Industrial thin-film deodorization of seed oils withSoftColumnTM technology

Development of thin-film deodorizers started in the 1970ies, and they have been in industrial use since the middle of the 1980ies. The latest type is the SoftColumn, a deodorizer specially developed for mild, low cost processing of seed oils. This deodorizer consists of a structured packing section and a flexible holding section. Regenerative oil heating/cooling and final heating is carried out in external, sparged vacuum heat exchangers, and the design of the heat exchangers leads to superior heat recovery and savings in fuel consumption. This set-up provides major advantages with regard to oil quality, economy, and flexibility. The extremely effective stripping of free fatty acids (FFAs) leads to shorter overall holding times of the oil at elevated temperatures, and steam consumption is cut to a third of the amount required in conventional deodorizers. The product oil has not only low acidity, low colour, good taste and stability, but also low trans fatty acid (TFA) concentrations. By adjusting the stripping steam flow the plant can be optimized both for tocopherol retention or removal. Flexible holding times allow optimization of heat bleaching/TFA formation without compromising on capacity. In this paper product analysis data on tocopherol and trans fatty acids from thin-film deodorizers in industrial operation are shown.