EVALUATION OF THE EFFICACY OF BITTERLEAF
(Veronina amygdalina) EXTRACT AS A MEANS OF EXTENDING THE SHELF
LIFE OF FRESH TOMATOES (Solanum Lycopersicum L.)
BY
ONISMUS FESTUS
UJ/2017/AG/0080
CHAPTER ONE
INTRODUCTION
1.1
BACKGROUND OF THE STUDY
Tomato (Solanum lycopersicum L.) is an edible fruit that is widely accepted and globally
consumed because of their high nutritional contents. Fruits and vegetables with high levels of
nutritive biomolecules, such as antioxidant-rich phytochemicals, minerals, vitamins, proteins,
essential amino acids, monounsaturated fatty acids, carotenoids (lycopene and β-carotenoids)
and phytosterols have been reported to be beneficial to humans’ health and wellness
(Tommonaro et al., 2012; Pem and Jeewon, 2015; Salehi et al., 2019; Aslam et al., 2020; Hou
et al., 2020). A previous report encouraged constant consumption of tomatoes and tomato
products for healthier life and reduction in debilitating health challenges like cancer,
osteoporosis and cardiovascular disease (Freeman and Reimers, 2010). Most of the health
benefits of tomatoes are attributed to its major carotenoids, lycpopenes. Other uses of tomato
fruits include as major raw materials in preparation of juice, salads, soup, paste or ketchups
(Freeman and Reimers, 2010).
One of the major challenges faced by farmers and retailers of tomatoes is post-harvest spoilage
leading to poor shelf-life of tomatoes (Ahmad et al., 2020). Some of these challenges occur
during transportation, storage, and marketing, thereby leading to colossal wastage of these
nutritive foods. Traditionally Vernonia amygdalina (bitter leaf) have been well documented
for the treatment of diverse ailments of humans and other animals. Vernonia amygdalina (VA)
is a shrub or small tree that grows throughout tropical Africa. It is popularly called bitter leaf
because of its abundant bitter principles (Ekpo et al., 2007). The leaves contain a considerable
amount of anti-nutritive factors like high level of tannic acid and saponin. Proximate
composition of Vernonia amygdalina leaf meal (VALM) shows a chemical composition of
527.83 ME kcal/ kg, 86.40% DM, 21.50% CP, 13.10% CF, 6.80% EE, 11.05% Ash, and the
result on mineral composition indicate that V. amygdalina has 3.85% Calcium, 0.40%
Magnesium, 0.03% Phosphorus, 0.006% Iron, 0.33% Potassium and 0.05% Sodium (Owen,
2011). Furthermore, Bitter leaves are widely used in folk medicine to treat diarrhoea,
dysentery, recurrent fever, stomach ulcer, headaches, diabetes, joint pains, skin disorders,
worm/parasitic infections, malaria, yellow fever, constipation in most African countries.
Considering the efficacy and eco-friendly natures of medicinal plants, it is pertinent to explore
their bio-preservative potentials on common perishable nutritive fruits and vegetables.
1.2
PROBLEM STATEMENT
Tomato (Solanum lycopersicum L.) is a vital fruit vegetable of local agriculture in many
regions, serving as a significant source of income for small and large-scale farmers. However,
the highly perishable nature of tomatoes results in substantial losses, leading to scarcity of the
commodity during the off season and food insecurity as well as economic instability.
Conventional preservation methods, such as refrigeration and chemical preservatives, are often
inaccessible or unsustainable in resource-constrained areas.
1.3
AIM AND OBJECTIVE
The main objective of this research is evaluation of the efficacy of veronina amygdalina extract
as a means of extending the shelf life of (solanum lycopersicum l.)
1.4
SIGNIFICANCE OF THE STUDY
This research is highly significant, due to the fact that it will shed more-light and add
knowledge to the existing works on the use of bitterleaf extract for preservation and shelf-life
extension of harvested tomato. It will also serve as a consult for further researches regarding
similar topics.
1.5
SCOPE OF THE STUDY
Tropical African native bitterleaf (Vernonia amygdalina) is well known for its therapeutic
qualities and culinary uses. Flavonoids, tannins, and saponins are just a few of the many
bioactive substances found in its bitter-tasting leaves. Because of these antibacterial and
antioxidant qualities, bitterleaf extract shows great promise as a natural preservative for a range
of food products. Solanum spp., or tomatoes, are a popular fruit that are prized for their
nutritional worth and adaptability in the kitchen. However, preserving quality and increasing
shelf life is severely hampered by their extreme perishability. Food waste and financial losses
are a result of postharvest losses brought on by enzymatic degradation and microbiological
spoiling. Recent research has explored the potential of bitterleaf extract as a natural alternative
to synthetic preservatives for enhancing the shelf life of harvested tomatoes. Studies have
demonstrated the efficacy of bitterleaf extract in inhibiting microbial growth, reducing decay,
and maintaining the quality of tomato fruits during storage.
CHAPTER TWO
LITERATURE REVIEW
2.1
Description of Solanum Lycopersicum L.
2.1.1 Nutritional Importance
2.1.2 Taxonomy
2.1.3 Postharvest Handling
2.1.4 Health Benefit
2.1.5 Diseases
2.2
Description of Vernonia amygdalina
2.2.1 Taxonomy
2.2.2 Phytochemical Composition
2.2.3 Antioxidant Properties
2.2.4 Antibacterial Properties
2.2.5 Nutritional Composition
CHAPTER 3
RESEARCH METHODOLOGY
3.1
MATERIALS TO BE USED

Fresh ripe tomatoes (Solanum lycopersicum L.)

Bitterleaf (Vernonia amygdalina) leaves

Distilled water

Ethanol (95%)

Potato dextrose agar (PDA) plates

Weighing balance

Ruler

Sterilized glass jars

Parafilm
3.2
METHOD OF DATA COLLECTION
3.2.1 Preparation of bitterleaf extract

Wash the bitterleaf leaves thoroughly under running water.

Air-dry the leaves at room temperature for 2-3 days.

Grind the dried leaves into a fine powder using a blender or mortar and pestle.

Weigh 10g of the bitterleaf powder and mix it with 100ml of distilled water or ethanol.

Stir the mixture vigorously for 10 minutes.

Filter the mixture using a muslin cloth or Whatman filter paper No.1.

Collect the filtrate and store it in a sterilized glass bottle at 4°C until use.
3.2.2 Treatment of tomato fruits

Selection of fresh ripe tomatoes that are free from blemishes and defects.

Dip the tomatoes in the bitterleaf extract solution for 1-2 minutes.

Allow the tomatoes to air-dry for 10-15 minutes before storing them in sterilized glass
jars.

3.3
Seal the jars with Parafilm and label them accordingly.
PLANT MATERIAL
In this study, the leaves of the bitterleaf plant were collected, washed, air-dried, and ground
into a fine powder. The powder was then extracted with distilled water or ethanol to obtain the
bitterleaf extract. The tomato fruits were then dipped in the bitterleaf extract solution for 1-2
minutes and allowed to air-dry before storage.
3.4
DATA COLLECTION AND ANALYSIS
Data will be collected on weight loss, decay, and firmness which will be analysed using
statistical software to determine the effects of bitterleaf extract on the shelf life of tomato fruits.
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