Recent Developments in Chemical and Physical Refining

摘要

During the last few years, there has been considerable progress in the development and understanding of the pretreatment processes for vegetable oils and fats before the final high-temperature de-odorization stage. This has enabled physical refining processes to be developed for processing most vegetable oils and fats. However, during these same few years, the criteria used for establishing final oil quality have undergone some changes. Today, more attention is paid to the overall nutritional quality of the product. Oils should contain low trans fatty acid levels, low polymeric triglycerides, and low oxidation products, and should still contain adequate levels of natural antioxidants. These demands are in direct conflict with the high temperatures generally required in the physical refining process to remove free fatty acids. Changes have been made in the deodorization process and in equipment design to achieve the demands for better oil nutritional quality. This involves a comprehensive study of the temperature and steam profiling and optimization of the distillate recovery systems in order to provide a more valuable by-product.