Nanocapsules of β-carotene: Thermal degradation kinetics in a scraped surface heat exchanger (SSHE)

Response surface methodology was used to optimize the conditions of thermal degradation of beta-carotene nanocapsules in a scraped surface heat exchanger. The variables studied were volumetric flow (2.4 x 10(-6)-4.8 x 10(-6) m(3)/s), steam pressure (49-147 kPa), and rotor speed (10.4-31.2 s(-1)). Results showed that the experimental data could be adequately fitted into a second-order polynomial model with multiple regression coefficients (R-2) of 0.842-0.977, and that the variables with the greatest significance in the degradation of the beta-carotene were steam pressure and volumetric flow (p < 0.05). The responses analyzed were loss of beta-carotene and changes in the degradation rate (k) and activation energy (Ea). The highest process conditions obtained for thermal degradation prevention were 4.4 x 10(-6) m(3)/s of volumetric flow, steam pressure at 98 kPa, and a rotor speed of 38.29 s(-1), with optimum values of k = 0.049 min(-1), Ea = 171.49 kJ/mol, and loss of nanoencapsulated beta-carotene = 6.93%. (C) 2014 Elsevier Ltd. All rights reserved.