The variation in volatile oil yield according to enzyme activity at different pH levels (at 50◦C, incubation time 90 min and enzyme concentration 1%) demonstrated that the maximum enzyme activity was observed over a pH range of 4.5–5 (Fig. 2). It was observed that among the tested enzymes the optimum temperature (at pH 5, incubation time 90 min and enzyme concentration 1%) for a better enzymatic potential leading to higher volatile oil yield lies between 40 and 50◦C (Fig. 3). According to increase in temperature above the optimum temperature will lead to the loss of activity of many enzymes. This observation was in well agreement with our present study leading to a lower extraction yield as temperature increased above 50◦C.