Is fruit peel biodegradable? (7 substances found in fruit peel). 

This article shall answer the question, ” is fruit peel biodegradable?”.

In addition, it shall also cover other areas such as:

  • Parts of fruit peel.
  • Compound in fruit peel.
  • Applications of substances found in fruit peel.
  • Eco-friendliness of fruit peel.

Is fruit peel biodegradable?

Yes, fruit peel is a biodegradable material. Fruit peel is categorized as an organic material because it is part of the plant structure.

Plant products are organic and naturally break down into small biomass and give out products such as carbon dioxide, methane, and water.

Biodegradation is the process by which naturally occurring organic materials are broken down by microorganisms such as bacteria and fungi into small particles which are not harmful to the environment.

Biodegradation is carried out by different agents such as UV radiation, light, wind, and water but the most effective agents of biodegradation are bacteria and fungi.

Biodegradation occurs in three distinct stages: biodeterioration, bio-fragmentation, and assimilation.

The biodeterioration process loosens up the structure of the organic substance. For instance, the cell wall of plants is weakened by light, wind, water, and UV radiation.

Bio-fragmentation involves the breakdown of organic matter into smaller, nontoxic particles by bacteria and fungi, releasing water and carbon dioxide in the process.

Assimilation is the last stage of biodegradation and it involves the microorganisms taking up the products of bio-fragmentation into their biological machinery to be used to make energy.

Biodegradation can either involve the microorganisms using oxygen, aerobic biodegradation or it can involve the microorganisms which do not use oxygen, anaerobic biodegradation.

Aerobic biodegradation breaks down organic matter into small biomass, producing carbon dioxide and water.

Anaerobic biodegradation breaks down organic matter into small biomass and in the process carbon dioxide and methane gases are produced.

Aerobic biodegradation occurs at a faster rate than anaerobic biodegradation whereas anaerobic respiration is more efficient and produces more gases and other products.

Different fruit peels take different periods to break down completely. It is estimated that banana peels take weeks to 2 months to break down while lemon peels take the longest time, up to 6 months to break down.

What is a fruit peel?

This is the outer covering of fruit. It is also called a fruit skin or rind. The skin can be peeled like in a banana or be eaten together with the fruit like in apples.

In most cases, the peel is bitter, unpleasant, and inedible. It is estimated that the outer part of the fruit contains dietary fiber, vitamin C, and calcium.

Parts of a fruit peel.

The fruit peel is made up of two main layers, the exocarp, and the mesocarp.

Exocarp.

This is the outermost part of the peel. It is also called the epicarp. It forms a tough outer skin. In citrus fruits, it is called the flavedo.

The flavedo contains mostly the cellulose material, but it also contains other compounds such as essential oils, paraffin waxes, steroids, triterpenoids, fatty acids, limonin( the bitter material), and enzymes and color pigments such as carotenoids, chlorophylls, and flavonoids.

When the fruit is ripening, the flavedo contains carotenoids, mostly xanthophyll, inside the Chromoplasts, which contained chlorophyll during the previous stage of fruit development.

The hormonal change of pigments from chlorophyll to xanthophyll leads to fruits changing from green to different colors, for instance, yellow in oranges, upon ripening.

Mesocarp.

The mesocarp is the middle layer of the fruit structure. It is the layer between epicarp and endocarp. 

In some fruits, the mesocarp is eaten together with the fruit, but in citrus fruits, the mesocarp, also called albedo or pith, is the inner part of the peel and is removed before eating fruit.

What are the compounds found in fruit peel?

Fruit peel is one of the most complex structures of fruits. The layers of the peel, the epicarp, and the mesocarp contain a lot of compounds that help the fruit in healthy development.

The compounds found in a fruit peel include the following:

  • Pigments such as carotenoids, chlorophyll, and flavonoids.
  • Essential oils.
  • Triterpenoids.
  • Fatty acids.
  • Limonin.
  • Paraffin waxes.
  • Enzymes.

What are fruit pigments?

These are compounds that help the plant develop its characteristic color.

The pigments include carotenoids, chlorophyll, and flavonoids.

Carotenoids.

These pigments are also called tetraterpenoids. They occur in yellow, red, and orange colors.

Carotenoids are produced by plants, algae, and several bacteria and fungi. They give colors to carrots, salmon, shrimp, lobster, parsnips, pumpkins, corn, and tomatoes.

Carotenoids can also be produced by aphids and spider mites.

Carotenoids are subdivided into two classes: xanthophylls( oxygen-containing carotenoids) and carotenes ( which are hydrocarbons; containing carbon, oxygen, and hydrogen atoms)

Carotenoids are all tetraterpenes; they contain 8  isoprene molecules. Carotenoids absorb light in the wavelength of 400-550nm; the violet and green light region.

Carotenoids absorb light for photosynthesis and also they protect the plants from harmful light radiations

Chlorophyll.

This is a color pigment found in the plants, some bacteria, and algae plants. The chlorophyll gives the plant parts their characteristic green colors.

The green color in fruits is caused by chlorophyll, but the color changes from green to different colors depending on the chlorophyllin cells.

The chlorophyll helps the plant absorb a certain light wavelength which is used in photosynthesis. There are different types of chlorophyll pigments, a and b. 

They occur in different plants and algae.

Flavonoids.

These are compounds that are secondary metabolites of plant cells. They are classified into different classes such as:

  • Flavonoids or bioflavonoids.
  • Isoflavonoids.
  • Neoflavonoids.

Flavonoids are used in phytochemistry and medicinal chemistry to form organic medicine and other biologically important compounds.

Essential oil.

This is a hydrophobic, volatile, chemical liquid that is produced by plants.

Oils derived from plants are used in several fields. The essential oils contain the essence of the fragrance of the fruit from which they are produced.

Essential oils have been used for medication, although sometimes the user can cause allergic reactions, inflammations, and skin irritation.

Examples of essential oils include olive oil, lavender oil, peppermint, tea tree oil, patchouli, eucalyptus, sandalwood oil, Neem oil, and many others.

The oils are harvested by crushing the fruit peels or other plant parts and heating them in a soxhlet extractor and then distilling. 

Essential oils can be used as local anesthetics, counterirritants, fragrances, and flavors. The oils are also used as pesticides.

Steroids and triterpenoids.

These are compounds produced by plants for various purposes.

They are used to synthesize hormones and chemicals such as vitamin D3.

Types of steroids include cholesterol, sex hormones ( estradiol and testosterone), anti-inflammatory drug; dexamethasone.

Steroids have been used to produce antibiotics such as amphotericin B and azole antifungals. 

Triterpenoids or triterpenes are chemical compounds made from terpene monomers. In animals, the isoprene monomer of triterpenoid is used to make cholesterol.

Triterpenoids are produced by plants mainly for self-defense mechanisms. They include ginsenosides and eleutherosides.

Limonin.

Limonin is a white and bitter substance found in citrus fruits. It is found in large concentrations in the fruit peels.

Limonin and other related compounds contribute to the bitter taste of fruits and fruit peels. 

Oranges and lemons are some of the citrus fruits with the highest concentration of limonoids.

Research has shown that limonin has the following medical advantages:

  • It can be used to inhibit the replication of retroviruses such as HIV-1 and HTLV-I.
  • It can be used as a neuroprotector.
  • It reduces the growth of colon cancer cells.
  • It has been tested as an anti-obesity agent in mice.

Is fruit peel eco-friendly?

Yes, fruit peel is eco-friendly because it can easily degrade in the environment into small non-toxic substances.

Fruit peels can also be composted and improve the nutrients in the compost. They are high in calcium and other nutrients which are essential for crop growth.

According to a study, it does not mean that fruit peels should be disposed of improperly. Some peels such as lemon peel can take a longer time to break down and therefore if poorly disposed of, they may accumulate in the environment, causing pollution.

Conclusion.

This article has answered the question of the biodegradability of fruit peel.

It has also covered other areas such as:

  • Parts of fruit peel.
  • Compounds are found in fruit peels.
  • Application of compounds found in fruit peel.
  • Eco-friendliness of fruit peel.

For any questions or comments please use the comment section below.

Frequently Asked Questions (FAQs): is fruit peel biodegradable?

Are fruits biodegradable?

Yes, fruits are organic substances produced by plants. They are susceptible to microbial degradation, a process called biodegradation.

They, therefore, do not pollute the environment.

Is orange peel biodegradable?

Yes, orange peel is broken down by microorganisms such as bacteria and fungi into small biomass that is non-toxic to the environment.

Is banana biodegradable?

Yes, bananas are biodegradable. Bananas are organic substances produced by plants. Plant products are susceptible to microbial degradation and are broken down to produce small biomass, water, and carbon dioxide.

Citations.

Jayachandra S.Yaradoddiab, Nagaraj R. Banapurmath, Sharanabasava V. Ganachariab Manzoore, Elahi M. Soudagard, Ashok M. Sajjana Shrinidhi Kamatab M.A. Mujtabae Ashok. ( April 2022). Bio-based material from fruit waste of orange peel for industrial applications: Journal of Materials Research and Technology. Volume 17, Pages 3186-3197.

Retrieved from:

https://www.sciencedirect.com/science/article/pii/S2238785421009972#!

Jana Hemphill. (Jun 27, 2019). I CAN THROW MY PEEL ON THE GROUND, RIGHT?: Just how long does it take for things like orange peels and pistachio shells to decompose outdoors? Let’s take a look!

Retrieved from:

https://www.deschuteslandtrust.org/news/blog/2019-blog-posts/decomposition-organic-litter

Rodrigo, María Jesús; Cilla, Antonio; Barberá, Reyes; Zacarías, Lorenzo (2015). “Carotenoid bioaccessibility in pulp and fresh juice from carotenoid-rich sweet oranges and mandarins”. Food & Function. 6 (6): 1950–1959. doi:10.1039/c5fo00258c. 

What was missing from this post which could have made it better?

Leave a Comment