ABSTRACT
The research was carried out to find out the effect of processing on the nutrient composition of moringa leaves and evaluate the sensory properties of the produced from the different samples.one (1) kg of Moringa leaves was harvested from stem by hand, sorted. They was divided into five parts of 200g each for two techniques of drying drying used which are oven and sun drying and. The first 2 portions were not blanched for drying, each part was washed under a running tap and poured into a basket to drip excess water. One part was oven dried at 60C for 6hrs, the other sample was sun dried by spreading two trays on a table under the sun consecutively for 6 days. The second 2 portions were blanched. For the blanching process, the leave was washed and drained, steam blanched at 95°C for 5 minutes, 10 minutes and 15 minutes in a steam cooker before oven drying at 60oC for 6hrs and sundrying for 6 consecutive days. The last portion was analysed fresh. The samples were analysed for their proximate value using AOAC (2015) methods, while vitamins, minerals and phytochemicals were using, Onwuka (2018) methods. The samples were coded as FML which is the fresh moringa leave, BOML which is the blanched oven dried moringa leaves, UOML which is the unblanched oven dried moringa leaves, BSML which is the blanched sun dried moringa leaves and USML which is the unblanched sun dried moringa leaves. The result of the proximate composition showed that the moisture content of the FML (75.69%) was higher than other samples with a significant difference (P<0.05) and was least in sample UOML (5.39%). Protein contents was highest in sample UOML (22.05%) and was least in sample FML (10.54%). The fat contents was highest in sample USML (2.85%) and least in sample FML (0.73%) with a significant difference (P<0.05). Crude fibre was highest in sample UOML (11.17%) and least in sample FML (8.85%). Ash was highest in sample UOML (9.21%) and least in sample FML (2.45%) and carbohydrate contents was highest in sample BSML (56.55%) and least in sample FML (1.73%). The result of the mineral and vitamin content revealed that calcium, magnesium, phosphorus and zinc was highest in sample UOML (702.41/100mg, 95.91/100mg,155.63/100mg and 0.16/100mg) respectively. Vitamin E was highest in sample UOML while vitamin K was highest in sample BSDML (P<0.05). Oxalate, saponin, tannin and flavonoid was highest in sample FML (7.83, 1.30, 0.90 and 1.86/100mg) respectively with a significant difference (P<0.05). The result of the sensory properties showed that there was no significant difference (P<0.05) in the color, taste, flavor and general acceptability of all the samples.
TABLE
OF CONTENTS
Title
page i
Certification ii
Dedication
iii
Acknowledgements
iv
Table
of Contents v
List
of Tables ix
List
of Figures x
Abstract
xi
CHAPTER
1: INTRODUCTION
1.0.
Background
of the Study 1
1.1
Statement
of Problems 3
1.2 Objectives 4
1.2.1 General objective 4
1.2.2 Specific
objectives 4
1.3
Significance of the Study 5
CHAPTER
2: LITERATURE REVIEW
2.1 Origin and Distribution 6
2.2 Consumption Pattern of Moringa oleifera 6
2.3 Nutritional Aspect of Moringa
Leaves 7
2.4 Nutritive Properties 8
2.5 Uses of Moringa: A Multipurpose Tree 11
2.6 Medicinal Importance of Moringa oleifera 12
2.7 Drying 12
2.7.1 Mechanism of drying 13
2.7.2 Different Methods of Drying 14
2.7.2.1 Sun Drying 14
2.8 Blanching 15
2.8.1 Effect on Foods by Blanching 16
2.8.1.1 Color 16
2.8.1.2 Texture 17
2.8.1.3 Flavor 17
2.8.1.4 Nutrients 17
2.8.2. Methods of blanching 18
2.8.2.1 Hot water blanching 18
CHAPTER
3: MATERIALS AND METHODS
3.1 Collection of Raw Materials 20
3.1.1 Preparation of Moringa Sample 20
3.2 Preparation of Moringa Green Tea Leaf
Powder 21
3.3 Proximate
Composition Analyses of Fresh, Blanch and Dried
Moringa
Leaves 22
3.3.1 Moisture Content Determination 22
3.3.2. Ash content determination 22
3.3.3 Determination of crude fibre 23
3.3.4 Protein Content 24
3.3.5 Carbohydrate determination 25
3.4 Mineral Content Determination 25
3.4.1 Determination of calcium and magnesium 25
3.4.2 Determination of potassium 26
3.4.3 Determination of sodium 27
3.4.4 Determination of phosphorous 28
3.4.5 Zinc (Zn) 28
3.5 Vitamin Content Determination 29
3.5.1 Determination of pro-vitamin A 29
3.5.2 Determination of vitamin B1 (thiamin) 30
3.5.3 Determination of vitamin B2 (Riboflavin) 31
3.5.4 Determination of vitamin C (Ascorbic acid) 32
3.5.5 Vitamin E 32
3.6 Phytochemical Composition of Samples 33
3.6.1 Determination of oxalate: 33
3.6.2 Determination
of saponins: 33
3.6.3 Flavonoids 34
3.6.4 Tannin
determination 34
3.7. Sensory Evaluation 35
3.8 Statistical Analysis 35
CHAPTER
4: RESULTS AND DISCUSSION
4.1 Nutrient Composition of the Moringa Samples 37
4.1.1 Proximate Composition of the Moringa Samples 37
4.2
Vitamin Composition of the Moringa
Samples 42
4.3 Minerals Composition of the Moringa
Samples 47
4.4 Antinutrient Properties of the Moringa
Samples 51
4.5
The Sensory Attribute of the Moringa
Samples 55
CHAPTER 5: CONCLUSION AND
RECOMMENDATIONS
5.1 Conclusion 59
5.2 Recommendations 60
REFERENCES 61
LIST OF TABLES
Table 4.1 Proximate and
energy value composition of Moringa leaves samples 38
Table 4.2. Vitamin Composition of the Moringa Samples 43
Table 4.3 Minerals Composition of the Moringa Samples 48
Table
4.4. Antinutrient Properties of the Moringa Samples 52
Table
4.5: The Sensory Attribute of the Moringa Samples 56
LIST OF FIGURES
Fig 3.1: preparation of moringa tea
(unblanched) 21
Fig 3.2: preparation of moringa tea
(blanched) 12
CHAPTER 1
INTRODUCTION
1.0.BACKGROUND
OF THE STUDY
Moringa oleifera is one out of numerous under-exploited crops
with great potentials (Magbagbeola et
al., 2010). The plant is a small fast growing tree found in the tropical
regions, easy to cultivate and resistant to drought .This plant is very useful
in that most of its parts are edible. Moringa oleifera is referred to as
a miracle tree or wonder tree (Kasolo et
al., 2010) of socio economic importance because of its several nutritional,
pharmacological and industrial applications as reported long ago by Caceres et al. (1991) and Makkar and Becker,
(1996).
Fahey (2005) described moringa as a plant food
of high nutritional value, ecologically and economically beneficial, readily
available and therefore of great benefit in places where starvation is eminent.
The Moringa tree is
known by different names in different places. English common names include:
moringa, drumstick tree (from the appearance of the long, slender, triangular
seed-pods), horseradish tree (from the taste of the roots, which resembles
horseradish), ben oil tree, or benzoil tree (from the oil which is derived from
the seeds) (Bashir et al., 2017). It
is called the drumstick tree in India due to the long pods or the horseradish
tree as the roots may be used to make a spice resembling horseradish. In
Senegal it is known as Nebeday, which means “Never Die”, it is also known as
Ben oil tree in Haiti. In Nigeria, the Hausas call it Zogale, Kilba-Kabbi, and
Fulani-Kabije (Dahiru et al.,
2006), the Igbos on the other hand call it okweoyibo or Agbaji.
Moringa leaves are rich in nutrients with the
dry leaves containing as much as 30% protein. The leaves are sources of the
Sulphur containing amino acid such as methionine and cystine which are often in
short supply in most legumes (Martin et
al., 1998) and contain high amount of vitamin B-complex, calcium,
potassium, iron and protein (Hassan et
al., 2016). Fuglie (2001) reported that moringa leaves are very high in
iron, weight for weight moringa leaves powder contains 14 times more iron than
roasted beef (one of the richest iron sources). According to Rweyemamu et al. (2006), 100g of Moringa
oleifera leaves can meet the daily requirements of vitamin A for 17
children at the age of 1-3 years, 10 pregnant women and 7 lactating mothers.
They are rich in phytochemicals/antioxidants such as ascorbic acid, flavonoids,
phenolics and carotenoids (Anwar et al.,
2005); making them useful in the reduction of oxidative stress which has been
implicated in the etiology of a wide range of chronic diseases.
Moringa leaves are extensively utilized to
improve nutritional and sensory evaluation by incorporating its extract into
food products like sauces, juices, spices, milk, moringa powder (Mukunzi et al., 2011). Moringa leaves are highly
perishable and they require processing treatment to prevent post-harvest
losses. This implied that treatment such as drying preserves them from fast
deterioration. Drying is a great way of preserving Moringa leaves and to reduce
them into powder, making it easier to store and use at any time. Even if a
large amount of water soluble vitamins are lost during drying and storage, the
leaf powder still constitutes a very rich nutritional supplement which are concentrated in the dried leaves (Oluwalana,
2011).
Enoh-Arthur and Damme (2008)
stated that using Moringa leaf powder is a way of preserving nutrients as the
powder can be added to food after cooking. Adeyemi et al. (2014) reported that Moringa powder can be added to almost any
food as a nutrient supplement. The nutritive values of pap, cereals and drinks
can be improved using dried Moringa powder and cookies can also be fortified
with Moringa leaf powder (Emelike et al.,
2015). Mbah et al. (2012) and
Adeyemi et al. (2014) studied
different drying methods on
the proximate, phytochemical and other nutrient composition of the dried Moringa oleifera leaves. This work
therefore, aim to determine the effect of blanching and drying processing
methods on the nutrient composition of Moringa
oleifera leaves and the sensory evaluation of foods produced from them
1.2 STATEMENT
OF PROBLEMS
Excess of free radicals in the body leads
to oxidative stress which plays an important role in the pathogenesis of
several human diseases, such as cardiovascular diseases, neurodegenerative
diseases, cancer, rheumatoid arthritis, and diabetes (Nobosse et al.,
2017). Natural antioxidants present in foods protect against these free
radicals and are therefore important in maintaining and preserving good health (Nimse
and Pal, 2015). Antioxidant-rich plants are the focus of intense interest since
recent reports have expressed safety concerns over the use of synthetic
antioxidants (Taghvaei and Jafari, 2015). Moringa oleifera leaves are
considered a significant source of phytochemicals (carotenoids, phenolic
compounds, vitamin C) and act as a good source of natural antioxidants.
In developing countries where Moringa leaves
are increasingly being used to resolve malnutrition problems, these leaves are
either cooked directly after harvesting or are sun or shade dried and stored
for future use. Therefore, this work is to determine the effect of blanching
and drying processing methods on the nutrient composition of Moringa oleifera leaves and the sensory
evaluation of foods produced from them.
1.2 OBJECTIVES
1.2.1 General objective
To study the effect of processing on the nutrient
composition of Moringa oleifera leaves
1.2.2 Specific objectives
The specific objectives of the study are to:
i.
Prepare moringe leave powder
ii.
determine
chemical composition (proximate, vitamin, mineral and anti-nutrient) of
processed moringa leaves.
iii.
determine the phytochemical
composition of processed leaves.
iv.
evaluate the sensory analysis
of processed moringa tea powder.
1.4 SIGNIFICANCE OF THE STUDY
The knowledge
and use of these plant foods can complement the conventional sources and hence
it will assist in eliminating malnutrition in our communities.
It will help the
consumers to know the nutritional value of what they consume, this information
can also be incorporated in food composition data in our country.
This study will
add to the existing stock of knowledge in this field of study. It will also
serve as reference material to students, health practitioners, food industries,
and other researchers in the field and other related areas.
The research
will serve as a guide for future researches to students on the possible use of
this moringa leaves in the production of other dietary related products like
cake, yoghurt, ice cream, etc.
This work will aid
health practitioners in advocating for the intake of alternative tea to
patients. This study also helps to remove the misconception among the people
that Moringa is a food item which is consumed not only by the grass level but
it can equally be consumed by affluent people. This dissertation will prove to
be beneficial in contributing to the socioeconomic development of Nigeria and
the people.
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