Why are fruits coated with a new layer?
Before you even see a shiny apple or a pristine lemon at the grocery store, it has undergone a process that is crucial for its journey from the farm. Fruits naturally produce a waxy layer to protect against moisture loss, decay, and environmental damage while growing. However, this natural wax is removed during the washing process after harvest to clean the produce of dirt and debris. To counteract the rapid moisture loss and shriveling that would occur without this protective barrier, a food-grade coating is applied. This practice is not new, with records of merchants waxing oranges as early as the 12th century to preserve them.
The primary goals of applying these coatings include:
- Extending shelf life: By creating a barrier that reduces moisture loss and respiration, the coating slows down the ripening and decay process.
- Enhancing appearance: Coatings give the fruit a desirable shine, making it more visually appealing and marketable to consumers.
- Protecting against damage: The thin layer protects the fruit from bruising and physical damage during transportation.
- Controlling microbial growth: Some coatings incorporate antimicrobial agents to inhibit the growth of mold and other microorganisms.
Types of coatings used on produce
Several different materials are used for coating fruit, with the most common being natural waxes. However, more advanced options like protein-based and herbal coatings are also in use.
Commonly used waxes:
- Carnauba Wax: Sourced from the leaves of the carnauba palm tree in Brazil, this is a very popular, natural, and edible wax that provides a high-gloss finish.
- Shellac Wax: Derived from the resin secreted by the female lac bug, shellac is a natural wax used to provide a durable, glossy barrier.
- Beeswax: A natural wax produced by honeybees, often used in conjunction with other ingredients for coatings.
- Food-Grade Paraffin Wax: A colorless and odorless wax derived from petroleum, it is considered safe for consumption by the FDA and is often used on produce and hard cheeses.
Other edible films and coatings:
- Chitosan: A natural polysaccharide derived from the shells of crustaceans, chitosan forms an effective antimicrobial and gas-barrier film.
- Proteins: Coatings can be made from plant-based proteins (like corn zein or soy protein) or animal-based proteins (like whey or milk casein).
- Herbal Extracts: Increasingly, extracts from plants like aloe vera gel, neem, and lemongrass are used for their natural antimicrobial properties.
Are fruit coatings safe to eat?
For most people, the edible coatings used on produce are safe to consume and are regulated by food safety authorities like the FDA. These coatings are applied in very thin layers and are often indigestible, simply passing through the body without being absorbed. However, some individuals may have concerns or specific dietary needs, such as:
- Allergies: Some coatings may contain protein allergens like soy or milk derivatives. Consumers with severe allergies should check product labels or avoid coated produce.
- Chemical Additives: While rare and regulated, some coatings may include morpholine, which has raised cancer concerns when combined with nitrates in the body. Experts generally consider the levels used to be low-risk, but sensitive individuals may prefer to avoid it.
- Personal Preference: Many people prefer to remove coatings for peace of mind or to avoid the texture, even if they are technically edible.
Comparison of common fruit coatings
| Feature | Carnauba Wax | Shellac Wax | Food-Grade Paraffin Wax | Chitosan Coating |
|---|---|---|---|---|
| Source | Palm leaves (natural) | Lac bug resin (natural) | Petroleum (synthetic, but food-safe) | Crustacean shells (natural) |
| Appearance | High-gloss, shiny finish | Durable, glossy finish | Shiny, polished look | Translucent, film-like |
| Primary Function | Moisture retention, aesthetic appeal | Preservative seal, high protection | Extends shelf life, prevents moisture loss | Antimicrobial, gas barrier |
| Organic Status | Permitted for organic produce | Natural, but not always suitable for vegans/vegetarians | Not permitted on organic produce | Source can be controlled for organic compliance |
| Key Benefit | Versatile, very high melting point | Effective preservative, durable | Economical, effective barrier | Excellent antimicrobial properties |
| Common Use | Apples, citrus fruits, candies | Citrus fruits, melons, some nuts | Apples, cucumbers, hard cheeses | Various fruits, especially berries and papayas |
How to remove wax coatings at home
For those who wish to remove the coating from their produce, a simple rinse under running tap water is often enough for surface-level dirt, but it may not be sufficient for the more water-repellent waxes. Here are a few more effective methods:
- Warm Water and Scrubbing: Use a soft brush or a clean cloth and scrub the fruit gently under warm running water. This can help soften and remove a large portion of the coating.
- Vinegar or Lemon Juice Soak: For a more thorough cleaning, prepare a solution of warm water mixed with a small amount of white vinegar or lemon juice. Soak the produce for a few minutes, then scrub and rinse thoroughly.
- Baking Soda Paste: Create a thin paste using baking soda and water. Apply the paste to the fruit, scrub, and then rinse it off completely. Baking soda is a gentle abrasive that can help lift the coating.
Conclusion
In summary, the glossy finish on many fruits is not a mysterious or harmful substance but a carefully applied, food-grade coating designed to extend shelf life and maintain quality. While some fruits have natural waxes, commercial cleaning removes this, necessitating a replacement. The coatings used are typically natural waxes, like carnauba and shellac, or other edible films, all regulated for consumer safety. For those concerned, simple washing methods can effectively remove most of the coating, allowing you to enjoy your produce with confidence.
Frequently Asked Questions
Is the shiny coating on apples and other fruits dangerous?
No, the coatings are food-grade and generally considered safe by regulatory bodies like the FDA. They are applied in small amounts and are usually indigestible, passing through the body without being absorbed.
Why do producers apply a coating if fruit has its own natural wax?
During the washing and cleaning process after harvest, the fruit's natural wax is removed along with dirt and debris. The new, food-grade coating is applied to replace this natural barrier and prevent rapid moisture loss and decay during shipping and storage.
Can people with allergies eat waxed fruit?
Some edible coatings may contain allergens, such as soy or milk proteins. Individuals with allergies should check for ingredient statements on shipping containers or choose produce from sources that can confirm the coating's composition.
How can I tell if a fruit has a wax coating?
Most produce with a commercial wax coating will have a shiny, uniform finish. In the United States, bulk shipping containers are required to display information about the type of coating used. Organic produce will typically use naturally derived, organic-approved coatings, if any.
Do organic fruits have a coating?
Organic produce may still have a coating, but it must be derived from natural sources that comply with organic standards, such as carnauba wax or beeswax. Petroleum-based paraffin wax is not permitted on organic fruits.
What is morpholine, and is it a concern?
Morpholine is sometimes used as an emulsifier to apply the wax more evenly. While morpholine itself is considered low-risk at the levels used, it can react with nitrates in the body to form a carcinogenic compound. The risk is generally considered slight, but some consumers prefer to avoid it.
Why does some fruit look cloudy after being refrigerated?
Some wax coatings, particularly shellac-based ones, can turn milky or cloudy when exposed to moisture condensation, such as when moved from cold storage to a warmer room. This is a physical change and does not affect the safety or flavor of the fruit.
What are they coating fruit with? Is it just wax?
Not always. In addition to natural and petroleum-based waxes, modern edible films can also be made from other materials like chitosan (from shellfish), protein isolates (like soy or corn zein), and even herbal extracts.
