Jussara palm tree (Euterpe edulis M.) açai-berry oil performance on auto- and photo-oxidation: Minor components’ stability and evolution of volatile compounds

Abstract

The oxidative stability of açai-berry oil relating with the formation of oxidation products, the stability of minor components, and the evolution of volatile compounds under accelerated auto- and photo-oxidation was investigated. In both tests, peroxide value increased linearly with time and was negatively associated (R² ≥ 0.98) with α- and β-tocopherols, and chlorophyll a. γ-Tocopherol was one of the most unstable compounds, reaching complete loss between 0-to-3 days in auto-oxidation, and between 3-to-5 days in photo-oxidation. α-Tocopherol remained stable during auto-oxidation whereas β-Tocopherol degraded from 5-to-7 days, reaching 57 % loss. At 7 days of photo-oxidation, α-Tocopherol reached a small 26 % loss and β-Tocopherol a 32 % loss. Anthocyanins content decayed exponentially with time, reaching a 93 % loss after 7 days of auto-oxidation and a complete loss between 0-to-3 days of photo-oxidation. Hexanal and nonanal were formed in the advanced stages of auto-oxidation and in early stages of photo-oxidation, reaching after 7 days of oxidation contents that were over 15-fold and over 7-fold higher in the later than in the former. Conversely, 2-heptenal was formed only in photo-oxidation. Açai-berry oil was highly stable in auto-oxidation in the dark, but it requires storage under protection from light due to its low photo-oxidation stability.