Calidad nutricional y propiedades físicas de panes libres de gluten / Nutritional quality and physical properties of gluten-free breads

Introducción: los panificados libres de gluten (LG) presentan dificultades tecnológicas en su elaboración, una textura muy diferente a sus homólogos con gluten y una calidad nutricional muchas veces deficiente por el uso de harinas refinadas y almidones, que proveen alta densidad energética y bajos valores nutricionales. Objetivo: evaluar las características nutricionales y físicas de panes libres de gluten empleando mezclas de harinas y almidones. Materiales y métodos: Los panes fueron elaborados con harina integral de quinoa (HQ), harina de arroz (HA), harina de lupino blanco (HL), almidones de maíz (MZ) y mandioca (MA). Se aplicó un diseño experimental de mezclas D-optimal ajustándose a una ecuación de segundo orden y considerando como variables predictoras el contenido de carbohidratos, proteínas, lípidos y minerales. Fueron elaboradas 20 formulaciones donde se analizaron el volumen específico, la dureza y uniformidad alveolar. La formulación optimizada fue comparada su composición proximal y perfil de aminoácidos con panes LG comerciales. Resultados y discusiones: los panes con mezclas del 35- 41% HQ, 18% HL y HA entre 18 y 29%, mostraron un destacado contenido en proteínas (9%), lípidos (3%) y minerales totales (1,8%). Estas formulaciones de panes LG presentaron una dureza que varió entre 4,09 y 7,51 N, un volumen específico entre 1,53 y 1,95 cm3/g y una uniformidad alveolar entre 1,38 y 2,7. La formulación optimizada (P0) fue la compuesta por 41% HQ, 20% HA, 18% HL, 11% MZ y 10% MA. Al comparar P0 con los panes comerciales, se pudo observar diferencias significativas (P<0,05) en el contenido de proteínas (11,21%), lípidos (3%) y minerales totales (2,27%), destacándose P0 por presentar los mayores valores nutricionales. Conclusiones: Se logró un producto panificable apto para celíacos donde el uso HQ y HL, como principales componentes, tuvieron un efecto positivo sobre la calidad nutricional y características físicas de los panes evaluados

Introduction: The gluten free bread (GF) free bread have technological difficulties in its development, the texture is very different from their counterparts with gluten and the nutritional quality is often poor by the use of refined flours and starches, which provide high energy density and low nutritional values. Aim: Nutritional and physical characteristics evaluation of breads from mixtures of gluten-free flours and starches. Materials & methods: Quinoa flour (HQ), rice flour (HA), white lupine flour (HL), cornstarch (MZ) and starch from cassava (MA) were used to make the breads dough. It was applied an experimental design of mixing D-optimal, adjusting to a second order equation and considering the content of carbohydrates, proteins, lipids and minerals as predictor variables. Volume, hardness and alveolar uniformity of crumb were analysed in 20 formulations. The optimized formulation was compared by their proximate composition and profile of amino acids with GF commercial breads. Results and discussions: Breads with mixtures of 35- 41% HQ, 18% HL, 18-29% HA has presented an outstanding content in proteins (9%), lipids (3%), and total minerals (1.8%). The 20 LG bread formulations presented a hardness that ranged between 7.51 and 4.09 N, a specific volume ranging from 1.53 to 1.95 cm3/g and alveolar uniformity between 1.38 and 2.7. The optimized formulation (P0) was composed of 41% HQ, 20%, 18% HL, 11% MZ and 10% MA. Comparing the P0 with the LG commercial bread loaf, significant differences could be observed (P<0.05) in the content of proteins (11.21%), lipids (3%) and total minerals (2.27%), highlighting the bread of the P0 by presenting the highest nutritional values. Conclusions: It was achieved a suitable gluten-free product where the use of quinoa and sweet lupine flours as main components had a positive effect on the nutritional quality and to the physical properties of testing bread loafs

Nodulation of Lupinus albus by strains of Ochrobactrum lupini sp. nov.

The nodulation of legumes has for more than a century been considered an exclusive capacity of a group of microorganisms commonly known as rhizobia and belonging to the alpha-Proteobacteria. However, in the last 3 years four nonrhizobial species, belonging to alpha and beta subclasses of the Proteobacteria, have been described as legume-nodulating bacteria. In the present study, two fast-growing strains, LUP21 and LUP23, were isolated from nodules of Lupinus honoratus. The phylogenetic analysis based on the 16S and 23S rRNA gene sequences showed that the isolates belong to the genus Ochrobactrum. The strains were able to reinfect Lupinus plants. A plasmid profile analysis showed the presence of three plasmids. The nodD and nifH genes were located on these plasmids, and their sequences were obtained. These sequences showed a close resemblance to the nodD and nifH genes of rhizobial species, suggesting that the nodD and nifH genes carried by strain LUP21T were acquired by horizontal gene transfer. A polyphasic study including phenotypic, chemotaxonomic, and molecular features of the strains isolated in this study showed that they belong to a new species of the genus Ochrobactrum for which we propose the name Ochrobactrum lupini sp. nov. Strain LUP21T (LMG 20667T) is the type strain.