ABSTRACT
This work was carried out to study raw ash yield, dry ash, mineral, emulsification and pH content of food grade ash obtained from cola leaves, okro leaves, cola hispida leaves and Wire weed leaves. The plant materials were sun dried and each was subjected to open air burning to obtain raw ash. Each raw ash sample was ashed in the muffle furnace to obtain dry ash that was used for the analyses using standard analytical methods. Both raw ash and dry ash yield were obtained by calculation. The results showed that raw and dry ash yields were for cola nut, wire weed, okra and ukukoro leaves respectively 7.26, 6.59, 16.14, 9.50 % and 58.08, 88.64, 62.91, 48.18 %. Calcium content were 4.93, 5.15, 110.84 and 13.56 mg/100 g. Phosphorous content were 33.13, 7.55, 2.96 and 1.91 mg/100 g. Magnesium content were 9.54, 2.85, 6.73 and4.26 mg/100 g. Sodium content were 6.23, 10.24, 1.57 and 11.32 mg/100 g. Potassium content of the samples were 36.63, 3.62, 38.34 and 8.28 mg/100g.Iron content were 0.98, 0.82, 1.44 and 2.67 mg/100 g. Zinc content were 0.83, 1.23, 1.57 and 0.05 mh/100 g. Copper content were 0.23, 0.14, 0.12 and 0.06 mg/100 g. The pH values of the samples were 13.45, 13.41, 13.33 and 13.09. Emulsion capacity were 50.02, 34.31, 48.38 and 45.97 % respectively for cola nut, wire weed, okra and ukukoro leave ashes. The ashes were good food with variations in mineral content and high pH, and also liable to make emulsion.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgement
v
Table of Contents vi
List of Tables x
List of Figures xi
List of Plates xii Abstract xiii
CHAPTER 1: INTRODUCTION
1. Background
of the study 1
2. Statement
of the problem 2
3. Justification
of the study 3
4. Objectives
of the study 3
CHAPTER 2: LITERATURE REVIEW
2.1 Plant ash 4
2.1.1
Utilization of Food Ash 5
2.1.2 Application of Ash in Food
Processing 5
2.2
Sources of Food Ash 7
2.2.1
Empty palm bunch (Elaeis guineensis) 8
2.2.2
Wire weeds (Sida acuta) 8
2.2.3 Kola (cola
nitida) 8
2.2.4
Okra (Abelmoschus esculentus) 9
2.2.5 Ukukoro (Cola hispida) 9
2.3 Uses of food ash 10
2.4 Mineral composition of food ash 10
2.4.1
Major mineral 11
2.4.2 Minor minerals 16
2.5
Factors Affecting Plant Ash Composition 19
CHAPTER 3: MATERIALS AND METHODS
3.1 Raw
material collection 20
3.2 Sample
preparation 21
3.2.1
Production of raw ash from ukukoro (Cola
hispida)
Leaves 21
3.2.2 Production of raw ash from okra, kola nut and wire weed
Leaves 22
3.2.3
Sample preparation 22
3.2.4 Dry ash content determination 22
3.3
Analysis 22
3.3.1 Ash yield calculations 22
3.3.2 Preparation of samples for AAS analysis 23
3.3.3 Determination of macro-minerals 25
3.3.3.1
Phosphorous 25
3.3.3.2 Calcium and Magnesium 25
3.3.3.3 Potassium and Sodium 26
3.3.4
Determination of micro metals 27
3.3.4.1 Iron, zinc and copper 27
3.3.5 pH and Emulsification
capacity 28
3.3.5.1
Determination of Emulsification capacity (EC) 28
3.3.5.2 pH determination 29
3.3.6 Statistical Analysis 29
CHAPTER 4: RESULTS AND DISCUSSION
4.1 Raw ash yield of the plant samples (%) 30
4.2 Dry ash content of the plant samples (%) 32
4.3 Mineral
Composition of Ash Samples 32
4.3. 1 Macro minerals 34
4.3.1.1 Calcium 34
4.3.1.2 Phosphorous 35
4.3.1.3 Magnesium 35
4.3.1.4 Sodium 36
4.3.1.5 Potassium 36
4.3.2 Micro minerals 37
4.3.2.1 Iron 37
4.3.2.2 Zinc 37
4.3.2.3 Copper 37
4.4
pH and emulsification capacity of plant ash samples 38
4.4.1 pH 38
4.4.2 Emulsification capacity 38
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 40
5.2 Recommendations 40
REFERENCES 41
LIST
OF TABLES
Table 4.1: Raw ash yield of the plant Samples 31
Table
4.2: Dry ash content of the plant samples 33
Table
4.3: Macro and micro mineral content of the
plant ash samples (mg/100g) 34
Table
4.4: pH and emulsion capacity of plant ash
samples 39
LIST
OF FIGURES
Figure
3.1: Flow chart for production of raw ash from
ukukoro leaves 24
LIST
OF PLATE
PLATE 3.1: Ukukoro 20
PLATE 3.2: Cola
Nut Leaves 20
PLATE 3.3: Okro
Leaves 21
PLATE 3.4: Wire
Weed 21
PLATE 3.5: Open
Air Burning 21
PLATE 4.1: Dry
Ash 30
CHAPTER 1
INTRODUCTION
1.1
BACKGROUND
OF STUDY
Ash
refers to all non-gaseous residues that remain after open air incineration or
burning in order to obtain the mineral content (Howard et al., 2002). Incomplete combustion usually still contains some
amount of combustible organic or other oxidizable residues. The best known type
of plant ash is wood ash from wood combustion in campfires, fire places and
others. The darker the ash colour, the higher the amount of incomplete
combusted materials. Like soap, ash is also a disinfecting agent (alkaline)
(Howard et al., 2002).
Food
ash can be gotten from plant materials most of which are undervalued and
regards as waste. Among the alternatives available to meet the food demands are
cultivable and wild vegetables which are cheap sources of food for the marginal
communities (Anon, 2004) and food ash. To apprehend the situation, interest has
been centralized on the exploitation, quantification and utilization of food
plant especially the vegetables (Agu et
al., 2013) for generation of food ash.
In
the context of nutrition, mineral is an inorganic chemical element required as
an essential nutrient by organisms to perform functions necessary for life.
However the four major structural elements in the human body by weight (oxygen,
hydrogen, carbon and nitrogen) are usually not included in the lists of major
minerals. Major elements (macro minerals) consist of about 96 % of the body
weight while minor minerals (trace elements) made up of the remainder (Zoroddu et al., 2019). The five major minerals
in the human body are calcium, phosphorus, potassium, sodium and magnesium. The
trace elements in the human body which have specific biochemical functions
include sulfur, iron, chlorine, cobalt, copper, zinc, manganese, molybdenum,
iodine, and selenium (Zoroddu et al.,
2019).
Some agricultural wastes have been known to
contain mineral elements when ashed or charred such as palm bunch, chaff, cola
leaves, okra leaves, wire weed, coca pods, maize cobs and others they contain
oxides of potassium, sodium, calcium which yield their corresponding hydroxides
upon dissolution in water. These hydroxides are of great importance in emulsion
especially when combined with palm oil during the preparation of African
tapioca salad (abacha) and acts as surfactants (Irvine, 1985). The filtrate
obtained from the mixture of ash and water normally has a brown colour and can
form emulsion with oil which is slippery to touch, giving an alkaline
impression (Udeotok, 2012). The ash is also used in making ‘Ngu’ used for
preparing traditional food such as ighu, ugba, Isiewu, nkwobi and may
also be used as a tenderizer for cooking hard to cook foods like African
breadfruit, meat, corn (Udeotok, 2012).
1.2
STATEMENT
OF PROBLEM
Lack of knowledge of the
composition and chemistry of ash and potash often leads to failure in producing
potash of good quality from some local plant ashes. It may also lead to wrong
determination and/or identification of components of potash in studying them
for various purposes.
Ash contains both
essential minerals like calcium and potassium and toxic minerals such as
mercury (Bhowmik et al., 2012) with
some risks (Schumacher, et al., 1991).It
is therefore important to determine the levels of these compounds in plant ash
for food applications.
1.3
JUSTIFICATION
OF THE STUDY
Issues of food waste
management would be solved by this study by turning the underutilized food
materials to useful sources of nutrients. The study will also reveal the
chemical compositions of these plant materials thereby offer options in
selection of food stuffs and possibly reducing the rate and cost of
importations since most of these materials is locally accessible.
1.4
OBJECTIVES
OF THE STUDY
The main objective of
this study is to evaluate both micro and macro elements and emulsion properties
of the plant ash from cola leaves, okra leaves, cola hispida, and wire weed.
Specific
objectives were to:
i. prepare
raw ash from the leaves.
ii . ash the raw ash in the furnace to obtain the dry
ash.
iii. determine the raw ash and dry
ash yields, their micro and macro metallic compositions.
iv.
determine their emulsion potentials.
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