Enzyme-assisted supercritical fluid extraction: an alternative and green technology for non-extractable polyphenols.
This contribution proposes an enzyme-assisted eco-friendly process for the extraction of non-extractable polyphenols (NEPPs) from black tea leftover (BTLO), an underutilized tea waste. BTLO hydrolyzed with various enzyme formulations was extracted using supercritical carbon dioxide and ethanol as co-solvent (SC-CO2+ EtOH). A conventional solvent extraction (CSE) was performed using EtOH + H2O (80:20, v/v) for comparison purposes. The results revealed that hydrolysis of BTLO with 2.9% (w/w) kemzyme at 45 °C and pH 5.4 for 98 min improved the liberation of NEPPs offering 5-fold higher extract yield (g/100 g) as compared with non-treated BTLO. In vitro antioxidant evaluation and LC-MS characterization of extracts revealed the presence of phenolic acids (mainly caffeic and para-coumaric acid) of high antioxidant value. Scanning electron micrograph of the hydrolyzed BTLO samples indicated noteworthy changes in the ultrastructure of BTLO. Moreover, polyphenol extracts obtained by SC-CO2+ EtOH extraction were found to be cleaner and richer in polyphenols as compared to CSE. The devised enzyme-assisted SC-CO2+ EtOH extraction process in the present work can be explored as an effective biotechnological mean for the optimal recovery of antioxidant polyphenols. Graphical abstract Enzymatic pretreatment can effectively liberate non-extractable polyphenols (NEPPs) while hydrolyzing the cellulosic and hemicellulosic framework of black tea left overs (BTLO).
Department of Chemistry, University of Agriculture, Faisalabad, 38040, Pakistan.|Food Science, Cornell University, 366 Stocking Hall, Ithaca, NY, 14852, USA.|Department of Chemistry, GC University, Lahore, 55300, Pakistan.
Muhammad
M
Mushtaq
Department of Chemistry, University of Agriculture, Faisalabad, 38040, Pakistan. bushrasultana2005@yahoo.com.
Bushra
B
Sultana
Department of Chemistry, University of Agriculture, Faisalabad, 38040, Pakistan.|Food Science, Cornell University, 366 Stocking Hall, Ithaca, NY, 14852, USA.
Sumia
S
Akram
Department of Chemistry, University of Sargodha, University Road, Sargodha, 40100, Pakistan.
Farooq
F
Anwar
Department of Chemistry, GC University, Lahore, 55300, Pakistan.
Ahmad
A
Adnan
Food Science, Cornell University, 366 Stocking Hall, Ithaca, NY, 14852, USA.
Syed S H
SSH
Rizvi
D000975:Antioxidants / Q000302:isolation & purification*; D055162:Biocatalysis; D002109:Caffeic Acids / Q000302:isolation & purification; D028241:Camellia sinensis / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D025924:Chromatography, Supercritical Fluid / Q000295:instrumentation / Q000379:methods*; D003373:Coumaric Acids; D004867:Equipment Design; D000431:Ethanol / Q000737:chemistry; D055772:Green Chemistry Technology / Q000295:instrumentation / Q000379:methods*; D006868:Hydrolysis; D059808:Polyphenols / Q000302:isolation & purification*; D011422:Propionates / Q000302:isolation & purification; D012037:Refuse Disposal; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013662:Tea / Q000737:chemistry*
D000975:Antioxidants; D002109:Caffeic Acids; D003373:Coumaric Acids; D059808:Polyphenols; D011422:Propionates; D012997:Solvents; D013662:Tea; D002245:Carbon Dioxide; D000431:Ethanol; C495469:p-coumaric acid; C040048:caffeic acid
BTLO; Enzymatic hydrolysis; Green extraction; Non-extractable polyphenols; SC-CO2; Scanning electron micrograph