ENHANCING PRODUCTION THROUGH OPTIMISATION OF DPPH AND RADICAL SCAVENGING ACTIVITY OF GRAPE SEED EXTRACTS

Abstract

Polyphenols are important for their pharmacological activity and positive contribution to cellular processes within the body. They have the capacity to protect against oxidation of High Density Lipids (HDL) and, thus help the body to retain HDL, while removing the problematic Low Density Lipids (LDL). Polyphenols also possess anti-ulcer, anti-carcinogenic and anti-mutagenic activities. The objective of this study was to evaluate the effect of temperature and grain size of grape seed on the efficiency of extraction of polyphenols from grape seed, using the compressed hot water and solvent extraction techniques. Polyphenols were extracted from milled (<0.5 mm) and whole grape seed, using compressed hot water (high temperature and high pressure) and solvents (Acetone, Methanol and Ethanol). The total polyphenol content and DPPH radical scavenging activity of the extracts were determined using spectrometer and the active compounds identified using HPLC. Total polyphenol content increased with extraction temperature, but decreased at 200 \ub0C. The difference in polyphenol extracts from the milled and whole seed decreased with increase in temperature, but was more evident at 135 \ub0C. The 2 hour extracts showed relatively higher values than those for 1 hour, with the lowest difference occurring at 165 \ub0C and the highest at 180 \ub0C. Solvent extracts from whole seeds were very low compared with the milled seeds, with acetone showing the highest value of 105 mg g-1 dry matter for polyphenol content and 110 mg g-1 of dry matter for DPPH radical scavenging activity. Methanol had the lowest value (78 mg g-1 dry matter) for polyphenol extracts and 80 mg g-1 for the DPPH radical scavenging activity. The main extract compounds were gallic acid, catechin and epicatechin.Les polyph\ue9nols sont importants eu \ue9gard \ue0 leur activit\ue9 pharmacologique et leur contribution positive aux processus cellulaires dans le corps. Ils sont dou\ue9s d\u2019une capacit\ue9 protective contre l\u2019oxydation des Lipides \ue0 Densit\ue9 Elev\ue9e (HDL) et, ainsi aident le corps \ue0 maintenir le HDL, tout en \ue9liminant les probl\ue9matiques Lipides \ue0 Basse Densit\ue9. Les polyph\ue9nols poss\ue8dent aussi des activit\ue9s anti-ulc\ue8res, anticarcinog\ue8nes et antimutag\ue8nes. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer les effets de la temp\ue9rature et taille des grains de raisin sur l\u2019efficacit\ue9 de l\u2019extraction des polyph\ue9nols des grains de raisin, utilisant une eau chaude compress\ue9e et des techniques d\u2019extraction au solvant. Les polyphenols \ue9taient extraits des grains entiers de raisin et des grains moulus (<0.5 mm) \ue0 l\u2019aide d\u2019une eau chaude compress\ue9e (temp\ue9rature \ue9lev\ue9e et haute pression) et des solvants (Ac\ue9tone, M\ue9thanol et Ethanol). La concentration totale des polyph\ue9nols et l\u2019activit\ue9 d\u2019absoption du radical DPPH des extraits \ue9taient d\ue9termin\ue9s \ue0 l\u2019aide du spectrophotom\ue8tre et les compos\ue9s actifs identifi\ue9s par HPLC. La concentration totale des polyph\ue9nols a augment\ue9 avec la temp\ue9rature d\u2019extraction, mais a diminu\ue9 \ue0 200 \ub0C. La diff\ue9rence dans les extraits de polyph\ue9nol des grains moulus et entiers a diminu\ue9 avec l\u2019augmentation de la temperature, mais \ue9tait plus \ue9vidente \ue0 135 \ub0C. Les extraits de deux heures ont montr\ue9 des valeurs relativement plus \ue9lev\ue9es que ceux d\u2019une heure, avec les diff\ue9rences les plus faibles apparaissant \ue0 165 \ub0C et les plus \ue9lev\ue9es \ue0 180 \ub0C. Les extraits de graines enti\ue8res aux solvants \ue9taient de faible quantit\ue9 en comparaison avec ceux des grains moulus, les valeurs les plus \ue9lev\ue9es \ue9tant de 105 mg g-1 de mati\ue8re s\ue8che de polyph\ue9nol et 110 mg g-1 de mati\ue8re s\ue8che d\u2019absorption du radical DPPH obtenues en utilisant l\u2019ac\ue9tone comme solvant. Les extraits obtenus au m\ue9thanol comme solvant \ue9taient encore en plus faible quantit\ue9 avec 78 mg-1 de la mati\ue8re s\ue8che pour les extraits du polyph\ue9nol et 80 mg g-1 pour l\u2019activit\ue9 d\u2019absorption du DPPH. Les principaux compos\ue9s de ces extraits \ue9taient des acides galliques, des cat\ue9chines et des epicat\ue9chines