Investigating carotenoid loss after drying and storage of

Sample area (cm2)
91
3. Preliminary study
Figure 3-7: Reduction of sample visible surface area during open air-sun-drying.
F=fresh; I=after two hours of drying; D=dried. Each value is a mean of 30 samples.
When drying chips, there was a significant difference between sun and solar-drying in
terms of carotenoid content under the same conditions (Table 3-3 ).
Table 3-3: Influence of size reduction and drying treatment on total carotenoid
content of dried sweet potato ("g.g -1 ) on a dry weight basis (db)
Solar Sun
Chip 294(17)a 250(8)b
Crimped slice 307(20)a 319(18)a
Each value corresponds to an average of three extractions made on 100g flour from
milled dried slices. Values in brackets refer to the standard deviation. Values followed
with different letters are significantly different; ANOVA Tukey (p #0.05).
The difference was, however, not significant in crimped slices. Although data are only
available for sun-dried samples it would appear that chips which had the greatest
carotenoid loss had the greatest degree of “shrinkage”. It can be therefore hypothesised
that there is relationship between degree of “shrinkage” and carotenoid degradation but
this would need further investigation.
7
6
5
4
3
2
1
0
F
F
88.8%
I
I
66.5%
70.5%
D
51.2%
crimp chip
0 2 4 6 8 10
Drying time (h)
The role of direct sun radiation in carotenoid degradation in chip samples was not clear;
there could be a relationship between cellular collapse caused by “shrinkage” and
susceptibility of degradation of provitamin A by sun radiation.
D