TITLE:
Extraction of Total Phenolic Compounds, Flavonoids, Anthocyanins and Tannins from Grape Byproducts by Response Surface Methodology. Influence of Solid-Liquid Ratio, Particle Size, Time, Temperature and Solvent Mixtures on the Optimization Process
AUTHORS:
Hiba N. Rajha, Nada El Darra, Zeina Hobaika, Nadia Boussetta, Eugene Vorobiev, Richard G. Maroun, Nicolas Louka
KEYWORDS:
Phenolic Compounds; Grape Byproducts; Extraction Optimization; Response Surface Methodology; Antioxidant
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.5 No.4,
February
12,
2014
ABSTRACT: The current work concerns the
optimization process of phenolic compounds solid liquid extraction from grape
byproducts at high temperatures and short incubation times. The effect of five
experimental parameters (solidliquid ratio, particle size, time, temperature and solvent mixture)
mostly believed to affect the extraction process was undertaken. A first
response surface methodology experimental design was used to optimize the
solid-liquid ratio and milling time parameters. A second design was used for
the optimization of the quantitative and qualitative parameters. The quantitative
parameters studied are: total phenolic compounds, flavonoid content, total
monomeric anthocyanin composition and tannin concentration. The qualitative
parameters analyzed are: antiradical activity and antioxidant capacity. The second design was based on
the use of time, temperature and solvent mixture as optimization parameters.
The assays were first conducted separately revealing the best experimental
conditions for the maximization of each response variable alone. A simultaneous
response surface methodology of all the responses taken together was then
conducted, showing the optimal extraction conditions to be: 93 minutes at 94?C and in 66% ethanol/water solvent. The
maximal response values obtained for each parameter are: Total Phenolic
Compounds yield (5.5 g GAE/100g DM), Flavonoid Content (5.4 g GAE/100g DM), Total Monomeric
Anthocyanin yield (70.3 mg/100g DM), Tannin Concentration (12.3 g/L), Antiradical
Activity (67.3%) and Total Antioxidant Capacity (393 mgAAE/L). All of the optimal values
were acquired at 3 mL/g solid-liquid ratio and 6.8 min milling time. The
obtained extracts could be used as natural bioactive compounds in several industrial
applications.