Evaluación de los cambios estructurales de galletas elaboradas con sustitutos de grasa

Abstract

[EN] In a social context in which the consumer values increasingly healthy and low-fat foods, biscuits reformulation has been studied to decrease its lipid content. In order to investigate it, two variables were selected, first of all, the emulsion substitute of the fat, and secondly, the role that the glycerol had both in the dough and in the biscuit. The chosen emulsion was one of type oil in water, with sunflower oil and stabilized with different cellulose ethers: F4M (hydroxypropylmethylcellulose), A4M (methyl cellulose) and MX (methyl cellulose with a high degree of methylation). Seven types of doughs and biscuits were prepared: control dough /biscuit in which the butter was used as fat, and doughs /biscuits in which the fat was replaced with cellulose ethers emulsion, the above mentioned were formulated with and without glycerol. Doughs and biscuits texture were evaluated. Results showed that glycerol affected the hardness dough, making them more extensible and cohesive; as a result, glycerol biscuits were less hard than the others elaborated without glycerol. Both, sample calorimetric properties and microstructure were also evaluated. In the calorimetric properties no differences between doughs elaborated with emulsions and control dough were obtained, thereby replacing the fat emulsions of the cellulose ethers and the presence of glycerol did not affect starch gelatinization. Doughs microstructure was performed by Confocal Laser Scanning Microscopy and Cryo-Scanning Electron Microscopy while biscuits microstructure was carried out by Cryo-Scanning Electron Microscopy. In both cases very different results were obtained, being biscuits and doughs elaborated with the emulsion MX the most different. Finally, a sensory analysis was carried out with the samples that better attributes demonstrated in the previous tests, where the best valued biscuit was the MX without glycerol.

[ES] Se desarrollaran galletas bajas en grasa mediante la sustitución de este ingrediente por diferentes hidrocoloides. Se determinará los cambios que produce dicha sustitución en la estructura del producto final desarrollado mediante el estudio de su reología, calorimetria diferencial de barrido y microscopía. Tambien se evaluaran cambios macroscópicos como la modificación en sus dimensiones y la textura.