lowed by 96 h control percolation with 0.1 BV/h to ensure total
extraction. This procedure is state-of-the-art [11]. For the total
amount of polyphenols and hence a yield of Yi = 100% a loading
of cpolyphenols = 211.4 g/kgDry substance tea is determined. The dry substance
of the extract is defined as a further side component.
Ultrasound-assisted extractions (UAE) were performed in an
ultrasonic extraction reactor PEX1 (R.E.U.S., Contes, France) with
14 10 cm internal dimensions and maximal capacity of 1 L,
equipped with a transducer at the base of jug operating at a frequency
of 25 kHz with maximum input power (output power of
the generator) of 150 W. The double-layered mantle (with water
circulation) allowed the control of extraction temperature by cooling/
heating systems. Considering the actual input power from the
device is converted to heat which is dissipated in the medium,
calorimetric measurements were performed to assess actual ultrasound
power, calculated as shown in the Eq. (1) below.