GB567682A - Process for preparing carotenoid concentrates from palm oil - Google Patents

Abstract

A carotenoid pigment concentrate is prepared from palm oil by alcoholizing palm oil with a low molecular weight aliphatic monohydric alcohol in the presence of an alkaline alcoholysis catalyst, distilling off the alkyl esters so formed and concentrating the carotenoid pigment in the residue of the distillation. It is an essential feature of the process that the temperature of the distillation and concentration should be kept low. In all cases below 150 DEG C. If the concentrates are to be exposed to an elevated temperature over an extended period, the temperature should not exceed 140 DEG C., or preferably 130 DEG C. As alkaline alcoholysis catalyst there is employed sodium or potassium hydroxide, or a preformed alkali metal methoxide or ethoxide. The palm oil may either be refined before use or not. In the latter case, an excess of the alkaline alcoholysis catalyst is used to neutralize the free fatty acids present. The alcoholized reaction product comprises the acyl esters of the monohydric alcohol, excess alcohol, carotenoid pigment, catalyst in solution and liberated glycerine. The glycerine may either be removed by distillation or preferably by a separate process prior to the distillation. If this is the case, it is carried out by a water washing. In order to prevent the formation of emulsions it is desirable to render the catalyst inactive by treatment with an equimolecular quantity of an acid reacting substance such as phosphoric acid. In an example, sodium hydroxide is dissolved in methyl alcohol and alkali refined palm oil is then added and the mixture refluxed for one hour. On cooling, the glycerine which forms the lower layer is separated off, and the upper layer is washed first with a water-alcohol solution and then with water alone. After drying, the mixture is distilled at 0.04 mms. pressure at 135 DEG -140 DEG C. The distillate consists of the alcohol esters of the palm oil fatty acids and is of very light colour. If a small column is used, a completely white product may be obtained, together with a residue of the carotenoid pigment. Specification 531,226 is referred to.