Potential application of pulsed electric fields to improve the recovery of bioactive compounds from sour cherries and their by-products
2017
Bobinaite, R., Lithuanian Research Centre for Agriculture and Forestry, Babtai, Kaunas distr. (Lithuania). Inst. of Horticulture | Pataro, G., University of Salerno, Fisciano (Italy). Dept. of Industrial Engineering | Visockis, M., Lithuanian Research Centre for Agriculture and Forestry, Babtai, Kaunas distr. (Lithuania). Inst. of Horticulture | Bobinas, C., Lithuanian Research Centre for Agriculture and Forestry, Babtai, Kaunas distr. (Lithuania). Inst. of Horticulture | Ferrari, G., University of Salerno, Fisciano (Italy). Dept. of Industrial Engineering;ProdAl Scarl, Fisciano (Italy) | Viskelis, P., Lithuanian Research Centre for Agriculture and Forestry, Babtai, Kaunas distr. (Lithuania). Inst. of Horticulture
Pulsed electric fields (PEF) treatment induces transmembrane potential by means of an externally applied electric field of sufficient intensity, which causes an increase in the permeability of a cell membrane. PEF can be applied for plant cell disruption as upstream step to enhance the efficiency of mass transfer in further processing such as hydraulic pressing or extraction. The objective of the study was to evaluate the potential of using PEF technology for the increase of the juice yield and improved extraction of bioactive compounds from sour cherries (Prunus cerasus L.) and their by-products. PEF treatments (1 – 5 kV cmE-1 at 10 kJ kgE-1) were applied to cherries before the juice pressing. The by-products (press cake) generated were extracted with aqueous methanol. The samples from PEF pre-treated cherries and their by-products were compared to both untreated (control) samples and samples obtained from freeze- thawed (PEF untreated) cherries. The highest increase in juice yield by 45% was obtained at PEF intensity of E=3 kV cmE-1, showing similar results to freeze-thawed sample (41%). The application of PEF significantly increased the release of total anthocyanins (48.3 – 53.3 mg 100 mLE-1 ) and total phenolics (126.6 – 133.9 mg 100 mLE-1 ) into juice as compared with the control (33.8 and 112.9 mg 100 mLE-1, respectively), whereas juice from freeze-thawed sample exhibited the highest value only for total phenolics content (164.4 mg 100 mLE-1). The extracts from by-products obtained after PEF assisted juice pressing of cherries showed significantly higher contents of bioactive compounds and higher antioxidant power as compared with the control extract and the extract of freeze- thawed sample. Overall, the results of this work demonstrated promising use of PEF technology in sour cherry processing.
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