NOVELTY - Method (M1) to treat base composition of oils and/or fats, involves: (A) stripping, where base composition and stripping fluid are in contact and at 150-280 degrees C and pressure of less than or equal to 100 mm Hg, where at least part of stripping fluid forms with first portion of composition, separating mixture, that separates in gaseous phase from liquid phase composition; and (B) condensation, where separating mixture is at temperature lower than stripping and greater than or equal to 4 degrees C and pressure of less than or equal to 10 mm Hg, so that at least part of stripping fluid condenses to maintain pressures during stripping and condensation.    USE - For treatment of base composition including oil and/or fat by deacidification, deodorization and/or purification (all claimed), which is useful for production of biodiesel.    ADVANTAGE - The method for treatment of base composition containing lipids i.e. oils and/or fats, at least overcomes drawbacks of the state of the art, offers considerable advantages, and is at the same time, simple and inexpensive to produce and manage. The prior art use of steam as stripping fluid has disadvantages, such as (relatively high) energy cost related to vaporization of water; production of polluted water, which increases considerably if, water vapor is extracted from stripping zone by steam-jet ejectors and condensed in mixing condensers, usually barometric condensers, in which steam is condensed by direct contact with large flow of water at low temperature; and causes hydrolysis of glycerides and formation of emulsions. Carrying out stripping at low pressures reduces quantity of stripping fluid employed and stripping temperature and consequently operating cost of plant, as well as reduces losses of end products along with improving quality of end products. The costs of construction of plants and implementation of method are relatively low; particularly, method can be carried out in plants where steam is not available (in particular, motive steam) and which therefore do not require boiler house to produce it; and implementation of the method has modest environmental impact as little energy is consumed and minimum quantities of effluents are produced. The method does not make use of or uses very little steam (in particular, motive steam); uses little electricity; produces minimum quantities of effluents, because it is possible to operate in almost closed circuit; does not cause hydrolysis of glycerides; and requires low investments for construction of plants, as plants have low complexity.    DETAILED DESCRIPTION - Method (M1) for the treatment of a base composition, which comprises a mixture of lipids, particularly is mainly made up, in terms of weight, by oils and/or fats, involves:    (A) stripping step, during which the base composition and a stripping fluid are in contact with one another and are treated at 150-280 degrees C and at a pressure less than or equal to 100 mm Hg (13.33 mbar), where at least part of the stripping fluid forms, together with a first portion of the base composition, a separating mixture, that separates, in the gaseous phase, from the base composition, which is in the liquid phase, in the area of a stripping zone; and    (B) condensation step, during which the separating mixture in the gaseous state is caused to reach a temperature that is lower than the temperature of the stripping step and greater than or equal to 4 degrees C and a pressure that is less than or equal to 10 mm Hg (13.33 mbar), so that at least part of the stripping fluid condenses in the area of a condensation zone different from the stripping zone and interposed between the stripping zone and a suction device, which maintains the pressures during the stripping and condensation steps in the stripping zone and in the condensation zone, respectively.    An INDEPENDENT CLAIM is included for a plant (1) for performing the method (M1) comprising: greater than or equal to 1 stripping device (4), which is designed to perform the stripping step, during which the base composition and the stripping fluid are in contact with each other and treated at 150-280 degrees C and at a pressure lower than 10 mm Hg (13.33 mbar) and at least part of the stripping fluid forms together with the first portion of the base composition forms a separating mixture, which separates out in the gaseous phase from the base composition; greater than or equal to 1 condenser (9, 9', 9''), which is fluidly connected to the stripping device and is designed to perform the condensation step, during which the separating mixture in the gaseous state is brought to a temperature lower than the temperature of the stripping step and greater than or equal to 4 degrees C and to a pressure less than or equal to 10 mm Hg (13.33 mbar) so that at least part of the stripping fluid condenses; and a pumping device (10), which is designed to reduce the pressure in the stripping device and in the condenser and is fluidly connected to the condenser; the condenser is interposed between the stripping device and the pumping device; the condenser, the stripping device and the pumping device are connected in such a way that the pressure in the condenser is less than or equal to the pressure in the stripping device; and the condenser is not designed to cause the formation of solid condensates.    DESCRIPTION OF DRAWING(S) - The figure shows the plant for treatment of base composition containing oils and/or fats.    Plant (1)    Heater (3)    Stripping device (4)    Evaporator (9, 9', 9'') Condenser (6)    Pumping device (10)    Separator (12)    Stripping fluid reservoir (15)    Cooler (18)