Investigating carotenoid loss after drying and storage of

- On a dry weight basis:
C
loss = 1%
− (Equation 1-1)
C
0
- On a fresh weight basis taking into account loss of mass over the process:
Cm
loss = 1% − (Equation 1-2)
Cm
00
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1. Literature review
C: Carotenoid content of food (!g.g -1 ) at time t (e.g. after processing or after storage)
C0: Carotenoid content of food (!g.g -1 ) at initial time (e.g. before processing or before
storage)
m: mass of food at time t (g)
m0: initial mass of food (g)
The second formula was initially written by Murphy et al. (1975). The basis is fresh
food weight and not dry matter weight in order to take into account soluble solid losses
occurring during cooking (Rodriguez-Amaya 1997; Rodriguez-Amaya and Kimura
2004). Provitamin A true retention was calculated by 1- % loss from Equation 1-2.
In processes where soluble loss is negligible (in the case of drying for instance or in
storage of dried foodstuff) both formulas give equivalent results and the first formula is
sufficient. However when soluble loss becomes more significant (e.g. cooking,
blanching, chemical dipping, etc) the second formula that takes into account soluble
losses was used.
Degradation kinetics
Another more precise way of measuring the degradation of carotenoids in a food product
is the measurement of the kinetics of degradation.
The kinetics of degradation of "-carotene follows either zero-order in an aqueous
medium or first-order in an anhydrous medium (Minguez-Mosquera and Jaren-Galan
1995). The degradation rate is described in Equations 1-3 and 1-4:
Zero order: C C − kt
= 0 (Equation 1-3)
First order: ln C ln C − kt (Equation 1-4)
= 0
C: Carotenoid content of food (!g.g -1 ) at time t (e.g. after processing or after storage)
C0: Carotenoid content of food (!g.g -1 ) at initial time (e.g. before processing or before
storage)
t: time (day)
k: constant rate of degradation (day -1 )