Amido da semente da Araucaria angustifolia: caracterização e efeito das modificações química e física e da incorporação de extratos da casca de pinhão nas suas propriedades

Abstract

ABSTRACT In the Northern Plateau of Santa Catarina Plateau, the Três Barras National Forest - Flona is a reserve with remnants of Araucaria angustifolia, nowadays included in the list of endangered species. From its seed, named pinhão, the starch is the main component and the coat is considered a residue. The aim of this work was to evaluate the thermal, paste, structural and morphological properties of Araucaria angustifolia seed starch in native form, modified by chemical and physical treatments and after incorporation with extracts obtained from the pinhão coat. The pinhão were collected after the natural fall of the pine cones in the A, B and C plots of Flona. Pinhão starch was obtained by aqueous extraction, which process showed good yield. Residual bagasse can be considered a source of fiber. The thermal stability and gelatinization temperatures were lower for the starch whose seed was collected in plot A, and the peak viscosity was similar between the three samples. Subsequently, corn and pinhão starches were modified with sodium tripolyphosphate in a three step process. Unlike the behavior of the other samples, four mass losses were verified by thermogravimetry in the intermediate stages of this treatment. Phosphate starches showed reduction in the initial temperature and gelatinization enthalpy; was observed an increase in peak and final viscosities, setback and breakdown. In sequence, native and phosphate starches were submitted to ball milling treatment. Grinding reduced the phosphorus content, mainly for native starches. In general, changes in all properties were more intense for phosphate starches after milling. Finally, corn and pinhão starches were incorporated with two extracts (ethanolic and aqueous) obtained from pinhão coats. In relation to the native starches, the thermal stability was lower for the samples incorporated with extract and higher for the control samples, which were produced under the same conditions, in contact with only solventes, without extracts. Regarding gelatinization, few changes were observed in temperature, but incorporation reduced the enthalpy of both starches. In all results no changes were observed in X-ray diffraction patterns, however the relative crystallinity increased after phosphating, while the ball milling treatment caused reduction. Only the physical modification promoted changes in granule morphology. The results are a source of relevant information about this unconventional starch. However, without exhausting the possibilities of starch modification for specific applications, pinhão starch showed properties that make it interesting for application in food and pharmaceutical products. Providing a more noble and sustainable use of pinhão can contribute to the conservation of Araucaria angustifolia, whose natural regeneration is constantly falling.