Investigating carotenoid loss after drying and storage of

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1. Literature review
Carotenoid degradation kinetics can be evaluated using different models. The most well
known is Arrhenius model. Other models however exist such as the Eyring model,
which is based on the transition state theory in which enthalpy of activation (%H*) and
entropy of activation (%S*) are the model’s parameters. The Arrhenius model is an
empirical collision model that describes the relationship between reaction constant rates
and temperature using activation energy (Ea) and a pre-exponential factor (k∞). The
model’s parameters were identified from experimental data measured using linear
regressions (Cisse et al. 2009).
Carotenoid degradation rate has been described by various authors including Koca et al.
(2007), Hidalgo and Brandolini (2008) and Cisse et al. (2009) using the Arrhenius
model (Equation 1-5).
Arrhenius model:
−
Ea
RT
= ek (Equation 1-5)
∞
k : degradation constant rate (day -1 )
k∞ : value of k at T = & (day -1 )
T : temperature (K)
Ea : Activation energy (kJ.mol -1 )
R : Molar gas constant = 8.314 J · K−1 · mol −1
Practically the graphical representation gives the following equation:
abk
T
1
ln = − where b and a are constant of linear equation. b= ln k∞.
Ea
Ea was calculated from the linear equation following the formula: a =
R
For the validation of the Arrhenius model using temperature (T) expressed in Kelvin, the
predicted data can be calculated using Equation 1-6:
=
k e
t
− Ea
RT
∞
0
−
eC !
dt
0 (Equation 1-6)
Determination of Ea and k∞, the parameters helps predict carotenoid degradation for
known temperatures and storage times.