## 3 Processing and Extraction
### Pulsed Electric Field-Assisted Extraction  
A review by [PERSON] et al. [119] described a pulsed electric field (PEF) applied in short duration pulses of moderate voltage to a material placed between two electrodes. The effect of PEF includes electroporation caused by damage to cell membranes. The formation of pores leads to mechanical breakdown of cell membranes and the material is defined as disintegrated, as presented at Figure 4. Factors involved in PEF-assisted extraction are the intensity of the electric field, the duration of treatment, the waveform of the pulse, conductivity, the porosity of the material, pH and the ionic strength of the solvent. PEF  
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Source of Waste** & **Pretreatment Method** & **Extraction Conditions (E—Equipment, P—Power, T—Temperature, ——Time, f—Frequency, S—Solvent, S–  
technology results in improved extraction of intracellular compounds due to increased diffusivity of intracellular substances and increased mass transfer rates. The conditions and effects of PEF applied in the pretreatment of berry fruits before juice pressing on antioxidant content and antioxidant capacity in pomace extracts are summarized in Table 7.  
PEF was applied to improve the extraction of juice from blueberries. Anthocyanins from blueberry pomace were investigated by [PERSON] et al. [120]. Blueberries, cut in half, were pretreated by PEF with different input energy values--1 kJ/kg, 5 kJ/kg or 10 kJ/kg--before juice pressing. In all the samples of pomace obtained after pressing blueberries pretreated with PEF, TAC and AA were increased compared to the control (a sample of pomace remaining after pressing the juice from blueberries untreated with PEF). A correlation between increased energy input and increased values of both TAC and AA was noticed. PEF was also applied to crushed blueberries before juice-pressing in a study conducted by [PERSON] et al. [121]. An influence of field strength value on the SLE of pomace efficiency was studied and it was found that the highest used field strength--5 kV/cm--resulted in the highest antioxidant content and capacity of blueberry pomace extracts. The values of antioxidant content and antioxidant activity were increased compared to extracts obtained from blueberry pomace untreated with PEF before juice pressing. [PERSON] et al. [113] applied PEF to freeze-dried and milled pomace, which was then extracted (SLE) with acidulated ethanol or with acidulated methanol used as a solvent. The correlation between specific phenolic yields and variable numbers of pulses, energy inputs and solvent types was studied. For TPC, phenolic acids and flavochols, the most suitable conditions were: 100 pulses, a field strength of 20 kV/cm and acidulated ethanol used as a solvent. For TAC and flavanols, the number of pulses and the field strength defined as most efficient did not change, but acidulated methanol was preferable as a solvent. The DPPH of an extract was highest (830 umol TE/g dm) when the number of pulses was 100, the field strength was 20 kV/cm and acidulated ethanol was used as a solvent. Another example of PEF application in antioxidant extraction from blueberry pomace was described by [PERSON] et al. [122]. The researchers treated with PEF pomace thawed to a liquid state and ground in a colloid mill. The influence of variable conditions of treatment on anthocyanin yield was studied: the number of pulses, field strength and liquid-liquid ratio. The highest extraction yields were obtained after 10 pulses of PEF with a field strength of 20 kV/cm and using acidic ethanol in a ratio of one-to-six. Compared with UAE, PEF extraction resulted in higher anthocyanin extract yields despite a shorter time and lower temperature for the process.