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The reaction of olive oil and glycerol over immobilized lipases was studied. For oil samples with free fatty acid (FFA) contents larger than 2%, FFA esterification and glycerolysis took place simultaneously, but the esterification reaction was faster than glycerolysis. Similar product distributions were obtained for glycerol/oil mole ratios of 3:1 and 6:1. Therefore, an excess of glycerol does not result in a significant increase in monoglyceride yield within the experimental range tested. The main reaction product at 80°C was diglyceride. No increase in monoglyceride yield was observed by lowering the reaction temperature to 10°C. JAOCS 75, 657-660 (1998).Monoglycerides are widely used in the food industry as emulsifiers for bakery products, margarines, dairy products, confectionery, etc. They also have important applications in the cosmetic and pharmaceutical industry for the preparation of oil/water (O/W) emulsifying systems and for improving the consistency of creams and lotions. In addition, owing to their excellent lubricant and plasticizing properties, monoglycerides are used in textile processing, production of plastics, and formulation of oils for different types of machinery. The most commonly used products are glycerol monostearate, monooleate, and monoricinoleate (1).Mixtures that contain 40-48% monoglycerides (MG), 30-40% diglycerides (DG), 5-10% triglycerides (TG), 0.2-9% free fatty acids (FFA), and 4-8% free glycerol are generally termed monoglycerides. These mixtures have applications in food fats (margarine, ice cream, sweets, etc). Pure MG (90-97%), obtained by molecular distillation of the above mixtures, are also commercially available. The higher-purity MG are preferred for bakery uses because of their good amylasecomplexing ability. Most commercial MG are produced from edible, refined, hydrogenated animal fats (tallow, lard, etc.) or from hydrogenated vegetable oils (palm, soybean, etc.). Higholeic vegetable oils can also be used as raw materials for the production of emulsifiers for liquid and low-fat margarines. Owing to the large content of monounsaturated fatty acids, improved consistency and stability is obtained and can be compared to conventional MG based on hardened fats and oils.

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The development and optimisation of the synthesis of an analogue of jojoba oil has been carried out. The product is an ester with characteristics similar to those of sperm whale oil and jojoba oil. This permits its use as a substitute for these two natural oils. A central composite design has been used in the synthesis of this fine chemical. The variables selected for the present study are reaction temperature, initial concentration of catalyst and working pressure. Temperature is the most significant factor in the esterification process, and its influence is positive. Pressure has a negative influence, and the concentration of catalyst a positive influence, on the process. Depending on the temperature value, the influence of the interactions can be more important than that of the other two main effects, pressure and catalyst concentration. Response surface models have been found adequately to represent the yield of ester. The commercial quality of the synthesised product is very similar to that of natural jojoba oil. Because of its low cost, this synthesis process is considered, from an economical point of view, very attractive.