Oxidative stability of lard and sunflower oil supplemented with coffee extracts under storage conditions

Grażyna Budryn,Ewa Nebesny,Dorota Żyżelewicz

doi:10.3989/gya.067210

Abstract

The oxidative stability of sunflower oil and lard supplemented with water extracts of green and roasted, Arabica and Robusta coffee beans was estimated. A decrease in the rate of fat oxidation reactions during the storage of samples for 12 weeks at ambient temperature which resulted from the addition of coffee extracts was evaluated using standard chemical methods such as the determination of peroxide and p-anisidine value and the assays of conjugated dienes and trienes as well as physical methods such as the determination of thermal profile by DSC. The sensory properties of all fat samples were also determined. These measurements showed that 0.1% water coffee extracts in fats decreased (p green Arabica > roasted Robusta > roasted Arabica.

Highlights

The majority of oils and edible fats are chemically unstable, in particular when exposed to oxygen and light which bring about oxidation even under standard storage conditions
Detection of the initial products of fatty acid oxidation is of particular importance during investigations of long term storage at ambient temperature when comparing to high temperature conditions, where these substances are quickly destroyed
The initial peroxide value (PV) of sunflower oil was 2.7 meq O2 kg21 and after a 12 week storage period it increased approximately 25-fold in the control free from coffee extracts (Fig. 1b). It is a consequence of the fatty acid profile of sunflower oil which usually contains approximately 90% unsaturated fatty acids while lard only contains 50%

Summary

Introduction

The majority of oils and edible fats are chemically unstable, in particular when exposed to oxygen and light which bring about oxidation even under standard storage conditions. Oxidation decreases the stability of oils and fats during long term storage and negatively affects the stability of lipid containing foods, in particular those which were thermally processed like fried foodstuffs (Anwar et al, 2006). To some extent these disadvantageous processes taking place during the storage of fats can be slowed down through supplementation with antioxidants.

Objectives

Methods

Results

Conclusion