Application of high pressure techniques on the reactions of oils and fats chemistry such as esterification of long-chain fatty acids and alcoholysis of triacylglycerol was introduced, and was compared to the conventional techniques and supercritical methanol techniques. The esterification of long-chain fatty acids in excess alcohol was very greatly accelerated under high pressure, and the activation volumes of some reactions in dichloromethane solvent were estimated to be as much as-80 cm³/mol. In the case of the esterification of mixed fatty acids, high selective esterification based on the difference of chain length is possible by compression. The alcoholysis of triacylglycerols was also accelerated greatly by compression to give the corresponding ester of fatty acids in high yield when CH₂Cl₂ or CCl₄ was used as a solvent.

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High-pressure has been focused on as a new technology for the processing food, since the report in 1987 by Hayashi et al. However, almost all researches were regarding to denaturation of protein or gelatinization of carbohydrate and were concerned about sterilization of food. There was almost no research to investigate the effect of high-pressure for the crystallization behavior of fats. Fats and oils are one of the most important row materials for many foods. To study relationship between high-pressure and crystal structure of fats, the cooling curves and solid fat contents under various pressure conditions were measured. As a result, it was cleared that high-pressure should induce crystallization of fats. Solid fat contents of the samples were also increased by the high-pressure treatment. Creaming ability was increased by high-pressure treatment. It was supposed that the crystal structure was stabilized by high-pressure treatment. Microscopic observation showed the high-pressure made fat crystals small. The margarine, which produced under high-pressure, makes high quality bakery and confectionary products.

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