ABSTRACT
Lecithin is used for applications in human food, animal feed, pharmaceuticals, paints, and other
industrial applications, but consistent importation of lecithin has a negative effect on foreign
exchange leading to devaluation of the naira. The need to explore locally available products such
as cassava starch as a possible substitute to the use of lecithin is paramount, hence, the reason for
this work. This research was carried out to evaluate the emulsification properties of
Hydroxypropylated Cassava Starch (HPCS) in cocoa beverage.
The chemical modification of Native Cassava Starch (NCS) was achieved using propylene oxide
in an alkaline medium, after it was washed and dried. The modified starch and lecithin were then
used to produce cocoa beverage samples by agglomeration. Emulsification index was tested along
with functional properties such as solubility index, bulk density, wettability, dispersibility, total
soluble solids, swelling power and water absorption capacity.
The emulsification index measured (0.211 - 0.316) after 24h & 7 days and the cocoa agglomerate
exhibited good solubility index (76%-84%), bulk density (0.8347g/ml - 1 g/ml), wettability (3mins
10secs – 3mins 46secs), dispersibility (41%-45%), total soluble solids (50-80o
). The HPCS had a
slightly better swelling power (14%) compared to that of NCS (13.8%) and water absorption
capacity (171%) to NCS (47%).
The emulsification index revealed that a more stable emulsion was formed using a lower
percentage of lecithin and a lower percentage of HPCS. This work showed that HPCS has the
potential of being used as a possible substitute for the use of lecithin in emulsions and cocoa
beverage as there is no much difference in the emulsions formed by the emulsifiers used.
TABLE OF CONTENTS
Title Page
Certification ii
Dedication iii
Acknowledgement iv
Abstract v
Table of Contents vi
List of Table x
List of Figure xi
CHAPTER ONE
Introduction 1
1.1Background Study 1
1.2 Justification 2
1.3 Objectives 2
CHAPTER TWO
Literature Review 3
2.1 Emulsifiers 3
2.2 Emulsion Theory and mechanism of action of Emulsifiers 4
2.3 Formation of Emulsions 8
2.4 Classification of emulsions 10
2.5 Lecithin 11
2.5.1 Application of Lecithin 13
2.6 Starch modification 14
2.6.1 Physical Modification 15
2.6.2 Chemical modifications 15
2.6.2.1 Hydroxypropyl Starch (HP) 16
2.6.2.2 Applications of modified starches 17
2.7 Cocoa and cocoa products 19
CHAPTER THREE
Materials and Method 22
3.1 Materials 22
3.2 Sample Preparation 22
3.3 Methodology 22
3.3.1 Hydroxypropyl starch 22
3.3.2 Evaluation of emulsion stability 23
3.3.2.1 Emulsion preparation 23
3.3.2.2 Emulsification Index 23
3.3.3 Agglomeration of cocoa powder with Hydroxypropylated cassava starch 23
3.3.4 Functional properties 24
3.3.4.1 Dispersibility 24
3.3.4.2 Wettability 24
3.3.4.3 Bulk density 24
3.3.4.4 Total soluble solids 25
3.3.4.5 Solubility and Swelling power 25
3.3.4.6 Water Binding Capacity 26
CHAPTER FOUR
Results and Discussion 27
4.1 Emulsification Index 27
4.2 Dispersibility 27
4.3 Wettability 30
4.4 Bulk Density 30
4.5 Total Soluble Solids 30
4.6 Solubility and swelling power 31
4.7 Water Absorption Capacity 31
CHAPTER FIVE
Conclusion and Recommendation 377
5.1 Conclusion 37
5.2 Recommendation 37
References 38
