Application of pulsed electric field in the production of juice and extraction of bioactive compounds from blueberry fruits and their by-products

Abstract

The influence of Pulsed Electric Field (PEF) pretreatment of blueberry fruits (Vaccinium myrtillus L.), both on the extraction yield and antioxidant properties of juice obtained by pressing and on the on the recovery of bioactive compounds from berry by-products (press cake) by extraction with solvent, was investigated. PEF treatments carried out at field strengths of 1, 3, and 5 kV/cm and an energy input of 10 kJ/kg achieved a cell disintegration index (Z p ) of 0.70, 0.80, and 0.87, respectively. Mechanical pressing (1.32 bar for 8 min) of PEF-treated berries (1, 3, and 5 kV/cm at 10 kJ/kg) significantly increased the juice yield (+28 %) compared with the untreated sample. The juice obtained from PEF pre-treated berries also had a significantly higher total phenolic content (+ 43 %), total anthocyanin content (+60 %) and antioxidant activity (+31 %). However, PEF treatment intensity higher than 1 kV/cm did not significantly improve the quantitative or qualitative characteristics of the juice. Compared to the untreated sample, higher amounts of total phenolics (+ 63 %), total athocyanins (+78 %) and antioxidant activity (+ 65 %) were detected in the press cake extracts. PEF treatment of higher intensity resulted in better extractability of bioactive compounds from blueberry press cake. The results obtained from this study demonstrate the potential of PEF as a mild pretreatment method to improve the efficiency of the industrial processing of berry fruits.

Effect of dried powder preparation process on polyphenolic content and antioxidant capacity of cranberry ( Vaccinium macrocarpon L.)

“…Celli et al, (2014) reported a range from 7.57 to 113 mol/g FW of FRAP values in different berries, which was quite similar to our results. Bobinaitė et al (2014) reported that FRAP capacity in blueberry juice varied from 5 to 7 mol/ml, which was quite similar to our results. Borges et al (2010) found that anthocyanins had the highest influence on the antioxidant capacity, followed by flavanols and flavonols.…”

Potential application of pulsed electric fields to improve the recovery of bioactive compounds from sour cherries and their by-products

“…higher electric field strength applied did not further enhance the extraction of phenolic compounds from sour cherry by-products (Table 2). Interestingly, in our previous work, the extractability of phenolic compounds from blueberry by-products was shown to be dependent on the applied electric field strength (Bobinaitė et al, 2015). As it was previously documented, the influence of PEF treatment on extractability of phenolic compounds depends on the location of these compounds in the plant cell and also on the cell size distribution between berry skin and flesh (Corrales et al, 2008;Barba et al, 2015).…”

Acoustic emission as a tool to assess the changes induced by pulsed electric field in apple tissue

“…Thus, performed experiment indicates that there are some optimal conditions for the electroporation to proceed. What more, in some publications we can see that the electric field intensity plays a role even more important role than specific energy input (Bobinaitė et al, 2015;Toepfl & Heinz, 2011). However, such statement should be rather considered as an assumption and it requires more research in order to make a general conclusions.…”