Is fruit biodegradable? (3 layers of fruits)

This article shall answer the question, “is fruit biodegradable?

It shall also cover other areas such as:

  • The biodegradation process.
  • Factors affecting biodegradation of fruits.
  • Compounds are produced by fruits.
  • Parts of a fruit.

Is fruit biodegradable?

Yes, fruits are biodegradable because they are naturally occurring, organic substances of plants.

The process of biodegradation involves different agents but bacteria and fungi are the primary agents of biodegradation.

Biodegradation is the process by which natural organic materials are broken down into small particles, water, and carbon dioxide by microorganisms.

Some microorganisms produce methane instead of carbon dioxide, depending on the material broken down or their biological machinery.

The agents of biodegradation include:

  • Water.
  • Sunlight.
  • Temperature.
  • Bacteria.
  • Fungi.

Water.

This causes biodegradation by carrying the materials and causing mechanical breakdown.

Sunlight.

Some light wavelengths cause the mechanical breakdown of organic materials into smaller particles.

Temperature.

Temperature causes the expansion and contraction of organic materials.

This causes the material to experience stress which in return results in mechanical breakdown.

Bacteria.

Bacteria break down organic material through the process of respiration to form small particles which they use to acquire energy.

The most common and active bacteria include:

  • Pseudomonas.
  • Bacillus.
  • Mycobacteria.
  • Aspergillus.

Fungi.

They break down organic matter into small particles which they then assimilate into their body systems.

They include:

  • Yeasts.
  • Mushrooms
  • Molds.
  • Mildew.
  • Lichens.

Types of biodegradation.

Types of biodegradation include:

Aerobic biodegradation.

This entails bacteria and fungi breaking down organic matter by the use of oxygen.

The end products include water, carbon dioxide, small particles( small biomass), and energy.

This process is faster than anaerobic biodegradation.

Anaerobic biodegradation.

This entails the bacteria breaking down organic matter in the absence of oxygen.

The end products include water, methane gas, small particles ( small biomass), and energy.

This process is slower as compared to aerobic biodegradation although it is more efficient.

Steps of biodegradation.

Biodegradation occurs in three distinct steps:

  • Biodeterioration.
  • Bio-fragmentation.
  • Assimilation.

Biodeterioration.

This is the first stage of biodegradation.

Organic materials are mechanically broken down by light, water, and temperature into smaller particles that are easily acted upon by bacteria and fungi.

Bio-fragmentation.

This is the second stage of biodegradation.

Organic matter is broken down by bacteria and fungi, either aerobically or anaerobically.

Water, carbon dioxide, methane gas, energy, and small biomass are produced depending on the type of process.

Assimilation.

It’s the last stage of biodegradation.

Involves the uptake of biomass produced into the body system of the bacteria or fungi to be used in various biological processes.

What are the factors affecting fruit biodegradation?

The rate of fruit biodegradation depends on several factors in the environment.

The different factors include the following:

Available minerals.

The nutrients and minerals available in the environment of the bacteria and fungi determine the rate of biodegradation.

Some nutrients such as proteins are required for the synthesis of bacterial and fungal enzymes and mineral metals are required to activate the enzymes.

 Enzymes increase the speed of biodegradation.

Temperature.

There is a wide range of temperatures that bacteria use to break substances.

Bacteria are categorized based on the temperature of their environment. Mesophilic bacteria live at room temperatures, psychrophilic bacteria live at very low temperatures while thermophilic bacteria live at very high temperatures.

Under low temperatures, the psychrophilic bacteria become active and their metabolism increases, the rate of biodegradation also rises.

Under high temperatures, the thermophilic is their optimum best and they degrade fruits at a higher rate.

Mesophilic bacteria are the majority, these bacteria are always amongst us and they are always actively degrading different organic substances.

Aeration.

As pointed out before, there are 2 types of biodegradation, aerobic and anaerobic. Aerobic biodegradation requires oxygen while anaerobic doesn’t require oxygen.

Aerobic biodegradation occurs at a faster rate than the anaerobic one, but anaerobic biodegradation is more efficient than aerobic biodegradation.l

pH.

The microbial environment can be acidic, neutral, or alkaline. The fungi are best active at acidic low pH while the bacteria are more active in neutral and alkaline conditions.

Bacterial and fungal enzymes involved are activated or denatured at different pH. In acidic conditions, fungal enzymes are activated and bacterial enzymes are inactivated or denatured.

In neutral to alkaline pH, the bacterial enzymes are activated while the fungal enzymes are inactivated.

Moisture.

Some enzymatic reactions such as hydrolysis require water to happen. Water helps in the breakdown of bonds between molecules which hastens the action of microorganisms.

Animals.

Animals such as rodents, insects, and even humans weaken the fruit structures. The weakened structures are easily degraded by the microorganisms because there is low resistance.

What are the parts of fruits?

Fruits are divided into three main parts or layers.

The biodegradation of fruits is limited by the outermost covering which acts as the protective barrier from the microbes.

The 3 layers of fruits are:

  • The epicarp.
  • The mesocarp.
  • The endocarp.

The epicarp.

This is the outermost part of the peel. It is also called the exocarp. 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.

Endocarp.

This is the innermost part of the fruit. It is the edible part that covers the seeds. In some fruits, the endocarp may be a hard part, but in most cases, mostly in citrus fruits, the endocarp is soft, fleshy, and juicy.

What are the compounds produced by plants?

Apart from the nutrients which include vitamins, proteins, lipids, and cellulose fiber, fruits also release other compounds as secondary metabolites.

Some of the compounds include:

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.

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.

Are fruits eco-friendly?

Yes, according to a study, fruit parts are eco-friendly. They are biodegradable to produce simple molecules that are used to enrich the soil as humus.

It’s good though to practice responsible disposal of fruits and their wastes. Some fruits and their peels may take longer to degrade and therefore may lead to environmental pollution.

Conclusion.

The article has answered the question of the biodegradability of fruits.

It has also looked into other areas such as:

  • The biodegradation process.
  • Factors affecting fruit biodegradation.
  • Parts of a fruit.
  • Eco-friendliness of fruits.

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

Frequently Asked Questions (FAQs): is fruit biodegradable?

Are all fruits and vegetables biodegradable?

Yes, all fruits and their wastes are biodegradable. They are organic materials and therefore susceptible to microbial degradation.

Are fruit peels biodegradable or non-biodegradable?

Fruit peels are biodegradable. They are organic matter which is broken down by the microorganisms such as bacteria and fungi.

Is banana peel littering?

Yes, reckless throwing away of banana peels into the environment is littering. Although banana peels are biodegradable, they do not do so overnight. They take up to 6 months to break down and therefore they litter the environment.

Citations.

Geronimo. (3 years ago). Is Biodegradable Littering Okay? It’s Definitely Not and Here’s Why.

Retrieved from:

https://earthbuddies.net/biodegradable-littering/amp/

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#!

Diet High in Fruit and Vegetables Helps the Environment. (Published: February 12, 2018): An article on Technology Networks.

Retrieved from:

https://www.technologynetworks.com/applied-sciences/news/diet-high-in-fruit-and-vegetables-helps-the-environment-297373

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