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UNIVERSITY OF NAIROBI

PRODUCTION OF PROTEIN ENRICHEDCOOKIES USING CASSAVA, WATERMELON

SEED AND WHEAT FLOURS

PRESENTED TO:DEPARTMENT OF FOOD SCIENCE AND

TECHNOLOGY

BY:

NAME: NZEMBEI PAUL M. MUTUKUREG: NUMBER: A24/0214/2oo6

SUPERVISOR: MR.P.O.lAMUKA

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DECLARATION

This project is my original work and has not been presented for a degree inanyother~ersity.

signed ~ ~!.l.~.7:.1.!.C?..,

This report has been submitted for examination with approval of my

:::::~.~~~~.~, .

Mr.P.O. Lamuka

Department of Food Science Nutrition and Technology.

University of Nairobi.

---~ ---

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DECLARATION

This project is my original work and has not been presented for a degree inanyother~iversity.

.' ~, Or! 10Signed.v... . 1 .,

This report has been submitted for examination with approval of my

~:::'~.~uF~·~····,··················Mr.P.O. Lamuka

Department of Food Science Nutrition and Technology.

University of Nairobi.

IIIIII

I

ACKNOWL WDGEMENT

Mv unreserved thanks IW to all members and staff in the Deoartment ofDFSTN who

contributed immensely towards making this work a success, and especially Mr P.O.

Lamuka who was so kind and sacrificed his time to attend to me. To all my classmates who

selflessly assisted me in so many ways. To my beloved parents who saw me through

encouragement and financial support .THANKS TO YOU ALL.

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TABLE OF CONTENTS.

DECLARATION 2

ACKNOWL WDGEMENT 3

ABSTRACT 5

INTRODUCI'ION 6

PROBLEM STATEMENT R

PROBLEM JUSTIFICATION 8

'I1lE Ol1E.RA.LOBJECTIVE 8

'I1lE NULL HYPO'I1lESIS 8

LITERATURE REVIEW 9

MATERIAIB AND CHEMICAlS : ]5

SAMPL"ES PREPARATION 16

AN AT.vnC.AT. MF.THOnS TTSF.n lfl

RESEARCH DESIGN A..1VDMETODOLOGY 17

~'H;;:rTT.~ .- - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - - _ _ -. ~

DISCUSSION 22

r.{)1V-rl.TT.~l{)N.- - - ~ - - - - - - - _ - _ _ _ _ _ _ 24

RECOMEMDATIONS 24

REFERENCES 25

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Page 5 0[25 5

ABSTRACTThe use of composite flour from watermelon seed, cassava and wheat in theproduction of cookies was investigated. The proximate composition and functionalproperties of the samples were determined. Quality of cookies made with theblends was evaluated by a 20-rnernber sensory panel. The watermelon seed flourwas blended with wheat and cassava flour at the ratios of 0:100, 10:90, and 20:80,respectively. The protein and fat content of (watermelon seed flour/wheat-cassavaflour !p~o ratio) was highest. Cookies (wheat-cassava flour/watermelon seed flour80:20) ranked best in sensory evaluation conducted. All cookies were acceptable,scoring above 4.00 on a o-pcint hedonic scale. Up to 20% wheat- cassava flourscould be replaced with watermelon seed flour in cookies.

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INTRODUCI10N

I

Wheat :Is the world's most consumed cereal. It is the main cereal used inproduction of baked products, mostly due to its baking characteristics like qualitygluten. Its inclusion in this research is made to promote the good bakh;g vrovertiesof the cooKies. e trend in the substitution can be extrapolated and find out thepossibilities of making cookies in wheat Sh0 ( \-<AJI! .

The approximate Nutritional composition of wheat flour in 100g is:

~4' protein 10,crude fat 1,crude fiber 0.4, ash 1.4,Moisturecontent 13, others 0.2 g

Cassava :Cassava -Manihot esculenta is a shrubby, tropical, perennial plant thatis not well known in the temperate zone. The plant grows tall, sometimes reaching15feet, with leaves varying in shape and size. The edible parts are the tuberous rootand leaves. The tuber (root) is somewhat dark brown in color a grows up to 2feet long.

ICassava thrives better in poor soils than any other major food plant. As a result,fertilization is rarely necessary. However, yields can be increased by plantingcuttings on well drained soil with adequate organic matter. Cassava is a heat-lovingplant that requires a minimum temperature of up to 30°C grow. Since manycultivars are drought resistant, cassava can survive even during the dry seasonwhen the soil moisture is low, but humidity is high.

IAround the world, cassava is a vital staple for about 500 million people. Cassava'sstarchy roots produce more food energy per unit of land than any other staple crop.Its leaves, commonly eaten as a vegetable in parts of Asia and Africa, providevitamins and protein. Nutritionally, the cassava is comparable to potatoes, exceptthat it has twice the fiber content and a higher level of potassium.The cassava used in Indies International Cassava Chips is known by the Latin nameManihot Utilisima.

IThe approx. nutritional composition cassava in 100g

Moisture content 62, CHO25, protein 2, fat 0.3. fiber 2. minerals 1.others 6.

Has been identified as the most important root crop terms of food security,employment creation and income generation for many house-holds. Its majorhandicap is the presence of cyanogenic glycosides (linamarin and

lotaustralin), However, several studies have shown that these cyanogenicglycosides are volatile and highly soluble in water and therefore easily eliminatedby processing methods such as drying, soaking, and fermentation (Cardosoet al., 1999). One study has shown that some cassava varieties are naturally lowin these cyanogenic glycosides thus enhancing their utilization in several foodformulations (Ubbor et al., 2006).

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Watermelon (Catullus lanatus) :This flowering plant produces a specialtype of fruit known by~opmists as a pepo, a berry, which has a thick rind(exocarp) and fleshy center (mesocarp and endocarp); pepos are derived from aninferior ovary and are characteristic of the Cucurbitaceae. The watermelon fruit,loosely considered a type of melon (although not in the genus Cucumis), has asmooth exterior rind (green, yellow, and sometimes white) and a juicy, sweetinterior flesh (usually pink, but sometimes orange, yellow, red, and sometimesgreen if not ripe).

Watermelon seed: Is reported to be high in protein and has excellentfunctional properties and has been found to be effective in baking (EI-Adawy,2001;Nasr and Abufoul, 2004). It is usually consumed inform offleshand the seeds discarded, yet it has high protein content that canalleviate rampant malnutrition in the area.

The approx. nutritional composition of melon seeds in 100g

CHO15,protein 29, fiber 2, ash 0.8, fat 48, moisture content 5.05

Cookies: Are small, round and flat cakes commonly called biscuits elsewhere.Traditionally, cookies are made from wheat flour but could be produced fromcassavaflour and other composites (Cock, 1985; Oyewoleet al., 1996)

Composite flour for cookies can be described as a mixture of several flours obtainedfrom roots and tubers, cereal, legumes etc with or without the addition of wheatflour. It can also be a mixture of different flours from cereal, legumes or root cropsthat is created to satisfy specific functional characteristics and nutrientcomposition.

PROBLEM STATEMENf

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• Wheat is becoming a rare commodity owing to high rate ofpopulation growth and its high consumption rate across the globe.

• Composites flours of wheat and.cassava have been made to augmentwheat in making baked based products

• Wheat and cassava ours ave Ow protein content, hence their bakedproducts. J /

• Watermelon seeds ar~..consumed due to lack of value addition,notwithstanding their richness in protein content -their flour has beenfound to have good baking qualities.-Nasr, S.l. and Abufoul, 2004

PROBLEM JUSTIFICATION

Watermelon seed is rich in protein and has excellent functionalproperties.Watermelon seeds are usually discarded off after consumption of

fleshy part. However the seeds are rich in protein content, whichusually goes to waste.

THE OVERAL OBJECTIVE

Toproduce watermelon seeds/cassava/wheat cookies

Thespecific objectives of this work are to:

THE NUll HYPOTHESIS

• To produce flours from cassava roots, wheat and watermelon seeds• To formulate flour composites of watermelon seeds/cassava, wheat and

examine their proximate composition• To examine functional properties of the composite flours• To produce cookies from the composite flours• Evaluate the quality of cookies organoletically.• Evaluate the shelf life of the cookies

Watermelon seeds/cassava/wheat cookies can be produced

II

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LITERATURE REVIEW

II

WHEAT:

Nutritional Value of Wheat (Whole Grain):Wheat grains are used tomake flour, which is transformed into doughs and then breads, which is a staplefood in every country and culture. Eating whole grains are advisable to women forstaying slim and healthy. It is rich in protein and provides daily requirement ofenergy. Works as a-&Qodlaxative. It has wide culinary uses, from the making ofbreads, pasta and cakes to fermentation of alcoholic beverages.

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Nutrition Facts and Information about Wheat: It contains Manganese,Phosphorus, Magnesium and Selenium in very large quantities. Rich in Zinc,Copper, Iron and Potassium. However, Calcium is also present in small amounts.

Vitamin Content of Wheat: It is rich in Vitamin B6, Niacin, Thiamin, fglate,Riboflavin and Pantothenic Acid.Vitamin E and Vitamin K are also present insmall but considerable amounts.

Calorie Content of Wheat: Wheat has a calorific value of 339.0per 100 gm.Being a grain, it is very appropriate in calories and hence, filling as a food.

Health Benefits of Wheat: Consumption of whole wheat is necessary for ahealthy metabolism, as it prevents Breast Cancer, Gallstones, childhood Asthmaand heart risks. Definitely an essential food to intake for women for gastro-intestinal health, also reduces risk of high blood pressure, Diabetes and highcholestrol. To add up to it all, it has phytonutrients which promotes better healththrough maintaining high blood levels.

CASSAVA

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Human food: Cassava are widely consumed wherever the plant iscultivated. Some of these dishes have regional, national, or ethnicimportance. Cassava must be cooked properly to detoxify it before it iseaten.

Cassava can be cooked in various ways. The soft -boiled root has a delicate flavorand can replace boiled potatoes in many uses: as an accompaniment for meatdishes, or made into purees, dumplings, soups, stews, gravies, etc. Deep fried (afterboiling or steaming), it can replace fried potatoes, with a distinctive flavor. Tapiocaand foufou are made from the starchy cassava root flour. Tapioca is an essentiallyflavourless starchy ingredient, or fecula, produced from treated and dried cassava(manioc) root and used in cooking. It is similar to sago and is commonly used tomake a milky pudding similar to rice pudding. Cassava flour, also called tapiocaflour or tapioca starch, can also replace wheat flour, and is so-used by some people

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with wheat allergies or coeliac disease. Boba tapioca pearls are made from cassavaroot. It is also used in cereals for which several tribes in South America have used itextensively. It is also used in making cassava cake, a popular pastry.

The juice of the bitter cassava, boiled to the consistence of thick syrup and flavoredwith spices, is called cassareep. It is used as a basis for various sauces and as aculinary flavoring, principally in tropical countries. It is exported chiefly fromGuyana.Cassava is used in bubble drinks in East Asia.Frozen cassava leaves fromthe Philippines sold at a Los Angeles market

The leaves can be pounded to fine chaff and cooked as a palaver sauce in SierraLeone, usually with palm oil but vegetable oil can also be used. Palaver saucescontain meat and fish as well It is necessary to wash the leaf chaff several times toremove the bitterness. In DR Congo the leaves are used in a stew called Pondu.

Cassava was also used to make alcoholic beverages. The English explorer andnaturalist Charles Waterton reported in Wanderings in South America (1836) thatthe natives of Guyana used cassava to make liquor, which they abandoned whenrum became available. Hamilton Rice, in 1913,also remarked on liquor being madefrom cassava in the Brazilian rainforest.

Biofuel: In many countries, significant research has begun to evaluate the use ofcassava as an ethanol biofuel feedstock. Under the Development Plan forRenewable Energy in the nth Five-Year Plan in China, the target is to increase theapplication of ethanol fuel by non-grain feedstock to 2 million tonnes, and that ofbio-diesel to 200 thousand tonnes by 2010. This will be equivalent to a substituteof 10 million tonnes of petroleum. As a result, cassava (tapioca) chips havegradually become a major source for ethanol production. On December 22, 2007,the largest cassava ethanol fuel production facility was completed in Beihai withannual output of two hundred thousand tons, which would need an average of oneand half million tons of cassava. In November 2008, China-based Hainan YedaoGroup reportedly invested $51.5m (£31.8m) in a new biofuel facility that isexpected to produce 33 million gallons a year ofbio-ethanol from cassava plants.

Animal feed: Cassava is used worldwide for animal feed as well. Cassava hay isproduced at a young growth stage, 3-4 months, harvested about 30-45 cm aboveground, and sun-dried for 1-2 days until it has final dry matter of at least 85%. Thecassava hay contains high protein content (20-27% Crude Protein) and condensedtannins (1.5-4% CP). It is used as a good roughage source for dairy, beef, buffalo,goats, and sheep by either direct feeding or as a protein source in the concentratemixtures.

Ethnomedicine: The bitter variety of Manihot root is used to treat diarrhea andmalaria.The leaves are used to treat hypertension, headache, and pain. Cubanscommonly use cassava to treat irritable bowel syndrome, the paste eaten in excessduring treatment.As cassava is a gluten-free natural starch, there have been

increasing incidences of its appearance in Western cuisine as a wheat alternativefor sufferers of coeliac disease.

Food use processing and toxicity: Cassava roots and leaves should not beconsumed raw because they contain two cyanogenic glucosides, linamarin andlotaustralin. These are decomposed by linamarase, a naturally occurring enzymein cassava, liberating hydrogen cyanide (HCN). Cassava varieties are oftencategorized as either "sweet" or "bitter", signifying the absence or presence oftoxic levels of GYPnogenicglucosides. The so-called "sweet" (actually "not bitter'')cultivars can produce as little as 20 milligrams of cyanide (CN) per kilogram offresh roots, ~s "bitter" ones may produce more than 50 times as much (1gjkg). Cassavas grown during drought are especially high in these toxins. A dose40 mg of pure cassava cyanogenic glucoside is sufficient to kill a cow. It can alsocause severe calcific pancreatitis in humans, leading to chronic pancreatitis.Cassava bread

Societies which traditionally eat cassava generally understand that some processing(soaking, cooking, fermentation, etc.) is necessary to avoid~ekHowever,consumption of insufficiently processed bitter cassava may cause konzo (also calledmantakassa), a paralytic neurological disease. A safe processing method used bythe pre-Columbian indigenous people of the Americas is to mix the cassava flourwith water into a thick paste and then let it stand in the shade for five hours in athin layer spread over a basket. In that time about 5/6 of the cyanogenic glycosidesare broken down by the linamarase; the resulting hydrogen cyanide escapes to theatmosphere, making the flour safe for consumption the same evening.

For some smaller-rooted "sweet" varieties, cooking is sufficient to eliminate alltoxicity. The cyanide is carried away in the processing water and the amountsproduced in domestic consumption are too small to have environmental .impact. The larger-rooted "bitter" varieties used for production of flour or starchmust be processed to remove the cyanogenic glucosides. The large roots are peeledand then ground into flour, which is then soaked in water, squeezed dry severaltimes, and toasted. The starch grains that float to the surface during the soakingprocess are also used in cooking. The flour is used throughout South America andthe Caribbean. Industrial production of cassava flour, even at the cottage level, maygenerate enough cyanide and cyanogenic glycosides in the effluents to have asevere environmental impact.

The traditional method used in West Africa is to peel the roots and put them intowater for 3 days to ferment. The roots then are dried or cooked. In Nigeria andseveral other west African countries, including Ghana, Benin, Togo, Ivory Coast,and Burkina Faso, they are usually grated and lightly fried in palm oil to preservethem. The result is a foodstuff called 'Gari'. Fermentation is also used in otherplaces such as Indonesia (see Tapai). The fermentation process also reduces thelevel of antinutrients, making the cassava a more nutritious food. The reliance oncassava as a food source and the resulting exposure to the goitrogenic effects ofthiocyanate has been responsible for the endemic goitres seen in the Akoko area of

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WATERMELON SEEDS

southwestern Nigeria. Historically. people economically forced to depend oncassava risk chronic poisoning diseases, such as tropical ataxic neuropathy (TAN),or such malnutrition diseases as kwashiorkor and endemic goitre.

Eating Watermelon Seeds: In Western culture, the watermelon is a fruit withwidespread appeal. As with most fruits, its seeds are almost always discarded andnot eaten, but they can be consumed, and in other parts of the world, theirconsumption is more common. In Asian and Middle Eastern countries, watermelonseeds are collected and roasted so they can be served as a snack. In Nigeria,watermelon seeds are used in certain soups. Watermelon seeds have their ownnutritional makeup,jncluding proteins, fats, iron and other nutrients. Watermelonseeds are also a source of calories.

Calories: I~108 g) of watermelon seeds, ther~::frt~ft 602 calories.Contrastedwith 1cup of cooked brown rice, which con ams on y 216 calories, /watermelon seeds are relatively high in the number of calories per gram or per--iu

Fat: Of the 602 calories in 1cup of watermelon seeds, 428 calories come from fat,whereas in the same volume of rice, only 15of 216 calories come from fat.Watermelon seeds are composed of about 50 percent oil, which helps to explain itsrelatively high fat content=gi g of fat per 108 g of watermelon seeds, or 79 percentof the recommended daily value. There are 11g of saturated fa~ in the 51g of fatand no Trans fats.

II

Protein: Watermelon seeds are composed of about 35 percent protein and are agood source of protein on a per-gram basis. In 1cup of watermelon seeds, there are31 g of protein. The protein in watermelon seeds is of reasonably high quality; ofthe nine essential amino acids, watermelon seed protein ranks highly in all but one,lysine.

Chewing the Seeds: Because of their size and hard outer coating, watermelonseeds, if not chewed or otherwise broken down before swallowing, can easily passthrough a person's digestive tract undigested. If this happens, none of the seedsand none of its nutrients are absorbed into the body. Watermelon seedsshould be chewed before swallowing ifits nutritional content is desired.IOther Nutrients: Watermelon seeds are a good source of several vitamins andminerals. Per 1 cup, watermelon seeds contain a significant amount of the followingvitamins: Thiamin (14 percent of recommended daily value), riboflavin (9 percent),niacin (19 percent) and folate (16 percent). Regarding minerals, watermelon seedsprovide calcium (6 percent), iron (44 percent), magnesium (139 percent),phosphorus (82 percent), potassium (20 percent), zinc (74 percent), copper (37percent) and manganese (87 percent).

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COOKIES

Cookies are most commonly baked until crisp or just long enough that they remainsoft, but some kinds of cookies are not baked at all. Cookies are made in a widevariety of styles, using an array of ingredients including sugars, spices, chocolate,butter, peanut butter, nuts or dried fruits. The softness of the cookie may depend onhow long it is baked.

A general theory of cookies may be formulated this way. Despite its descent fromcakes and other sweetened breads, the cookie in almost all its forms has abandonedwater as a medium for cohesion. Water in cakes serves to make the base (in the caseof cakes called "batter"l) as thin as possible, which allows the bubbles - responsiblefor a cake's fluffiness - to form better. In the cookie, the agent of cohesion hasbecome some form of oil. Oils, whether they be in the form of butter, egg yolks,vegetable oils or lard are much more viscous than water and evaporate freely at amuch higher temperature than water. Thus a cake made with butter or eggs insteadof water is far denser after removal from the oven.

There are two main types of cookies, hard and soft. Soft (soft batter)cookies contain a maximum amount of moisture. They may require agreater percentage of eggs to produce the necessary structure.Characteristics of good soft cookies are moistness and softness. Hardcookies contain a minimum amount of moisture. Desired characteristicsof hard cookies are crispness and brittleness.

FUNCTION OF INGREDIENTS USED.

Each ingredient used in cookie baking is employed for the specific characteristics ithas and/or the result it has on the finished product- If these effects are understood,the ingredients may be selected with the assurance that the products produced willbe good.

Flour -Flour is the principle structure builder or binding agent in most cookieformulas. It provides the framework around which the other ingredients aregrouped in varying proportions. Flour is a toughening agent because when it comesin contact with the liquids in the formula, the flour proteins (gluten) form the mainstructure of the cookies. Either bread flour, pastry flour or cake flour can be used tomake hard and soft cookies. Hard flour may cause some types of cookies to lackspread while cake flour may cause some cookies to spread too much. It is best touse the type of flour specified in the formula. If a recipe calls for pastry flour and itis not available, use 50 percent bread flour and 50 percent cake flour or use allpurpose flour.

Sugar- Sugar in some form is used in all cookie recipes. It is an importanttenderizing ingredient. Undesolved sugar crystals melt during baking whichcontributes to the flow or spread of the cookies.

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Shortening -Shortening promotes tenderness in the cookie and preventsexcessive gluten development during mixing. Without shortening, cookie doughwould be tough and rubbery, which would result in cookies being dry and lackingin eating qualities. Shortening contributes to the spread of the cookies. Regularhydrogenated shortening having a bland flavor is preferred and commonly used.Butter and margarine produce cookies with a more desirable taste and flavor.

Eggs Eggs are both tenderizers and tougheners in cookie baking. Egg yolks containa very large percentage of fat which helps to tenderize the cookie. On the otherhand, the egg whites acts as structure builders because of the proteins whichcoagulate during baking. Eggs also contribute moisture. Some cookie recipes suchas macaroon coconut cookies call for egg whites. Whole eggs contribute thecombined characterists of shortness, aeration, and tenderness.

T.iouids T.inuid in some form is necessarv in all cookie recines. Water is necessarv.•..•. J... *'to moisten the flour proteins to form gluten so the structure can be formed. Wateralso contributes to dough consistency and helps to control the temperature of thedough or batter. It also dissolves the chemicals in baking powder so that carbondioxide can be produced to leaven the cookie and to assist in the spread of thecookie during baking.

Milk solids Dry milk solids tend to exert a slight binding action on the doughs.Milk solids are a valuable addition to cookie recipes because they provide addednutritional value. The milk sugar lactose, adds to the richness of the crust color.

Leavening Ingredients Leavening ingredients help to control spread or size,produces volume and promote proper crust color through regulation of acidity oralkalinity (pH) of the dough. Cookies that are hand dropped, deposited with apastry tube, or machine deposited, need the spread control of leavening agents. Analkali such as baking soda exerts a weakening effect on the flour proteins (gluten)and helps to promote spreading. Since most cookie ingredients are neutral toslightly acid, they are usually sufficient to neutralize any reasonable quantity of4c;J 'Baking Powder Baking Powder is a mixed blend of food acids of which there areseveral types and Bicarbonate of Soda with starch added to prevent the BakingPowder from lumping during storage. During the baking process the acidingredients and the baking soda contained in the baking powder are dissolved inthe liquid forming carbon dioxide gas. None of the acid nor the the soda remain inthe finished product, because they neutralize each other.

Flavoring Ingredients ,Salt Salt is used for its own flavor and to bring out thenatural flavors of the other ingredients. The amount of salt must be reducedslightly when salted butter is used as the shortening ingredient in the recipe.Cocoa The use of cocoa reouires an adiustment to the formula. Suzar is added tocounteract the tendency of cocoa to toughen the dough and to sweeten and enhancethe cocoa flavor. A slight adjustment in liquid may be necessary also.

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MIXING-There is two ways of mixing dough ingredients

ONE-STAGE METHOD: The One-Stage Mixing Method is preferred because itssimplicity reduces the possibility of errors. Sift the dry ingredients together. Placeall the ingredients, both wet and dry into the mixing bowl and mix in slow speeduntil they form a smooth dough or batter.

CREAMING METHOD: The main portion of the sugar (about 75 percent),shortening, salt and vanilla are creamed together. The eggs are added in three partsand mixed until smooth after each addition. Add the liquids and stir. The flour,baking powder, and remaining sugar (about 25 percent) are sifted together andadded. In this method of mixing, the longer the sugar and shortening are creamed,the less spread the product will have because the sugar crystals are broken up more

, '~.~~

thoroughly. Mixing for a long period of time after the flour has been added willdevelope the gluten excessively. This will result in cookies with insufficient spread.When a portion of the sugar is added in the final step with the flour, better spreadwill be obtained. Nut, raisins, and chocolate chips are added at the end of themixing period and mixed only long enough to incorporate them in the dough orbatter

MATERIALS AND CHEMICALS

• Fresh roots of cassava variety to be obtained from the local market or Kabetecampus farm

• Watermelon fruits were purchased from Kangemi market/Kabete farm.• knives• Portable water• Grater• Sack/bag• Capillary tubes• Cotton wool• Muslin cloth• Aluminum plates• Miller/hammer mill/grinder• Sieves(60 mesh)• Cellophane bag• Kraft package bags• Biscuits packages• AOAC-for proximate analysis

SAMPLES PREPARATION

• Cassava flour production:

The cassava roots were bought, peeled, washed and grated. The resulting mash wasbagged in a sack. The cake was sun dried and then further dried effectively inthermo-regulated oven at a temperature of 600Cfor 3-4 h. The resulting materialwas milled and sieved into flour of 250 pm particle size. The flour was sealed incellophane bag and stored at room temperature (25°C) until needed for furtheranalysis

• Production of watermelon seed flour:dV/e..,...

The watermelon seeds were extracted, washed, drained and dried using solar. Thedried seeds were milled and sieved through 60 mesh sieve. The watermelon seedflour were sealed in a cellophane bag and stored at room temperature (25°C) forfurther analysis

• Formulation offlour composites:

Flour composites of wheat! cassava and water melon seed were formulated

Constant rat!e!1o! ~~sava to wheat flour was taken as (2o:Bo%)-the optimum asresearch by (~oe~ Wanjekeche -~996)

ANALYrICAL METHODS USED

Proximate analysis of samples:

The crude protein, crude fat, crude fiber, moisture contents andash were determined according to AOAC, while the carbohydratewas determined by difference.

NBj Food grade analytical chemicals were usedfor the analyses. The values werebased on 100g of the sample under study.

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RESEARCH DESIGN AND METODOLOGY

RESEARCH DESIGN and METHODOLOGYRAW CASSAVA

JWASH &PEEL

IGRATE

1 . WHEAT FLOURDEWATER

1SUN-DRY

1MILL - 2500

1PACKAGE

1STORE

WATERMELON

JSEEDS EXTRACTION

1WASHING AND DRAIN

IOVEN DRY(600 C)

JMILLING

1sirPACKAGE

JSTORE

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MC

PROTEIN

CHO

CRUDE FAT

CRUDE FIBRE

ASH

.. .. ;.. •o S 10 20

/

The cooki quality wai assessedby a test panel of 20 judges1=LlKE EXTREMELY

9=DISLlKE EXTREMEL.:

I

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.. .. :, .S 10 20

I

C//

III • SHELF LIFE DETERMINATION

Determination of moisture gain (g)of wrapped cookies and thecritical and equilibrium points of cookies in a watch glass over

days.

•

/

• FUNCTIONAL PROPERTIES F THE SAMPLES

Bulky density

Water absorptioncapacity

Oil absorptioncapacity /

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RESULTS

PROXIMATE COMPOSITION(H coov;.,~5

0,5,10,20 Shows % of watermelon seed flour in the composite flour.

; I I •0 5 10 20

MC 11.30 9.10 8.70 7.90

PROTEIN 6.20 7.35 8.80 11.70

CHO 64.20 60.99 57.70 51.36

CRUDE FAT 14.47 17.23 21.54 24.80

CRUDE FIBRE 0.97 1.24 1.57 1.75

ASH 1.35 1.29 1.16 0.97

~.;e,f'!6z-~.v1\..k cYf- ~~ Vr?~ !C/~.

0/7

SENSORY EVALUATION·WH·EAT:CASSAVA=80:20·CONSTANT~-""::.~..-..~~~-.;;..-~~-

WATERMELON

AROMA 5 5 3 2

COlOR 5 3 2 2

TASTE 4 3 2 2

CRISPNESS 3 3 2 2

CHEW QUALITY 4 3 3 2

TEXTURE 3 3 4 4

OVERAll 4 2.8 2.7 2.3ACCEPTABILITY

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• SHELF LIFE DETERMINATION• Determination of moisture gain (g)of wrapped cookies and the

critical and equilibrium points of cookies in a watch glass overdays.CRlIlCAL.MCGAl -EQUJUBRlUMMC-GAlN

0 67.31 5.53

1 67.49 5.57

2 67.82 5.62

3 68.10 5.66

4 5.70

5 5.72

6 5.78

7 5.84

8 5.89

9 5.92

5.70 =0.17g

5.92 =0.39g

V~L;x V1 Oo\. hffl-1 <Y'J-

ftQ ve-~h'

• FUNCTIONAL PROPERTIES OF THE SAMPLES

WHEAT:CASSAVA=80:20-CONSTANT

Bulky density(w/v) 0.595 0.683 0.703 0.725

Water absorption 1.435 2.370 2.564 2·798

capacity(g/lOOg)

Oil absorption 2.170 1.667 1.543 1.370capacity(g/lOOg)

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DISCUSSIONThis result show that the blend watermelon seed flour 20% had the highest proteincontent while sample watermelon seed flour 0% had the lowest. There wassignificant difference (p~o.OS) in protein content among the blends. The high proteincontent of the watermelon seed flour 20% is due to the level of watermelon seedflour, which contains high protein content. According to Padmaja and Jisha (200S),protein content of the cassava based composite flours could be elevated through theincorporation of legume flours.

The blend watermelon seed flour, 0% had the highest carbohydrate content whilethe blend watermelon seed flour 20% had the lowest. There was significantdifference (p<o.OS)among the blends.

There was high content of fat in watermelon seed flour 20%, followed by 10%.There was significant difference among the blends.

Watermelon seed tlour 0% blend had the highest moisture content. 20% had thelowest.

The blend watermelon 20% had the highest crude fibre content while watermelon0% had the lowest. The increase in crude fibre may be as a result of increase inwatermelon seed flour. From the result, there was a significant difference (p<o.Os)among the samples.

It was also observed from the result that the ash content was highest in watermelono%.Therewas a significant difference in the ash content among the samples.

Sensory evaluation:

The scores were subjected to analysis of variance (ANOVA).The cookies in whichwatermelon seed flour was blended tasted better than those without watermelonflour. The cookies with 20% watermelon seed flour was the best in overallacceptability.

The result confirmed that the quality of color, aroma, crispness, texture and tasteindeed influence the overall acceptability of the cookies.

Color is an important sensory attribute of any food because of its influence onacceptability. The old adage that the eye accepts the food before the mouth is very true.The brown color resulting from Millard reaction is always associated with baked goods.The cookies scored between 2.30 and 4.0 on the 9 point-hedonic scale indicatingthat the cookieswere at least liked slightly.There were significant differences among the

Page 22 of25 22

cookie samples. The color of the watermelon 20% cookies was superior to the allwheat/ cassava flour cookies.

Aroma is another attribute that influences the acceptance of baked good even beforethey are tasted. Substitution of wheat/cassava flour with watermelon seed flour atdifferent levels did not significantly (P.:5.0.0S)affect the sensory scores of aroma. Thehighest score of (like slightly) in aroma was obtained for cookie with 20% watermelon~~~A .fI~,, __ ~~1~~~~~~-t- ~+'oT1-.~~-t-/~~~~~ •• ~ .fI~,,_1-.~A -t-1-.~ h~~-t- ~_~~~ ~+ n •••.•••.~C;vu. J..1VUJ. .lCP.lQ\.;C.l.1.1C.I..lL V.1. ~"J.J.c;a.LI \..,Q~ya. J...l.VU.I. .l.lau. U.1tC 1.IC;~'" Q.l.V.l.lJ.Q VJ.. ~.,;)~.

Crispness is a desirable quality of cookies. Crispness scores were significantly(P.:5.0.0S)superior in cookies with all cassava/wheat flour than in cookies withwatermelon seed flour. The highJat content of watermelon seedJlour was-obviouslu responsible for the higher scores and less crispness. The effect offat on biscuit texture and other baked goods is well known. Cookies with 20%watermelon seed flour replacement of wheat flour had the best texture witha score of 2.05. There was significant difference (p<o.OS) in the texture of the cookiesamples but all the cookies were al least liked slightly.

Functional properties of the samples:The bulk density of the samples ranged from 0.595-0.725. Watermelon seedflour 20% sample had the lowest bulk density among the blends while watermelon0% had highest. There was no significant difference among the blends within thecomposite flours. Bulk density gives an indication of the relative volume of packagingmaterial required and high bulk density is a good physical attribute when determiningthe mixing quality of a particulate matter (Lewis, 1990).

The water absorption capacity of the blends was between 1.400 and 2.790 cc.watermelon seed flour 20% had the highest gelatinization temperature andwatermelon seed flour 0% had the lowest gelatinization temperature. This resultshowed that the composite flours had good gelling property. Water absorption capacityis important in bulking and consistency of product as well as in baking applications.

The oil absorption capacity ranged from 1.370-2.170 cc. watermelon seedflour 20% had the highest oil absorption capacity while (watermelon seed flour 0%had the lowest. There was a significant difference among the different blends.

Oil flavours and gives soft texture to food. Absorption of oil by food products improvesmouth feel and flavour retention. The high oil absorption capacity suggests thelipophilic nature of the flour constituents of the flour. The increase in oil absorptionmay also be attributed to the presence of more hydrophobic proteins which showsuperior binding oflipids (Kinsella, 1976).

Page 23 of25 23

• CRITICAL POINI' OF MOISTURE GAIN&ORGANOLEPTIC

Shelf lifeAccelerated shelf life

Moisture content here was taken as the main cause of the cookies deterioration. Asimple equation that permits extrapolation was used in terms of time, rather thanacceleration by use of temperature.

This was only done on the most acceptable product (20% watermelon). Anestimated time of 60 days was calculated against the expected shelf life of about 90days of similar existing products.

DETERIORATION (=3%)

• EQUILIBRIUM LEVEL OF MOISTURE GAIN-WATCH GLASS =~~

CONCLUSION

• Wheat/cassava flour could be replaced with up to 20% with watermelonseed flour in cookie production without affecting the sensory qualitiesadversily,in the quest to increasing protein content, with the resultant effectof increase intake dietary fiber.

RECOMEMDATIONS

• The quality of the protein improved should be investigated to determine theprotein nutritional quality.

• Further investigations to establish whether other baked products areacceptable using this composite flour.

• Further the inclusion of legumes flour in this composite flour since mostlegumes (soyabeans) have superior proteins can be investigated.

• Investigate the extent of cyanogenicglycosidedestruction during baking.

Page 24 of25 24

REFERENCES

• Ugwu, B.O., 1996. Increasing cassava production trend in Nigeria andprospects for sustaining the trend.

• 4th yr root crop notesieooo/eoio academic yr) by George Ooka Abong'• Vijagolpal, K., C.Balagoplan and S.N. Moorthy, 1988. Gelatinization and

liquefaction of cassava flour: Effect of temperature, substrate and enzymeconcentration. Starch-Starke

• Padmaja, G. and S. Jisha, 2005. Nutritional characteristics of cassavabased composite flours. J. Root Crops.

• Oyewole, O.B., L.O. Sanni and MA. Ogunjobi, 1996. Production of biscuitsusing cassava flour. Nig. Food J.

• Niba, L.L., M.M. Bokanga, F.L. Jackson, D.S. Schimme and B.W. Li, 2001.Physicochemical properties and starch granular characteristics offlourfrom various Manihot esculenta (Cassava) genotypes. J. Food Sci.

• Nasr, S.l. and Abufoul, 2004. Usingfree fat watermelon Citrullus vulgarisseed kernels in preparing high protein biscuits.

• Elizabeth Wanjekeche -:1996) on the utilization of cassava andsweet potatoes and wheat composites in cake making

• (Cardoso et al., :1999)• Padmaja and Jisha (2005),• (Lewis, 1990).• (Kinsella, 1976).• 4thyr construction and packaging notes- E.G Karuri (2010 )-estimation of

accelerated shelf life.