A higher yield of essential oil was also observed in
cardamom on enzyme treatment. As in the case of black
pepper, there were structural changes in cell wall of
cardamom following enzyme treatment (Fig. 3a). The
enzyme untreated cardamom could be identified with the
presence of only spherical structures where as the enzyme
treated sample can be distinguished with both spherical and
cylindrical structures which were brought about by the
action of enzyme mixtures (Fig. 3b) on the cell wall. These
structural changes in the cell wall might have resulted in an
increase in the yield of essential oil from black pepper and
cardamom in the present study. SEM of cardamom seeds
treated by microwave extraction and hydrodistillation
showed that the cells are broken and damaged during
microwave extraction in contrast to conventional hydrodistillation
which was attributed for its better quality (24).