Abstract
Caffeic, syringic, and protocatechuic acids are phenolic acids with important antioxidant activity. In this work we studied how the oxidative stability of rosehip, hemp, and passion fruit oils improves with the addition of these antioxidant acids. We used the BQC-Redox System method to measure the antioxidant activity of oils and phenolic acids, and compared these results with other methods described in the literature. In addition, principal components analysis was used to show the relationship between oxidant activity and fatty acids in the oils studied. The results show, in most cases, the improvement of oxidative stability of oils by addition of phenolic acids, and that oxidative stability is determined by the molecular structure of phenolic acids, solubility of oils, the composition of oils in fatty acids, and the influence of temperature in stabilizing phenolic acids and oils. In addition, we support that the BQC-Redox System (BRS) is a suitable method to measure antioxidant activity.