Apples are universally relished fruits that are commonly characterised by their rosy red or green tinge and crunchy fresh bites with bursts of aromatic flavours. Its importance in the human growth and healing process is evident in the common phrase “An apple a day keeps the doctor away”. The nourishing aspect of apples is attributed to the bounteous presence of dietary fibre, Vitamin C, fruit sugars and potassium. Similarly, it is rich in polyphenols with antioxidants like Quercetin, Catechin and Chlorogenic acid which have anti-inflammatory traits, anticancer properties and improve brain and muscle functions. Manganese, copper, calcium and Vitamins A, E, B1, B2, B6 and K are also present in apples. Hence, it is one of the most common nourishing fruit choices for children, adults and sick alike.
Mythological references also validate the goodness of apples. The age-old aura of apples can be linked to its reference in the Bible, where apples are interestingly linked to the start of human life on earth. Ironically, apple is encrypted here as ‘the forbidden fruit’. The first human male Adam and female, Eve was forbidden by God to eat the apples from the ‘Tree of knowledge’ in the "Garden of Eden". So tempting was the fruit that Eve and Adam could not resist eating it and were consequently denied of that paradise and doomed to face hardship on Earth.
As with any fresh fruit, the commercial value of apples is challenged by its gradual loss of moisture and shiny appeal during ambient storage. Wax coating is an innovative process by which shelf life can be extended and shininess can be maintained.
Apples shine due to the vibrant natural tinge on its skin owing to the presence of carotenoids, pigments and natural wax. A wide array of esters and triterpenioids are present in the natural wax in apple peel. Wax helps to seal loss of moisture thereby preventing it from shrivelling and losing its crispiness. Ursolic acid, a major component in natural wax, is water repellant and inhibits the proliferation of cancer cells. It also acts as a precursor to potent bioactive compounds like anti-tumor agents. Apple skin, while providing glossiness to the fruit, also serves as a source of nutrients including vitamins and fibre.
Fresh apples are normally preserved in Cold Storage or Controlled Atmosphere (CA) storage. Coating apples with wax helps to preserve it in its near natural form.
Coating Wax On Fruits
Wax is an inert compound and poses no reactions to possible acidity or alkalinity of food. The application of molten wax is a traditional means of food preservation. The application of bottled jam, jelly, pickles etc. is still in practice in some home scale operations. The scope of use of wax is now gradually widening.
Coatings like Carnauba wax extracted from a Brazilian palm, Candelilla originating from a desert plant, Bees wax from honeycomb and Shellac from Indian lac bug have commercial applications worldwide. Globally apples, tomatoes, melons, peppers, peaches, plums, cucumbers, eggplants, lemons, mangoes, oranges, papaya etc. are treated with wax.
Wax coating obstructs air passage in fruits, thereby reducing oxidation processes which could otherwise catalyze ripening and ageing reactions. Furthermore, it protects the surface from damage or infestation.
Scientific studies infer that edible wax coating in fruits significantly reduces firmness, water activity, change in appearance and weight loss as compared to those stored under room temperature. Post-harvest treatment related scientific studies in Nepal have inferred that wax coating reduced loss of juice and enhanced shelf life in Mandarin (Citrus reticulata Blanco), commonly referred to as species of orange.
Common techniques of coating wax on fruits include dipping, brushing and spraying like fine aerosols or Nano emulsions. Wax layers inside bottled food like jam, jelly etc. can easily be removed before using because the wax layer is in a solid ring form. However, thin wax coatings on fruit may not be visible and are often removed by scraping or peeling.
Permitted Edible Wax
Permitted edible wax like Candelilla wax, Carnauba Wax, Beeswax (yellow and white) have been enlisted in Title 21- Food and Drugs, Chapter 1, Part 184— “Direct food substances affirmed as GRAS (generally reconised as safe)” of the Code of Federal Regulations of the US FDA (United State Food and Drug Administration). Furthermore, packaged forms of waxed fruits and vegetables require declaration. In case of bulk sale, it is the responsibility of the retailer to provide information by displaying the bulk packaging labels or use of counter cards.
The CODE General Standard for Food Additives (CODE STAN 192-1995- Revision 2008) outlines the use of Beeswax, Candelilla wax and Shellac under GMP (Good Manufacturing Practice) for surface-treated fresh fruit since its adoption in 2003. Similarly, the Carnuba wax was adopted by Codex Standard in 2004 for use in surface-treated fruits with a maximum permissible rate of 400mg/kg.
With easier access to global markets, Nepalese consumers today have the choice of a wide variety of imported fruits, including apples. Regular monitoring by regulatory authorities is thus indispensable and pivotal. The Department of Food Technology and Quality Control under the Ministry of Agriculture and Livestock Development is the focal point for enforcement of Food Act, 2023 and Food Rules, 2027 in Nepal. Nepalese Food Rules and Regulations are in line with the CODEX framework
Handling Wax Coated Fruits
The amount of wax and carrier material, if used, during wax coating of fruit needs to comply with applicable regulations. This is more significant in cases where fruits are normally eaten with the peel like in case of apples.
Available literatures haven’t outlined any significant adverse health impacts of wax coating. However, wax layers, if thick enough, could cause internal choking or blockade within the body. Wax is normally not absorbed after ingestion and is known to pass through the digestive system without being assimilated. Synthetic wax coating, if present in significant amounts, may cause harm to the colon or small intestine.
Some people peel apples skin before eating. By doing so, wax coating, if applied, is eliminated however valuable nutrients on the fruit peel are also lost. Thin wax layers can be washed off in hot water or vinegar to some extent. But prolonged washing or dipping in water could leach some water soluble vitamins from the fruits.
Monitoring Food Safety
It is always healthier to consume near natural food. However, food processing technologies have to be applied to preserve fresh harvest and enhance its shelf life. Today, it is almost impossible to imagine a life without processed food in some form or the other.
Use of food additives, including technologies like wax coating necessities compliance to applicable regulations. Adoption of safe food practises, especially on the part of food handlers, is crucial.
Access to safe food is a basic human right. Well-informed citizens can make sensible food choices and adopt safer ways of handling food. For this, consumers need to be aware of emerging technologies in the food they consume.
Government’s role to ensure fair practice in trade and disseminate relevant information will be in the interest of the public. A systemic approach for sustained management of food safety shall ensure prosperity as every healthy citizen is an asset to the nation.
(The author is a food technologist and can be contacted at firstname.lastname@example.org)