Characterizing the kinetic of browning index, total chlorophyll and total phenolic content of clinacanthus nutans extract
Abstract
Clinacanthus nutans is well known for a long time for being used as traditional
medicine in Malaysia to treat skin rashes, venomous insect bite and fever. Due to the benefits
of this plant, a few manufacturer starts to commercialize this plant by producing numbers of
product such as extract, juice and herbal drinks (tea). It is known that many plant based food
products will turn brown during thermal processing due to non-enzymatic reactions. Thermal
degradation kinetics of browning index, total chlorophyll and total phenolic content in C.
nutans extract was investigated at varying levels of processing temperature (40–90 °C) and
retention time (0-120 min). Both browning index and total chlorophyll content followed firstorder
reaction kinetics while total phenolic content is zero order. In browning index, overall
respective coefficient of determination (R2) is 0.9237 while the activation energy is 1.6629 ×
10-3 Jmol-1. While for kinetic of total chlorophyll the respective coefficient of determination
(R2) is 0.8808 and the activation energy is 3.3256 × 10-3 Jmol-1. For total phenolic content
the R2 is 0.9543 is and the activation energy of 8.314 × 10-4 Jmol-1 . It is concluded that the
optimization condition for thermal treatment of C. nutans extract at 55 ˚C is best for retaining
total chlorophyll content and total phenolic content and at 71.7 ˚C it is best for preserving
green color of C. nutans and total phenolic content. Results indicated that, the browning is
increase due to chlorophyll degradation in C. nutans during thermal processing while Total
phenolic content value increase at elevated temperature.