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Cell disintegration of apple peels induced by pulsed electric field and efficiency of bio-compound extraction

Wang, Lu, Boussetta, Nadia, Lebovka, Nikolai, Vorobiev, Eugène
Food and bioproducts processing 2020 v.122 pp. 13-21
apple peels, brix, electric field, electrical conductivity, microstructure, polyphenols, pulsed electric fields, total soluble solids
The pulsed electric field (PEF) assisted extraction of bio-compounds (soluble solids concentration, °Brix, and total polyphenol content, TPC) from apple peels was studied. The aqueous suspensions of apple peels were treated by PEF with different intensities, E (480–1200V/cm), and different treatment times, tPEF (0–2s). The cell disintegration was analyzed using measurement of electrical conductivity (disintegration index, Zc) and microstructure evaluation by confocal laser scanning microscopy (microscopic cell disintegration index, Zd). The near linear Zc (Zd) dependencies were obtained for PEF treatment protocols with different treatment time, tPEF, and electric field intensity, E. The °Brix and TPC extraction efficiencies were dependent upon applied value of E. For example, at the highest PEF intensity, E=1200V/cm, and Zc≈1, the enhancements in values of °Brix and TPC were approximately the same ≈3.15. However, at lower PEF intensities (480, 600 and 800V/cm) and the fixed value of Zc the extraction of soluble matter was more effective compared to TPC. Therefore, the extraction efficiency of different bio-molecules is not only affected by the level of tissue disintegration (by value of Zc). The other details of PEF protocols (e.g., value of E) may be also important.