SPOILAGE OF BANANA

R.M.Prabath Tharuka Rajapaksha

RT/FDT/22/14
Food Technology
University College of Ratmalana
FRUIT AND VEGETABLE PROCESSER
Title: Spoilage of fruits and vegetables
Objectives:
• To observe and explain the physical changes associate with the spoilage of selected
commodity.
• To be familiarized with the shelf life of the selected commodity.
• To determine the storage conditions to be applied to the selected commodity.
Introduction:
Spoilage, the gradual decline in quality and edibility of fruits and vegetables, arises from intricate
interactions between microorganisms, enzymes, and environmental conditions. Microbes such as
bacteria, molds, and yeasts, naturally present in the surrounding environment or introduced during
handling, can multiply rapidly on the surfaces of these produce items, leading to unsightly changes
in appearance, texture, and taste. Enzymes, the catalysts of biochemical reactions, become active
post-harvest, causing the breakdown of pigments, textures, and nutrients.

Temperature, humidity, and exposure to oxygen are critical determinants of spoilage rates.
Improper storage conditions can accelerate decay and cause the loss of essential vitamins and
antioxidants. In a globalized world, where fruits and vegetables traverse vast distances before
reaching consumers, understanding and managing spoilage is essential for reducing food waste
and promoting food security.

Spoilage of Banana

• Choose a representative sample of fresh, unripe bananas.

• It was stored in the ambient temperature in insect and pest attacks free place.
• Following criteria were observed and changes were recorded.
a. Aroma
b. Colour
c. Surface appearance
d. Presence of physical damages.
e. Texture/ Firmness
f. Other observable changes.

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Observations

➢ Day: - 01
➢ Aroma: - Aroma was raw
➢ Colour: - Green colour
➢ Surface appearance: - A black mark was observed.
➢ Physical damages: - Any physical damages weren’t observed.
➢ Texture: - Texture was hard.

➢ Day: - 02
➢ Aroma: - Fresh banana odor was felt.
➢ Colour: - Yellow colour observed.
➢ Surface appearance: - The fresh appearance and black mark was observed.
➢ Physical damages: - Any damages weren’t observed.
➢ Texture: - Stiffness was relieved.

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➢ Day: - 03
➢ Aroma: - Fresh and nice banana odor was observed.
➢ Colour: - Deep yellow colour was observed.
➢ Surface appearance: - The peel was appeared somewhat soft.
➢ Physical damages: - It wasn’t damaged physically.
➢ Texture: - when it was touched easy to press.

➢ Day: - 04
➢ Aroma: - Banana odder was higher than previous day.
➢ Colour: - Colour was deep yellow and some black.
➢ Surface appearance: - Some places on the peel was appeared very thin and watery.
➢ Physical damages: - It was not physical damage.
➢ Texture: - When it was touched it could be pressed very easily.

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➢ Day: - 05
➢ Aroma: - Strong aroma
➢ Colour: - Deep yellow and Black
➢ Surface appearance: - Banana peel was damage and some molds are there.
➢ Physical damages: - There was a bruise.
➢ Texture: - Peel was more than and surface was wet and easy to press.

➢ Day: - 06
➢ Aroma: - Strong odor
➢ Colour: - Black and some yellow.
➢ Surface appearance: - Peel was appeared more than and watery.
➢ Physical damages: - There was a bruise more than previous day.
➢ Texture: - Peel was easy to press more than previous day.

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➢ Day: - 07
➢ Aroma: - Unpleasant odor
➢ Colour: - Black colour
➢ Surface appearance: - Peel was dry and molds are there.
➢ Physical damages: - Can see damaged place and shrinking.
➢ Texture: - Texture was soft and more wet. When pressed it enters well. The liquid
continued to flow out.

➢ Day: -.08
➢ Aroma: - Smell was unpleasant.
➢ Colour: - Colour was black.
➢ Surface appearance: - Peel was appeared like dry and shrinking.
➢ Physical damages: - The damage had become fully.
➢ Texture: - It was completely dry.

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Discuss the changes you encountered during the experiment.

• Color Change: As the banana ripens, you'll notice changes in its color. The green skin
starts turning yellow due to the breakdown of chlorophyll and the production of
carotenoids.
• Texture Change: The banana becomes softer and less firm as enzymes break down the
starches into sugars. The texture changes from starchy to creamy, making it easier to eat.
• Aroma Development: The banana emits a distinctive aroma as it ripens. This is due to
the breakdown of certain compounds and the release of volatile organic compounds.
• Sweetness Increase: The levels of sugars, particularly glucose and fructose, increase
significantly. This leads to the sweeter taste associated with ripe bananas.
• Microbial Growth: As the banana becomes softer and sweeter, it becomes more
susceptible to microbial growth. Bacteria, molds, and yeast that are naturally present in
the environment and on the fruit's surface start to multiply. This can lead to visible mold
growth on the skin.
• Spoilage: The growth of microorganisms accelerates the decomposition of the banana.
The fruit may develop soft spots, brown or black areas, and an overall unpleasant
appearance. The texture becomes mushy, and the fruit may have off-putting odors due to
microbial activity.

Chemical Reactions during experiment

1. Enzymatic Browning:
• Enzyme: Polyphenol oxidase (PPO).
• Reaction: PPO catalyzes the oxidation of phenolic compounds (present in bananas) to
form brown pigments called melanin’s.
• Result: Brown spots and discoloration on the banana's skin and flesh.
2. Ethylene Production:
• Ethylene: A natural plant hormone.
• Production: Bananas release ethylene gas as they ripen.
• Effect: Accelerates the ripening process, leading to softening, sweetness, and changes in
flavor and texture.

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3. Starch to Sugar Conversion:
• Enzymes: Amylases.
• Reaction: Amylases break down starch (complex carbohydrate) into simpler sugars like
glucose and fructose.
• Result: Increased sweetness as the banana ripens.
4. Pectin Degradation:
• Enzymes: Pectinases.
• Reaction: Pectinases break down pectin, a complex carbohydrate that holds plant cells
together.
• Result: Softening of the banana's texture as cell walls break down.
5. Microbial Activity:
• Microorganisms: Bacteria, yeasts, molds.
• Action: Microbes thrive on the sugars and nutrients in the banana, leading to decay.
• Result: Off flavors, unpleasant odors, and visible mold growth.

Suggestions to discourage those reaction and increase shelf life, Pre-treatment,

Packaging requirement and optimum storage conditions.

Pre-treatment for Bananas

• Ripening Control: To extend the shelf life, control the ripening process. You can do this
by regulating the temperature and humidity during ripening. Use ethylene gas to initiate
and control ripening, and then store them under refrigeration to slow it down.
• Surface Cleaning: Clean the surface of bananas to remove dirt, dust, and potential
contaminants. A mild detergent or a vinegar solution followed by rinsing can help.
• Antifungal Treatment: Applying a natural antifungal treatment like neem oil can help
reduce the risk of fungal growth and spoilage.

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Packaging requirement

Bananas require minimal packaging. To protect against bruising and maintain freshness, they are
typically packed in clusters or individually in biodegradable, thin plastic bags or foam
cushioning within cardboard boxes. Adequate ventilation is crucial to prevent ripening and mold.
Labels indicating origin, variety, and nutritional information are also common.

Optimum Storage Conditions for Bananas:

• Temperature: Store bananas at temperatures around 13-15°C (55-59°F). This slows

down the ripening process but keeps the fruit from becoming too cold, which can damage
the texture and flavor.
• Humidity: Maintain high humidity (around 85-95%) in the storage area to prevent
moisture loss, which can lead to dehydration and browning.
• Ventilation: Proper air circulation is crucial to remove ethylene gas produced by the
fruit, which can accelerate ripening. Use well-ventilated storage rooms.
• Ethylene Control: Separate bananas from other ethylene-sensitive fruits and vegetables
as bananas produce ethylene, which can affect the ripening of neighboring produce.
• Packaging: Store bananas in perforated plastic bags or with a covering like plastic wrap
to regulate humidity and reduce exposure to external air, which can dry out the fruit.
• Regular Inspection: Check stored bananas regularly and remove any overripe or spoiled
fruit to prevent the spread of decay.

References

Kulkarni, S.G., Kudachikar, V.B. and Keshava Prakash, M.N. (2010) ‘Studies on physico-
chemical changes during artificial ripening of banana (Musa sp) variety “robusta”’,
Journal of Food Science and Technology, 48(6), pp. 730–734. doi:10.1007/s13197-010-
0133-y.

Storing bananas correctly do’s and don’ts (no date) Fresh bananas, pineapples, vegetables and
more from Dole.com. Available at: https://www.dole.com/en-gb/blog/nutrition/storing-
bananas-correctly-dos-and-donts (Accessed: 02 October 2023).

Maduwanthi, S.D.T. and Marapana, R.A.U.J. (2017) Biochemical changes during ripening of
Banana: A Review, DSpace Home. Available at:
http://dr.lib.sjp.ac.lk/handle/123456789/7777 (Accessed: 05 October 2023).