Antioxidant Stability of Edible Oil Using Rheological Behaviour and in vitro Analysis

Abstract

In food industry, rheological behaviour and thermal degradation
are the important parameters required to determine the quality and
stability of food system. In this paper, the rheological behaviour and
thermal degradation of sunflower oil and palm oil, is investigated. The
Newtonian behaviour of the oils are studied from the kinematic viscosity
of unused edible oils (sunflower oil, palm oil, groundnut oil, coconut
oil, olive oil, sesame oil) using redwood viscometer at temperatures from
30 to 90 ºC. Increase in viscosity of used (heated to frying condition,
210 ºC) edible oils like sunflower oil, palm oil are studied in the same
variation of temperature shows the non-Newtonian behavoiur of the
oils. This oxidation process can be prevented or retarded by the addition
of synthetic or natural antioxidants. The antioxidant activities in oils on
heating to smoke point are analyzed using in vitro studies. The free
radical scavenging activity of the samples using ABTSH and DPPH is
measured and the antioxidant activity of sunflower oil is much effective
than palm oil.