Alvin B. Hernandez¹, Edralina P. Serrano² and Ernesto J. del Rosario^1
1Institute of Chemistry, College of Arts and Sciences, University of the Philippines Los Baños, College, Laguna 4031, Philippines
²Crop Science Cluster, College of Agriculture, University of the Philippines Los Baños, College, Laguna 4031, Philippines

Alvin Hernandez

Edralina Serrano

Ernesto del Rosario

Ethylene (C₂H₄) is a gaseous phytohormone that regulates physiological changes in fruits and vegetables; at high concentration it reduces the storage life of these perishable commodities. Ripening of fruits and vegetables can be delayed by ethylene removal from the storage atmosphere using potassium permanganate (KMnO₄) impregnated on a suitable porous material. Several materials can be used as KMnO₄ carriers for scrubbing ethylene; rice hull ash, lahar (volcanic ejecta) ash and coconut coir dust have been evaluated in the present study.

The ethylene scrubbing efficiency and stability of rice hull ash, lahar ash and coconut coir dust were studied. The oxidation of C₂H₄ by KMnO₄ was found to be approximately first order for the three carriers. Based on the calculated values of the reaction rate coefficients, the most efficient KMnO₄ carrier for KMnO₄ oxidation was rice hull ash per gram of scrubber followed by lahar ash and then coconut coir dust. Calculated values of the intrinsic rate coefficient indicate that, at the same KMnO₄ loading, lahar ash scrubs ethylene more efficiently, followed by rice hull ash and then coconut coir dust. However, in practical terms, the most efficient scrubber is that based on rice hull ash. This material was also found to be the most stable among three carriers based on the color intensity (chromacity) of the reflected light from the scrubber.

Reference:

Alvin B. Hernandez, Edralina P. Serrano and Ernesto J. del Rosario, “Kinetics Studies of Ethylene Oxidation by Potassium Permanganate Adsorbed on Rice Hull Ash, Lahar Ash or Coconut Coir Dust”, Philipp Agric Scientist 90: 28-39 (2007).