EFFECTIVENESS OF MUSSEL SHELLS AND EGGSHELLS AS AN AGENT

OF MANGO (Mangifera carabao) RIPENING

A Research Proposal Presented to the Faculty of the Senior High School

Department, Science, Technology, Engineering Mathematics
Juan R. Liwag Memorial High School, Gapan City
Nueva Ecija in Partial Fulfillment Of the
Requirements for the Subject

RESEARCH CAPSTONE

Bacas, Allyza Mae M.

Bermejo, Princess Angelica P.
Brananola, Jonette Faye F.
De Guzman, Jenna Rose M.
Esquivel, Angel Diana L.
Liwag, Alexa Marie A.
Mallare, Joetherese Y.
Maniego, Anna Lorein D.C.
Marcos, Jennilyn Cole G.
Nava, Honey Lei
Ocampo, Mary jane S.

Divine Claire L. San Diego

Adviser

MARCH 2023
Background of the Study
The ripening of mangoes is an essential process that affects the quality

and taste of the fruit. The use of synthetic ripening agents such as calcium

carbide poses a health hazard to consumers and can also damage the

environment. Calcium carbide contains traces of arsenic and phosphorous, and

once dissolved in water, it produces acetylene gas, which triggers the ripening

process in fruit by mimicking the effects of ethylene gas, a natural hormone

produced by fruit during ripening process (Okeke et al.,2022).

Arsenic, phosphorous and acetylene gas may affect the different body

organs and causes various health problems. The toxins in this species of

mango are found in the skin and flesh of the fruit and are known to cause an

allergic reaction in some people. The symptoms of this allergic reaction can

include itching, swelling, and difficulty breathing (Asif, 2012).

Mangoes (Mangifera carabao) are a popular nutritional tropical fruit

which are one of the most important fruit crops in tropical and subtropical

areas of the world. The global value chain (GVC) for mangoes has a large

share of the Philippine market share. Philippines was the seventh largest

exporter of fresh and dried mangoes in 2015. Four percent of global exports

of fresh and dried mangoes worth US$91 million are marketed (UN Comtrade,

2016). It accounts for an average of 10% of fresh and exported dried mangoes

(FAO, 2016).

Mussels’ shells are composites of calcium carbonate and organic

material created through a process known as biomineralization. Mussels draw

bicarbonate ions from seawater and use proteins in their bodies to make

crystals of calcium carbonate to form their two-layer shells. The shells outer

layer is composed of calcite and the inner layer is made of aragonite. In more

acidic water, there are less bicarbonate ions available for the mussels to make

their shells.

Joyce et al., (2001) investigated that the use of calcium improves the

ripening and postharvest quality of mangoes. It is known that calcium, a

mineral present in mussel shells, plays a crucial role in fruit ripening. Calcium

helps to regulate the enzymatic breakdown of pectin, a structural component

of plant cell walls, which leads to the softening of fruits during ripening.

An eggshell is the hard outer covering of an egg. It is consisting mostly

of calcium carbonate, a common form of calcium. It is a semi permeable

membrane, which means that air and moisture can pass through its pores

(Daengprok et al., 2003).

Eggshells contains calcium carbide which is used for the artificial

ripening of fruits. The fruit ripens because of the heat evolved while calcium

carbide reacts with moisture. During this reaction calcium hydroxide and

acetylene gas is formed. The most common use of calcium carbide is for the

preservation and maintenance of the firmness of fresh fruits (Martin et al.,

2007).

Thakur et al., (2019) investigated the use of different concentration of

ethylene gas produced by eggshells. The researchers found that ethylene gas
produced by eggshells was effective in ripening and improved the overall

quality of the fruit.

Mango (Mangifera carabao) is a juicy and sweet tropical fruit that grows

on the tropic regions throughout the world. It has a smooth, thin, and slightly

waxy skin that ranges in color from green to yellow to red, depending on the

variety and ripeness. The flesh of the mango is soft and juicy with a fibrous

texture and a sweet, fragrant flavor. It is a popular fruit around the world,

particularly in tropical regions such as South Asia, Southeast Asia, and the

Caribbean. It is not only enjoyed for its delicious taste but also valued for its

nutritional benefits, as it is a rich source of vitamins A and C, potassium, and

fiber (Lauricella et al.,2017).

However, mangoes do not ripen on the tree. Instead, these ripen after

harvest. This process can take anywhere from a few days to a few weeks,

depending on a variety of factors. The ripening process of mangoes can be

divided into two phases: pre-climacteric and climacteric. In the pre-climacteric

period, the mango is still green and hard and not yet ripe. However, once the

mango has reached its climacteric period, it begins to ripen rapidly. The

climacteric is triggered by the release of ethylene gas, a natural plant hormone

that helps regulate the fruit's ripening process. The mango itself produces

ethylene gas, which speeds up the ripening process. Other factors that can

trigger the release of ethylene gas include temperature, humidity, and contact

with other ripe fruit. As the mango matures, it undergoes several changes.

The pulp becomes softer and juicier, and the skin takes on a yellow or orange

hue. The taste becomes sweeter and more complex (Tharanathan et al.,2006).
 Mangoes are typically harvested when they are still unripe and firm,

and then allowed to ripen off the tree. Mango trees require specific conditions

and care to grow and produce healthy fruit, some factors that affect its growth

are climate, soil, fertilization, pruning, pest and disease control and harvesting.

With that said Fertilization plays a role in mango ripening it is a requirement

in which a mango needs a balanced fertilizer with equal parts of nitrogen,

phosphorus, and potassium every two or three months during the growing

season in order to promote healthy growth and fruit production and with the

use of Eggshells that contains Calcium carbide which is used for the artificial

ripening of fruits.

Eggshells and mussel shells as ripening agent is more organic and

natural because it does not contain any synthetic chemicals or harmful

substances. Eggshells are a good source of carbon carbonate, which can

provide some nutritional benefits to mangoes as they ripen. It is also low cost

and easily accessible ripening agent that can be obtained from households or

local farms. Eggshells and mussel shells does not have an impact on taste or

flavor of mangoes. They are more natural and nutrient rich way to ripen

mangoes.

This study will examine the effectiveness of mussel shells and eggshells

as an agent in mango ripening. To determine whether eggshells and mussel

shells can accelerate or delay the ripening process of mangoes.

STATEMENT OF THE PROBLEM

The study aims to investigate the effectiveness of mussel shells and

eggshells as natural ripening agents for mangoes. `

Specifically, the study aims to answer the following question:

1. What is the best treatment using mussel shells and eggshells as an

agent in mango ripening?

2. How effective are the different treatments of mussel shells and

eggshells on the ripening of mangoes in terms of:

a. Ripening time

b. Color

c. Firmness

d. Acidity

3. Is there a significant difference between the effectivity of the

experimental and control groups?

a. Ripening time

b. Color

c. Firmness

d. Acidity
HYPOTHESIS

1. Treatment 1 (pure eggshells) has the best treatment on ripening of

mangoes (Thakur et., al 2019). Ethylene gas produced by eggshells was

effective in ripening and improved the overall quality of the fruit.

2. The application of mussel shells and eggshells result in shorter ripening

time, with an average time of 5 days. The acidity level is also lower, with

a pH of 4.0. The fruit was softer with a scale of 4 in firmness and a color

range in yellow Thakur et al., (2019). Mangoes ripened in control group

(calcium carbide) results in 3 to 4 days ripening time with higher acidity

3.08 Ph, a scale of 5 in fruit firmness and a color range to yellow. Mangoes

ripened naturally with no agents took 7 or more days to ripen, with an

acidity level of 5.0 Ph or higher, a fruit firmness of 5 and a color range

from yellow (Shar Andre et al., 2017)

3. Null Hypothesis (HO): There is no significant difference between the

ripening rates of mangoes treated with mussel shells and eggshells

compared to the control group in terms of ripening time, color, firmness,

and acidity.

Alternative Hypothesis (Ha): There is a significant difference between the

ripening rates of mangoes treated with mussel shells and eggshells

compared to the control group in terms of ripening time, color, firmness,

and acidity.
SIGNIFICANCE OF THE STUDY

Synthetic ripening agents have been traditionally used to accelerate the

ripening process of mangoes, but they can be expensive and potentially

harmful to human health. This study will be undertaken to investigate the

effectiveness of mussel shells and eggshells as a natural ripening agent for

mango. This study will provide a potential alternative to the use calcium

carbide, which are commonly used to ripen mangoes. This study aims to

produce a low cost, easily accessible ripening agent that can be obtained from

the households and local farms.

The findings of the study are beneficial for the people that rely on the

agriculture, farmers and mango growers that want to utilize induced ripening

agent on the fruits effectively and to generate significant methods and signifies

for faster fruit development. The use of waste-derived materials can promote

sustainable practices in agriculture, reduce dependence on synthetic agents,

and provide high quality and safe mangoes. For the wider community, this

study can contribute to low expenses and production of high-quality safe and

sustainably grown mangoes promoting human health and well-being. This

study will also be relatively helpful for the future researchers as they can

gather data and use our sources as their references that are related to their

research study. Moreover, this study will be beneficial to the agricultural sector

as it promotes the adoption of sustainable and natural practices in food

production, reducing waste and cost and improving the quality and safety of

mangoes.
SCOPE AND DELIMITATION

This study was conducted to determine the ability of mussel shells and

eggshells as a natural ripening agent for mango carabao. The experiment will

involve obtaining a batch of mango carabao that are similar in level of ripeness.

The mangoes will be divided into six groups: one group to be ripened with

pure eggshells, one with pure mussel shells, two groups with mixed mussel

shells and eggshells, one with 70% mussel shells and 30% eggshells and one

with 30% mussel shell and 70 % eggshells and two control groups: one with

calcium carbide and one group to be ripened without any agents. The study

will be observed for 7 days and will be monitor the time it takes for each group

to ripen, color, acidity level and firmness. The study findings will provide

valuable insights into the potential use of mussel shells and eggshells as an

agent in ripening mango, which could have practical application in mango

industry.

The study was limited to only one variety of mangoes, and it may only

be applicable for mango carabao. The study will only observe for 7 days and

will not observe the changes in ripening after seven days. Furthermore, the

study will not investigate the chemicals used in ripening mangoes.

The experiment was conducted at the STEM Department at Juan R.

Liwag Memorial High School, Bayanihan, Gapan City, Nueva Ecija, from the

first week of March to May 2023.

Definition of Terms

The following terms in the study are defined operationally to ensure

clarity and better understanding.

a. Acidity- a measure of the sourness of the mango. The acidity will

be measured using pH meter. The lower the pH values the higher

the acidity of mango.

b. Calcium carbide- hazardous chemical compound that is used to

ripen fruits, particularly mangoes.

c. Climacteric period- is the final stage of ripening, which the fruit

reaches its peak quality and nutritional value.

d. Color- the measure of the visual appearance of the mango. The

color value will be used to determine the level of ripeness of

mangoes.

e. Eggshells – the thin, hard outer layer of an egg, especially a hen’s

egg.

f. Firmness- a measure of hardness of the mangoes. Firmness will

be measured using a penetrometer to determine the amount of

force requires to penetrate mango flesh.

g. Mangoes- a tropical usually a large or oblong fruit with a firm

yellowish-red skin, hard central stone, and juicy aromatic pulp.

h. Mussel shells- outer covering of a mussel, also composed mainly

of calcium carbonate.
i. Pre- climacteric period- is the early phase of ripening, which is

the fruit is still developing and maturing.

j. Ripening- is the process by which fruits attain their desirable

flavor, quality, color, palatable nature, and other textural properties.

 CHAPTER II
METHODOLOGY

Figure 1. Flowchart of Activities

COLLECTION OF MATERIALS

PREPARATION OF TREATMENTS

FRUIT RIPENING ASSAY

GATHERING OF DATA

WASTE DISPOSAL
Collection of materials

The fresh mangoes were obtained in a farm in Malimba, Gapan City,

Nueva Ecija. All mangoes were harvested in a single tree, picked on the same

day, and selected based on its uniformity in size, shape, and maturity. The

mussel shells and eggshells are collected from household wastage and chosen

based on availability and good condition. The calcium carbide was obtained in

the local market in San Vicente, Gapan City, Nueva Ecija and used as a

negative control group. All materials were carefully selected based on their

quality, availability, and suitability for the study’s objectives.

Preparation of treatments

Six treatments were prepared for the fruit ripening assay. The mangoes

were first rinsed thoroughly with clean water to remove any dirt and debris.

The mussel shell and eggshell were also rinsed with water to remove any

unnecessary substances that could interfere the ripening process. After

rinsing, the materials were dried under direct sunlight for 24 hours to eliminate

any remaining moisture that could lead to bacterial growth or spoilage. The

eggshell and mussel shells were then manually crushed using a mortar and

pestle, most likely to create a fine powder that can be easily added to the

mangoes to promote ripening.

Table 1 provides an overview of the different treatment groups used

and agents applied in ripening mangoes.

 Table 1. Treatment groups and agents in mango carabao ripening.

TREATMENTS COMPOSITION

Treatment 1 (Test Group)

100% eggshells
EXPERIMENTAL

Treatment 2 (Test Group)

GROUP

100% mussel shells

Treatment 3 (Test Group)
70% eggshells + 30% mussel shells
Treatment 4 (Test Group)
70% mussel shells + 30% eggshells
Treatment 5 (Positive control)
CONTROL

calcium carbide 10 g
GROUP

treatment 6 (Negative control)

No ripening agent

Fruit Ripening Assay

The groups were divided into 6 groups and labeled with the type of

treatment. The treatment involves placing the mangoes in container with clean

treatment concentration. The mangoes were then covered with a newspaper

to ensure the powder or treatment that will be using stayed in contact with

them. The mangoes will be sealed and will be assessed by measuring the fruit

firmness, color, acidity and ripening time. Throughout the ripening period,

observations were made to note any physical changes on mangoes.

For fruit firmness testing, the hand method is the simplest and

commonly used technique to measure fruit firmness. The mangoes were

gently squeeze at the stem end using the thumb and forefinger of the other

hand. Pressure is applied gradually until the fruit starts to yield and give way.

Using a firmness scale record the firmness from the scale 1 to 5, where 1 is
very soft and 5 is very firm. For the number of days, the mangoes were

monitored from the start of the ripening process for a 7-day period and will

be monitored based on visual inspection and testing of firmness. For the skin

color testing, the mango will visually be evaluated and recorded according to

a color chart with a range of colors from green to yellow to orange. For the

acidity testing, a strip of pH paper is dipped into the fruit juice or pulp for a

few seconds, and the color of the paper is compared to a color chart to

determine the pH value. The pH of the juice was then measured using a pH

paper on the 7th day.

Gathering of Data

The data gathering process involved the measurements of multiple

variables. Four specific variables were analyzed:

Firmness: measured by determining the force required to penetrate flesh of

each mango using a hand method. The firmness will be evaluated on the 7th

day using a scale from 1 to 5 where 1 is very soft and 5 is very firm.

Ripening time: The number of the days taken to mangoes to ripe will be

monitor and recorded for seven days.

Color: visually evaluated and recorded according to a color chart with a range

of colors from green to yellow to orange.

Acidity: measured using a pH paper, with a small sample of mango juice

extracted and the pH recorded.

 All the data will be collected every 2 days for a period of 7 days. The

number of days to optimum ripeness will be recorded once the mango reached

the desire level of ripeness based on color and firmness within the 7-day

period.

Disposal of waste

Organic waste such as leftover mangoes, eggshells and mussel shells

will be disposed in a compost pit in Malimba, Gapan city, Nueva Ecija. Chemical

waste such as calcium carbide will be sealed and disposed of in accordance

with local regulation. Non-organic waste including plastics, container and any

other non-organic material used in experiments will be disposed in the

appropriate recycling or waste disposal bins in Juan R. Liwag Memorial

Highschool.