Home > Artificial Ripening of Fruits

Fruit ripening is a combination of physiological, biochemical, and molecular processes which lead to changes in colour, sugar content, acidity, texture, and aroma. In general, it is a physiological process which makes the fruit edible, palatable and nutritious. Fruits are classified into two categories according to the ripening pattern:

Climacteric fruits: These fruits are usually harvested once they have reached its full maturity and can be further ripened during transit or storage. These include banana, guava, avocado, mango, apple, pears, apricots, peach, tomato etc.

Non-climacteric fruits: These fruits do not ripen after harvest. Thus, in order to attain full ripeness and flavour, these fruits are often harvested once they have fully matured and ripened in the orchard. It includes fruits such as lemons, orange, grape, cherry, pineapple, strawberry etc.

Need for artificial ripening:

Artificial ripening is the process by which ripening is controlled to achieve desired characteristics intended for better consumer acceptance and improving sales. It is generally done for climacteric fruits such as mango, papaya, banana, etc. to achieve faster and uniform ripening characteristics. Globally, artificially ripened fruits are considered as safe for human consumption if done using safe ripening agents. It facilitates the transportation of fruits like mango, banana, etc. which become soft and perishable after ripening. These fruits are transported to distant places in unripe condition to avoid loss and are artificially ripened at the destination market before sale.

Provisions for artificial ripening under FSS Regulations:

Artificial ripening of fruits by acetylene gas, commonly known as carbide gas is prohibited as per the provision in sub regulation 2.3.5 of Food Safety and Standards (Prohibition and Restrictions on Sales) Regulation, 2011. It permits the use of ethylene gas at a concentration up to 100 ppm (100µl/L) depending upon the crop, variety and maturity for artificial ripening of fruits.

Issues in Artificial ripening:

The Industrial-grade calcium carbide, popularly known as “masala” is often used by some unscrupulous traders to release acetylene gas for artificial ripening of fruits like mango, banana, papaya, etc. Calcium carbide contains traces of arsenic and phosphorus which is harmful for humans and may cause dizziness, frequent thirst, irritation, weakness, difficulty in swallowing, vomiting, skin ulcer, etc. The acetylene gas released from calcium carbide is equally harmful for handlers. There are chances that calcium carbide may come in direct contact with fruits during application and leave residues of arsenic and phosphorus on fruits. Thus, use of this chemical for ripening of fruits is banned in India.

Considering the issue of rampant use of banned calcium carbide and non-availability of alternative ripening agent, Food Safety & Standards Authority of India (FSSAI) permitted the use of ethylene gas for ripening of fruits in India vide notification dated 23.08.2016.

Artificial ripening using ethylene gas:

Ethylene is a hormone naturally produced within the fruit and regulates fruit ripening by initiating and controlling a series of chemical and biochemical activities. The treatment of unripe fruits with ethylene gas triggers the natural ripening until the fruit itself starts producing ethylene in large quantities.

A Standard Operating Procedures (SOP) detailing all aspects of artificial ripening of fruits by ethylene gas is developed by the Working Group constituted at FSSAI on the recommendation of Scientific Panel on Fruits & Vegetables and their Products (Including dried fruits and nuts, salt, spices and condiments). The Working Group consists of members from the Scientific Panel and experts from relevant research institutes.

Standard Operating Procedure:

1. Restrictions

• Any preparation containing calcium carbide or acetylene gas
• Any source of ethylene gas coming in direct contact with fruits

2. Requirements for Ethylene Ripening System/Chamber

• Air tight room, preferably an insulated one for better temperature control
• Temperature regulation systems (cooling heating)
• Humidity regulation system
• Proper air circulation and ventilation
• Ethylene gas generation / injection system
• Ensured power supply (for ripening chambers)
• Display board indicating temperature, relative humidity, ethylene concentration, CO2 concentration

3. Suggested handling conditions for stacking of fruits and air circulation

Fruits should be kept in ventilated plastic crates or stackable fruit boxes inside the ripening chamber/temporary structure. Stacking of boxes should be done keeping minimum 4–6-inch space from the walls and between the adjacent crates. For uniform ripening, airflow throughout the chamber shall be maintained. Fruit should not occupy more than 75% of the volume of the chamber (as well as crate) during the treatment.

For food business operators/traders:

1. Pre-treatment operations:
   • Harvest the fruits at optimum maturity
   • Treatment with ethylene up to 100 ppm
   • Procure ethylene cylinder/aerosol cans/Ethephon/Ethrel from reputed companies
   • Ensure authenticity / purity of the sachet containing ethephon in powder form and other components.
   • Use well labelled sachets mentioning details of manufacturer, composition, instructions for use etc.
   • Ethylene releasing agents shall not come in direct contact with fruits.
   • For uniform ripening in chambers, airflow throughout the room shall be maintained. Fruit should not occupy more than 75% of the volume of the chamber (as well as crate) during the treatment.
   • Relative Humidity, temperature and exposure time shall be maintained during ripening for best results.
   • CO2 concentration shall be maintained below 5000 ppm
2. Post-treatment operations:
   • Transfer the fruits to ventilated room with appropriate storage temperature and relative humidity for ripening after completion of the treatment.
   • Remove the sachet out of the fruit boxes after completion of the treatment
3. Guidelines for safety
   • Ethylene gas is highly inflammable. Cylinders should be used with caution. Ethylene concentrations above 27000 ppm are explosive.
   • Smoking should be strictly prohibited around the premises.
   • Electrical circuits should be properly monitored.
   • Gas leakage monitoring system should be installed in the commercial ripening chambers.

Guidelines for natural ripening:

Fruits may be ripened naturally using the below mentioned methods within 4-6 days, if kept at room temperature These methods entrap ethylene around fruit and facilitates faster ripening.

• Harvest the fruits at optimum maturity.
• Wrap the fruits individually with paper or place it in paper bag.
• Keep unripe fruits as layers over paddy husk or wheat straw.
• Keep unripe fruits inside an air tight rice bin/container.

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• Guidance Note – Artificial Ripening of Fruits

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