TY - JOUR
T1 - Combination of Pulsed Electric Field and Ultrasound in the Extraction of Polyphenols and Volatile Compounds from Grape Stems
AU - Ntourtoglou, George
AU - Drosou, Fotini
AU - Chatzimitakos, Theodoros
AU - Athanasiadis, Vassilis
AU - Bozinou, Eleni
AU - Dourtoglou, Vassilis G.
AU - Elhakem, Abeer
AU - Sami, Rokayya
AU - Ashour, Amal Adnan
AU - Shafie, Alaa
AU - Lalas, Stavros I.
N1 - Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2022/6/1
Y1 - 2022/6/1
N2 - Increasing the yield of extraction of bioactive compounds from plants is of high importance. Grape stems are widely discarded during the wine‐making process, despite their high content in many valuable compounds. The aim of this work was to examine whether the use of pulsed electric field (PEF) treatment of the stems could increase the yield of polyphenol and volatile compounds in the extracts. For this reason, a relatively low‐energy consuming PEF process was employed (low‐electric field strength, 1 kV/cm) for a short time (30 min) at the grape stems. In addition, the effect of different solvents during this pretreatment step was examined. With the use of Folin–Ciocalteu assay, the extracts were compared with the respective control samples (not pretreated with PEF). Moreover, extracts were prepared to assess whether changes occur to the volatile profile of the extracts. The results were conclusive that not only PEF can increase the yield of polyphenols (up to 35% increase recorded), but also that the solvent used during PEF pretreatment can affect the process. Furthermore, a 234% increase in the total content of volatile compounds was recorded, when PEF was used as a pretreatment step. Therefore, the combination of PEF and ultra-sound‐assisted extraction is highly promising to obtain grape stem extracts with a higher content of bioactive compounds.
AB - Increasing the yield of extraction of bioactive compounds from plants is of high importance. Grape stems are widely discarded during the wine‐making process, despite their high content in many valuable compounds. The aim of this work was to examine whether the use of pulsed electric field (PEF) treatment of the stems could increase the yield of polyphenol and volatile compounds in the extracts. For this reason, a relatively low‐energy consuming PEF process was employed (low‐electric field strength, 1 kV/cm) for a short time (30 min) at the grape stems. In addition, the effect of different solvents during this pretreatment step was examined. With the use of Folin–Ciocalteu assay, the extracts were compared with the respective control samples (not pretreated with PEF). Moreover, extracts were prepared to assess whether changes occur to the volatile profile of the extracts. The results were conclusive that not only PEF can increase the yield of polyphenols (up to 35% increase recorded), but also that the solvent used during PEF pretreatment can affect the process. Furthermore, a 234% increase in the total content of volatile compounds was recorded, when PEF was used as a pretreatment step. Therefore, the combination of PEF and ultra-sound‐assisted extraction is highly promising to obtain grape stem extracts with a higher content of bioactive compounds.
KW - by‐product
KW - extraction
KW - gas chromatography–mass spectrometry
KW - phenolics
KW - pulsed electric field
KW - ultrasonication
UR - http://www.scopus.com/inward/record.url?scp=85132784855&partnerID=8YFLogxK
U2 - 10.3390/app12126219
DO - 10.3390/app12126219
M3 - Article
AN - SCOPUS:85132784855
SN - 2076-3417
VL - 12
JO - Applied Sciences (Switzerland)
JF - Applied Sciences (Switzerland)
IS - 12
M1 - 6219
ER -