Amira MnariUniversity of Monastir, Tunisia
Title: Effects of grape leaves and grape seeds extracts on oxidative stability of corn oil during heating in comparison with naturally commonly used antioxidant
The antioxidative effects of grape leaves (GLE) and grape seeds (GSE) extract on corn oil (CO) stability, heated for 0, 4 and 8 hours at 180 C were investigated. Grape leaves and seeds extracts were separately prepared by dissolving 20 g of dried, ground and sieved samples into 200 ml of methanol for three days. The methanol GLE and GSE were then added separately at varying concentrations (200–1000 ppm) to CO. Another sample of CO which contained 200 ppm BHT as well as CO that contained no additive were also studied. Oxidation was followed by determining free fatty acid value (FFA), peroxide value (PV), p-anisidine value (p-AV), conjugated dienes (CD), trienes (CT) as well as TOTOX values. Furthermore, total phenolic content and DPPH radical scavenging activity were measured before and after heating. According to the obtained results, there was no significant difference at TO in FFA, PV and p-AV of CO containing GLE, BHT, GSE and CO containing no additive. During heating for 4 and 8 hours, FFA, PV, p-AV and TOTOX values increased in all samples, while those of polyphenols content as well as DPPH scavenging activities decreased. The FFA, AV, p-AV and TOTOX values of CO containing additive (GLE and GSE) were lower than those of CO containing BHT followed by CO with no additive. It is concluded that the antioxidant activities of GSE and GLE were high and retarded the oil oxidation and can be used in the food industry for commercial purposes.
Amira Mnari Bhouri, PhD in Biological Sciences and Biotechnology is an Assistant Professor in Physiology and Researcher member of Research Laboratory - LR12ES05 Lab-NAFS ''Nutrition-Functional Food & Vascular Health'' at Faculty of Medicine of Monastir - University of Monastir- Tunisia. She is the head of Medical Biology Department at the Higher School of Health Sciences and Technology of Monastir at University of Monastir in Tunisia. Amira carries with over 11 years of experience in teaching and research at university level. She has successfully completed several projects in the area of functional foods. She has 29 publications that have been cited over 736 times.