Investigating carotenoid loss after drying and storage of

166
8. Study under controlled conditions
Chromatography (HPLC) and Gas Chromatography/Mass Spectrometry (GC/MS) for
the determination of loss of pure !-carotene and formation of volatiles (Mordi et al.
1993). But to our knowledge, a kinetic study including the comparison of !-carotene
degradation together with the formation of volatile degradation products has not been
reported in a dried food product matrix such as OFSP.
This study therefore seeks to relate !-carotene to its degradation products in order to
understand the pathway of !-carotene degradation in a dried food product.
8.2 MATERIALS & METHODS
8.2.1 Raw materials
Sweet potato chips from the Ejumula variety were harvested in Luwero, Uganda in
March 2008 after a growing season of 5-6 months. Roots were chipped and dried using
an open air sun dryer at the National Agricultural Research Laboratories (NARL),
Kawanda, Uganda with an average drying temperature of 28.8±2.8 ºC and 53.3±13.6%
relative humidity. Dried chips were stored in a freezer (about -20ºC). Carotenoid
content did not change significantly during storage in a freezer over a six month period
(Chapter 2).
8.2.2 Storage conditions
Storage system
A storage study was undertaken at Natural Resources Institute, UK. The storing system
used is shown in Figure 8-1.