and texture.
1.3 OBJECTIVE OF THE STUDY
1.3.0 MOTIVATION
The growing need for the variety of food in Nigeria has become a primary concern
for the urban and rural households in Nigeria. In recent times, the concern has
raised much researcher’s interest to do related studies. As reported in many
different studies around the world, food security is a common problem.
1.3.1 OBJECTIVES
The present study aims at carryout an experiment on fresh yams, optimize the
drying parameters and investigate the effect of drying conditions on the quality of
the yam. To result to this, the present study which will address particular issues1.4 SCOPE OE THE WORK
To carryout drying experiment on fresh yams and optimize the drying
parameters.
To determine the effect of drying on the quality properties
Process the yam samples into chips and carryout approximate analysis of
the fresh and dried samples.
Production of flour from the yam chips
Compare flour samples in terms of colour and texture evaluation
food drying could stimulate producers, farmers, agriculturists, educational
practitioners on the phenomenon of drying to enhance the quality of yams to
solve past harvest losses.1.4 SCOPE OE THE WORK
To carryout drying experiment on fresh yams and optimize the drying
parameters.
To determine the effect of drying on the quality properties
Process the yam samples into chips and carryout approximate analysis of
the fresh and dried samples.
Production of flour from the yam chips
Compare flour samples in terms of colour and texture evaluation
Production Of Yam Flour:
Yam flour, also known as yam flour or elubo in Nigeria, is a popular staple in many West African countries. It is made from yams, which are peeled, sliced, and processed into a fine powder. Yam flour is commonly used to prepare a variety of dishes, including amala, fufu, and porridge. Here is a simplified outline of the production process for yam flour:
Ingredients and Equipment:
Yam tubers
Water
Knife or yam peeler
Cutting board
Drying equipment (e.g., sun drying or mechanical dryer)
Grinding machine or mill
Sieve
Packaging materials
Production Steps:
Yam Selection:
Choose mature and healthy yam tubers for processing. Avoid yams with bruises, cuts, or signs of rot.
Peeling:
Peel the yam tubers to remove the skin using a knife or a yam peeler. Ensure that the yam flesh is clean and free from dirt or blemishes.
Slicing:
Slice the peeled yams into thin, uniform slices. This can be done manually or with the help of a slicing machine. Thinner slices will dry faster.
Drying:
There are two common methods for drying yam slices:
a. Sun Drying: Spread the yam slices on clean, flat surfaces, such as mats or trays, in a sunny location. Turn the slices regularly to ensure even drying. Sun drying may take several days, depending on weather conditions.
b. Mechanical Drying: Use a mechanical dryer to speed up the drying process. This method is more efficient and hygienic, especially for large-scale production. The temperature and drying time will vary depending on the type of dryer used.
Milling:
Once the yam slices are completely dried and brittle, grind them into a fine powder using a grinding machine or mill. The resulting powder is yam flour.
Sieving:
Pass the yam flour through a fine sieve or mesh to remove any remaining coarse particles or impurities. This step helps achieve a smooth and uniform texture for the flour.
Packaging:
Package the yam flour in clean, airtight containers or bags to prevent moisture and contaminants from entering. Label the packaging with necessary information, such as product name, date of production, and expiry date.
Storage:
Store the yam flour in a cool, dry place to maintain its quality and shelf life. Properly sealed containers will help preserve the flour for an extended period.
Yam flour is versatile and can be used in various recipes to prepare traditional West African dishes. It is essential to maintain good hygiene throughout the production process to ensure the safety and quality of the final product.