Ultrasound-assisted extraction using ethanol efficiently extracted carotenoids from peels of peach palm fruits (Bactris gasipaes Kunth) without altering qualitative carotenoid profile

Peach palm (Bactris gasipaes Kunth) is an amazonian fruit in which its peel has been appointed as a carotenoid-rich byproduct with biological properties. For analytical purposes, carotenoids are frequently extracted by non-green (use of toxic organic solvents) and time-consuming methods, which can affect the quality (carotenoid profile) and safety of extracts for direct food applications. We investigated herein the effect of different extraction methods on the individual carotenoid profile of extracts of peach palm peels by HPLC-DAD. Carotenoid extractions were carried out by maceration in mortar with pestle (with acetone or ethanol), magnetic stirring, shaker and ultrasound-assisted extraction (UAE) using ethanol. UAE provided the highest carotenoid contents (67 mg/100 g), followed by maceration with acetone and ethanol (63 and 52 mg/100 g, respectively), while the lowest contents were observed for the magnetic stirring and shaker extractions (44 mg/100 g), being (all-E)-β-carotene and a Z-isomer of γ-carotene accounted 54-73% of the carotenoid composition. HPLC-DAD data showed the same carotenoid profile regardless the extraction method, yet the percentage of Z-isomers of β-carotene was higher for the shaking (18%), UAE (17%) and magnetic stirring (15%) than for both maceration methods (7 and 8%, with acetone and ethanol, respectively). Thus, the tested extraction methods affected the total carotenoid contents, whereas the chromatographic profile did not change. Furthermore, a carotenoid-rich extract was effectively obtained by using ethanol associated with ultrasound technique (less time-consuming) instead of toxic and non-safe solvents.