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ABSTRACT

Not all things in this world are eternal. In fact, almost everything has its

limitation. People will die, plants will wither and even the fruit that we need in our daily

diet will undergo the process of spoilage. The latter is one of the problems the people are

facing nowadays, specifically, the fruit vendors, and consumers who don’t have

refrigerators at home and cannot afford any commercial preservative, in turn cannot store

fruits for a long time.

Thus, the researcher, being one of those consumers who cannot buy more fruits or

commercial preservatives, came up with the idea to produce a home-made, easily

available, affordable, easy-to-made, and safe-to-use fruit preservative-guava leaves

extract.

One-fourth kilogram of guava leaves was put into a casserole together with 500

mL water. It was boiled within 30 minutes then the residue was separated from the filtrate

which is the final product. The latter contains essential oil rich in cineol and

phytonutrients, such as carotenoids, isoffavonoids and polyphenols (flavonoids) as well

as saponins, 4 triterpenic acids (including ascorbic acid or Vitamin C) and tannins

existing in aqueous and ethanolic extract.

The product was tested in bananas for 12 days and the result showed that the

constituents of the extract led to it being able to prolong the shelf-life of fruits.

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CHAPTER I

PROBLEM AND BACKGROUND OF THE STUDY

This part introduces the study by stating the objectives of the study, the problems

to be answered, the significance of the study to certain populations, the hypothesis to be

proved and terms to be defined.

Introduction

Guava (scientific name: Psidium Guajava Linn), a member of family Myrtaceae,

is a plant with several medicinal uses which are known and recognized worldwide, and

studies and researches are still being conducted to discover its other uses.

Guava is a very good source of vitamins, fibers as well as minerals. Being rich in

Vitamin C; guava is effective in treating male infertility caused by sperm clumping,

adhesion and other abnormalities. It has been associated with healing of wounds, when

applied externally. Also, guava has general haemostatic properties and can be used for

treating bleeding nose, gums and minor internal hemorrhaging. Guava, having high

content of roughage, no cholesterol & less digestible carbohydrates, is good for those

trying to lose weight.

Researches have shown that guava is pretty effective in preventing cancer and

even heart diseases in people. Guava is also effective in lowering cholesterol and blood

sugar levels due to the presence of complex carbohydrates and dietary fibers.

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Guava leaves help cure dysentery, by inhibiting microbial growth and removing

extra mucus from the intestines. Guava is one of the richest sources of dietary fiber and

thus, strengthens and tones up the digestive system and even disinfects the same. It is also

good for those suffering from constipation. Guavas can improve the texture of skin and

help avoid skin problems. For the purpose, you can either eat it raw or make wash your

skin with a decoction of its immature fruits and leaves, which is also known to bring

relief in cough and cold.

The presence of ascorbic acid and other phytonutrients, such as carotenoids,

isoffavonoids and polyphenols (quercetin in particular), in guava leaves has led to it

being an effective antioxidant. Thus, help the body in combating free radicals produced

during metabolism and aids in preventing age-related chronic diseases, such as

Alzheimer’s, cataract and rheumatoid arthritis.

Much of the therapeutic activity of guava is attributed to the flavonoids of the

leaves which also demonstrate antibacterial and antioxidant effect together with Vitamin

C and other phytonutrients. Since certain antibacterial and antioxidants nowadays are

being used in industry as food preservatives, guava leaves may be a source of

preservative for fruits like bananas.

Some of the commercial food preservatives available today contain harmful

substances which may not be safe for human health. Due to this, researchers are now

searching for alternative preservatives which are cheaper and safer to use. Guava leaves

may be the answer.

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Statement of the Problem

The study was conducted to determine the effect of guava leaves extract in

bananas.

The following questions need to be answered:

1) What are the components of guava leaves extract which have uses and abilities

similar to commercial preservatives?

2) How effective is the guava leaves extract in preserving bananas?

3) What makes guava leaves extract different compared to commercial

preservatives in terms of:

-effectivity -affordability

-eye appeal -availability

-odor -safetiness

4) Is guava leaves extract feasible as a substitute for commercial preservatives?

Hypothesis

Is there a significant relationship between guava leaves extract and commercial

preservatives in preserving fruits like bananas?

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Objectives

1) General Objective

The study aims to lengthen the shelf-life of fruits like bananas.

2) Specific Objective

The study was conducted to produce an alternative preservative from guava

leaves which is more affordable, more available and safer to use.

Scope and Limitation

The study was conducted in Dipaculao, a town in Aurora which is plenty of

guavas and bananas, and during the peak season of the latter.

Basically, the study was limited to families and individuals consuming bananas

but do not have refrigerators and cannot afford to buy commercial preservative, thus

cannot consume bigger mass of bananas. However, it may also be applicable to vendors

of bananas who are in the need of a preservative but cannot afford any.

Significance of the Study

The study aims to benefit the following populations:

To the researcher, this may help him to have the ability to buy bigger mass of

bananas without the need to worry of its shelf-life.

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To the small farmers and vendors of bananas, this may be a help for them in

maintaining the texture of bananas until these were delivered and consumed.

To the families without refrigerators and cannot afford commercial preservatives,

this may cause them not to buy retail bananas or that which will be consumed for a short

span of time anymore. Instead, they can buy more bananas which can stay in shelves for

longer time.

To the entire population, this may be the answer in its search for available,

affordable, and safer-to-use preservative.

CHAPTER II

REVIEW OF RELATED LITERATURE

This study have included in this chapter some literature relevant to the conduct of

the study as well as discussions of the findings of the various studies conducted which

were related with this study to shed light towards better understanding of this study.

Related Literature

Antioxidant is a type of molecule that neutralizes harmful compounds called free

radicals that damage living cells, spoil food, and degrade materials such as rubber,

gasoline, and lubricating oils. These work against the molecules that form free radicals by

destroying them before they can begin the domino effect that leads to oxidative damage.

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Although oxygen metabolism is essential to life, the antioxidants diminish excessive

activity and damage to the cell.

Antioxidants can take the form of enzymes in the body or vitamin supplements.

They are routinely added to metals, oils, and other materials to prevent free radical

damage. Antioxidants are also used as industrial additives and food preservative.

Industrial antioxidants slow or prevent oxidative damage that causes food to spoil, and

fats and oil to change color or go rancid. Ascorbic acid or vitamin C and the synthetic

antioxidants butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are

among the antioxidants used nowadays as food preservative. These antioxidants are

added to foodstuffs in concentrations of much less than 1 percent.

It was also reported that carotenoids, molecules found in tomatoes, carrots and

guavas, have the ability to neutralize harmful compounds such as free radicals that are

known to damage cells. Therefore, this compound is now accepted as an antioxidant.

However, antibacterial or antimicrobials are chemical compounds used to kill or

inhibit the growth of microorganisms. These work against organic compounds produced

by bacteria or molds to prevent the damages caused by these.

Antibacterial may be classified as bactericidal (killing bacteria) or bacteriostatic

(stopping bacterial growth and multiplication). Some types of antibacterial are antiviral,

antibody, antitoxin, antispasmodic and antiseptics.

Antiseptic, a type of antibacterial, is a physical or chemical agent that prevents

putrefaction, infection, and analogous changes in food and living tissue by destroying or

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arresting the development of microorganisms. In ancient times some antiseptic agents

used were heat in cooking; niter, salt, and vinegar in corning and pickling; and wood

smoke (containing creosote) in the smoking of meats. Meanwhile, in modern times we

have processes like canning, pasteurization, and refrigeration.

In 1955, the Food and Drug Administration permitted for the first time the use of

an antibiotic in food. The antibiotic chlorotetracycline is used as a preservative for

uncooked poultry and is called Acronize. Added to the water in which poultry is chilled

after dressing, the antibiotic stops the early growth of bacteria responsible for most food

spoilage. Acronize introduces no change in taste, color, or appearance of the poultry. The

quantities of antibiotic added are so small that they are destroyed by cooking. Other

formulations, adaptable to the red meat and fish industries, are being developed.

Related Studies

Nowadays, studies are being conducted by many researchers to discover new

scientific uses of many natural sources. Psidium Guajava Linn (Myrtaceae) is one of such

natural sources which can have many potential scientific uses.

On 2002, a study regarding on the antimicrobial activity of guava leaves was

conducted by Anthony C. Dweck, a chartered chemist and scientist, and a fellow of the

Linnean Society. The study showed that the guava leaves contain an essential oil rich in

cineol, and 4 triterpenic acids as well as 3 flavonoids, quercetin, its 3-L-4-4-

arabinofuranoside (avicularin) and its 3-L-4-pyranoside, components with strong

antibacterial action. The leaves were extracted and the product showed in vitro

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antimicrobial activity against Escherichia coli, Salmonella typhus, Staphylococcus

aureus, Proteus mirabilis, and Shigella dycenteria. The tannin in the leaves was capable

of these. The flavone derivatives also in guava leaves were reported to inhibit the growth

of Staphylococcus aureus.

Similarly, a broad spectrum of the antimicrobial activity of guava leaves was

proved (Ibrahim Iliya et al., 2010).In the study, the leaves were extracted with hexane,

ethyl acetate and methanol which were tested in vitro for activity against standard strains

of microbes and clinical isolates. The in vitro antimicrobial screening revealed that the

extract inhibited varying activity against different microbes with zones of inhibition-

Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MIB)

and Minimum Fungicidal Concentrations (MIF). The highest activity was in MIC of 1.25

mg/mL and MBC of 2.5 mg/mL and none in fungi isolates except the Candida albicans.

The activities observed in the study were due to the presence of some secondary

metabolites such as tannins, saponins, terpenes and flavonoids which were detected and

have previously been reported in the plant.

Photochemical from guava leaves extract has also showed antioxidant activity

(Venent Nihorimbere et al., 2004). Dried ground guava leaves were extracted by water

and aqueous ethyl alcohol 50% (1:10 ratio), and total phenolic content in the extracts was

determined spectrophotometrically. By means of a 2, 2-diphenyl-1-picrylhydryzyl

(DPPH*) colorimetry with detection scheme at 515 nm, at ambient temperature, the

antioxidant activity of lyophilized extracts was determined. The activity was evaluated by

the decrease in absorbance as the result of DPPH* color change from purple to yellow.

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The results obtained implied that ascorbic acid, constituent of guava leaves extract, was a

substantially powerful antioxidant. This revealed that guava leaf extracts comprise

effective potential source of natural antioxidants.

Similarly, tannins from guava leaves extract which exist in aqueous and ethanolic

extracts act as antioxidants (Simeray et al., 1982; Yoshizawa et al., 1987).

It was also reported that the presence of Vitamin C and other phytonutrients, such

as carotenoids, isoffavonoids and polyphenols in guava has led to it being a substantially

effective antioxidant (Formica and Regelson, 1995).

CHAPTER III

METHODS OF RESEARCH AND PROCEDURE

This chapter offers discussions of the main method of research used in the

conduct of the study and the procedures in the conduct of the experiment.

Method of Research

The sole purpose of the study is to produce a natural fruit preservative from guava

leaves that is cheaper, more available and has no side effects to health but is as effective

as commercial preservative. The method of research used for the conduct and purpose of

this study was experimental method.

Methodology

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A) Materials and Equipments

¼ kg guava leaves

500 mL water

Cloth

Casserole

Container (preferably, a sprayer)

Bananas (at least 9 pieces; for experimentation)

B) Procedures

1) Preparation

The things needed-the casserole, ¼ kg guava leaves, 500 mL water,

bananas, cloth and container-were washed and placed on a clean table.

2) Formulation

One-fourth kilogram of guava leaves was put into the casserole together

with 500 mL water. It was boiled for 30 minutes. Then, using the cloth, the

residue was separated from the filtrate which is the final product. The product was

left to cool for 15 minutes and was poured into the container.

3) General Procedure

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Using the sprayer, guava leaves extract was sprayed to a group of bananas

(at least 3 pieces, for some unavoidable situations). It was left in a place where it

is safe and exposed in air together with another group of bananas without any

preservative, and a group with commercial preservative. The set-up was observed

daily for 12 days and the results were recorded.

CHAPTER IV

PRESENTATION, ANALYSIS AND INTERPRETATION OF

DATA

This chapter involves the discussion of results thru the analysis and interpretation

of data. It also presents all the data gathered from the perception of the respondents on

the natural and commercial preservatives in terms of cost, eye appeal, odor, effectivity,

availability and effects on health.

Findings

Table 1

Images of the Different Groups of Bananas in a Given Period of time

Period

Groups of Bananas

Without any

Preservative

With Natural

Preservative

With Commercial

Preservative

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Day 0

Day 3

Day 6

Day 9

14

Day 12

Table 2

Scores of 10 Respondents of the Natural and Commercial Preservative

in Terms of Effectivity, Eye Appeal and Odor

Sample Preservative Effectivity Eye Appeal Odor

Natural 5 5 6

Commercial 5 5 4

Table 3

Scores of 10 Respondents on the Secondary Evaluation of

Guava Leaves Extract as Preservative

Sample Preservative Availability Cost Effects on Health

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Natural 7 8 9

Commercial 3 2 1

Analysis of Data

Table 1 shows that the guava leaves extract is as effective as commercial

preservative. On the first 3 days of evaluation, all the bananas have almost the same peel

color-all are still yellow with dark spots and regions. After 6 and 9 days, these regions

turn larger for all the bananas, but the two sets of bananas with preservative have lesser

dark regions than the other one. When the bananas were all peeled on Day 12, images

show that those without any preservative have been totally spoiled, but still, in the two

other groups, bananas are still edible.

Table 2 shows that 50% of the respondents chose natural preservative in terms of

effectivity and eye appeal. It implies that they perceived that the natural preservative is as

effective as the commercial one. Meanwhile, most of them chose the natural one in terms

of odor.

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Table 3 shows that the respondents perceived that the natural preservative is more

available and affordable than the commercial one. Majority of the respondents also trust

the natural one when it comes to effects on human health.

CHAPTER V

SUMMARY OF FINDINGS, CONCLUSIONS AND

RECOMMENDATIONS

This section covers the summary of findings and generalizations formed based on

the results. Using the findings and conclusions, recommendations were also given.

Summary of Findings

The study was conducted to test the feasibility of the guava leaves extract in

preserving fruits, specifically bananas. The data gathered showed that the flavonoids and

other phytonutrients which are found in guava leaves and are also known as antioxidants

and antibacterial, have the ability to preserve fruits like bananas.

Since it has been found that it is effective, guava leaves extract was compared to

commercial preservative in terms of many aspects. The researcher used 10 respondents

who are vendors and consumers of bananas, and are aware on some aspects of

preservatives.

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The respondents found that guava leaves extract is as effective as commercial

preservatives. They also preferred both in terms of eye appeal. Yet, in terms of odor and

availability, guava leaves extract obtained better results. Meanwhile, most of the

respondents chose the natural one when it comes to cost. The data also showed that the

respondents perceived that guava leaves extract gives no side effect to human health.

Conclusions

Using the results as bases, the subsequent conclusions were drawn:

- The cineol and phytonutrients, such as carotenoids, isoffavonoids and

polyphenols (flavonoids) as well as saponins and Vitamin C found in guava leaves

extract make it effective in lengthening the shelf-life of fruits like bananas and thus, it is

acceptable as a preservative.

-It is as effective as commercial preservative but is cheaper, since guava leaves

are easily available and the extract is easy to make.

-It is feasible as a substitute for commercial preservative because aside from the

reasons which are already mentioned, it has no adverse effect on human health since it is

from natural and fresh leaves, and does not contain any amount of chemical or artificial

additives.

Recommendations

Based on the foregoing data, here are the recommendations given:

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-Guava leaves extract is recommended for preservative use, especially at home,

not only for bananas, but for other fruits and vegetables.

-For future researchers, further studies can be done to search for other plant

alternative containing flavonoids, carotenoids, or those having antioxidant and

antibacterial effect such as tomatoes (Lycopersicon esculentum), and carrots (Daucus

carota).

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Jonny Bowden. The 150 healthiest foods on earth.

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