EFFECT OF MODIFICATION ON THE PHYSICAL PROPERTIES OF TIGER NUT STARCH (IMUMU)

CHAPTER ONE

1.0            INTRODUCTION

Tigernut (cyperus esculentus) is an underutilized crop which belongs to the division magnolophyta, classliliosida, order – cyperales and family cyperaceae (family) and was found to be a cosmopholitan, perennial crop of the same genus as the papyrus plant of her names of the plant are earth almond as well as yellow nut grass. (Codoemelan, 2003; Belewu and Belweu 2007).

Tigernut has been cultivated since early times for the its small tuberous rhizornes which are eaten raw or roasted used as hogfeed or pressed for its juice to make a severage. Non – drying oil (usually called chufa) is equally obtained from the rhizome. (umerie and emebli 1998).

The nut was found to be rich in myristic acid, oleic acid, lin oleic acid. In Egypt, it is used as a source of food, medicine and perfumes (De varies, 1991). Tigernut is commonly known as earth almond, chufa and chew – fa and Zulu nuts. It is known in Nigeria as Aya in Hausa, Ofio, Imumu in Yoruba and Akiausa in Igbo where three varieties (black, brown and yellow) are cultivated. Among these only two varieties because of its inherent properties like its bigger size, attractive colour and flesher.

The yellow variety also yields more milk upon extraction, contains lower fat and more protein and possess less anti – nutritional factors especially polyphenols

 (Oladele and Aina, 2007). Tigernut can be eaten raw, roasted, dried, baked or be made into refreshing beverage called Horchata De Chufa or tigernuts.

Tigernut milk is a very nutritive and an energetic drink both for young and old. It is a tremendous high in starch, glucose and proteins. Also rich in minerals like potassium, phosphorus, vitamin E and C. Tigernut milk contain a large amount of oleic acid and is cardiac preventive. (Okezie and Bello, 1998). It defend the internal mechanisms and prevents both constipation and diarrhea. Tigers have long been recognized for their health benefits on the account of their high fibre and sugar contents.

Cyperus esculentus (Tigernuts) is a perennial growing to 0.9m (3ft) at a fast rate. It is hardly to zone B. the flowers are harmaphrodise (have both male and female organs) and are pollinated by wind (Perera and Hoover 1998). Suitable for light (sandy), medium (loamy) and heavy (clay) soils and can grow in heavy clay soil suitable PH: acid, neutral and basic (alkaline) soils. It cannot grow in shade. It prefers moist or wet soil.

Edible uses; tuber – raw, cooked or dried and ground into a powder (Juliano, 1992). They are also used in confectionary, a delicious nut – like flavour (Oladele and Aina, 2007) but rather chewy and with a tough skin. They taste best when dried. They can be cooked in barley water to give them a sweet flavour and then be used as a dessert nut. A refreshing beverage is made by mixing and ground tubers with water, cinnamon, sugar, vanilla and ice.

The ground up tuber can also be made into plant milk with water wheat and sugar. An edible oil is obtained from the tuber, it is considered to be a superior oil that compares favorably with olive oil. The roasted tubers are coffee substitute (Torrie, 1996). The base of the plant can be used in salad. This probably means the base of the leaf steams.

1.1            CYPERSUS ROTUNDUS (COCO – GRASS, PURPLE NUTS)

Sedge, red nut sedge, Khmer drunk is a species of sedge (cyperceae) native to African, southern and Central Europe north to France and Austria and Southern Asia. The word cyperus derives from the Greek “Kutepox” and rotundus is from Latin, meaning “round” (Singh, 2006).

The earliest attested from the word cyperus is the Mycenaean Greek ku-pa-ro, written in linear B syllabic. Cyperus rotundes is a perennial plant that may reach a high of up to 140 cm (55 inches). The names “nut” grass and nut sedge (shared with the related species cyerus esculentus) are derived from its tubers, that some what resemble nuts, powder that is insoluble in cold water or alcohol. It consist of the types of molecules the linear and helical amyclose and the branched amylopectin (Evans and Haisemen, 1999).

Starch is processed to produce many of the sugar ion processed from. Dissolving starch in warm water gives wheat paste which can be used as a thickening, stiffening or gluing agent. The biggest industrial non – food use of starch is as adhesive in the paper making process. (Betaneur Ancona, 2008).

The word “starch” is derived from Middle English stretched; meaning to stiffen amyleom is Latin for starch from the Greek “amylon” which means “not ground at a mill”. The root amyl is used in biochemistry for several compound related to starch (Chopra et al, 1996)

1.3            SOURCES OF STARCH

Starch is the major carbohydrate reserves in plant tubers and seed endosperrm where it is found as granules each typically containing several million amylopection molecules accomplished by a much larger number of smaller amylase molecules. By far the largest source of starch is corn (maize) with other commonly used sources being wheat, potato, tapioca and rice. (Solomon and Olatunji, 2008). Amylopectin (without amylose) can be isolated from “waxy” maize starch where as amylose (without amlylopectin) is best isolated after specifically hydrolyzing the amylopectin with pullulanase Genetic modification of starch crops has recently led to the development of starches with improved and targeted functionality.

For the purpose of this project starch will be extracted from tigernuts for modification as one of the physical properties.

Starch is the most abundant storage reserve carbohydrate in plants. It is found in many different plant organs, including seeds, fruits tubers and roots, where it is used as a source of energy during periods of dormancy and re growth many of these starch – storing from example the grains of maize and rice or the tuber of cassava and potatoes and staple foods stuffs in the human diet starch is a versatile (FAO/WHO/UNO, 2005) and useful polymer not only because of the ease with which its physiochemical or enzyme modification and physical treatment (Oladele and Aina, 2007).

The very high fibre content combined with a delicious taste, make them ideal for healthy eating.

Typically, 100 g tigernuts contains 386 kcal (1635 kg) as 7% protein, 26% fats oils, 31% starch, 21% glucose. They contain  although botanically they have nothing to do with nuts. Is in other eyperaceae, the leaves spout in ranks of three from the base of the plant, around 2 – 20 cm long. The flower lead have 3.8 unequal rays. The fruit is a three angled achere (Odoemlan, 2003).

The root system of a young plant initially forms while; fleshing rhizomes, up to 25 mm in dimension in chains. Some rhizomes grow upward in the soul then form a bulb – like structure from which new shoots and roots, new rhizomes grow. Other rhizome grows horizontally or downward and form dark red – dish brown tubers or chains or tubers it prefer dry conditions, but will tolerate moist oils, it often grows in waste lands and in crop fields.

1.4            STARCH

Starch or amylum is a carbohydrate consisting of a large number bonds. This polysaccharide is produced by all green plants as an energy store. It is the most common carbohydrate in the human that and is contained in large amounts diet and is contained in large amount in such staple food. Foods as potatoes, wheat, maize (corn), rice and cassava. (Takizawa and Silva, 2004)

Pure starch is a white, tasteless and odurless, 26% fibre of which 14% is non soluble and 12% soluble.

The nut is high in oil content and the oil was implicated  as lauric acid grade oil, non acidic stable and very low unsaturated. The nuts were  valued for their nutritious starch contain, dietary fibre and carbohydrate (Sandhu and Singhu 2007).

The isolation of the starch from cyperus esculentus. (Tigernuts) tubers were easy decanted off. The nuts which are high in starch are yet to be exploited commercially because functional groups introduced in their structure help is the formulation of the products with improves characteristics (Eteshola and Oraedu, 1996). There has been no report on the properties of the starch of Tigernuts (cyperus esculentus).

1.5            OBJECTIVES

i)              To extract starch from tigernuts

ii)         To modify the starch

iii)        Determination of proximate analysis of the starch

iv)To determine the physicochemical quality of the starch