Guava extract as preservative

STEPHEN T. TO-ONG 8-RUBY 1

THE EFFECTIVENESS OF GUAVA LEAVES EXTRACT AS A NATURAL PRESERVATIVE

FOR VEGETABLES AND FRUITS

Science Investigatory Project Presented to

Mrs. Josephine Impe

Science 8 Teacher

Napnapan National High School

Tigbauan, Iloilo

Stephen T. To-ong

8-Ruby

2013-2014


Acknowledgment

The researcher would like to extend his sincere thanks and appreciation to

the following people who have contributed, in one way or another, to the

realization of this study.

Mr. Paul T. Tejero, for the assistance and valuable suggestions,

conceptualization, editing the study, helping the researcher for the study, and

for the invaluable tips to improve the quality of the research study;

Mrs. Josephine Impe, research adviser, for the encouragement and

support to the completion of the study. Also, for the assistance and valuable

suggestions and for the invaluable tips to improve the quality of the research

study;

To-ong and Tejero families, the wind beneath my wings as I reach my

goals in life, for the unconditional love and prayers, for understanding, and

moral support, despite of the challenges that come along;

Most of all, to Almighty God, for giving the researcher the courage,

knowledge, guidance, love and blessings.

Stephen T. To-ong


Table of Contents

Page

Title Page

Acknowledgment

Chapter

1 Problem & Background of the Study

Introduction

Statement of the Problem.

Hypothesis.

Objectives of the Study.

Scope and Limitations.

Definition of Terms .

Significance of the study.

2 Review of Related Literature

Related Literature

Related Studies

3 Methods of Research and Procedure

Method of Research

Methodology

4 Presentation, Analysis & Interpretation of Data

Findings


Analysis of Data

5 Summary of Findings, Conclusions & Recommendations

Summary of Findings

Conclusions

Recommendations

References


List of Tables

Table Page

1 Images of the Different Groups of Bananas in a Given

Period of time

2 Scores of 20 Respondents of the Natural and Commercial

Preservative in Terms of Effectivity, Eye Appeal and

Odor..

3 Scores of 20 Respondents on the Secondary Evaluation

of Guava Leaves Extract as Preservative..

4 Operating Procedure..


Stephen T. To-ong. FEASIBILITY STUDY OF THE GUAVA LEAVES EXTRACT AS A

NATURAL PRESERVATIVE FOR VEGETABLES AND FRUITS. Unpublished Science

Investigatory Project (SIP). Napnapan National High School, Tigbauan, Iloilo.

ABSTRACT

For generations, people bought, caught, or raised fresh foods and

cooked them at home to feed their families every day. From the beginning,

people struggled to preserve what they gathered, in order to ensure food

reserves during times of scarcity. Vegetables and fruits were also dried or stored

below ground in a safe place.

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 spoilage is one of the

problems the people are facing nowadays, specifically, the vegetable and fruit

vendors, and consumers who dont have refrigerators at home and cannot

afford any commercial preservative, in turn cannot store vegetables and fruits

for a long time.

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

commercial preservatives to preserve the vegetables and fruits, came up with

the idea and experiment to produce a home-made, easily available,


affordable, easy-to-made, and safe-to-use vegetable and fruit preservative

from the guava leaves extract.

One-fourth (1/4) 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 (it can be applied or used

also to any vegetables or fruits) and the result showed that the constituents of

the extract led to it being able to prolong the shelf-life of fruit- banana.


THE EFFECTIVENESS OF GUAVA LEAVES EXTRACT AS A NATURAL PRESERVATIVE

FOR VEGETABLES AND FRUITS

Stephen T. To-ong

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

Since the beginning of time, people have looked for ways to preserve

food. Without preservation, all foods will spoil in time. Pests, chemicals, and

micro-organisms are the great agents most often responsible for food spoilage.

They can be found everywhere that vegetables and fruits are grown, harvested

and stored. However, spoilage may occur before changes in the flavor or odor

can be noticed. For those who cannot afford to buy preservatives for the food,


the researcher have studied guava as a natural preservative to solve the main

problem in preserving foods.

Guava (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, fibres 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 haemorrhaging. 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 fibres.

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 Alzheimers, 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,

researcher is now searching for alternative preservatives which are cheaper and

safer to use. Guava leaves may be the answer.


Statement of the Problem

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

in vegetables or fruits like bananas which is the subject of the study.

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 vegetables or fruits like bananas?


Objectives of the study

1) General Objective

The study aims to lengthen the shelf-life of vegetables or fruits like

bananas which is the subject of the study.

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 Sitio Gines, Barangay Napnapan Sur,

Tigbauan, Iloilo which has plenty of guavas and bananas, and during the peak

season of the latter.

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

vegetables or fruits specifically bananas but do not have refrigerators and

cannot afford to buy commercial preservative, thus cannot consume bigger

mass of any vegetables or fruit specifically bananas. However, it may also be

applicable to vendors of any vegetables or fruits specifically bananas who are

in the need of a preservative but cannot afford any.


Definition of terms

Bananas- A banana is an edible fruit produced by several kinds of large

herbaceous flowering plants of the genus Musa.

Carotenoids- are organic pigments that are found in the chloroplasts and

chromoplasts of plants and some other photosynthetic organisms like algae,

some bacteria, and some fungi. Carotenoids can be produced from fats and

other basic organic metabolic building blocks by all these organisms.

Carotenoids generally cannot be manufactured by species in the animal

kingdom so animals obtain carotenoids in their diets, and may employ them in

various ways in metabolism.

Cineol- is a natural organic compound which is a colorless liquid. It is a

cyclic ether and a monoterpenoid.

Commercial preservative- are those preservatives which can be bought

in the market.

Dysentery- is an inflammatory disorder of the intestine, especially of the

colon, that results in severe diarrhea containing blood and mucus in the feces

with fever, abdominal pain, and rectal tenesmus (a feeling of incomplete

defecation), caused by any kind of infection.


Extract- is a substance made by extracting a part of a raw material, often

by using a solvent such as ethanol or water. Extracts may be sold as tinctures or

in powder form.

Flavonoids- are a class of plant secondary metabolites. Flavonoids were

referred to as Vitamin P (probably because of the effect they had on the

permeability of vascular capillaries) from the mid-1930s to early 50s, but the term

has since fallen out of use.

Food- material consisting essentially of protein, carbohydrate, and fat

used in the to sustain growth, repair, and vital processes and to furnish energy.

Guava- any of several tropical American shrubs or small trees of the

myrtle family. It is widely cultivated for its sweet acid yellow or pink fruit.

Guava Leaves Extract- the liquid produced from the guava leaf after it

has been boiled.

Isoffavonoids- are a class of flavonoid phenolic compounds. They are

biologically active compounds, such as phytoestrogens, produced by pea

family plants. Isoflavonoids are derived from the flavonoid biosynthesis pathway

via liquiritigenin or naringenin.


Natural preservative-it is not required that it can be bought in the market.

It has no other chemicals mixed not just like commercial preservative.

Photochemical- The chemistry of the effects of light on chemical systems.

Phytonutrients- natural chemicals that are found in a variety of plant

foods.

Polyphenols- are a structural class of mainly natural, but also synthetic or

semisynthetic, organic chemicals characterized by the presence of large

multiples of phenol structural units. The number and characteristics of these

phenol structures underlie the unique physical, chemical, and biological

(metabolic, toxic, therapeutic, etc.) properties of particular members of the

class. They may be broadly classified as phenolic acids, flavonoids, stilbenes,

and lignans.

Preservative- is a naturally occurring or synthetically produced substance

that is added to products such as foods, pharmaceuticals, paints, biological

samples, wood, etc. to prevent decomposition by microbial growth or by

undesirable chemical changes.

Spoilage- is the process in which food deteriorates to the point in which it

is not edible to humans or its quality of edibility becomes reduced.


Vegetables- is an edible plant or its part, intended for cooking or eating

raw.

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 any vegetables or fruits like bananas without the need to worry of its shelf-life.

To the small farmers and vendors of any vegetables or fruits like bananas,

this may be a help for them in maintaining the texture of their products until

these were delivered and consumed.

To the families without refrigerators and cannot afford commercial

preservatives, this may cause them not to buy retail any vegetables or fruits like

bananas or that which will be consumed for a short span of time anymore.

Instead, they can buy more any vegetables or fruits like 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

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. 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 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.

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 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. 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 vegetable and 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. Any vegetables or fruits may be used as the subject of the study but in

this case, the researcher used banana as a subject of the study.

Methodology

A) Materials and Equipments

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, 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

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 through 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

Day 0


Day 6

Day 8

Day

10

Day

12


Table 2

Scores of 20 Respondents of the Natural and Commercial Preservative in Terms

of Effectivity, Eye Appeal and Odor

Sample

Preservative

Effectivity Eye Appeal Odor

Natural 12 13 12

Commercial 8 7 8

Table 3

Scores of 20 Respondents on the Secondary Evaluation of Guava Leaves

Extract as Preservative

Sample

Preservative

Availability Cost Effects on Health

Natural 14 16 18

Commercial 6 4 2


Analysis of Data

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

preservative. On the first 6 days of evaluation, all the bananas have almost the

same peel color-all are still yellow with dark spots and regions. After 8 and 10

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 most 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.

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.


Table 4

Operating Procedure

PROCEDURE PICTURE

One-fourth kilogram of guava leaves

was put into the casserole together

with 500 mL water.

Boil for 30 minutes

Using the cloth, the residue was

separated from the filtrate which is the

final product.

Left the product to cool for at least 15

minutes and pour it into the container.


Using the sprayer, spray the guava

leaves extract to a group of bananas

Left the bananas in a place where it is safe and exposed in air

Observe the set-up for 12 days. The

result should be recorded daily.


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 vegetables and 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 20 respondents who are vendors and consumers of bananas, and are

aware on some aspects of preservatives.


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.

In this study, it was found out that it should not need to buy commercial

preservatives in the local market just to preserve the vegetables and fruits that

have in the table for a longer time. What should be needed is just to look for

guava (any variety will do) leaves and have with you the natural preservative

that youre looking for. Today, we should be more practical, save for money

and protect our health. Let ourselves not to be encouraged by advertisements

either in radio or TV, because in fact, we dont really need it much but be wise

all the time in all aspects that we need for ourselves. Its always in the

environment, dont need to go far just look for what you want.

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:

Guava leaves extract is recommended for preservative use, especially at

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

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 and carrots. Further, theres a million

of topics that can be used by the different plants in the environment. What

should need to do is to experiment, study and research. Just like this study, it was

just an experimental study in which accidentally gave a good result. Always


remember, almost all discoveries by the people are all the result of accidents

that even them dont really expect such much.


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Guava extract as preservative