Emilce Llopart

Effects of extrusion conditions on physical and nutritional properties of extruded whole grain red sorghum (sorghum spp)

Abstract In order to analyze the effects of extrusion temperature (T: 164, 182, 200 °C) and grits moisture content (g/100 g sample) (%M: 14, 16.5, 19) on textural and physicochemical properties of red sorghum extrudates, whole grain flour was extruded according to a factorial experimental design. The higher values for specific mechanical energy consumption (1006.98 J/g) and expansion (3.36) were obtained at 164 °C–14%M and for sensorial hardness at 164 °C–19%M. While for specific volume, the highest value (10.41 cm3/g) was obtained at 200 °C–14%M. Water solubility and water absorption were directly related with T and inversely with M. Microscopic observation of the samples indicates that the greatest cooking degree was obtained at 200 °C–4%M and the lowest at 164 °C–19%M. Extrusion at 182 °C–14%M allows obtaining an expanded product with good properties. Proximal composition did not show statistically significant differences with raw sample. Extruded sample showed a 25.4% reduction of available lysine and a 31% increase in protein digestibility.

Colonic and systemic effects of extruded whole-grain sorghum consumption in growing Wistar rats

Colonic effects of extruded whole-grain sorghum diets were evaluated using a model of growing rats. In all, twenty-four male Wistar rats were fed control (C), extruded white sorghum (EWS) or red sorghum (ERS). Consumption of sorghum diets showed satiety properties, with reduction of caecal pH, and lower activity of β-glucosidase and β-glucuronidase enzymes. Decreased copper zinc superoxide dismutase and manganese superoxide dismutase and increased catalase and glutathione peroxidase levels were observed in colonic mucosa. The induction of antioxidant enzymes occurred through the activation of the nuclear factor erythroid 2-related factor 2 protein and its subsequent translocation into the nucleus. ERS was able to decrease the proliferation of proximal mucosa of colon, demonstrating a possible effect against colorectal tumourigenesis. EWS increased proliferation and also apoptosis, ensuring the re-establishment of homoeostasis of the colonic mucosa. No antioxidant systemic effect (serum or hepatic level) was observed. It is likely that despite the extrusion the low bioavailability of the phenolic compounds of sorghum diets caused them to exert mainly acute effects at the colon level. Extruded whole-grain sorghum is a good functional ingredient that might be promising in dietary prevention of intestinal diseases.

Losses of nutrients and anti-nutrients in red and white sorghum cultivars after decorticating in optimised conditions

Abstract The aims were to optimise pearling process of red and white sorghum by assessing the effects of pearling time and grain moisture on endosperm yield and flour ash content and to assess nutrient and anti-nutrient losses produced by pearling different cultivars in optimised conditions. Both variables significantly affected both responses. Losses of ashes (58%), proteins (9.5%), lipids (54.5%), Na (37%), Mg (48.5%) and phenolic compounds (43%) were similar among red and white hybrids. However, losses of P (30% vs. 51%), phytic acid (47% vs. 66%), Fe (22% vs. 55%), Zn (32% vs. 62%), Ca (60% vs. 66%), K (46% vs. 61%) and Cu (51% vs. 71%) were lower for red than white sorghum due to different degree of extraction and distribution of components in the grain. Optimised pearling conditions were extrapolated to other hybrids, indicating these criteria could be applied at industrial level to obtain refined flours with proper quality and good endosperm yields. Graphical Abstract

Complejos vitamina E-β-lactoglobulina incluidos en películas biopoliméricas de alginato de sodio

Se optimizaron las condiciones para la preparacion de peliculas biopolimericas capaces de encapsular los valores diarios maximos recomendados de la vitamina liposoluble E (α-tc), incorporando nanocomplejos formados por la proteina lactea beta lactoglobulina (b-lg) y la vitamina en soluciones alginato de sodio (AS), a una relacion β-lg/AS determinada previamente. En primer termino, se estudio por turbidimetria la interaccion entre β-lg (nativa y desnaturalizada por calor) con α-tc, a diferentes pHs, y se comprobo la eficacia de β-lg nativa a pH 6,80 para solubilizar la α-tc en soluciones acuosas. Se realizaron ensayos de opacidad y color de las peliculas y no se encontraron diferencias por la incorporacion del α-tc. Se evaluo por HPLC la integridad de la estructura de α-tc en los nanocomplejos formados en soluciones acuosas y en las peliculas de alginato a lo largo de un periodo de tiempo. La pelicula seca mejoro la proteccion de la estructura del α-tc al ser expuesta al oxigeno del aire y luz controlada, efecto atribuible a la barrera al oxigeno y luz ultravioleta (UV) que ofrecen las peliculas secas de polisacaridos.