Abstract:

In this paper, kinetic studies were carried out to investigate the extraction of carotenoids from carrot powders of
different particle sizes by three different methods, namely water bath, ultrasonic-assisted and microwave-assisted extraction,
at different temperatures respectively, using vitamin C and BHT as antioxidants and petroleum:acetone (4:1, V/V) as
extractant. The results showed that the kinetic models for water bath and ultrasonic-assisted extraction conformed to the
internal diffusion-controlled chemical kinetic models, which were as follows: y = 0.009 9t + 0.110 7 (R2 = 0.920 9, 30 ℃), y =
0.018 6t + 0.096 1 (R2 = 0.893 7, 40 ℃), y = 0.018 2t + 0.088 6 (R2 = 0.965 7, 45 ℃) for water bath extraction; y = 0.001 1t +
0.080 9 (R2 = 0.917 9, 30 ℃ ), y = 0.001 6t + 0.043 9 (R2 = 0.978 8, 40 ℃ ), y = 0.001 8t + 0.039 (R2 = 0.964 2, 45 ℃ ) for
ultrasonic-assisted extraction. In addition, the values of activation energy were Ea (water bath extraction) = -26.825 1 kJ/mol
and Ea (ultrasonic-assisted extraction) = -35.196 5 kJ/mol. However, the kinetic model for microwave-assisted extraction
conformed to the hybrid-controlled kinetic model and the fitted equations were as follows: y = 0.027 5t + 0.344 6 (R2 = 0.972 3,
30 ℃), y = 0.031 9t + 0.426 5 (R2 = 0.868 9, 40 ℃), y = 0.058 7t + 0.275 1 (R2 = 0.973 4, 45 ℃); the value of activation
energy, Ea(microwave-assisted extraction), was -36.105 2 kJ/mol. The extraction efficiency and rate with water bath was
affected by raw material particle size in the decreasing order of 60–80 mesh > 40–60 mesh > 20–40 mesh. Therefore, small
particle size is beneficial for the extraction of caroteinoids.

Key words: carrot powder, carotenoids, extraction methods, extraction kinetics, kinetic equation, activation energy