ETHYLENE REMOVAL AND FRESH PRODUCT STORAGE:

A CHALLENGE AT THE FRONTIERS OF CHEMISTRY

Nicolas Keller, Marie-Noelle Ducamp, Didier Robert, and Valerie Keller

SHOIBAM ANILKUMAR SINGH12CHMS48

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Chem. Rev., 2013, 113 (7), pp 5029–5070

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CONTENTS

1.TYPE OF FRUITS2. HOW ETHYLENE ENTER THE CELL WALL OF PLANT CELL3.HOW TO REMOVE ETHYLENE4.CONCLUSION

Type of fruits and ethylene sensitivity

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Climatic APPLEBANANAMANGOTOMATOGUAVAJACK GRAPE

fresh produce type ethylene production rate (μL kg–1 h–1)

ethylene sensitivit

y

principal reaction to ethylene

cherries very low <0.1 L softening

potatoes very low <0.1 M sprouting

cut flowers very low <0.1 H sleepiness, leaf curl

cucumber low 0.1–1.0 H yellowing

decay

banana moderate 1.0–10 H decay

tomato moderate 1.0–10 H shrink, decay

apricot, avocado high 10–100 H decay

apple very high >100 H scald, lose crunch

passion fruit very high >100 H decay

CAPSICUM PINEAPPLEORANGE LEMONCHERRY GRAPE

Non climatic

No “safe” level of ethylene for which no deleterious effect on postharvest.

Origin and Destiny of Ethylene in Air

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Figure: Binding of ethylene molecule with the receptor “unlocks” the receptor and leads to a chemical reaction in the plant tissue.

Chem. Rev., 2013, 113 (7), pp 5029–5070

Diagram adapted with permission ,Copyright 2004 American Association for the Advancement of Science.

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GENETIC MODIFICATION

PLANT LEVEL ACTIONS

INHIBITIONS

ENVIRONMENT LEVEL ACTIONS

UV-C

ETHYLENE CONTROL AND REMOVAL

CHEMICAL TREATMENT

k VENTILATION CONTROLLED ATMOSPHERE AT

KMnO4 OZONE

CHEMICAL

PHOTOCATALYSIS

3CH2CH2+2KMnO4 2MnO2 +3CH3CHO+2KOH 1

3CH2CHO +2KMnO4+H2O 3CH3COOH +2MnO2+2KOH 23CH3COOH+8KMnO4 6CO2+8MnO2+8KOH+2H2O 3

3CH2CH2 +12 KMnO 4 12MnO2+12KOH+6CO2 4

CH3COOH+ KOH KCOOCH3 + H2O 5

OVERALL REACTION

3CH2CH2 +4 KMnO4 3KCOOCH3 + 4MnO2 + KOH+ H2O 6

COMBINING WITH 1,2 AND 5

1.KMnO4

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+H2O

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Ethylene can be removed by the use of UV-lamp. The lamp emit ultra violet radiation which can degradation of the ethylene. It is most efficient in 184 and 214 nm and it releases ozone as a byproduct.

OZONEOzone is a powerful oxidant/ disinfectant which remains technically more difficult due to its toxicity. Ozone can control postharvest diseases on fruit, the delay of spore production from decaying fruits, the sanitation of surfaces, and ethylene removal.

2O3 + C2H4 → 2CO2 + 2H2O

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UV-C

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PhotocatalysisChange in the rate of chemical reaction or its initiation under the action of ultraviolet ,visible or infrared radiation in the presence of a substance –the photocatalyst-that absorbs light and involved in the chemical transformation of the reaction pattern.

Ref. from IUPAC definition.

In 1967 , Prof. Fujishima of the University of Tokyo discovered. The technology of photocatalysis is gaining the attention of key

technology of 21st centaury.

By taking into account the very restricted storage conditions for fresh products, photocatalysis technology appears to be the promising ecotechnology for removing

ethylene from storage air.

Photocatalytic reaction of TiO2 is a possible method for ethylene decomposition in fruit and vegetable

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10chem. Rev. 2012, 112, 5919−5948

•TiO2 exhibits strong oxidizing photoactivity when irradiated by UV ray as OH radicals produced.

•TiO2 is stable and not soluble in H 2 O, acidic, organic solvent.

•TiO 2 is a relatively inexpensive, nontoxic, and easy to handle material.

•TiO2 is highly efficient due to high quantum yield. low toxicity, and low cost.

Why TiO2 ?

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Various TiO2 –based photocatalysts have been reported for ethylene photo degradation under UV light. The reaction of ethylene oxidation as follows: TiO2

1.C2H4 + 3O2 2CO2 + 2H2O UV

2. Park et al. have reported that the photo catalytic oxidation at room temperature is C2H2 + O* (C2H2O)* finally CO2

3. By contrast ,Yamazaki et al. suggested that adsorbed ethylene react alcohol radical to form ethyl alcohol radical intermediate that are subsequently react with adsorbed super oxide radical to reach mineralization into carbon dioxide. C2H2 +OH* C2H2OH*

C2H2OH* +O2* mineralization to CO2

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TiO2- based photocatalyts1.Pt/TiO2

2.Au/TiO2

3.TiO 2 /SiO 2 & TiO 2 /ZnO2

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A significant role of water in the oxidation process was demonstrated over the Au/TiO2 photo catalysts

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CONCLUSION• As mention earlier TiO2 -based photocatalyst method can

be used in military units, navy ships, submarines, space , etc.

• In photo catalytic processes no solid waste generation and no photocatalytic material is consumed.So it is one of future method for removing ethylene.

• Removal of ethylene can retain quality of fruits and vegetables for longer time.

• Can transported for longer periods of time

• Reduction in post harvesting 13

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THANK YOU