Evaluation of liquid-liquid extraction to reducing the acidity index of the tucuma (Astrocaryum vulgare Mart.) pulp oil

Tucuma (Astrocaryum vulgare Mart.) is a native South American palm from the Amazon River drainage region. Tucuma fruits contain edible oils presenting high amounts of unsaturated fatty acids in the mesocarp and expressive amounts of saturated fatty acids in the endocarp. Besides this, tucuma pulp oil contains appreciable amounts of carotenoids, allowing for the replacement of palm oil in numerous industrial applications. Due to the presence of endogenous lipases, tucuma pulp oil can present an acid value three times above the acceptable limit for crude edible oils. In the present study, tucuma oil deacidification was evaluated using ethanol 94 degrees GL at a 2:1 (w/w) solvent/oil ratio. After processing in two stages, edible oil presented a reduction in acid value from 17.65 +/- 0.67 mg KOH g(-1) to 3.5 +/- 0.01 mg KOH g(-1). Deacidification process promoted losses of unsaponifiable matter, and total carotenoids of 24% and 35%, respectively. However, free fatty acid (FFA) removing significantly improved tucuma pulp oil quality, such as reduction of the peroxide value (11.53 +/- 0.10 mEq kg(-1) to 6.02 +/- 0.46 mEq kg(-1)) and the increase of the thermal and oxidative stability, from 13.8 +/- 0.5 h to 22.5 +/- 0.2 h, without changing its crystallization and melting profiles, and the tucuma oil functional quality, preserving the omega-6:omega-3 ratio (1:1).