TITLE:
Multiple Response Optimization of High Temperature, Low Time Aqueous Extraction Process of Phenolic Compounds from Grape Byproducts
AUTHORS:
Hiba N. Rajha, Nicolas Louka, Nada El Darra, Zeina Hobaika, Nadia Boussetta, Eugène Vorobiev, Richard G. Maroun
KEYWORDS:
Phenolic Compounds; Grape Byproducts; Optimization; Aqueous Extraction; Response Surface Methodology
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.5 No.4,
February
11,
2014
ABSTRACT: In this study phenolic compounds extraction from
grape byproducts was conducted using pure water as a solvent. High temperatures
and low time incubation periods were used in the aim of reducing the cost of
the process and heightening the phenolic compounds yield. Response surface
methodology (RSM) was realized to study the effect of time and temperature on
crushed and uncrushed grape pomace. The phenolic content was evaluated considering
the quantity (total phenolics (TPC), flavonoids (FC), total monomeric
anthocyanins (TMA) and tannins (TC)), and quality (antiradical activity (AA)
and antioxidant capacity (AC)) of the extracts. High temperature low time
extraction design used in this study was compared to the extraction process at
moderate temperatures with relatively long periods of time. This was proved to
ameliorate the quantitative extraction of phenolic compounds from grape pomace
without affecting their bioactivity. Moreover, multiple response optimization
showed the optimal extraction parameters to be 81?C and 140 minutes for the unmilled pomace samples,
and 88?C and 5 minutes for the milled. TPC, FC, TMA, TC, AA and AC are almost
the same for both optimums. Thus the possibility
of replacing the milling process by the extraction time prolongation (for the
unmilled pomace) of 135 minutes seems to be very plausible. HPLC analysis
showed different quantity and diversity of extracted phenolics for the
optimums. However this difference did not significantly affect the overall
activity, showing that PC in the different extracts act in complete synergy all
together leading to important biological properties. The obtained results using
the extraction strategy adopted in this work could lead to several industrial
applications.