As temperature and drying time increased the colour of leaves became dark green. Leaves dried with all
temperatures showed an increased in a* value (0.39, 0.51 and 1.06 at 40, 50 and 60 °C respectively). The natural
green colour of leaves is due to mixture of chlorphyll which is directly related to magnesium. During drying, the
magnesium molecules are changed to pyropheophytin and pheophytin (Buchaillot et al., 2009). Therefore, at higher
temperatures greenness is reduced. Visually, dark green colour of the leaves seemed as dull green-yellow due to
degradation of chlorophyll.