Estudio de las propiedades funcionales de harinas de trigo sarraceno obtenidas a partir de granos tratados con altas presiones hidrostáticas

Abstract

En este trabajo se ha evaluado el efecto de cuatro tratamientos con altas presiones hidrostáticas (APH) realizados a 600 MPa de presión: APH en 1 ciclo (30min9 y APH en 2 ciclos (15min cada uno), con y sin remojo previo a 40ºC. El tratamiento APH fue aplicado sobre granos enteros de trigo sarraceno, posteriormente, se obtuvo su harina cuyas propiedades funcionales y nutricionales fueron caracterizadas. Los resultados obtenidos muestran un aumento de las propiedades de hidratación, la viscosidad final y la de caída y la estabilidad con el tratamiento APH y remojo previo, mientras que se redujeron las propiedades emulsionantes y espumantes, la viscosidad de pico y la retrogradación. Tras los tratamientos APH se obtuvieron harinas más oscuras y de un color más intenso. Además, estos tratamientos no parecieron afectar negativamente a su concentración de compuestos fenólicos totales

High hydrostatic pressure (HHP) is one of the different innovative techniques used for physical modification of flours. However, the application of this treatment on whole grains has been scarcely studied. In this work, the effect of four treatments with HHP at 600 MPa have been evaluated: HHP in 1 cycle during 30 minutes with and without presoaking at 40ºC, and HHP in 2 cycles of 15 minutes each cycle with and without presoaking at 40ºC. HHP treatment was applied on whole grains of buckwheat, and then flour was obtained. This flour was characterized by its functional and nutritional properties. The obtained results showed a significant increase in all hydration properties values after HHP treatment with pre-soaking at 40ºC, while the emulsifying and foaming properties were reduced with high hydrostatic pressure. In relation to the pasting properties, it has been observed that the presence of pre-soaking in HHP treatment significantly reduced peak viscosity and setback, as well as increased trough viscosity, final viscosity and breakdown. Peak viscosity was also affected by the number of cycles, with higher values after HHP in 2 cycles. Gel viscoelastic properties were not significantly influenced by any studied factor. Considering the color parameters, hue was not affected by number of cycles and pre-soaking. Lightness significantly decreased in pre-soaked samples, but it was not influenced by the number of cycles. Finally, chroma also increased in pre-soaked samples, with higher values after the HHP treatment in 2 cycles. Regarding nutritional properties, the content of polyphenols has also been evaluated, since this pseudocereal is characterized by a high concentration of these compounds. HHP treatments did not affect negatively this parameter, so the antioxidant characteristics associated with buckwheat flour is expected to be maintained