Microwave-assistance provides very rapid and efficient extraction of grape seed polyphenols

Yinping Li; George K Skouroumounis; Gordon M Elsey; Dennis K Taylor

doi:10.1016/j.foodchem.2011.04.068

Microwave-assistance provides very rapid and efficient extraction of grape seed polyphenols

Food Chem. 2011 Nov 15;129(2):570-576. doi: 10.1016/j.foodchem.2011.04.068. Epub 2011 Apr 30.

Authors

Yinping Li¹, George K Skouroumounis², Gordon M Elsey², Dennis K Taylor³

Affiliations

¹ College of Enology, Northwest A&F University, Yangling, Shaanxi 712100, PR China; School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5064, Australia.
² School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5064, Australia.
³ School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5064, Australia. Electronic address: dennis.taylor@adelaide.edu.au.

PMID: 30634269
DOI: 10.1016/j.foodchem.2011.04.068

Abstract

A microwave assisted extraction (MAE) method has been developed for the extraction of polyphenols from grape seeds of Vitis vinifera cultivars Cabernet Sauvignon, Shiraz, Sauvignon Blanc and Chardonnay. An initial five-factor (ethanol concentration in the extraction solvent, liquid:solid ratio, time, power and temperature), five-level orthogonal experimental array was designed and three factors (ethanol concentration in the extraction solvent, liquid:solid ratio and time) plus their best levels were chosen to optimise the extraction using a central composite rotatable design (CCRD) experiment. This revealed, after the use of response surface methodology, that the optimal extraction conditions were ethanol concentration (47.2%), liquid:solid ratio (45.3:1) and time (4.6min). Total polyphenols were determined by application of the Folin-Ciocalteau method. Sequential application of the optimal conditions to one sample revealed that approximately 92% of the total polyphenols were extracted in the first instance. In comparison with other extraction methods, MAE provided comparable or better extraction, but was very much quicker. One key finding was that varying the applied power to the extraction was essentially irrelevant; inspection of the applied power profile during extraction revealed that the power was strictly modulated to maintain a constant temperature in the reaction cell.

Keywords: Experimental design; Folin–Ciocalteau method; Grape seeds; Microwave assisted extraction (MAE); Polyphenols; Response surface methodology.