<p>These fruits are subsequently allowed to ripen because of the action of ripening hormone (ethylene) naturally produced by fruits. However, natural ripening in some fruits is a slow process, which leads to high weight loss, desiccation of fruits and uneven ripening. Most fruit traders resort to artificial ripening. Smoking and calcium carbide treatments are the widely used artificial ripening methods used by small traders. The smoke treatment involves burning heaps of straw, leaves and cow-dung in a closed chamber, and allowing mangoes to ripen in this condition. Calcium carbide is a banned chemical and treatment of fruit with this chemical has several bad-effects. In fact, the government has banned the use of calcium carbide for ripening fruits under PFA Act 8-44 AA, 1954. <br /><br />Alternatives to calcium carbide<br />Ethrel or ethephon is a commercially available plant growth regulator. It is a source of ethylene similar to the organic compound naturally released by fruits during the ripening process. Although dipping of fruits in diluted ethrel solution is recommended for ripening, it is a cumbersome process and may cause some problems if commercially available ethrel contains chemical impurities. To overcome these problems, ethylene gas is commercially used in modern ripening chambers which requires huge investment and is not economical for farmers or small traders. Catalytic reactor-based ethylene generators, which produce ethylene gas using ethanol, methanol or ethrel, are also available.<br />The Indian Institute of Horticultural Research (IIHR) Hessarghatta, Bangalore, has evolved a simple solution to enhance the ripening process by exposing fruits to ethylene gas released from ethrel/ethephon solution. <br />This is a simple method wherein a small quantity of alkali is added to ethrel to release ethylene. <br /><br />The fruits are exposed to this liberated gas in air-tight portable plastic tents. In this method, the fruits are placed in ventilated plastic crates inside air-tight plastic tents of known volume. <br /><br />The required quantity of ethrel is placed in a container and placed inside the tents. Alkali (sodium hydroxide) is added to release ethylene gas from ethrel solution. The tents are sealed and kept air-tight. A small battery-operated fan is placed inside the tent for uniform circulation of released ethylene gas. <br /><br />After 18-24 hours of exposure, the fruits are taken out for completing the ripening process at room temperature or 18-24°C especially for the Robusta banana variety. Using dessert coolers during ripening at room temperature reduces temperature and increases the relative humidity thereby reducing weight loss.<br />Mango fruits exposed to 100 ppm ethylene gas for 24 hours can be ripened in five days at room temperature as compared to 10 days in non-treated fruits without adversely affecting the quality. Similarly, banana bunches exposed to 100 ppm ethylene gas for 18 hours can be ripened in four days at room temperature and six days at 20°C. Papaya fruits exposed to ethylene gas ripens with uniform surface colour and uniform firmness in four days at room temperature.<br /><br />Bad effects of calcium carbide<br />Fruits are still being commercially ripened with a banned chemical like calcium carbide. The chemical reacts with water vapour in the atmosphere and releases acetylene gas. <br />Some traders ripen fruits like banana in closed chambers where large quantities of calcium carbide are placed and water sprinkled. <br />The chambers are then sealed. While the released acetylene triggers ripening in fruits, it is an inflammable gas involving risk of fire hazards. <br />There are who traders still place calcium carbide in small packets in fruit boxes. In some cases, traders sprinkle calcium carbide onto the fruit surface. <br />Calcium carbide contains chemical impurities such as arsenic hydride and phosphorus hydride which are considered highly carcinogenic compounds, and is therefore dangerous if consumed. <br />Shrinidhi Adiga</p>
<p>These fruits are subsequently allowed to ripen because of the action of ripening hormone (ethylene) naturally produced by fruits. However, natural ripening in some fruits is a slow process, which leads to high weight loss, desiccation of fruits and uneven ripening. Most fruit traders resort to artificial ripening. Smoking and calcium carbide treatments are the widely used artificial ripening methods used by small traders. The smoke treatment involves burning heaps of straw, leaves and cow-dung in a closed chamber, and allowing mangoes to ripen in this condition. Calcium carbide is a banned chemical and treatment of fruit with this chemical has several bad-effects. In fact, the government has banned the use of calcium carbide for ripening fruits under PFA Act 8-44 AA, 1954. <br /><br />Alternatives to calcium carbide<br />Ethrel or ethephon is a commercially available plant growth regulator. It is a source of ethylene similar to the organic compound naturally released by fruits during the ripening process. Although dipping of fruits in diluted ethrel solution is recommended for ripening, it is a cumbersome process and may cause some problems if commercially available ethrel contains chemical impurities. To overcome these problems, ethylene gas is commercially used in modern ripening chambers which requires huge investment and is not economical for farmers or small traders. Catalytic reactor-based ethylene generators, which produce ethylene gas using ethanol, methanol or ethrel, are also available.<br />The Indian Institute of Horticultural Research (IIHR) Hessarghatta, Bangalore, has evolved a simple solution to enhance the ripening process by exposing fruits to ethylene gas released from ethrel/ethephon solution. <br />This is a simple method wherein a small quantity of alkali is added to ethrel to release ethylene. <br /><br />The fruits are exposed to this liberated gas in air-tight portable plastic tents. In this method, the fruits are placed in ventilated plastic crates inside air-tight plastic tents of known volume. <br /><br />The required quantity of ethrel is placed in a container and placed inside the tents. Alkali (sodium hydroxide) is added to release ethylene gas from ethrel solution. The tents are sealed and kept air-tight. A small battery-operated fan is placed inside the tent for uniform circulation of released ethylene gas. <br /><br />After 18-24 hours of exposure, the fruits are taken out for completing the ripening process at room temperature or 18-24°C especially for the Robusta banana variety. Using dessert coolers during ripening at room temperature reduces temperature and increases the relative humidity thereby reducing weight loss.<br />Mango fruits exposed to 100 ppm ethylene gas for 24 hours can be ripened in five days at room temperature as compared to 10 days in non-treated fruits without adversely affecting the quality. Similarly, banana bunches exposed to 100 ppm ethylene gas for 18 hours can be ripened in four days at room temperature and six days at 20°C. Papaya fruits exposed to ethylene gas ripens with uniform surface colour and uniform firmness in four days at room temperature.<br /><br />Bad effects of calcium carbide<br />Fruits are still being commercially ripened with a banned chemical like calcium carbide. The chemical reacts with water vapour in the atmosphere and releases acetylene gas. <br />Some traders ripen fruits like banana in closed chambers where large quantities of calcium carbide are placed and water sprinkled. <br />The chambers are then sealed. While the released acetylene triggers ripening in fruits, it is an inflammable gas involving risk of fire hazards. <br />There are who traders still place calcium carbide in small packets in fruit boxes. In some cases, traders sprinkle calcium carbide onto the fruit surface. <br />Calcium carbide contains chemical impurities such as arsenic hydride and phosphorus hydride which are considered highly carcinogenic compounds, and is therefore dangerous if consumed. <br />Shrinidhi Adiga</p>
