Kinetics of Chlorophyll Pigment Leaching From Iraqi Alfalfa

Abstract

An experimental method of batch leaching was studied to obtained chlorophyll pigment from dehydrated alfalfa using ethanol – hexane mixture as solvent. The aim of this research is to study the extraction kinetics and the effects of temperature (30 – 60)°C, solvent concentration of ethanol (40% to 60%) and particle size (0.2 – 0.5, 0.5 – 1.0 and 1.0 – 2.0)mm as well as the effect of gathering, drying and transport of alfalfa on the extractability of total chlorophyll from dehydrated Iraqi alfalfa. The maximum extraction value of chlorophyll obtained was found to be 0.31% of alfalfa. The major part of the extractable chlorophyll is water soluble type, which could be used as pigment in toothpastes, soaps, shampoos and medical products. A batch leaching model was developed and solved numerically. The model parameters were predicted by applying existing experimental correlations and data gathered during this work. The model allows us to predict the rate constant and the saturation capacity with various temperatures. In addition, the activation energy and the frequency factor of the leaching process were also determined and found that the process is an endothermic process with activation energy equal to 30.7 kJ/mol.