Plum ( <i>Prunus domestica</i> L.) leaves extract as a natural antioxidant: Extraction process optimization and sunflower oil oxidative stability evaluation
Nesren Elsayed, Karima Said Mohamed Hammad, Ekarm Abd El-Salam Abd El-Salam
Abstract
The current work aimed to maximize the yield of total phenolic content (TPC) and associated antioxidant activity of plum leaf extract. The feasibility of using the optimal extract as a natural antioxidant for retarding the oxidation process in sunflower oil using rancimat method was also investigated. One-factor-at-a-time (OFAT) method and 32 full factorial design were implemented in sequence to optimize the studied factors (extraction time [ET] (10–60 min) and ethanol percentage [EtOH%] (0%–75%)). DPPH scavenging ability of the obtained extracts were positively (r ≥ 0.7493) and significantly (p < .0001) correlated to TPC yield. The optimal conditions for extraction plum leaves were 64.37% EtOH% and 60 min with desirability of 0.856. The optimal plum leaves extract was subjected to HPLC analysis. At the same concentration (200 ppm), the protection factor of BHT and optimal plum leaves extract against sunflower oxidation were insignificantly (p > .05) differed. Practical applications Plum (Prunus domestica L.) leaves are characterized by a high content of phenolic compounds which varied between 66.50 to 143.7 mg GAE/g powder. Plum leaf extracts exhibited high scavenging activity against DPPH radicals. The protection factor of the freeze-dried optimal leaves extract was insignificantly differed than that of BHT at the concentration of 200 ppm. These findings indicate that plum leaves extract could efficiently retard the oxidation process of edible oils; and consequently, improve their quality and extend their shelf life.