Instrumental Methods for the Evaluation of Interesterified Fats Ana Paula B. Ribeiro & Rodrigo Côrrea Basso & Renato Grimaldi & Luiz Antonio Gioielli & Lireny Aparecida Guaraldo Gonçalves Received: 28 October 2008 / Accepted: 26 January 2009 / Published online: 24 February 2009 # Springer Science + Business Media, LLC 2009 Abstract Chemical interesterification is currently the main alternative for the production of plastic fats containing no trans fatty acids. However, directing the industrial applica- tion of an interesterified fat requires a complete understand- ing of its physicochemical, functional and technological properties, and also of its stability during and after process- ing. The objective of the present article was to carry out an ample review of the experimental methodologies applied to the study of interesterified fats. The methodologies consid- ered include techniques employed in the investigation of the triacylglycerol composition, solid fat content, crystallization kinetics, thermal behavior, polymorphism, microstructure, and consistency. The methodologies considered include some official methods currently in use and new techniques recently developed and employed. Sample preparation methods, interpretation of the results and the results recently published in the literature in question are also detailed and discussed. Keywords Interesterification . Pulsed Nuclear Magnetic Resonance . Differential Scanning Calorimetry . Cone Penetrometry . X-Ray Diffraction . Polarized Light Microscopy Introduction The majority of natural fats and oils present limited application in their unaltered form due to their particular fatty acid and triacylglycerol compositions. Due to recent concern about the nutritional impact of trans fatty acids on the health, chemical interesterification has been shown to be the main method to prepare plastic fats not containing these compounds. This process allows for a modification in the behavior of the fats and oils, offering important contributions for the increase and optimization of their use in food products (Ribeiro et al. 2007a; Chiu et al. 2008a). In contrast to partial hydrogenation, interesterification does not promote isomerization of the double bonds of the fatty acids and does not affect their degree of saturation (Haumann 1994). The fatty acids remain unaltered during the interesterification reaction, but a redistribution of these components on the triacylglycerol molecules occurs. Thus, the process consists of the simultaneous breakage of existing ester bonds and the formation of new bonds on the glyceride molecules (Rozendaal 1992). In this way, chemical interesterification causes a modification in the triacylglycerol composition of a fat or blend of fats and, consequently, in its physical characteristics at all structural levels (Rousseau and Marangoni 2002; Dian et al. 2007). A complete understanding of the functions and proper- ties of the fats or oily bases produced by interesterification is primordial for the design of application plans for their use and for obtaining food products with the desired final attributes, particularly when one considers the recent substitution of partially hydrogenated fats. The satisfactory performance of a fat depends on important elements that determine its applicability. These include, primarily, stabil- ity during the post-processing period and total compatibility of the fat base with the product for which it is destined. Food Anal. Methods (2009) 2:282–302 DOI 10.1007/s12161-009-9073-4 A. P. B. Ribeiro (*) : R. C. Basso : R. Grimaldi : L. A. G. Gonçalves Food Technology Department, Faculty of Food Engineering, State University of Campinas–UNICAMP, Bertrand Russel street, C.P. 6041, 13083-970 Campinas, SP, Brazil e-mail: badanribeiro@yahoo.com.br L. A. Gioielli Department of Biochemical and Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, University of São Paulo–USP, 05508-900 São Paulo, SP, Brazil