Ultrasound-Assisted Extraction of Carotenoids from Pulps of Tucumã Fruits (Astrocaryum vulgare Mart.) Using Protic Ionic Liquids

Carotenoids are lipophilic pigments with broad industrial relevance, especially as natural colorants in food and cosmetics. However, their conventional extraction typically relies on volatile organic solvents, raising environmental and safety concerns. In this study, we propose an alternative carotenoid extraction method from the pulp of tucumã fruits (Astrocaryum vulgare Mart.) using protic ionic liquids (PILs) in combination with ultrasound-assisted extraction (UAE). Three PILs were synthesized and characterized: 2-hydroxyethyl ammonium acetate (2-HEAA), 2-hydroxyethyl ammonium formate (2-HEAF), and 2-hydroxypropyl ammonium acetate (2-HPAA). Among them, 2-HEAA demonstrated the highest carotenoid extraction efficiency under conventional conditions (117 μg/g, dry basis), with no significant difference compared to ethanol (111.51 μg/g). Therefore, 2-HEAA was selected for optimization using UAE and the optimized conditions (0.17 g/L of 2-HEAA, 30 min, 1:10 solid–liquid ratio) resulted in a total carotenoid yield of 189 μg/g. UAE proved to be more effective than the conventional method, increasing yield by ~38%, while also reducing processing time. (all-E)-β-Carotene was the major compound (~89%), but its Z-isomers along with (all-E)-α-carotene and (all-E)-α-cryptoxanthin were also detected (>5%), and the carotenoid profile remained unchanged between solvents (2-HEAA vs. acetone). The combination of 2-HEAA in ethanol with UAE represents a promising alternative for carotenoid extraction from tucumã pulp, whose environmental performance and industrial applicability require further evaluation.