Natural antioxidants and their effects on vegetable oil

• Grant number: 10/10282-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2010
• End date: August 31, 2011
• Field of knowledge: Agronomical Sciences - Food Science and Technology
• Principal Investigator: Neuza Jorge
• Grantee: Simara Pícoli Pitaro
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil

Abstract

This work has as objective to know the antioxidant effect of extracts from thyme added to soybean oil and to evaluate the synergistic and isolated from natural extracts of thyme, basil and oregano, added to soybean oil under different heating conditions. In extracts of thyme will be determined to quantify total phenolics and antioxidant activity by the method of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Different concentrations of extracts were applied in soybean oil will be tested for oxidative stability using the Rancimat equipment, defining the most effective. The treatments: soybean oil, soybean oil with TBHQ, soybean oil with extract of thyme, soybean oil with a mixture of extracts of thyme and basil, soybean oil with a mixture of extracts from thyme and oregano are undergoing termoxidation (180ºC/30 hours) and the accelerated storage test(60ºC/10 days), which samples are taken at time intervals of 0, 5, 10, 15, 20, 25 and 30 hours and 0, 2, 4, 6 , 8 and 10 days, respectively. The samples will be analyzed according to the determinations of oxidative stability, total polar compounds, the peroxide value, conjugated diene and fatty acid profile. The results will be submitted to analysis of variance and Tukey test for the average 5% using the ESTAT program version 2.0.