title: Antioxidant activity of raspberry (Rubus fruticosus) leaves extract and its effect on oxidative stability of sunflower oil.
abstract: Efficacy of R. fruticosus leaves extract in stabilizing sunflower oil during accelerated storage has been studied. Extracts of R. fruticosus were prepared in different solvents which methanolic extract yield with 15.43 % was higher than water and acetone ones (11.87 and 6.62 %, respectively). Methanolic extract was chosen to evaluate its thermal stability at 70 °C in sunflower oil, due to the highest yield, antioxidant and antiradical potential and also high content of phenolic compounds campared to other solvents. So, different concentrations of methanolic extract (200, 400, 600, 800 and 1,000 ppm) were added to sunflower oil. BHA and BHT at 200 ppm served as standards besides the control. Peroxide value (PV) and thiobarbituric acid (TBA) were taken as parameters for evaluation of effectiveness of R. fruticosus leaves extract in stabilization of sunflower oil. Moreover, antioxidant activity index (AAI) of the extract at 120 °C at rancimat were conducted. Results from different parameters were in agreement with each other, suggesting the highest efficiency of 1,000 ppm of the extract followed by BHT, BHA and other concentrations of the extract. Results reveal the R. fruticosus leaves extract to be a potent antioxidant for stabilization of sunflower oil.
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Asnaashari
authors.affiliation: Department of Food Science and Technology, Varamin Branch, Islamic Azad University, Varamin, Iran.
authors.forename: Raheleh
authors.initials: R
authors.lastname: Tajik
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran.
authors.forename: Mohammad Hossein Haddad
authors.initials: MH
authors.lastname: Khodaparast
keywords: Antioxidant activity; R. fruticosus leaves extract; Sunflower oil; Thermal stability