Plums South Africa Peaches South Africa ARTIFICIAL RIPENING : WHAT WE ARE EATING

In recent times there is much concern about artificial ripening of fruits in many parts of the world including Bangladesh. Large amount of tropical fruits are produced in Bangladesh. Though fruits like mango naturally ripen in trees; some chemicals are used to ripen them artificially which hasten the ripening process. Ripe fruits are not suitable to carry & distribute as they get rotten. So fruit traders pick unripe fruits & use certain methods to increase the shelf life of them. For many years Ethylene had been used as a fruit ripening agent. But nowa-days Calcium carbide is getting popular in this regard as it has a faster ripening property. But inappropriate use of Carbide to ripen fruits is associated with many health hazards. In this topic we have tried to reveal the essentials of this burning issue & looked for solutions. 1. Post Graduate Trainee, Dept. of Medicine, Dhaka Medical College Hospital. 2. Post Graduate Trainee, Dept. of Medicine, Dhaka Medical College Hospital. 3. Associate Professor, Dept.of Medicine, Dhaka Medical College. J MEDICINE 2008; 9 : 42-44

Ripening is a process in fruits that causes them to become more edible.In general, a fruit becomes sweeter, less green, and softer as it ripens.However the acidity as well as sweetness rises during ripening, but the fruit still tastes sweeter regardless.An organic compound involved with ripening is ethylene, a gas created by plants from the amino acid methionine.Ethylene increases the intracellular levels of certain enzymes in fruit and fresh-cut products, which include: • Amylase, which hydrolyzes starch to produce simple sugars, and • Pectinase, which hydrolyzes pectin, a substance that keeps fruit hard.
Other enzymes break down the green pigment chlorophyll, which is replaced by blue, yellow, or red pigment. 1 Mango fruits ripen unevenly on the tree and natural ripening can be very slow and unpredictable.Hence, to overcome these problems certain chemicals are used to ripen the fruits artificially.Fruits are briefly exposed to ethylene or similar gases like acetylene to initiate the ripening process.Ethylene is known to be a plant hormone that triggers fruit ripening.It has been reported that if ethylene is applied exogenously it helps fruit ripening. 2Ethylenetreatment is usually given at the packing house or at the point of distribution.Ethephon is known as one of the most common ethylene-generating chemical and post harvest treatments.Ethephon accelerates ripening and improves the peel color of the mangoes.

Abstract:
In recent times there is much concern about artificial ripening of fruits in many parts of the world including Bangladesh.Large amount of tropical fruits are produced in Bangladesh.Though fruits like mango naturally ripen in trees; some chemicals are used to ripen them artificially which hasten the ripening process.

VIEW POINT
It has been reported that compared to ethylene, high concentrations of acetylene are required to initiate the ripening process. 7Calcium carbide not only changes the skin color of the fruits but it also initiates the enzymatic action that breaks down the glucose resulting in a quick ripening of the fruits.Use of calcium carbide sometimes gives ripening color to a raw fruit.It also increases the shelf life and maintains the ripened color.

Methods of Carbide Application:
The recommended way of application is to use a large vessel of water and added sufficient quantity of carbide and placing them in a well-ventilated chamber.Acetylene, which is then generated, is responsible for the fruit ripening as shown by the following equation. 6C2 + 2 H2O = Ca (OH)2 + C2H2 India is one of the major mango producing country and it also uses calcium carbide as a fruit ripening agent.Mann (1974) 8 studied different doses of calcium carbide on mature hard green mango.The fruits were packed with calcium carbide and were moistened by a drop of water before being tightly covered with newspaper to prevent the leakage of acetylene.The fruits ripened within 8 days and the result showed that those fruits (4-5 kg), which were ripened with 2 g of calcium carbide, developed most desirable taste and flavor.Nagaraj et al., (1984) 9 used ventilated wooden boxes with 2 g of calcium carbide kg-1 of mango fruits, which were covered with straw and craft paper.The calcium carbide was removed after 96 hrs after which the fruit was kept in a well -ventilated room.The results showed that calcium carbidetreatments gave uniform yellow color and acceptable texture to the fruits.The treatment significantly reduced the number of days required for fruit ripening.In Senegal, calcium carbide is commercially used to ripen banana and mangoes and fruits are harvested green.
By now commercially two methods for calcium carbide application have been used.In one method fruits are placed in a basket made up of palm leaves and calcium carbide wrapped in a cloth or newspaper placed at the bottom of the basket.In order to increase the basket temperature and maintain the humidity level, the basket is covered with strong craft paper.The basket is placed in a closed room for 3-4 days and when the fruits developed a yellow skin color they are selected for sale.In another practice, a large heap of fruits (1 or 2 tons) is placed at the corner of a room with calcium carbide spread in several places and then the heap is covered with craft paper.The fruits ripened in both of these ways have good skin color with high acidity and low sugar content but poorly developed flavor. 6 Malaysia, mangoes are picked slightly unripe and then calcium carbide is applied for artificial color development.In this method soapboxes or basket lined with banana leaves are used on which calcium carbide is sprinkled and then this box is filled to the top with the fruits and then the fruits are covered with more leaves on which calcium carbide is scattered.The fruits develop uniform yellow color within 2 or 3 days with a poor flavor. 10 Tamil Nadu, India; now there is a solution to ripen mango in the right way that a mixture of water (5 litre), ethephon 39% (10 ml) and sodium hydroxide (2 gm), kept in a bucket close to mangoes heaped in an airtight chamber would release ethylene gas, which naturally facilitates the ripening of fruits without any harmful effect.11

Health hazards associated with Carbide:
Though calcium carbide is used methodically in many countries including India, in our country it is being used openly, commonly & in an inappropriate way for ripening fruits.A very strong reactive chemical, calcium carbide has carcinogenic properties.Acetylene generated from carbide is flammable and explosive even in a low concentration as compared to ethylene. 12etylene gas is an analogue of ethylene and quickens the ripening process.Sometimes only the skin color is changed while the fruit remains unripe and raw.When a high dose of carbide is used on a raw fruit for ripening purposes it results in poor flavor of the fruit and possibly toxic.It is also considered as extremely hazardous as it may contain traces of arsenic and phosphorus Hydride. 13Early symptoms of arsenic and phosphorus poisoning include vomiting, diarrhea with or without blood, burning sensation of the chest and abdomen, thirst, weakness and difficulty in swallowing and speech.Other effects include numbness in the legs and hands, cold and damp skin and low blood pressure and in cases it can become fatal if not treated in time.Acetylene gas had an unpleasant odor and produced a noticeable flavor in the treated fruits. 14It is not only toxic to the fruits but it may be harmful to those who handle it.It affects the neurological system resulting in headache, dizziness, mood disturbances, sleepiness, mental confusion and seizures on a shortterm basis, while in the long-term it can cause memory loss and cerebral edema.
Use of ethylene and (methyl jasmonate) MJ for fruit ripening purposes is not harmful for human consumption but these compounds are quite expensive hence developing countries use low cost calcium carbide, which is harmful and has many disadvantages compared to ethylene.In developed countries fruits are ripened commercially in an artificial chamber having no health hazards.But in our country traders are using obsolete chemical, carbide being propelled by the quick-buck syndrome.Thus we are in risk of short-term as well as long-term health effects simply by eating fruits.

Recommendations :
1. Ethephon 39%, which is available in the market in the commercial name of ethrel, is being used as plant growth regulator in mango, pineapple, coffee, tomato, cucumber, groundnut and rubber.As this cost-effective method retains the actual colour and taste of the fruit and increases its shelflife, this harmless method to ripen fruits could be a hit and a boon to the traders.It is essential to control the delivery system of acetylene from calcium carbide, which must be safe and applicable to the wide range of users.
2. Government, Concerned health authorities and law enforcing agencies should pay attention to this illegal practice of using carbide openly, which is occurring in many parts of Bangladesh.
3. It is important to develop new and better technique of application, which prevents direct contact of the substance with the fruits.
4. New compound, which are environmentally safe and not harmful for human health, must be discovered and tested.
Commercial ripening is an essential part of business as ripe fruits are not suitable to carry & distribute, as they get rotten.So fruit traders pick unripe fruits & use certain methods to increase the shelf life of them.Valid and acceptable methods of using chemical are desirable in this regard.Anything breach of that might be hazardous for our health.
Ripe fruits are not suitable to carry & distribute as they get rotten.So fruit traders pick unripe fruits & use certain methods to increase the shelf life of them.For many years Ethylene had been used as a fruit ripening agent.But nowa-days Calcium carbide is getting popular in this regard as it has a faster ripening property.But inappropriate use of Carbide to ripen fruits is associated with many health hazards.In this topic we have tried to reveal the essentials of this burning issue & looked for solutions.