ABSTRACT

Kolanuts (Cola ,zi1ida were stored in seven different places viz, refrigerator (7 ± 3°C). earthenware pot a cylindrical transparent plastic container with a base and a cover. aluminium foil, Raphia baskets lined with leaves, jute bag and black cellophane bags at room temperature (29 ± 2°C). The effectiveness of these storage materials were determined by monitoring the moisture contents and the bulk densities of the nuts. The effect of infestation on the chemical and functional properties of red and white varieties of Cola nitida was also studied. Finally, the toxicitY effects of the essential oils of Lavandula hybrida, ()cirn urn basilicurn and ('vnhopogan nardus to the kola weevil (Balanogastris koiae) were also studied. The kolanuts stored in the black cellophane bags, plastic containers and those in baskets lined with leaves appeared to have longer shelf life than others. Their moisture contents at the 48th week (when the experiment ended), were 52.75%, 38.85%, and 9.75% respectively, as compared with their initial valves of 66.13%, 62.68% and 64.62% at the onset of the experiment. The percentage critical point of moisture for freshness retention in stored nuts is 36 ± 2°C. The bulk densities of the kolanuts stored in the black cellophane bags. plastic containers arid those in raphia baskets lined with leaves also increased by 28.57%. 88.23% and 125% respectively. Varietal differences also existed in the ash contents, wettability, whippability, caffeine, and water absorption values. Infestation decreased the protein and total carbohydrate contents by 7.65% and 64.54% respectively. It also increased the crude fibre, phosphorus and potassium contents by 26.29%, 26.03% and 68.25% respectively. The tannin content of the kolanuts was found to be relatively low and similar in the two varieties. The essential oils of Oci,nu,n basilicznn and Lavandula hybrida had insecticidal action against Balanogusiris kniac. ('vmboJ)ogall izarcius had no such action against Balanogasiris koiae as only 10% mortality wa observed at 80% concentration of application of this essential oil.

TABLE OF CONTENTS

Title Page

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of tables ••. viii

List of figures ix

Abstract X

1.0 Introduction ... 1

CHAPTER TWO

2.0 Literature Review 3

2.1 Kolanuts 3

2.2 Harvesting of kolanuts 5

2.3 Uses of kolanuts 7

2.4 Kola infestation ... 9

2.4.1 Physical control of kolanut infestation 10

2.4.2 Chemical control of kolanut infestation 11

2.5 Essential oils: Definition and composition 12

2.5.1 Uses of essential oils 13

2.5.2 Essential oils as phytochemlcals 14

3.0 CHAPTER THREE 16

Materials and Methods 16

3.1 Materials 16

3.2 Storage of kolanuts 16

3.3 Preparation of samples for chemical analyses 17

3.4 Chemical analyseis 17

3.4.1 Moisture content determination 17

3.4.2 Crude fat determination 18

3.4.3 Crude protein determination 18

3.4.4 Ash content determination 20

3.4.5 Crude fibre determination 20

3.4.6 Total carbohydrate determination 21

3.4.7 Mineral analyses 21

3.4.8 Calcium and magnesium determination... 22

3.4.9 Sodium and potassium determination ... 22

3.4.10 Phosphorus determination 23

3.4.11 Vitamin C determination 23

3.4.12 Tannic acid determination 24

3.4.13 Caffeine content determination 24

3.5 Determination of functional properties ... 25

3.5.1 Bulk density determination ... 25

3.5.. Wettability ... 26

3.5.3 Whippability determination ... 26

3.5.4 Water absorption capacity 26

3.5.5 Statistical Analyses 27

3.6 Rearing of the weevils Balaizogastris kolac ... 27

3.7 Determination of the toxicity effects of the essential oils ... 28

4.0 Results and Discussion 29

4.1 The effects of different storage materials on the moisture contents of stored

(Jola nitida 29

4.2 Effects of different storage materials on the bulk densities of stored

Cola nitida 34

4.3 Effect of infestation on the chemical composition of red and white

varieties of Cola ni/ida 34

4.4 Effect of infestation on some functional properties of red and white

Varieties of Cola nitida 38

4.5 Effects of the essential oils of Ocimurn hasilicurn, Cyinhopogan iardus

and Lavandula hybrida on the kolanut weevil, Balanogastris kolae ... 40

5.1 Conclusion and Recommendation 46

References 47

Appendices 53