An important point of the methodology is that ultrasound was applied to a packed in vacuum. The vacuum-packed sample was used to avoid adverse effects of rinsing out substances contained in the raw material. However vacuum-packaging might reduce the effect of cavitation over the sample and mostly the sponge effect will be the main physical phenomenon affecting the sample [26,31]. Therefore, it can be assumed that packaging will reduce the effect of cavitation over the sample, will refrain mass transfer (which is somewhat important in the pre-treatment) and, moreover,probably the sponge effect will be the main physical phenomena affecting the sample.