Abstract:
The use of Alternanthera sessilis, which is
commonly known as Mukunuwenna in Sri Lanka as a source
of chlorophyll was examined. The extraction of chlorophyll
was carried out using buffered 80 % (v/v) aqueous acetone.
The optimum operating conditions such as solvent to A. sessilis
ratio, extraction temperature and extraction time were found
to be 5 mL/g, 50 °C and 45 minutes, respectively. The yield of
chlorophyll a and chlorophyll b under these optimum operating
conditions were 659 and 261 μg/g of A. sessilis, respectively.
Mechanical grinding of A. sessilis gave a higher yield as
compared to blanching and drying. Refrigeration at 15 °C was
found to be ideal for storing of fresh A. sessilis up to 3 days
without a considerable loss of chlorophyll content. Chlorophyll
extraction could be modelled successfully using basic mass
transfer equations up to 30 °C. It failed above this temperature
due to the degradation effect. Kinetic study on the degradation
of chlorophyll extracted from A. sessilis confirmed first order
reaction model and the effect of temperature on the rate constant
was also adequately modelled by the Arrhenius equation.
