Chapter 4 - Oxidative Stability and Shelf Life of Vegetable Oils

Abstract

Oils and fats play a major functional role in foods, both that are cooked at home and that are produced industrially. It is important to understand the comparative shelf stability of oils to be used in producing foods, as the quality of oil greatly impacts the quality and shelf life of the food. The data set produced by the 24-month ambient shelf stability study of multiple oils suggested that fatty acid profile of an oil is an extremely useful tool in predicting the comparative oxidative stability, and that oxidative stability index, as well as primary and secondary oxidation compounds, as expressed by peroxide value and para-anisidine value, are very useful measures of the oxidative state of an oil when stored at room temperature. Oils containing higher levels of monounsaturated fatty acids resisted oxidative breakdown much longer than the ones containing higher levels of polyunsaturated fatty acids. The slopes of the rate of change in oxidative stability index of oils stored at ambient versus that at elevated temperature were different for different oils. There was no direct correlation between the oxidative breakdown of oils and changes in their sensory attributes, as determined by the trained sensory panel. Oils from a crop species behaved differently from other crop species, in terms of oxidation and sensory characteristics.