Investigating carotenoid loss after drying and storage of

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5. Mozambican field study
The geographical position of the dryers was determined using GPS (GPS 60,
GARMIN®). Dryers were positioned facing north; this allowed maximum sun insulation
in the southern hemisphere. Temperature/humidity dataloggers (Tinytalk 2
Geminidatalogger, Chichester, UK) were placed in the tunnel dryer and under the shade
for ambient temperature.
5.2.3. Drying
Drying trials were carried out in duplicate. Five fresh roots per variety were collected for
carotenoid analysis. On the drying day, unpeeled roots were chipped using either a
mechanical rotary disc chipper producing either thick and thin chips, or by traditional
hand slicing. Size (thickness, width, length) of ten fresh chips or slices was recorded
using a digital calliper. Samples (4kg) were weighed (Hanson Electronic; ±1 g) after
carefully mixing (using a quartering technique). Sweet potato samples were evenly
spread on drying trays (6 trays per dryer) at a density of 3.9 kg.m -2 (see Chapter 2 section
2.2.3). Sweet potato thin and thick chips and slices from MCL01 and Resisto after 4
hours of drying are shown in Figure 5-1.
MGCL01 thin chips MGCL01 thick chips MGCL01 slices
Resisto thin chips Resisto thick chips Resisto slices
Figure 5-1: OFSP chips of different sizes after 4h of open-air sun drying
Samples were left overnight on dryers because rain was very improbable at the time of
the study. A night guard ensured that samples or plastic coverage from the tunnel dryer
were secure. The fresh samples of chips/slices per treatment with an initial weight of 4