Efficacy of Psidium Guajava Linn (Guava) Leaves Extract in Preserving Musa Acuminata Linn (Banana)

July 18, 2017 | Author: Hari Ramos | Category: Antioxidant, Antibiotics, Nutrition, Dietary Fiber, Food & Wine
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My science investigatory project in high school. This is now not downloadable since I saw a recent high school SIP which...



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.


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.

1 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.

1 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


-eye appeal




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?


1 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. 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.

1 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. Although oxygen metabolism is essential to life, the antioxidants diminish excessive activity and damage to the cell.

1 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

1 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-4-4arabinofuranoside (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

1 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 inhibitionMinimum 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

11 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 A) Materials and Equipments

11 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 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

11 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

Groups of Bananas Period

Without any

With Natural

With Commercial





Day 0

Day 3

Day 6

Day 9


Day 12

Table 2 Scores of 10 Respondents of the Natural and Commercial Preservative in Terms of Effectivity, Eye Appeal and Odor Sample Preservative


Eye Appeal










Table 3 Scores of 10 Respondents on the Secondary Evaluation of Guava Leaves Extract as Preservative Sample Preservative



Effects on Health










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. 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.



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. 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:

11 - 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 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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