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One of the most obvious changes when oils are heated is color darkening. Palm oil darkens very rapidly compared to other oils. The cause of this rapid color development was investigated. Various methods used to pretreat Lotox crude palm oil (CPO) to retard darkening during heating were by agitation with activated carbon S511, by water and water/isopropyl alcohol (95:5) washing of neutralized and unneutralized oil, and by liquid/liquid extraction of oil using water and water/isopropyl (95:5). Pretreatment of CPO did succeed in retarding color development. Retardation was especially evident in oils previously neutralized with sodium hydroxide before washing with water and water/isopropyl alcohol. The UV spectra of the liquid/liquid extracts showed strong absorption maxima at 256 nm. The addition of a base resulted in darkening of the extracts accompanied by shifts to longer wavelengths (288 nm). Reaction with freshly diluted 1–2% ferric chloride solution gave a brown color. The development of paper chromatography in butanol: acetic acid:water (6:1:2) revealed a blue fluorescence near the solvent front, with the same relative retention time as that of tannic acid. This evidence indicates that phenolic compounds were responsible for color darkening in palm oil.

PORIM can look back at its first six years of existence with pride. It is now permanently housed in its own buildings on a site which provides pleasant working conditions. It has recruited a large, well qualified and enthusiastic staff. This rapid progress is due mainly to the unanimous support and collaboration of the industrial and government organizations involved. Significant contributions to the technology of the industry are being made, and the institute is established on the international scene. However, both individual scientists and PORIM are more interested in the future. They are confident of making continued contributions to the production and use of basic foodstuff which is economical for the world population and of major economic importance to Malaysia.