Food Sciences And Technology

1. ETHYLENE
GAS
PREPARED BY: ABDUL RAUF
RAJPUT
PRESENTATION ON:

2. ETHYLENE GAS:
ETHYLENE IS A HYDROCARBON WHICH HAS THE FORMULA
IT IS A COLORLESS FLAMMABLE GAS WITH A FAINT "SWEET AND MUSKY" ODOUR
WHEN
PURE. IT IS THE SIMPLEST ALKENE (A HYDROCARBON WITH CARBON-
CARBON DOUBLE BONDS).
ETHYLENE IS ALSO AN IMPORTANT NATURAL PLANT HORMONE, USED IN
AGRICULTURE TO
FORCE THE RIPENING OF FRUITS.

3. Uses of ETHYLENE GAS:
ETHYLENE IS WIDELY USED IN THE CHEMICAL INDUSTRY.
IT CAN BE USED IN LABORATORY SYNTHESIS.
IT CAN ALSO BE USED TO SPEED UP THE RIPENING PROCESS OF FOODS
AND VEGETABLES.
IT CAN ALSO BE ENVIRONMENTAL AND BIOLOGICAL TRIGGER.

4. CHEMICAL INDUSTRY:
ETHYLENE IS PRODUCED IN
THE PETROCHEMICAL INDUSTRY BY STEAM
CRACKING. IN THIS PROCESS, GASEOUS OR LIGHT
LIQUID HYDROCARBONS ARE HEATED TO 750–950 °C,
INDUCING NUMEROUS FREE
RADICAL REACTIONS FOLLOWED BY
IMMEDIATE QUENCH TO STOP THESE REACTIONS.
THIS PROCESS CONVERTS LARGE HYDROCARBONS
INTO SMALLER ONES AND INTRODUCES
UNSATURATION. ETHYLENE IS SEPARATED FROM THE
RESULTING MIXTURE BY
REPEATED COMPRESSION AND DISTILLATION.

5. LABORATORY SYNTHESIS:
ALTHOUGH OF GREAT VALUE INDUSTRIALLY, ETHYLENE IS RARELY USED IN
THE LABORATORY AND IS ORDINARILY PURCHASED. IT CAN BE PRODUCED
VIA DEHYDRATION OF ETHANOL WITH SULFURIC ACID OR IN THE GAS
PHASE WITH ALUMINIUM OXIDE.

6. RIPENING OF FRUITS AND
VEGETABLES:ETHYLENE GAS, IN TURN, STIMULATES THE PRODUCTION OF SEVERAL ENZYMES
THAT CHANGE
THE COLOR, TEXTURE AND FLAVOR OF THE FRUITS AND VEGETABLES.

7. ENVIRONMENTAL AND
BIOLOGICAL TRIGGER
ENVIRONMENTAL CUES SUCH AS FLOODING, DROUGHT,
CHILLING, WOUNDING, AND PATHOGEN ATTACK CAN
INDUCE ETHYLENE FORMATION IN PLANTS. IN FLOODING,
ROOTS SUFFER FROM LACK OF OXYGEN, OR ANOXIA,
WHICH LEADS TO THE SYNTHESIS OF 1-
AMINOCYCLOPROPANE-1-CARBOXYLIC ACID (ACC). ACC IS
TRANSPORTED UPWARDS IN THE PLANT AND THEN
OXIDIZED IN LEAVES. THE ETHYLENE PRODUCED
CAUSES NASTIC MOVEMENTS (EPINASTY) OF THE
LEAVES, PERHAPS HELPING THE PLANT TO LOSE WATER.

8. ETHYLENE GAS HAZARDS:
THE FOLLOWING HEALTH EFFECTS MAY OCCUR IMMEDIATELY OR SHORTLY
AFTER EXPOSURE TO ETHYLENE:
SKIN CONTACT WITH LIQUID ETHYLENE CAN CAUSE FROSTBITE.
EXPOSURE TO ETHYLENE CAN CAUSE HEADACHE, DIZZINESS, FATIGUE,
LIGHTHEADEDNESS, CONFUSION AND UNCONSCIOUSNESS.

9. HOW TO REDUCE
ETHYLENE GAS
• STORE ETHYLENE SENSITIVE PRODUCE
ON ONE SIDE OF THE COOLER/SHELF AND
ETHYLENE PRODUCING PRODUCE ON THE
OTHER SIDE.
OR
• STORE FRUITS ON ONE SIDE OF THE
COOLER/SHELF – VEGETABLES ON THE
OTHER SIDE
• KEEP F/V ON THE HIGHER SHELVES TO
AVOID CROSS CONTAMINATION OF OTHER
PRODUCTS

10. QUESTIONS?