CONCLUSIONS
The exposure of food to sunlight has substantial effects on its safety
and quality. Therefore, this study focuses on the influence of sunlight
exposure on tropical oils. The study showed a significant (p< 0.05) increase in FFA levels and PV for the exposed TOs. The
IV and colour content also decreased significantly (p <0.05). FTIR analysis showed intense vibrational absorptions at 1721 and
3505 cm-3, 1720 and 3560 cm-3, and
1721 and 3554 cm-3 for the exposed CNO, PO, and PKO,
respectively. These bands correspond to the secondary oxidation
products, which were absent in the unexposed TOs. Simulation was
performed to support the FTIR results, which also indicated the
absorptions from the secondary oxidation products at 1744 and 3660
cm-1. However, the rate of oxidation of different
types of TOs differed significantly, and the trend followed the order:
PO > PKO > CNO. This study, therefore,
suggests several ways of minimising photooxidation, which should be
confirmed by further studies: (1) reduce the exposure of TOs during
processing, trading, and prolonged exposure to sunlight; (2) improve the
packaging materials to reduce the transmittance of light through oils;
and (3) increase the awareness on the consequences of exposing TOs to
sunlight. Hence, the findings of this work are essential and need to be
addressed to ensure appropriate handling of tropical oils during
distribution and storage.