Ultrasound assisted by microwave during the extraction of avocado oil: quality assessment by chromatographic techniques, Raman spectroscopy, and thermogravimetric analysis

Abstract

The aim of this study was to characterize the bioactive components in avocado oil (AVO) extracted by ultrasound combined with microwave, which are clean technologies used to assess oil quality. AVO samples were incubated for 30 min at 120 °C (T1), 180 °C (T2), and without any heat treatment (T3). Components were identified using chromatographic techniques, Raman spectroscopy, and thermogravimetric analysis (TGA). γ-Tocopherol and total carotenoids were affected in T2. The Raman spectrum of T3 and T1 presented a strong band at 1265 cm–1 related to the high content of linoleic acid and three bands associated with carotenoids. In the T2 sample, a weak intensity of the linolenic and linoleic acids was observed. In TGA, T2 showed a robust mass at 173.89 °C, characteristic of oxidized oil compounds. AVO treated at 120 °C for 30 min maintained the integrity of the bioactive compounds.

Keywords

• avocado
• oil
• bioactive compounds
• ultrasound
• microwave.