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 ß-glucosidase and ß-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.

Organocatalytic route for the synthesis of propionylated starch.

In recent years acetylated, propionylated and butyrylated starches have received special attention due to their capacity to deliver specific short chain fatty acids (SCFAs) to the colon in a sustained and predictable manner, and thus contribute to maintaining the normal physiologic function of the large bowel and preventing specific diseases. In the current contribution a non-conventional organocatalytic solventless route for the eco-friendly propionylation of corn starch is proposed. The catalyst used in the acylation is a naturally occurring α-hydroxy acid (l-tartaric acid). Propionylated starches with degree of substitution (DS) in the 0.05-1.59 interval were obtained and characterized in terms of chemical structure, morphology, crystallinity, thermal stability and hydrophilicity. Results showed that by the proposed methodology propionylated starch with the DS required for clinical use (i.e. 0.2-0.3) could be obtained within 2-3h of reaction. Characterization results evidenced the progressive loss of crystallinity of starch granules as higher substitution levels were conferred.