ABSTRACT

The source material includes white yam, plantain (Unriped) and breadfruit. The white yam was treated to different processing methods to get 4 flour samples. The first parboiled and peeled. The second portion peeled into hot boiling water. The third portion peeled into O.2g of sodium metabisulphite dissolved in l00mins of water. The fourth peeled into salt (Nacl) solution of 5g: l00mins of water. All dried between 65 — 75°C and milled into flour differently. The plantain was peeled and oven dried at 65°C and milled into flour. The breadfruit was parboiled de-hulled and dried in the oven at 65 before milling. Each yam flour sample was blended with plantain at different ratios as well as the breadfruit sample. Sensory evaluation was carried out to get the best blend from results. The best blend of yam flour sample was the one peeled into 0.2g of sodium metabisulphite with plantain at ratio 60:40. The best of yam flour plus breadfruit was at ratio 50:50. The final blending was at 100:50:40 yam; breadfruit; plantain flours respectively. This products on proximate analysis yielded an increase in Ash content to 6:30%. Lipid content 2.75% fibre content 6.88% protein content 12.60% carbohydrate content 66.17%, vitamin A and vitamin C determined to give. l.393mg1g and 9.998mg/g  respectively. The calorific value increase to 339.83 with increasing swelling power and solubility in water. The mineral composition increased also particularly the iron, phosphorus and calcium to 2.60, 4.82 and 3.10 respectively. These results confirmed the aims and objectives of the project work titled "composite (instant) poundo". of the South Sea Islands) D. Pyrenaica (native yam of Pyreness), D. villosa (wild root of North America), D. Dumentorum, etc.Yams provide several properties nutritionally outside being a chief source of carbohydrates and starch, it can also provide ash, mineral, vitamins, some pigments, sugars, tanins and related compounds. Nitrogen substances and some enzymes. Traditionally, In Nigeria for instance, yam tubers are stored for processing into flour, chips, starches, syrups, adhesives, Microbiological media, glucose and livestock's feeds. At this point in time yam production and utilization in Nigeria is constrained by lack of technological support systems (especially storage and processing facilities). There is high loss or biodeterioration sprouting, pest damage nematode attack. A number of operations are commonly used in the processing of yam. They include peeling, drying, boiling and steaming, frying and roasting, grating, pounding, de-watering, starch extraction, grinding, milling and serving. Yam has traditional products as fufu and flour, chips besides boiling and frying for food. We are going to be more concerned with fufu because it is the most consumed popularly in West Africa. The fufu (pounded yam) is one example of a range of sticky dough or porridge — like foods. Yam fufu (pounded yam) is prepared traditionally by the use of pistle and molter with little portable water. Pound until a smooth sticky dough forms which is ready for consumption. The already prepared fufu has a low keeping quality due to a phenomenon known as "weeping" after just about 15 — 20 hours of preparation, the fufu develops a watery nature (weeping) causing the stiffening of the dough and reducing smoothness,  Rheological characteristics and thus eating equality. Several species of yam have been tested and used for fufu; several results obtained following the knowledge about the properties of a particular starch which could be used to predict the behaviour under actual cooking conditions and can equally be modified if necessary to suit products and processing needs. From about four species of yam showed viscosities obtained with Disocorea rotundata starches being significantly greater than the rest and its gel strength were also moderately high which makes the Discorea rotundata. All yam starches have relatively high water biding capacity, a characteristic feature of loosely bound granular structure. Rheological examination of starch water paste from about four species of yam showed viscosities obtained with Dioscorea rotundata starches being significantly greater than the rest and its gel strength were also moderately high which makes the Disocorea rotundata the most preferred specie for the production of fufu (Pounded yam) for which stiff dough is required Dioscorea alata exhibits a very high gel strength and considerably lower viscosity. The starches of the other two species D. esculentum and D. dumentorum were found to have both viscosity and gel strength quite low. These rhelogoical characteristics are related to the swelling and solubility characteristics of the starch as reported by Rasper 1969, Emiola and Delarosa 1981). The percent starch of a mature tuber is of the range 20-30% and their grain size and shape varies with specie which is mostly the reason for getting fufu of different consistency and texture from difference species. To prepare pounded yam (fufu), the fresh yam is peeled, inedible parts removed and the remainder cut into evidently sized pieces and boiled in portable water until soft and then pounded in a wooden mortar with pestle until the cellular and to some extent the starch granular structure is broken down A stiff and some how glutinous dough is formed. This dough is usually sufficiently firm and elastic to be cut into coherent slices. It is normally served after moulding with hand into spheriodal mass or shape with stew or soup. There is so much work stress in preparing yam fufu and because of this strainous pounding of boiled yam tuber pieces into a dough. It has become increasingly distasteful to the modern aged busy house wives and an unpopular culinary activity among urban men thus discouraging pounded yarn consumption. Mechanical aids for the production of yam fufu has been introduced though by Addis and national companies (Makanjuola 1974). The fufu produced through this means still lack the tr.adifional rheological properties of resilience and elasticity which are mandatory for consumer acceptance. Based on these problems, this project work is targeted on the study of yam and their characteristics which causes traditionally prepared fufu not to keep long due torn weeping and low to improve on keeping quality without loss of colour, to retain its traditional rheological properties of resilience and elasticity through other scientific means thereby recapturing the popularity of yam fufu in Nigeria and the would generally also it is based on the fact that I want to produce a food product which in form of fufu would be able to furnish us with nutrients from plantain (unripe), yam and breadfruit when consumed. That is, the product would have minerals, protein, carbohydrate, vitamins, fat and crude fibre enough to take care of our daily need intake to support growth, body tissue repairs and energy.

TABLE OF CONTENT

PAGE

TITLE PAGE

CERTIFICATION ii

DEDICATION iii

ACKNOWLEDGEMENT.................................iv

TABLE OF CONTENT v

LIST OF TABLES vi

LIST OF FIGURES vii

ABSTRACT viii

CHAPTER 1 INTRODUCTION 1-5

CHAPTER 2 LITERATURE REVIEW

Nutritional properties (starch).........• 6-10

Physical characteristics of yam starches 11-33

Proteins 14-15

Minerals ............................... 15-17

Vitamins 17-18

General toxic factors & miscellaneous substances 19-20

Pigments and aromatic substances 20-22

Industrial range of uses of yams 22-24

Principles of processing techniques 24-26

Origin of instant yam poundo 26-23

Selected problems in yam processing 28-3 1

Elements of pounded yam texture measured 31-38

Fundamental Rheological test 38

Dehydration of yam in piece-form 39-42

The process of enzymic browning 42-45

Control of enzymic browning reaction... . 45-48

Recent reports on chemical composition of yam tubers 48-52

Some other chemicals and toxicants of yam tuber 53

CHAPTER 3 MATERIALS & METHODS

Materials and methods of analysis .................. 54

Materials...... ..............................54

Processing methods..........................................54-58

Methodology of proximate analysis 58-61

Functional properties determination.................. 61-64

CHAPTER 4 RESULTS AND ANALYSIS

Proximate analysis... 65-66

CHAPTER 5 CONCLUSION & RECOMMENDATIONS

Conclusion and Recommendation .... 67

REFERENCES... 68-70