Investigating carotenoid loss after drying and storage of

Ln C/C0
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
10ºC
20ºC
30ºC
40ºC
176
8. Study under controlled conditions
0 20 40 60 80 100 120
Storage time (days)
Figure 8-6: Trans-β-carotene degradation kinetics in dried sweet potato chips
influenced by temperature between 10 and 40ºC on a dry weight basis (mean of
triplicate determination; error bars show standard deviation). Oxygen level 21%
(air); aw 0.52-0.65.
Coefficients of correlation (R 2 ) in Table 8-4 suggest that a first-order equation fitted well
the carotenoid degradation.
Table 8-4: Rate of degradation of carotenoids (k) expressed in day -1 at various
temperatures in dried sweet potato chips on a dry weight basis. Oxygen level 21%
(air) ; aw 0.52-0.65. Mean of triplicate determinations (standard deviation).
Temperature (ºC)
10 20 30 40
Trans-!- k 0.0024 (0.0002) 0.0090 (0.0005) 0.0191 (0.0002) 0.0403 (0.0005)
carotene* R 2 0.757 (0.058) 0.914 (0.031) 0.986 (0.005) 0.965 (0.007)
5,6 epoxy-!- k 0.0021 (0.0002) 0.108 (0.0002) 0.0248 (0.0007) 0.0597 (0.0005)
carotene* R 2 0.583 (0.092) 0.889 (0.039) 0.869 (0.017) 0.987 (0.009)
Total k 0.0040 (0.0003) 0.0083 (0.0002) 0.0174 (0.0005) 0.0295 (0.0010)
carotenoids** R 2 0.825 (0.116) 0.978 (0.018) 0.987 (0.005) 0.987 (0.005)
* by HPLC; ** by Spectrophotometry
An exception nonetheless was at 10ºC where correlations observed were lower (R 2 ~0.8).
Lower correlations at low temperatures where there is minimum carotenoid degradation
could be explained by experimental errors (Hildago and Brandolini 2008). Degradation
rates of trans-β-carotene were significantly different at the four tested temperatures (10;