RESUMO
Alternative methods for wet extraction of coconut oil and protein assisted by ultrasound or microwave were developed and compared. Coconut milk was prepared by milling the pulp (5:1 water to coconut pulp ratio), further destabilised at pH 4 and centrifuged to obtain the cream and cream protein fractions (control process). Microwave-assisted treatment applied in milk (1 min, 3 pulses of 20 s; 2.5 GHz; 4.31 kW/kg by pulse) generated a significant increase in cream obtained, and in the coconut oil extraction yield (~ 20%) compared to its control. The ultrasound-assisted treatment (2.5 min; 24 kHz; 0.573 kW/kg, 6.85 W/cm2) also improved oil extraction (10-16%). Moreover, a higher protein yield was achieved in ultrasound treated samples when compared to their control (49.6-86.1%). Large particles of 11 m µ , probably aggregates of particles, and smaller particles of 3.6 m µ , were detected in coconut milk, which were reduced by ultrasound effect. Alternative treatments caused a greater liberation of total phenols in coconut cream. Coconut proteins in water (0.1%) showed high negative electrokinetic potential. The surface pressure of coconut proteins at the air/water interface was not modified by assisted treatments.
